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Table of Contents

Interface Commands

Interface Commands

This chapter contains the commands used to configure nonprotocol-specific interface features. The commands are in alphabetical order. For hardware technical descriptions, and for information about installing the router interfaces, refer to the hardware installation and maintenance publication for your particular product.

This chapter also includes Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) asynchronous connection commands. The router supports asynchronous connections via SLIP and PPP on the auxiliary port only.

For interface configuration tasks and examples, refer to the chapter entitled "Configuring Interfaces" in the Router Products Configuration Guide.

For a conversion table of the modular products and Cisco 7000 series processors, see the appendix entitled "Cisco 7000 Processors."

async default ip address

To assign the interface address that is used by the device connecting to the router via PPP or SLIP, unless you override the address at the command line, use the async default ip address interface configuration command. Use the no form of the command to remove the address from your configuration.

async default ip address ip-address
no async default ip address
Syntax Description
ip-address Address of the client interface
Default

No interface address is assigned.

Command Mode

Interface configuration

Example

The following example specifies address 182.32.7.51 on asynchronous interface 1:

interface async 1 async default ip address 182.32.7.51
Related Command

async dynamic address

async dynamic address

To specify an address on an asynchronous interface (rather than using the default address), use the async dynamic address interface configuration command. Use the no form of this command to disable dynamic addressing.

async dynamic address
no async dynamic address
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Example

The following example shows dynamic addressing assigned to an interface:

interface async 1 async dynamic address
Related Commands

ppp
slip

async dynamic routing

To implement asynchronous routing on an interface, use the async dynamic routing interface configuration command. The no form of this command disables use of routing protocols; static routing will still be used.

async dynamic routing
no async dynamic routing
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Example

The following example shows how to enable asynchronous routing on asynchronous interface 1. The ip tcp header-compression passive command enables Van Jacobson TCP header compression and prevents transmission of compressed packets until a compressed packet arrives from the asynchronous link.

interface async 1 async dynamic routing async dynamic address async default ip address 1.1.1.2 ip tcp header-compression passive
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

async dynamic address
ip tcp header-compression
+

async mode dedicated

To place a line into network mode using SLIP or PPP encapsulation, use the async mode dedicated interface configuration command. The no form of this command returns the line to interactive mode.

async mode dedicated
no async mode
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

With dedicated asynchronous mode, the interface will use either SLIP or PPP encapsulation, depending on which encapsulation method is configured for the interface. An EXEC prompt does not appear, and the line is not available for normal interactive use.

If you configure a line for dedicated mode, you will not be able to use async dynamic address, because there is no user prompt. You must configure either async default ip address and ip unnumbered or ip address.

Example

The following example assigns an Internet address to an asynchronous line and places the line into network mode. Setting the stop bits to 1 enhances performance.

interface async 1 async default ip address 182.32.7.51 async mode dedicated encapsulation slip
Related Command

async mode interactive

async mode interactive

To enable the slip and ppp EXEC commands, use the async mode interactive line configuration command. Use the no form of this command to prevent users from implementing SLIP and PPP at the EXEC level.

async mode interactive
no async mode
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Example

The following example enables the ppp and slip EXEC commands:

interface async 1 async mode interactive
Related Commands

async mode dedicated
ppp
slip

atm-dxi map

To map a given VPI and VCI, use the atm-dxi map interface configuration command. Use the no form of this command to remove the definition.

atm-dxi map protocol address vpi vci [broadcast]
no atm-dxi map protocol address
Syntax Description
protocol Specifies the protocol: apollo, appletalk, bridge, clns, decnet, ip, novell, vines, xns
address Protocol-specific address
vpi Virtual path identifier in the range 0 to 15
vci Virtual circuit identifier in the range 0 to 63
broadcast (Optional) Broadcasts should be forwarded to this address
Default

No map definition is established.

Command Mode

Interface configuration

Usage Guidelines

This command is used in configurations where the router is intended to communicate with an ATM network through an ATM Data Service Unit (ADSU). Given the circuit identifier parameters
(VPI/VCI) for the ATM virtual circuit, the DXI Frame Address (DFA) that is used for communication between the router and the ADSU is computed and used.

Example

In the following example, all IP packets intended for the host with IP address 131.108.170.49 are converted into ATM cells identified with a VPI of 2 (binary 0000 0010) and a VCI of 46 (binary 0000 0000 0010 1110) by the ADSU. Using the mapping defined in Annex A of the ATM DXI Specification, this combination of VPI and VCI maps into to a DFA of 558 (binary 1000101110). The ADSU will then extract the VPI and VCI information from the DFA of the incoming frame when formulating ATM cells.

interface serial 0 atm-dxi map ip 131.108.170.49 2 46 broadcast
Related Command

encapsulation atm-dxi

auto-polarity

To enable automatic receiver polarity reversal on a hub port connected to an Ethernet interface of a Cisco 2505 or Cisco 2507, use the auto-polarity hub configuration command. To disable this feature, use the no form of this command.

auto-polarity
no auto-polarity
Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Hub configuration

Usage Guidelines

This command applies to a port on an Ethernet hub only.

Example

The following example enables automatic receiver polarity reversal on hub 0, ports 1 through 3:

hub ether 0 1 3 auto-polarity
Related Command

hub

backup delay

To define how much time should elapse before a secondary line is set up or taken down after a primary line transition, use the backup delay interface configuration command. Use the no backup delay command to remove the definition.

backup delay {enable-delay | never} {disable-delay | never}
no backup delay {enable-delay | never} {disable-delay | never}
Syntax Description
enable-delay Integer that specifies the delay in seconds after the primary line goes down before the secondary line is activated.
disable-delay Integer that specifies the delay in seconds after the primary line goes up before the secondary line is deactivated.
never Prevents the secondary line from being activated or deactivated.
Default

never

Command Mode

Interface configuration

Usage Guidelines

When a primary line goes down, the router delays the amount of seconds defined by the enable-delay argument before enabling the secondary line. If, after the delay period, the primary line is still down, the secondary line is activated.

When a primary line comes back up, the router will delay the amount of seconds defined by the disable-delay argument.


Note In cases where there are spurious signal disruptions that may appear as intermittent lost carrier signals, it is recommended that some delay be enabled before activating and deactivating a secondary.

Note The interval configured with the backup delay command does not affect the operation of the backup load command.
Examples

The following example sets a 10-second delay on deactivating the secondary line; however, the line is activated immediately:

interface serial 0 backup delay 0 10

The same example on the Cisco 7000 requires the following commands:

interface serial 1/1 backup delay 0 10

backup interface

To configure the serial interface as a secondary, or dial backup line, use the backup interface interface configuration command. Use the no backup command with the appropriate serial port designation to turn disable this feature.

backup interface interface-name
backup interface interface-name slot/port (for the Cisco 7000 series)
no backup interface interface-name
Syntax Description
interface-name Serial port to be set as the secondary interface line.
slot On the Cisco 7000 series, specifies the slot number.
port On the Cisco 7000 series, specifies the port number.
Default

Disabled

Command Mode

Interface configuration

Examples

The following example sets serial 1 as the backup line to serial 0:

interface serial 0 backup interface serial 1

The following example on the Cisco 7000 sets serial 2 as the backup line to serial 1:

interface serial 1/1 backup interface serial 2/2
Related Command

down-when-looped

backup load

To set the traffic load thresholds for dial backup service, use the backup load interface configuration command. Use the no backup load command to remove the setting.

backup load {enable-threshold | never} {disable-load | never}
no backup load {
enable-threshold | never} {disable-load | never}
Syntax Description
enable-threshold Integer that specifies a percentage of the primary line's available bandwidth.
never Sets the secondary line to never be activated due to load.
disable-load Integer that specifies a percentage of the primary line's available bandwidth.
never Sets the secondary line to never be deactivated due to load.
Default

Both arguments default to never.

Command Mode

Interface configuration

Usage Guidelines

When the transmitted or received load on the primary line is greater than the value assigned to the enable-threshold argument, the secondary line is enabled.

When the transmitted load on the primary line plus the transmitted load on the secondary line is less than the value entered for the disable-load argument, and the received load on the primary line plus the received load on the secondary line is less than the value entered for the disable-load argument, the secondary line is disabled.

If the never keyword is used instead of an enable-threshold value, the secondary line is never activated because of load. If the never keyword is used instead of a disable-load value, the secondary line is never deactivated because of load.

Examples

The following example sets the traffic load threshold to 60 percent on the primary line. When that load is exceeded, the secondary line is activated, and will not be deactivated until the combined load is less than 5 percent of the primary bandwidth.

interface serial 0 backup load 60 5

The same example on the Cisco 7000 requires the following commands:

interface serial 1/1 backup load 60 5

bandwidth

To set a bandwidth value for an interface, use the bandwidth interface configuration command. Use the no bandwidth command to restore the default values.

bandwidth kilobits
no bandwidth
Syntax Description
kilobits Intended bandwidth in kilobits per second. For a full bandwidth DS3, enter the value 44736.
Default

Default bandwidth values are set during startup and can be displayed with the EXEC command show interfaces.

Command Mode

Interface configuration

Usage Guidelines

The bandwidth command sets an informational parameter only; you cannot adjust the actual bandwidth of an interface with this command. For some media, such as Ethernet, the bandwidth is fixed; for other media, such as serial lines, you can change the actual bandwidth by adjusting hardware. For both classes of media, you can use the bandwidth configuration command to communicate the current bandwidth to the higher-level protocols.

Additionally, IGRP uses the minimum path bandwidth to determine a routing metric. The TCP protocol adjusts initial retransmission parameters based on the apparent bandwidth of the outgoing interface.

At higher bandwidths, the value you configure with the bandwidth command is not what is displayed by the show interface command. The value shown is that used in IGRP updates and also used in computing load.


Note This is a routing parameter only; it does not affect the physical interface.
Example

The following example sets the full bandwidth for DS3 transmissions:

interface serial 0 bandwidth 44736
Related Command

A dagger (+) indicates that the command is documented in another chapter.

vines metric +

channel-group

Use the channel-group controller configuration command to define the timeslots that belong to each T1 circuit.

channel-group number timeslots range [speed {48 | 56 | 64}]
Syntax Description
number Channel-group number. Channel-group numbers can be a value from 0 to 23.
timeslots range Timeslot or range of timeslots belonging to the channel-group. The first timeslot is numbered 1, the last timeslot is numbered 24.
speed {48 | 56 | 64} (Optional) Specifies the line speed (in kilobits per second) of the T1 link.
Default

56 kbps

Command Mode

Controller configuration

Usage Guidelines

This command is used in configurations where the router is intended to communicate with T1 fractional data line. The channel-group number may be arbitrarily assigned and must be unique for the controller. The timeslot range must match the timeslots assigned to the circuit. The T1 service provider defines the timeslots that comprise a circuit.

Example

In the following example, three channel-groups are defined. Channel-group 0 consists of a single timeslot, channel-group 8 consists of 7 timeslots and runs at a speed of 64 kbps per timeslot, and channel-group 12 consists of a single timeslot.

channel-group 0 timeslots 1 shannel-group 8 timeslots 5,7,12-15,20 speed 64 channel-group 12 timeslots 2
Related Commands

linecode
framing

clear controller t1

Use the clear controller t1 EXEC command to reset the T1 controller interface on the Cisco 7000.

clear controller t1 slot/port
Syntax Description
slot Backplane slot number; can be 0, 1, 2, 3, or 4. The slots are numbered from left to right.
port Port number of the interface. It can be 0 or 1 depending on the type of controller, as follows:

  • MIP (Multichannel Interface Processor) 0 or 1

Ports on each interface processor are numbered from the top down.

Command Mode

EXEC

Example

The following example resets the T1 controller at slot 4, port 0:

clear controller t1 4/0
Related Command

controller t1

clear counters

To clear the interface counters, use the clear counters EXEC command.

clear counters [type number]
clear counters
[type slot/port] (for the Cisco 7000 series)
Syntax Description
type (Optional) Specifies the interface type; it is one of the keywords listed in Table 6-1.
number (Optional) Specifies the interface counter displayed with the show interfaces command.
slot (Optional) On the Cisco 7000 series, specifies the backplane slot number. On the 7000, value can be 0, 1, 2, 3, or 4. On the 7010, value can be 0, 1, or 2.
port (Optional) On the Cisco 7000 series, specifies the port number of the interface. Value can be 0, 1, 2, or 3 for the serial interface.

Clear Counters Interface Type Keywords
Keyword Interface Type
async Async interface
bri Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI)
dialer Dialer interface
ethernet Ethernet interface
fddi Fiber Distributed Data Interface (FDDI)
hssi High-Speed Serial Interface (HSSI)
loopback Loopback interface
null Null interface
pcbus ISA bus interface. Valid on LanOptics' Branchcard or Stacknet 2000 products only.
serial Synchronous serial interface
tokenring Token Ring interface
tunnel Tunnel interface
Command Mode

EXEC

Usage Guidelines

This command clears all the current interface counters from the interface unless the optional arguments type and number are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on).


Note This command will not clear counters retrieved using SNMP, but only those seen with the EXEC show interface command.
Example

The following example illustrates how to clear all interface counters:

clear counters
Related Command

show interfaces

clear hub

To reset and reinitialize the hub hardware connected to an interface of a Cisco 2505 or Cisco 2507, use the clear hub EXEC command.

clear hub ether number
Syntax Description
ether Indicates the hub in front of an Ethernet interface.
number Hub number to clear, starting with 0. Since there is currently only one hub, this number is 0.
Command Mode

EXEC

Example

The following example clears hub 0:

clear hub ether 0
Related Command

hub

clear hub counters

To set to zero the hub counters on an interface of a Cisco 2505 or Cisco 2507, use the clear hub counters EXEC command.

clear hub counters [ether number [port [port]]]
Syntax Description
ether (Optional) Indicates the hub in front of an Ethernet interface.
number (Optional) Hub number for which to clear counters. Since there is currently only one hub, this number is 0. If the keyword ether is specified, the number is required.
port (Optional) Port number on the hub. On the Cisco 2505, port numbers range from 1 through 8. On the Cisco 2507, port numbers range from 1 through 16. If a second port number follows, then this port number indicates the beginning of a port range. If no port number is specified, counters for all ports are cleared.
port (Optional) Ending port number of a range.
Command Mode

EXEC

Example

The following example clears the counters displayed in a show hub command for all ports on hub 0:

clear hub counters ether 0
Related Command

show hub

clear interface

To reset the hardware logic on an interface, use the clear interface EXEC command.

clear interface type number
clear interface type slot/port (on a Cisco 7000 series)
clear interface type slot/port [:channel-group] (on a Cisco 7000 MIP T1 interface)
Syntax Description
type Specifies the interface type; it is one of the keywords listed in Table 6-2.
number Specifies the port, connector, or interface card number.
slot On the Cisco 7000 series, specifies the backplane slot number. On the 7000, value can be 0, 1, 2, 3, or 4. On the 7010, value can be 0, 1, or 2.
port On the Cisco 7000 series, specifies the port number of the interface and can be 0, 1, 2, 3, 4 or 5 depending on the type of interface, as follows:

  • AIP (ATM Interface Processor) 0

  • EIP (Ethernet Interface Processor) 0, 1, 2, 3, 4, or 5

  • FIP (FDDI Interface Processor) 0

  • HIP (HSSI Interface Processor) 0

  • MIP (Multichannel Interface Processor) 0 or 1

  • TRIP (Token Ring Interface Processor) 0, 1, 2, or 3

channel-group

On the Cisco 7000 series supporting channelized T1, specifies the channel and can be between 0 and 23.

Clear Interface Type Keywords
Keyword Interface Type
async Async interface
atm Asynchronous Transfer Mode (ATM) interface
bri Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI)
ethernet Ethernet interface
fddi Fiber Distributed Data Interface (FDDI)
hssi High-Speed Serial Interface (HSSI)
loopback Loopback interface
null Null interface
pcbus ISA bus interface. Valid on LanOptics' Branchcard or Stacknet 2000 products only.
serial Synchronous serial interface
tokenring Token Ring interface
tunnel Tunnel interface
Command Mode

EXEC


Note Under normal circumstances, you do not need to clear the hardware logic on interfaces.
Example

The following example resets the interface logic on interface HSSI 1:

clear interface hssi 1

clear rif-cache

To clear entries from the Routing Information Field (RIF) cache, use the clear rif-cache EXEC command.

clear rif-cache
Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Example

The following example illustrates how to clear the RIF cache:

clear rif-cache
Related Command

A dagger (+) indicates that the command is documented in another chapter.

multiring +

clock source

Use the clock source controller configuration command to set the T1-line clock-source for the MIP in the Cisco 7000.

clock source {line | internal}
Syntax Description
line Specifies the T1 line as the clock source.
internal Specifies the MIP as the clock source.
Default

T1 line

Command Mode

Controller configuration

Usage Guidelines

This command is used in configurations where the MIP interfaces are connected back-to-back, rather than to a T1 line, and one of the interfaces must provide a clocking signal. When the MIP interface is connected to a channelized T1 line, this command need never be used.

Example

The following example enables internal clocking:

clock source internal
Related Commands

framing
linecode

clock rate

To configure the clock rate for appliques (connector hardware) on the serial interface of the MCI and SCI cards to an acceptable bit rate, use the clock rate interface configuration command. Use the no clock rate command to remove the clock rate if you change the interface from a DCE to a DTE device.

clock rate bps
no clock rate
Syntax Description
bps Desired clock rate in bits per second: 1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000, 72000, 125000, 148000, 500000, 800000, 1000000, 1300000, 2000000, or 4000000.
Default

No clock rate is configured.

Command Mode

Interface configuration

Usage Guidelines

Be aware that the fastest speeds might not work if your cable is too long, and that speeds faster than 148,000 bits per second are too fast for RS-232 signaling. It is recommended that you only use the synchronous serial RS-232 signal at speeds up to 64,000 bits per second. To permit a faster speed, use an RS-449 or V.35 applique.

Example

The following example sets the clock rate on the first serial interface to 64,000 bits per second:

interface serial 0 clock rate 64000

cmt connect

To start the processes that perform the connection management (CMT) function and allow the ring on one fiber to be started, use the cmt connect EXEC command.

cmt connect [interface-name [phy-a | phy-b]]
Syntax Description
interface-name (Optional) Specifies the FDDI interface.
phy-a (Optional) Selects Physical Sublayer A.
phy-b (Optional) Selects Physical Sublayer B.
Command Mode

EXEC

Usage Guidelines

In normal operation, the FDDI interface is operational once the interface is connected and configured. The cmt connect command allows the operator to start the processes that perform the CMT function.

The cmt connect command is not needed in the normal operation of FDDI; this command is used mainly in interoperability tests.

Examples

The following examples demonstrate use of the cmt connect command for starting the CMT processes on the FDDI ring.

The following command starts all FDDI interfaces:

cmt connect

The following command starts both fibers on the FDDI interface unit zero:

cmt connect fddi 0

The following command on the Cisco 7000 starts both fibers on the FDDI interface unit zero:

cmt connect fddi 1/0

The following command starts only Physical Sublayer A on the FDDI interface unit 0 (zero):

cmt connect fddi 0 phy-a

The following command on the Cisco 7000 starts only Physical Sublayer A on the FDDI interface unit 0 (zero):

cmt connect fddi 1/0 phy-a

cmt disconnect

To stop the processes that perform the connection management (CMT) function and allow the ring on one fiber to be stopped, use the cmt disconnect EXEC command.

cmt disconnect [interface-name [phy-a | phy-b]]
Syntax Description
interface-name (Optional) Specifies the FDDI interface.
phy-a (Optional) Selects Physical Sublayer A.
phy-b (Optional) Selects Physical Sublayer B.
Command Mode

EXEC

Usage Guidelines

In normal operation, the FDDI interface is operational once the interface is connected and configured, and is turned off using the shutdown interface configuration command. The cmt disconnect command allows the operator to stop the processes that perform the CMT function and allow the ring on one fiber to be stopped.

The cmt disconnect command is not needed in the normal operation of FDDI; this command is used mainly in interoperability tests.

Examples

The following examples demonstrate use of the cmt disconnect command for stopping the CMT processes on the FDDI ring.

The following command stops all FDDI interfaces:

cmt disconnect

The following command stops both fibers on the FDDI interface unit zero:

cmt disconnect fddi 0

The following command on the Cisco 7000 stops both fibers on the FDDI interface unit zero:

cmt disconnect fddi 1/0

The following command stops only Physical Sublayer A on the FDDI interface unit 0 (zero). This command causes the FDDI media to go into a wrapped state so that the ring will be broken.

cmt disconnect fddi 0 phy-a

The following command on the Cisco 7000 stops only Physical Sublayer A on the FDDI interface unit 0 (zero). This command causes the FDDI media to go into a wrapped state so that the ring will be broken.

cmt disconnect fddi 1/0 phy-a

compress predictor

To configure point-to-point software compression for a LAPB, use the compress predictor interface configuration command. To disable compression, use the no form of this command.

compress predictor
no compress predictor
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

You can configure point-to-point software compression for all LAPB encapsulations. Compression reduces the size of LAPB frames via lossless data compression. (An explanation of "lossless" data appears in the note below.) The compression algorithm used is a predictor algorithm (the RAND compression algorithm), which uses a compression dictionary to predict what the next character in the frame will be.

Compression is performed in software and may significantly affect system performance. We recommend that you disable compression if CPU load exceeds 65%. To display the CPU load, use the show process cpu EXEC command.

Compression requires that both ends of the serial link be configured to use compression. You should never enable compression for connections to a public data network.


Note The best performance data compression algorithms "learn", that is, adjust their compression methodology as they discover patterns in the data. For this to work well, no data can be lost, so the compression algorithm is run over LAPB to ensure that everything is sent in order, with no missing data and no duplicate data.

If the majority of your traffic is already compressed files, it is recommended that you not use compression.

When using compression, you should adjust the MTU for the serial interface and the LAPB N1 parameter as show in the example to avoid informational diagnostics regarding excessive MTU or N1 sizes.

Example

The following example enables compression on serial interface 0 for a LAPB link:

interface serial 0 encapsulation lapb compress predictor mtu 1509 lapb n1 12072
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

encapsulation lapb +
encapsulation lapb-dce
+
encapsulation multi-lapb +
encapsulation multi-lapb-dce +
encapsulation x25 +
show compress
show processes
+

controller t1

To configure a T1 controller interface and enter controller configuration mode, use the controller t1 global configuration command. This command is used only on a Cisco 7000.

controller t1 slot/port
Syntax Description
slot Backplane slot number; can be 0, 1, 2, 3, or 4. On the 7010, the slot number can be 0, 1, or 2. The slots are numbered from left to right.
port Port number of the interface. It can be 0 or1 depending on the type of controller, as follows:

  • MIP (Multichannel Interface Processor) 0 or 1

Ports on each interface processor are numbered from the top down.

Default

No T1 controller interface is configured.

Command Mode

Global configuration

Usage Guidelines

This command is used in configurations where the router is intended to communicate with a T1 fractional data line. Additional parameters for the T1 line must be configured for the controller before the T1 circuits can be configured by means of the interface global configuration command.

Example

In the following example, the MIP in slot 4, port 0 is configured as a T1 controller:

controller t1 4/0
Related Commands

channel-group
clear controller t1
clock source
framing
linecode

crc

To set the length of the cyclic redundancy check (CRC) on a Fast Serial Interface Processor (FSIP) or HSSI Interface Processor (HIP) of the Cisco 7000 series only, use the crc interface configuration command. To set the CRC length to 16 bits, use the no form of the command.

crc size
no crc
Syntax Description
size CRC size (16 or 32 bits)
Default

16 bits

Command Mode

Interface configuration

Usage Guidelines

All interfaces use a 16-bit cyclic redundancy check (CRC) by default, but also support a 32-bit CRC. CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting.

CRC-16, the most widely used throughout the United States and Europe, is used extensively with wide-area networks (WANs). CRC-32 is specified by IEEE 802 and as an option by some point-to-point transmission standards. It is often used on SMDS networks and LANs.

Example

In the following example, the 32-bit CRC is enabled on serial interface 3/0:

interface serial 3/0 crc 32

dce-terminal-timing enable

When running the line at high speeds and long distances, use the dce-terminal-timing enable interface configuration command to prevent phase shifting of the data with respect to the clock. If SCTE is not available from the DTE, use no dce-terminal-timing-enable, which causes the DCE to use its own clock instead of SCTE from the DTE.

dce-terminal-timing enable
no dce-terminal-timing enable
Syntax Description

This command has no keywords or arguments.

Default

DCE uses its own clock.

Command Mode

Interface configuration

Usage Guidelines

On the Cisco 4000 platform, you can specify the serial Network Interface Module timing signal configuration. When the board is operating as a DCE and the DTE provides terminal timing (SCTE or TT), the dce-terminal-timing enable command causes the DCE to use SCTE from the DTE.

Example

The following example prevents phase shifting of the data with respect to the clock:

interface serial 0 dce-terminal-timing enable

delay

To set a delay value for an interface, use the delay interface configuration command. Use the no delay command to restore the default delay value.

delay tens-of-microseconds
no delay
Syntax Description
tens-of-microseconds Integer that specifies the delay in tens of microseconds for an interface or network segment.
Default

Default delay values may be displayed with the EXEC command show interfaces.

Command Mode

Interface configuration

Example

The following example sets a 30,000-microsecond delay on interface serial 3:

interface serial 3 delay 30000
Related Command

show interfaces

description

To add a description to an interface configuration, use the description interface configuration command. Use the no description command to remove the description.

description string
no description
Syntax Description
string Comment or a description to help you remember what is attached to this interface
Default

No description is added.

Command Mode

Interface configuration

Usage Guidelines

The description command is meant solely as a comment to be put in the configuration to help you remember what certain interfaces are used for. The description appears in the output of the following EXEC commands: show configuration, show interfaces, and write terminal.

Example

The following example describes a 3174 controller on interface serial 0:

interface serial 0 description 3174 Controller for test lab
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

show configuration +
show interfaces
write terminal
+

down-when-looped

To configure an interface to inform the system it is down when loopback is detected, use the
down-when-looped interface configuration command.

down-when-looped
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command is valid for HDLC or PPP encapsulation on serial and HSSI interfaces.

When an interface has a backup interface configured, it is often desirable that the backup interface be enabled when the primary interface is either down or in loopback. By default, the backup is only enabled if the primary interface is down. By using the down-when-looped command, the backup interface will also be enabled if the primary interface is in loopback.

If testing an interface with the loopback command, or by placing the DCE into loopback, down-when-looped should not be configured; otherwise, packets will not be transmitted out the interface that is being tested.

Example

In the following example, interface serial 0 is configured for HDLC encapsulation. It is then configured to let the system know that it is down when in loopback mode.

interface serial0 encapsulation hdlc down-when-looped
Related Commands

backup interface
loopback

dte-invert-txc

On the Cisco 4000 platform, you can specify the serial Network Interface Module timing signal configuration. When the board is operating as a DTE, the dte-invert-txc command inverts the TXC clock signal it gets from the DCE that the DTE uses to transmit data. Use the no form of this command if the DCE accepts SCTE from the DTE.

dte-invert-txc
no dte-invert-txc
Syntax Description

This command has no arguments or keywords.

Default

Off

Command Mode

Interface configuration

Usage Guidelines

Use this command if the DCE cannot receive SCTE from the DTE, the data is running at high speeds, and the transmission line is long. This prevents phase shifting of the data with respect to the clock.

If the DCE accepts SCTE from the DTE, use no dte-invert-txc.

Example

The following example inverts the TXC on interface serial 0:

interface serial 0 dte-invert-txc

early-token-release

To enable early token release, a method whereby the Token Ring interfaces can release the token back onto the ring immediately after transmitting rather than waiting for the frame to return, use the early-token-release interface configuration command. This feature helps to increase the total bandwidth of the Token Ring.

The CSC-C2CTR, CSC-R16 (or CSC-R16M), CSC-2R, and CSC-1R cards and the Token Ring Interface Processor (TRIP) on the Cisco 7000 all support early token release. Once enabled, use the no early-token-release command to disable this feature.

early-token-release
no early-token-release
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Examples

The following example enables the use of early token release on interface Token Ring 1:

interface tokenring 1 early-token-release

On the Cisco 7000 series, to enable the use of early token release on your Token Ring interface processor in slot 4 on port 1, issue the following configuration commands:

interface tokenring 4/1 early-token-release

encapsulation

To set the encapsulation method used by the interface, use the encapsulation interface configuration command.

encapsulation encapsulation-type
Syntax Description
encapsulation-type Encapsulation type. See Table 6-3 for a list of supported encapsulation types.

Encapsulation Types
Keyword Encapsulation Type
arpa Standard Ethernet Version 2.0 encapsulation using a 16-bit protocol type code.
atm-dxi Asynchronous Transfer Mode-Data Exchange Interface.
bfex25 Blacker Front End Encryption X.25 operation (for serial interface).
ddnx25-dce DDN X.25 DCE operation (for serial interface).
ddnx25 DDN X.25 DTE operation (for serial interface).
frame-relay Frame Relay (for serial interface).
hdlc High-Level Data Link Control (HDLC) protocol for serial interface. This encapsulation method provides the synchronous framing and error detection functions of HDLC without windowing or retransmission.
sap IEEE 802.3 encapsulation. In this encapsulation, the type code becomes the frame length for the IEEE 802.2 LLC encapsulation (destination and source Service Access Points and a control byte).
lapb-dce X.25 LAPB DCE operation (for serial interface).
lapb X.25 LAPB DTE operation (for serial interface).
multi-lapb-dce X.25 LAPB multiprotocol DCE operation (for serial interface).
multi-lapb X.25 LAPB multiprotocol DTE operation (for serial interface).
ppp Point-to-Point Protocol (PPP) (for serial interface).
sdlc-primary IBM serial SNA (for serial interface).
sdlc-secondary IBM serial SNA (for serial interface).
smds Switched Multimegabit Data Services (SMDS) (for serial interface).
snap IEEE 802.2 Ethernet media. This encapsulation is specified in RFC 1042 and allows Ethernet protocols to run on IEEE 802.2 media.
stun Cisco Serial Tunnel (STUN) protocol functions (for serial interface).
x25-dce X.25 DCE operation (for serial interface).
x25 X.25 DTE operation (for serial interface).
Default

The default depends on the type of interface. For example, a synchronous serial interface defaults to HDLC. An Ethernet interface defaults to ARPA.

Command Mode

Interface configuration

Usage Guidelines

In order to use SLIP or PPP, the router must be configured with an IP routing protocol or with the ip host-routing command. This configuration is done automatically if you are using old-style slip address commands. However, you must configure it manually if you configure SLIP or PPP via the interface async command.

Examples

The following example reenables standard Ethernet Version 2.0 encapsulation on interface Ethernet 0:

interface ethernet 0 encapsulation arpa

The following example resets HDLC serial encapsulation on interface serial 1:

interface serial 1 encapsulation hdlc

The following example sets IEEE 802.3 encapsulation on Ethernet 1:

interface ethernet 1 encapsulation sap

The following example enables PPP encapsulation on interface serial 0:

interface serial 0 encapsulation ppp

The following example sets IEEE 802.2 encapsulation on Ethernet 1:

interface ethernet 1 encapsulation snap
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

keepalive +
ppp
ppp authentication chap
slip

encapsulation atm-dxi

Use the encapsulation atm-dxi interface configuration command to enable ATM-DXI encapsulation. The no encapsulation atm-dxi command disables ATM-DXI.

encapsulation atm-dxi
no encapsulation atm-dxi
Syntax Description

This command has no arguments or keywords.

Default

HDLC

Command Mode

Interface configuration

Example

The following example configures ATM-DXI encapsulation on interface serial 1:

interface serial 1 encapsulation atm-dxi
Related Command

atm-dxi map

fddi burst-count

To allow the FCI card to preallocate buffers to handle bursty FDDI traffic (for example, NFS bursty traffic), use the fddi burst-count interface configuration command. Use the no form of this command to revert to the default value.

fddi burst-count number
no fddi burst-count
Syntax Description
number Number of preallocated buffers in the range from 1 to 10
Default

3 buffers

Command Mode

Interface configuration

Usage Guidelines

This command applies to the FCI card only. The microcode software version should not be 128.45 or 128.43.

Example

The following example sets the number of buffers to 5:

interface fddi 0 fddi burst-count 5

fddi c-min

To set the C-Min timer on the PCM, use the fddi c-min interface configuration command. Use the no form of this command to revert to the default value.

fddi c-min microseconds
no fddi c-min
Syntax Description
microseconds Sets the timer value in microseconds.
Default

1600 microseconds

Command Mode

Interface configuration

Usage Guidelines

This command applies to the processor CMT only. You need extensive knowledge of the PCM state machine to tune this timer. Use this command when you run into PCM interoperability problems.

Example

The following example sets the C-Min timer to 2000 microseconds:

interface fddi 0 fddi c-min 2000
Related Commands
fddi tb-min fddi tl-min

fddi t-out

fddi cmt-signal-bits

To control the information transmitted during the connection management (CMT) signaling phase, use the fddi cmt-signal-bits interface configuration command. If neither the phy-a nor phy-b keyword is specified, the signal bits apply to both physical connections.

fddi cmt-signal-bits signal-bits [phy-a | phy-b]
Note Use of the fddi cmt-signal-bits configuration command is not recommended under normal operations. This command is used when debugging specific CMT implementation issues.
Syntax Description
signal-bits A hexadecimal number preceded by 0x; for example, 0x208. The FDDI standard defines ten bits of signaling information that must be transmitted, as follows:

bit 0--Escape bit. Reserved for future assignment by the FDDI standards committee.
bits 1 and 2--Physical type, as defined in Table 6-4.
bit 3--Physical compatibility. Set if topology rules include the connection of a physical-to-physical type at the end of the connection.
bits 4 and 5--Link Confidence test duration; set as defined in Table 6-5.
bit 6--Media Access Control (MAC) available for link confidence test.
bit 7--Link confidence test failed. The setting of bit 7 indicates that the link confidence was failed by the Cisco end of the connection.
bit 8--MAC for local loop.
bit 9--MAC on physical output.

phy-a (Optional) Selects Physical Sublayer A.
phy-b (Optional) Selects Physical Sublayer B.
Default

The default signal bits for the phy-a and phy-b keywords are as follows:

Command Mode

Interface configuration

Usage Guidelines

Use the following tables to set the physical type and duration bits.


FDDI Physical Type Bit Specifications
Bit 2 Bit 1 Physical Type
0 0 Physical A
1 0 Physical B
0 1 Physical S
1 1 Physical M

FDDI Link Confidence Test Duration Bit Specification
Bit 5 Bit 4 Test Duration
0 0 Short test (default 50 milliseconds)
1 0 Medium test (default 500 milliseconds)
0 1 Long test (default 5 seconds)
1 1 Extended test (default 50 seconds)
Example

The following example sets the CMT signaling phase to signal bits 0x208 on both physical connections:

interface fddi 0 fddi cmt-signal-bits 208

fddi duplicate-address-check

To turn on the duplicate address detection capability on the FDDI, use the fddi duplicate-address-check interface configuration command. Use the no form of this command to disable this feature.

fddi duplicate-address-check
no fddi duplicate-address-check
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

If you use this command, the router will detect a duplicate address if multiple stations are sharing the same MAC address. If the router finds a duplicate address, it will shut down the interface.

Example

The following example enables duplicate address checking on the FDDI:

interface fddi 0 fddi duplicate-address-check

fddi encapsulate

To specify encapsulating bridge mode on the CSC-C2/FCIT interface card, use the fddi encapsulate interface configuration command. Use the no fddi encapsulate command to turn off encapsulation bridging and return the FCIT interface to its translational, nonencapsulating mode.

fddi encapsulate
no fddi encapsulate
Syntax Description

This command has no arguments or keywords.

Default

The FDDI interface by default uses the SNAP encapsulation format defined in RFC 1042. It is not necessary to define an encapsulation method for this interface when using the CSC-FCI interface card.

Command Mode

Interface configuration

Usage Guidelines

The no fddi encapsulate command applies only to CSC-C2/FCIT interfaces, because the CSC-FCI interfaces are always in encapsulating bridge mode.The CSC-C2/FCIT interface card fully supports transparent and translational bridging for the following configurations:

The command fddi encapsulate puts the CSC-C2/FCIT interface into encapsulation mode when doing bridging. In transparent mode, the FCIT interface interoperates with earlier versions of the CSC-FCI encapsulating interfaces when performing bridging functions on the same ring.

Caution Bridging between dissimilar media presents several problems that can prevent communications from occurring. These problems include b it-order translation (or usage of MAC addresses as data), maximum transfer unit (MTU) differences, frame status differences, and multicast address usage. Some or all of these problems may be present in a multimedia bridged LAN and preventing communication from taking place. These problems are most prevalent when bridging between Token Rings and Ethernets or between Token Rings and FDDI nets. This is because of the different way Token Ring is implemented by the end nodes.

The following protocols have problems when bridged between Token Ring and other media: Novell IPX, DECnet Phase IV, AppleTalk, VINES, XNS, and IP. Further, the following protocols may have problems when bridged between FDDI and other media: Novell IPX and XNS. We recommend that these protocols be routed whenever possible.

Example

The following example sets interface FDDI 1 on the CSC-C2/FCIT interface card to encapsulating bridge mode:

interface fddi 1 fddi encapsulate

fddi if-cmt

To enable the connection management (CMT) onboard functions on the CSC-FCI and CSC-C2/FCIT interface cards, use the fddi if-cmt interface configuration command. Use the no fddi if-cmt command to disable these functions.

fddi if-cmt
no fddi if-cmt
Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Interface configuration

Usage Guidelines

The CSC-C2/FCIT and CSC-FCI interface cards provide CMT functions in microcode. These functions are separate from those provided on the processor card and accessed through EXEC commands.

A typical use of the no fddi if-cmt command is when you work with new FDDI equipment and have problems bringing up the ring. When you use this command to disable the CMT microcode, the following actions occur:

Example

The following example disables CMT functions on the FDDI interface cards:

interface fddi 0 no fddi if-cmt

fddi smt-frames

To enable the SMT frame processing capability on the FDDI, use the fddi smt-frames interface configuration command. Use the no form of this command to disable this feature, in which case the router will not generate or respond to SMT frames.

fddi smt-frames
no fddi smt-frames
Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Interface configuration

Usage Guidelines

Use the no form of this command to turn off SMT frame processing for diagnosing purposes. Use the fddi smt-frames command to reenable the feature.

Example

The following example disables SMT frame processing:

interface fddi 0 no fddi smt-frames

fddi t-out

To set the t-out timer in the physical connection management (PCM), use the fddi t-out interface configuration command. Use the no form of this command to revert to the default value.

fddi t-out milliseconds
no fddi t-out
Syntax Description
milliseconds Sets the timeout timer.
Default

100 milliseconds

Command Mode

Interface configuration

Usage Guidelines

This command applies to the processor CMT only. You need extensive knowledge of the PCM state machine to tune this timer. Use this command when you run into PCM interoperability problems.

Example

The following example sets the timeout timer to 200 milliseconds:

interface fddi 0 fddi t-out 200
Related Commands
fddi c-min fddi tb-min fddi tl-min

fddi tb-min

To set the TB-Min timer in the physical connection management (PCM), use the fddi tb-min interface configuration command. Use the no form of this command to revert to the default value.

fddi tb-min milliseconds
no fddi tb-min
Syntax Description
milliseconds Sets the TB-Min timer value in milliseconds.
Default

100 milliseconds

Command Mode

Interface configuration

Usage Guidelines

This command applies to the processor CMT only. You need extensive knowledge of the PCM state machine to tune this timer. Use this command when you run into PCM interoperability problems.

Example

The following example sets the TB-Min timer to 200 milliseconds:

interface fddi 0 fddi tb-min 200
Related Commands
fddi c-min fddi tl-min-time fddi t-out

fddi tl-min-time

To control the TL-Min time (the minimum time to transmit a Physical Sublayer, or PHY line state, before advancing to the next physical connection management (PCM) state, as defined by the X3T9.5 specification), use the fddi tl-min-time interface configuration command.

fddi tl-min-time microseconds
Syntax Description
microseconds Integer that specifies the time used during the connection management (CMT) phase to ensure that signals are maintained for at least the value of TL-Min so the remote station can acquire the signal.
Default

30 microseconds

Command Mode

Interface configuration

Usage Guidelines

Interoperability tests have shown that some implementations of the FDDI standard need more than 30 microseconds to sense a signal.

Examples

The following example changes the TL-Min time from 30 microseconds to 100 microseconds:

interface fddi 0 fddi tl-min-time 100

The following example changes the TL-Min time from 30 microseconds to 100 microseconds on a Cisco 7000:

interface fddi 3/0 fddi tl-min-time 100
Related Commands
fddi c-min fddi tb-min fddi t-out

fddi token-rotation-time

To control ring scheduling during normal operation and to detect and recover from serious ring error situations, use the fddi token-rotation-time interface configuration command.

fddi token-rotation-time microseconds
Syntax Description
microseconds Integer that specifies the token rotation time (TRT).
Default

5000 microseconds

Command Mode

Interface configuration

Usage Guidelines

The FDDI standard restricts the allowed time to be greater than 4000 microseconds and less than 165,000 microseconds. As defined in the X3T9.5 specification, the value remaining in the TRT is loaded into the token holding timer (THT). Combining the values of these two timers provides the means to determine the amount of bandwidth available for subsequent transmissions.

Examples

The following example sets the rotation time to 24,000 microseconds:

interface fddi 0 fddi token-rotation-time 24000

The following example sets the rotation time to 24,000 microseconds on a Cisco 7000:

interface fddi 3/0 fddi token-rotation-time 24000

fddi valid-transmission-time

To recover from a transient ring error, use the fddi valid-transmission-time interface configuration command.

fddi valid-transmission-time microseconds
Syntax Description
microseconds Integer that specifies the transmission valid timer (TVX) interval
Default

2500 microseconds

Command Mode

Interface configuration

Examples

The following example changes the transmission timer interval to 3000 microseconds:

interface fddi 0 fddi valid-transmission-time 3000

The following example changes the transmission timer interval to 3000 microseconds on a
Cisco 7000:

interface fddi 3/0 fddi valid-transmission-time 3000

framing

Use the framing controller configuration command to select the frame type for the T1 line.

framing {sf | esf}
Syntax Description
sf Specifies super frame as the T1 frame type.
esf Specifies extended super frame as the T1 frame type.
Default

sf

Command Mode

Controller configuration

Usage Guidelines

This command is used in configurations where the router is intended to communicate with T1 fractional data line. The T1 service provider determines which framing type, either sf or esf, is required for your T1 circuit.

Example

The following example selects extended super frame as the T1 frame type:

framing esf
Related Commands

channel-group
linecode

hold-queue

To specify the hold-queue limit of an interface, use the hold-queue interface configuration command. Use the no hold-queue command with the appropriate keyword to restore the default values for an interface.

hold-queue length {in | out}
no hold-queue {in | out}
Syntax Description
length Integer that specifies the maximum number of packets in the queue.
in Specifies the input queue.
out Specifies the output queue.
Default

The default input hold-queue limit is 75 packets. The default output hold-queue limit is 40 packets. These limits prevent a malfunctioning interface from consuming an excessive amount of memory. There is no fixed upper limit to a queue size.

Command Mode

Interface configuration

Usage Guidelines

The input hold queue prevents a single interface from flooding the network server with too many input packets. Further input packets are discarded if the interface has too many input packets outstanding in the system.

If priority output queueing is being used, the length of the four output queues is set using the priority-list global configuration command. The hold-queue command cannot be used to set an output hold queue length in this situation.

For slow links, use a small output hold-queue limit. This approach prevents storing packets at a rate that exceeds the transmission capability of the link. For fast links, use a large output hold-queue limit. A fast link may be busy for a short time (and thus require the hold queue), but can empty the output hold queue quickly when capacity returns.

To display the current hold queue setting and the number of packets discarded because of hold queue overflows, use the EXEC command show interfaces.


Note Increasing the hold queue can have detrimental effects on network routing and response times. For protocols that use seq/ack packets to determine round trip times, do not increase the output queue. Dropping packets instead informs hosts to slow down transmissions to match available bandwidth. This is generally better than having duplicate copies of the same packet within the network (which can happen with large hold queues).
Example

The following example illustrates how to set a small input queue on a slow serial line:

interface serial 0 hold-queue 30 in
Related Command

show interfaces

hssi external-loop-request

To allow the router to support a CSU/DSU that uses the LC signal to request a loopback from the router, use the hssi external-loop-request interface configuration command. Use the no form of this command to disable the feature.

hssi external-loop-request
no hssi external-loop-request
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

The HSA applique (on the HSSI) contains an LED that indicates the LA, LB, and LC signals transiting through the devices. The CSU/DSU uses the LC signal to request a loopback from the router. The CSU/DSU may want to do this so that its own network management diagnostics can independently check the integrity of the connection between the CSU/DSU and the router.

Use this command to enable a two-way, internal, and external loopback request on HSSI from the CSU/DSU.


Note If your CSU/DSU does not support this feature, it should not be enabled in the router. Not enabling this feature prevents spurious line noise from accidentally tripping the external loopback request line, which would interrupt the normal data flow.
Example

The following example enables a CSU/DSU to use the LC signal to request a loopback from the router:

hssi external-loop-request

hssi internal-clock

To convert the HSSI interface into a 45 MHz clock master, use the hssi internal-clock interface configuration command. Use the no form of this command to disable the clock master mode.

hssi internal-clock
no hssi internal-clock
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

Use this command in conjunction with the HSSI null-modem cable to connect two Cisco routers together with HSSI. You must configure this command at both ends of the link, not just one.

Example

The following example converts the HSSI interface into a 45 MHz clock master:

hssi internal-clock

hub

To enable and configure a port on an Ethernet hub of a Cisco 2505 or Cisco 2507, use the hub global configuration command.

hub ether number port [port]
Syntax Description
ether Indicates that the hub is in front of an Ethernet interface.
number Hub number, starting with 0. Since there is currently only one hub, this number is 0.
port Port number on the hub. On the Cisco 2505, port numbers range from 1 through 8. On the Cisco 2507, port numbers range from 1 through 16. If a second port number follows, then the first port number indicates the beginning of a port range.
[port] (Optional) Last port number of a range.
Default

No hub ports are configured.

Command Mode

Global configuration

Examples

The following example enables port 1 on hub 0:

hub ether 0 1 no shutdown

The following example enables ports 1 through 8 on hub 0:

hub ether 0 1 8 no shutdown
Related Command

shutdown

interface

To configure an interface type and enter interface configuration mode, use the interface global configuration command.

interface interface-type interface-number
interface
interface-type slot/port (for the Cisco 7000 series)
interface
interface-type slot/port:channel-group (for channelized T1 on the
Cisco 7000 series)

To configure a subinterface, use the interface global configuration command.

interface interface-type interface-number.subinterface-number [multipoint | point-to-point]
interface interface-type slot/port.subinterface-number [multipoint | point-to-point] (for the Cisco 7000 series)

Syntax Description
interface-type Type of interface to be configured. See Table 6-6.
interface-number Port, connector, or interface card number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed with the show interfaces command.
.subinterface-number Subinterface number in the range 1 to 4294967293. The
interface-number that precedes the period (.) must match the
interface-number this subinterface belongs to.
multipoint | point-to-point (Optional) Specifies a multipoint or point-to-point subinterface. The default is multipoint.
slot On the Cisco 7000 series, specifies the backplane slot number. On the 7000, value can be 0, 1, 2, 3, or 4. On the 7010, value can be 0, 1, or 2. The slots are numbered from left to right.
port On the Cisco 7000 series, specifies the port number of the interface. It can be 0, 1, 2, 3, 4, 5, 6, or 7 depending on the type of interface, as follows:

  • AIP (ATM Interface Processor) 0

  • EIP (Ethernet Interface Processor) 0, 1, 2, 3, 4, or 5

  • FIP (FDDI Interface Processor) 0

  • FSIP (Fast Serial Interface Processor) 0, 1, 2, 3, 4, 5, 6, or 7

  • HIP (HSSI Interface Processor) 0

  • TRIP (Token Ring Interface Processor) 0, 1, 2, or 3

Ports on each interface processor are numbered from the top down.

channel-group On the Cisco 7000 series on a MIP/CxCT1 card, specifies the T1 channel group number in the range of 0 to 23 defined with the channel-group controller configuration command.

Interface Type Keywords
Keyword Interface Type
async Auxiliary port line used as an asynchronous interface.
atm ATM interface.
bri Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI). This interface configuration is propagated to each of the B channels. B channels cannot be individually configured. The interface must be configured with dial-on-demand commands in order for calls to be placed on that interface.
dialer Dialer interface.
ethernet Ethernet IEEE 802.3 interface.
fddi Fiber Distributed Data Interface (FDDI).
hssi High-Speed Serial Interface (HSSI).
loopback Software-only loopback interface that emulates an interface that is always up. It is a virtual interface supported on all platforms. The interface-number is the number of the loopback interface that you want to create or configure.There is no limit on the number of loopback interfaces you can create.
null Null interface.
serial Serial interface.
tokenring Token Ring interface.
tunnel Tunnel interface; a virtual interface. The interface-number is the number of the tunnel interface that you want to create or configure. There is no limit on the number of tunnel interfaces you can create.
Default

The default mode for subinterfaces is multipoint.

Command Mode

Global configuration

Usage Guidelines

Subinterfaces can be configured to support partially meshed Frame Relay networks (refer to the chapter entitled "Configuring Interfaces" in the Router Products Configuration Guide).

Examples

In the following example, serial interface 0 is configured with PPP encapsulation:

interface serial 0 encapsulation ppp

The following example enables loopback mode and assigns an IP network address and network mask to the interface. The loopback interface established here will always appear to be up:

interface loopback 0 ip address 131.108.1.1 255.255.255.0

The following example for the Cisco 7000 shows the interface configuration command for Ethernet port 4 on the EIP that is installed in (or recently removed from) slot 2:

interface ethernet 2/4

The following example begins configuration on the Token Ring interface processor in slot 1 on
port 0 of a Cisco 7000:

interface tokenring 1/0

The following example shows how a partially meshed Frame Relay network can be configured. In this example, subinterface serial 0.1 is configured as a multipoint subinterface with three frame relay PVCs associated, and subinterface serial 0.2 is configured as a point-to-point subinterface.

interface serial 0 encapsulation frame-relay interface serial 0.1 multipoint ip address 131.108.10.1 255.255.255.0 frame-relay interface-dlci 42 broadcast frame-relay interface-dlci 53 broadcast interface serial 0.2 point-to-point ip address 131.108.11.1 255.255.0 frame-relay interface-dlci 59 broadcast

The following example configures circuit 0 of a T1 link for Point-to-Point Protocol (PPP) encapsulation:

controller t1 4/1 circuit 0 1 interface serial 4/1:0 ip address 131.108.13.1 255.255.255.0 encapsulation ppp
Related Commands

circuit
controller
ppp

show interfaces
slip

invert-transmit-clock

Delays between the SCTE clock and data transmission indicate that the transmit clock signal might not be appropriate for the interface rate and length of cable being used. Different ends of the wire may have variances that differ slightly. To invert the clock signal to compensate for these factors, use the invert-transmit-clock interface configuration command. This command applies only to the Cisco 7000 series.

invert-transmit-clock
no invert-transmit-clock
Syntax Description

This command has no arguments or keywords.

Command Mode

Interface configuration

Example

In the following example, the clock signal on serial interface 3/0 is inverted.

interface serial 3/0 invert-transmit-clock

isdn caller

To configure ISDN caller ID screening, use the isdn caller interface configuration command. To disable this feature, use the no form of this command.

isdn caller number
no isdn caller number
Syntax Description
number Telephone number for which to screen. Specify an x to represent a single "don't-care" character. The maximum length of each number is 25 characters.
Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

Caller ID screening is available only on Cisco 2500 and 3000 series routers that have a BRI.

The maximum length of each number is 25 characters. You can specify up to 64 numbers per interface.


Note Caller ID screening requires a local switch that is capable of delivering the caller ID to the router. If you enable caller ID screening but do not have such a switch, no calls will be allowed in.
Examples

The following example configures the router to accept a call with a delivered caller ID equal to 4155551234:

isdn caller 4155551234

The following example configures the router to accept a call with a delivered caller ID having 41555512 and anything in the last two positions:

isdn caller 41555512xx
Related Command

A dagger (+) indicates that the command is documented in another chapter.

show dialer +

isdn spid1

Use the isdn spid1 interface configuration command to define at the router the service profile identifier (SPID) number that has been assigned by the ISDN service provider for the B1 channel. Use the no isdn spid1 command to disable the specified SPID, thereby preventing access to the switch. If you include the LDN in the no form of this command, the access to the switch is permitted, but the other B channel may not be able to receive incoming calls.

isdn spid1 spid-number [ldn]
no isdn spid1
spid-number [ldn]
Syntax Description
spid-number Number identifying the service to which you have subscribed. This value is assigned by the ISDN service provider and is usually a ten-digit telephone number with some extra digits.
ldn (Optional) Local directory number. This is a seven-digit number also assigned by the service provider.
Default

No SPID number is defined.

Command Mode

Interface configuration

Usage Guidelines

You must define the LDN if you want to receive any incoming calls on the B2-channel. The ISDN switch (DMS-100) checks for the LDN to determine whether both channels can be used to transmit and receive data. If the LDN is not present, then only the B1-channel can be used for full-duplex communication. However, the other channel can still be used for making outgoing calls.

Example

The following example defines, on the router, a SPID and LDN for the B1 channel:

isdn spid1 415555121301 5551215

isdn spid2

Use the isdn spid2 interface configuration command to define at the router the SPID number that has been assigned by the ISDN service provider for the B2 channel. Use the no isdn spid2 command to disable the specified SPID, thereby preventing access to the switch. If you include the LDN in the no form of this command, the access to the switch is permitted, but the other B channel may not be able to receive incoming calls.

isdn spid2 spid-number [ldn]
no isdn spid2
spid-number [ldn]
Syntax Description
spid-number Number identifying the service to which you have subscribed. This value is assigned by the ISDN service provider and is usually a ten-digit telephone number with some extra digits.
ldn (Optional) Local directory number. This is a seven-digit number also assigned by the service provider.
Default

No SPID number is defined.

Command Mode

Interface configuration

Usage Guidelines

You must define the LDN if you want to receive any incoming calls on the B1-channel. The ISDN switch (DMS-100) checks for the LDN to determine whether both channels can be used to transmit and receive data. If the LDN is not present, then only the B2-channel can be used for full-duplex communication. However, the other channel can still be used for making outgoing calls.

Example

The following example defines, on the router, a SPID and LDN for the B2 channel:

isdn spid2 415555121202 5551214

isdn switch-type

To configure a central office switch on the ISDN interface, use the isdn switch-type global configuration command.

isdn switch-type switch-type
Syntax Description
switch-type Central office switch type; see Table 6-7 for a list of supported switches.

ISDN Office Switch Types
Keyword Switch Type
basic-1tr6 German switch standard
basic-5ess ATT 5ESS
basic-dms100 NT DMS-100
basic-net3 Switch type for NET3 in UK and Europe
basic-ni1 National ISDN-1
basic-nwnet3 Norway Net3 switches
basic-nznet3 New Zealand Net3 switches
basic-ts013 Australian TS013 switches
none No switch defined
ntt NTT ISDN switch (Japan)
vn2 French VN2 standard
vn3 French VN3 standard
Default

The switch type defaults to none, which disables the switch on the ISDN interface.

Command Mode

Global configuration

Usage Guidelines

To disable the switch on the ISDN interface, specify isdn switch-type none.

Example

The following example configures the French VN3 ISDN switch type:

isdn switch-type vn3

isdn tei

To configure when ISDN Layer 2 terminal endpoint identifier (TEI) negotiation should occur, use the isdn tei global configuration command. Use the no form of this command to restore the default.

isdn tei [first-call | powerup]
no isdn tei
Syntax Description
first-call (Optional) ISDN TEI negotiation should occur when the first ISDN call is placed or received.
powerup (Optional) ISDN TEI negotiation should occur when the router is powered on.
Default

powerup

Command Mode

Global configuration

Usage Guidelines

Use this command with care.

Example

The following example configures the router to negotiate TEI when the first ISDN call is placed or received:

isdn tei first-call

keepalive

Use the keepalive interface configuration command to set the keepalive timer for a specific interface. The no keepalive command turns off keepalives entirely.

keepalive [seconds]
no keepalive [seconds]
Syntax Description
seconds (Optional) Unsigned integer value greater than 0. The default is 10 seconds.
Default

10 seconds

Command Mode

Interface configuration

Usage Guidelines

You can configure the keepalive interval, which is the frequency at which the router sends messages to itself (Ethernet and Token Ring) or to the other end (serial), to ensure a network interface is alive. The interval in previous software versions was 10 seconds; it is now adjustable in 1-second increments down to 1 second. An interface is declared down after three update intervals have passed without receiving a keepalive packet.

Setting the keepalive timer to a low value is very useful for rapidly detecting Ethernet interface failures (transceiver cable disconnecting, cable unterminated, and so on).

A typical serial line failure involves losing Carrier Detect (CD). Since this sort of failure is typically noticed within a few milliseconds, adjusting the keepalive timer for quicker routing recovery is generally not useful.


Note When adjusting the keepalive timer for a very low bandwidth serial interface, large datagrams can delay the smaller keepalive packets long enough to cause the line protocol to go down. You may need to experiment to determine the best value.
Example

The following example sets the keepalive interval to 3 seconds:

interface ethernet 0 keepalive 3

linecode

Use the linecode command to select the line-code type for the T1 line.

linecode {ami | b8zs}
Syntax Description
ami Specifies AMI as the line-code type.
b8zs Specifies B8ZS as the line-code type.
Default

AMI

Command Mode

Controller configuration

Usage Guidelines

This command is used in configurations where the router is intended to communicate with T1 fractional data line. The T1 service provider determines which line-code type, either ami or b8zs, is required for your T1 circuit.

Example

The following example specifies B8ZS as the line-code type:

linecode b8zs

link-test

To re-enable the link test function on a port on an Ethernet hub (repeater) of a Cisco 2505 or Cisco 2507, use the link-test hub configuration command. Disable this feature if a pre-10BaseT twisted pair device not implementing Link Test is connected to the hub port, by using the no form of this command.

link-test
no link-test
Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Hub configuration

Usage Guidelines

This command applies to a port on an Ethernet hub only. Disable this feature if a 10BaseT twisted pair device at the other end of the hub does not implement the link test function.

Example

The following example disables the link test function on hub 0, ports 1 through 3:

hub ether 0 1 3 no link-test
Related Command

hub

loopback (controller)

To loop an entire E1 line (including all channel-groups defined on the controller) toward the line and back toward the router, use the loopback controller configuration command. To remove the loop, use the no form of this command.

loopback
no loopback
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Controller configuration

Usage Guidelines

This command is useful for testing the DCE device (CSU/DSU) itself.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on the E1 line:

controller e1 0 loopback

loopback (interface)

To diagnose equipment malfunctions between interface and device, use the loopback interface configuration command. The no loopback command disables the test.

loopback
no loopback
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

On HSSI serial interface cards, the loopback function configures a two-way internal and external loop on the HSA applique of the specific interface.

On MCI and SCI serial interface cards, the loopback functions when a CSU/DSU or equivalent device is attached to the router. The loopback command loops the packets through the CSU/DSU to configure a CSU loop, when the device supports this feature.

On the MCI and MEC Ethernet cards, the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.

On the CSC-FCI FDDI card, the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.

On all Token Ring interface cards (except the 4-megabit CSC-R card), the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.


Note Loopback does not work on an X.21 DTE because the X.21 interface definition does not include a loopback definition.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on Ethernet interface 4:

interface ethernet 4 loopback
Related Commands

down-when-looped
show interfaces loopback

loopback applique

To configure an internal loop on the HSSI applique, use the loopback interface configuration command. To remove the loop, use the no form of the command.

loopback applique
no loopback applique
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command loops the packets within the applique, thus providing a way to test for communication within the router. It is useful for sending pings to yourself to check functionality of the applique.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on the HSSI applique:

interface serial 1 loopback applique
Related Command
show interfaces loopback

loopback dte

To loop packets to DTE internally within the CSU/DSU at the DTE interface, when the device supports this feature, use the loopback interface configuration command. To remove the loop, use the no form of the command.

loopback dte
no loopback dte
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command is useful for testing the DTE-to-DCE cable.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on the DTE interface:

interface serial 1 loopback dte
Related Command
show interfaces loopback

loopback line

To loop packets completely through the CSU/DSU to configure the CSU loop, when the device supports this feature, use the loopback line interface configuration command. To remove the loop, use the no form of the command.

loopback line
no loopback line
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command is useful for testing the DCE device (CSU/DSU) itself.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on the DCE device:

interface serial 1 loopback line
Related Command
show interfaces loopback

loopback local (controller)

To loop an entire T1 line (including all channel-groups defined on the controller) toward the line and back toward the router, use the loopback local controller configuration command. To remove the loop, use the no form of this command.

loopback local
no loopback local
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Controller configuration

Usage Guidelines

This command is useful for testing the DCE device (CSU/DSU) itself.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on the T1 line:

controller t1 0 loopback local

loopback local (interface)

To loop a channelized T1 or channelized E1 channel-group, use the loopback local interface configuration command. To remove the loop, use the no form of this command.

loopback local
no loopback local
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command is useful to loop a single channel-group in a channelized environment without disrupting the other channel-groups.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures the loopback test on the T1 line:

interface serial 1/0:22 loopback local
Related Command

show interfaces loopback

loopback remote (controller)

To loop packets from a MIP through the CSU/DSU, over a dedicated T1 link, to the remote CSU at the single destination for this T1 link and back, use the loopback remote controller configuration command. To remove the loop, use the no form of this command.

loopback remote
no loopback remote
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Controller configuration

Usage Guidelines

This command applies only when the device supports the remote function. It is used for testing the data communication channels.

For MIP cards, this controller configuration command applies if only one destination exists at the remote end of the cloud, the entire T1 line is dedicated to it, and the device at the remote end is a CSU (not a CSU/DSU). This is an uncommon case; MIPs are not usually used in this way.

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures a remote loopback test:

interface serial 0 loopback remote
Related Command

show interfaces loopback

loopback remote (interface)

To loop packets through a CSU/DSU, over a DS-3 link or a channelized T1 link, to the remote CSU/DSU and back, use the loopback remote interface configuration command. To remove the loop, use the no form of this command.

loopback remote
no loopback remote
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command applies only when the remote CSU/DSU device supports the function. It is used for testing the data communication channels. The loopback usually is performed at the line port, rather than the DTE port, of the remote CSU/DSU.

For a multiport interface processor (MIP) connected to a network via a channelized T1 link, the loopback remote interface configuration command applies if the remote interface is served by a DDS line (56 Kbps or 64 Kbps), and the device at the remote end is a CSU/DSU. In addition, the CSU/DSU at the remote end must react to latched DDS CSU loopback codes. Destinations that are served by other types of lines or that have CSU/DSUs that do not react to latched DDS CSU codes cannot participate in an interface remote loopback. Latched DDS CSU loopback code requirements are described in AT&T specification TR-TSY-000476, "OTGR Network Maintenance Access and Testing."

To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.

Example

The following example configures a remote loopback test:

interface serial 0 loopback remote
Related Command

show interfaces loopback

media-type

To specify the Ethernet Network Interface Module configuration on the Cisco 4000 series, use the media-type interface configuration command.

media-type [aui | 10baset]
no media-type [aui | 10baset]
Syntax Description
aui (Optional) Selects a 15-pin physical connection.
10baset (Optional) Selects an RJ45 10BaseT physical connection.
Default

AUI 15-pin physical connection

Command Mode

Interface configuration

Example

The following example selects an RJ45 10BaseT physical connection on interface Ethernet 1:

interface ethernet 1 media-type 10baset

mop enabled

To enable an interface to support the Maintenance Operation Protocol (MOP), use the mop enabled interface configuration command. To disable MOP on an interface, use the no mop enabled command.

mop enabled
no mop enabled
Syntax Description

This command has no arguments or keywords.

Default

Enabled on Ethernet interfaces and disabled on all other interfaces.

Command Mode

Interface configuration

Example

In the following example, MOP is enabled for serial interface 0:

interface serial0 mop enabled
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

mop sysid
mop retransmit-timer
+
mop retries +

mop sysid

To enable an interface to send out periodic Maintenance Operation Protocol (MOP) system identification messages, use the mop sysid interface configuration command. To disable MOP message support on an interface, use the no mop sysid command.

mop sysid
no mop sysid
Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Interface configuration

Usage Guidelines

You can still run MOP without having the background system ID messages sent. This lets you use the MOP remote console, but does not generate messages used by the configurator.

Example

In the following example, serial interface 0 is enabled to send MOP system identification messages:

interface serial0 mop sysid
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

mop device-code +
mop enabled

mtu

To adjust the maximum packet size or maximum transmission unit (MTU) size, use the mtu interface configuration command. Use the no mtu command to restore the MTU value to its original default value.

mtu bytes
no mtu
Syntax Description
bytes Desired size in bytes
Default

Table 6-8 lists default MTU values according to media type.


Default Media MTU Values
Media Type Default MTU
Ethernet 1500
Serial 1500
Token Ring 4464
ATM 4470
FDDI 4470
HSSI (HSA) 4470
Command Mode

Interface configuration

Usage Guidelines

Each interface has a default maximum packet size or maximum transmission unit (MTU) size. This number generally defaults to the largest size possible for that type interface. On serial interfaces, the MTU size varies, but cannot be set smaller than 64 bytes.


Note Changing the MTU value with the mtu interface configuration command can affect values for the protocol-specific versions of the command (ip mtu for example). If the values specified with the ip mtu interface configuration command is the same as the value specified with the mtu interface configuration command, and you change the value for the mtu interface configuration command, the ip mtu value automatically matches the new mtu interface configuration command value. However, changing the values for the ip mtu configuration commands has no effect on the value for the mtu interface configuration command.
Example

The following example specifies an MTU of 1000 bytes:

interface serial 1 mtu 1000
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

encapsulation smds +
ip mtu +

nrzi-encoding

To enable non-return to zero inverted (NRZI) line coding format, use the nrzi-encoding interface configuration command. Use the no form of the command to disable this capability.

nrzi-encoding
no nrzi-encoding
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

All FSIP interface types support nonreturn to zero (NRZ) and nonreturn to zero inverted (NRZI) format. This is a line coding format that is required for serial connections in some environments. NRZ encoding is most common. NRZI encoding is used primarily with RS-232 connections in IBM environments.

Example

In the following example, serial interface 1 is configured for NRZI encoding:

interface serial 1 nrzi-encoding

ppp

To make an asynchronous connection from the auxiliary port using the Point-to-Point Protocol (PPP), enter the ppp EXEC command.

ppp [default | client [@tacacs-server]] [/routing]
Syntax Description
default (Optional) Makes PPP connection when a default address has been configured.
client (Optional) IP address or the name of the client workstation or PC.
tacacs-server (Optional) IP address or IP host name of the TACACS server to which the user's TACACS authentication request is to be sent.
/routing (Optional) Indicates asynchronous routing is enabled.
Command Mode

EXEC

Usage Guidelines

The IP address (indicated by the client and tacacs-server arguments) is the IP address of the system dialing in. This parameter can only be specified if the line is set for dynamic addresses using the line configuration command async dynamic address.

If you do not specify an address or enter default, you will be prompted for an IP address or host name. You can enter default at this point to use the default address configured for the line.

Using the tacacs-server argument, you can specify a TACACS server. If you do not specify a TACACS server for PPP address authentication, the TACACS server specified at login (if any) will be used for the PPP address query.

The /routing switch indicates that the remote system is a router and that routing messages should be exchanged over the link. The /routing switch can only be used if the line is configured for async dynamic routing. Static routing is always used.

Example

The following example shows a PPP EXEC command that specifies a TACACS authentication server and configured the line for routing:

ppp ntpc@server1 /routing
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

async default ip address
async dynamic address
async dynamic routing
async mode dedicated

async mode interactive

encapsulation ppp
interface async 1
tacacs-server +

ppp authentication chap

To enable Challenge Handshake Authentication Protocol (CHAP) on a serial interface, use the ppp authentication chap interface configuration command. Use the no ppp authentication chap command to disable this encapsulation.

ppp authentication chap
no ppp authentication chap
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

Once you have enabled CHAP, the local router requires a password from remote devices. If the remote device does not support CHAP, no traffic will be passed to that device.

Example

The following example enables CHAP on interface serial 4:

interface serial 4 encapsulation ppp ppp authentication chap
Related Command

encapsulation ppp

ppp authentication pap

To enable Password Authentication Protocol (PAP) on a serial interface, use the ppp authenticate pap interface configuration command. To disable this feature, use the no form of this command.

ppp authentication pap
no ppp authentication pap
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

When you enable PAP, it forces the router to negotiate with the remote device for the Password Authentication Protocol. If the remote device does not support PAP, no traffic will be passed to that device.

If both sides of the serial link are running PPP and PAP, both username entries and their passwords must be present on both sides of the link. You define these with the username name password secret global configuration command.

Example

The following example enables PAP on serial interface 4:

interface serial 4 ppp authentication pap
Related Commands

encapsulation ppp
username
password

ppp quality

To enable Link Quality Monitoring (LQM) on a serial interface, use the ppp quality interface configuration command. Use the no form of this command to disable LQM.

ppp quality percentage
no ppp quality
Syntax Description
percentage Specifies the link quality threshold. Range is 1 to 100.
Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

The percentages are calculated for both incoming and outgoing directions. The outgoing quality is calculated by comparing the total number of packets and bytes sent to the total number of packets and bytes received by the peer. The incoming quality is calculated by comparing the total number of packets and bytes received to the total number of packets and bytes sent by the peer.

If the link quality percentage is not maintained, the link is deemed to be of poor quality and is taken down. The policy implements a time lag so that the link does not bounce up and down.

Example

The following example enables LQM on interface serial 4:

interface serial 4 encapsulation ppp ppp quality 80
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

encapsulation ppp
keepalive
+

pulse-time

To enable pulsing DTR signal intervals on the serial interfaces, use the pulse-time interface configuration command. Use the no pulse-time command to restore the default interval.

pulse-time seconds
no pulse-time
Syntax Description
seconds Integer that specifies the DTR signal interval in seconds
Default

0 seconds

Command Mode

Interface configuration

Usage Guidelines

When the serial line protocol goes down (for example, because of loss of synchronization) the interface hardware is reset and the DTR signal is held inactive for at least the specified interval. This function is useful for handling encrypting or other similar devices that use the toggling of the DTR signal to resynchronize.

Example

The following example enables DTR pulse signals for three seconds on interface serial:

interface serial 2 pulse-time 3

ring-speed

To set the ring speed for the CSC-1R and CSC-2R Token Ring interfaces, use the ring-speed interface configuration command.

ring-speed speed
Syntax Description
speed Integer that specifies the ring speed, either 4 for 4-Mbps or 16 for 16-Mbps operation.
Default

16-Mbps operation

Caution Configuring a ring speed that is wrong or incompatible with the connected Token Ring will cause the ring to beacon, which effectively takes the ring down and makes it nonoperational.
Command Mode

Interface configuration

Example

The following example sets a Token Ring interface ring speed to 4 Mbps:

interface tokenring 0 ring-speed 4

show async status

To list the status of the asynchronous interface 1 associated with the router auxiliary port, use the show async status user EXEC command:

show async status
Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Usage Guidelines

Shows all asynchronous sessions, whether they are using SLIP or PPP encapsulation.

Sample Display

The following is sample output from the show async status command:

Router> show async status Async protocol statistics: Rcvd: 5448 packets, 7682760 bytes 1 format errors, 0 checksum errors, 0 overrun, 0 no buffer Sent: 5455 packets, 7682676 bytes, 0 dropped Int Local Remote Qd InPack OutPac Inerr Drops MTU Qsz 1 192.31.7.84 Dynamic 0 0 0 0 0 1500 10

Table 6-9 describes significant fields shown in the display.


Show Async Status Field Descriptions
Field Description
Rcvd: Statistics on packets received.
5548 packets Packets received.
7682760 bytes Total number of bytes.
1 format errors Packets with a bad IP header, even before the checksum is calculated.
0 checksum errors Count of checksum errors.
0 overrun Number of giants received.
0 no buffer Number of packets received when no buffer was available.
Sent: Statistics on packets sent.
5455 packets Packets sent.
7682676 bytes Total number of bytes.
0 dropped Number of packets dropped.
Int Interface number.
* Line currently in use.
Local Local IP address on the link.
Remote Remote IP address on the link; "Dynamic" indicates that a remote address is allowed but has not been specified; "None" indicates that no remote address is assigned or being used.
Qd Number of packets on hold queue (Qsz is max).
InPack Number of packets received.
OutPac Number of packets sent.
Inerr Number of total input errors; sum of format errors, checksum errors, overruns and no buffers.
Drops Number of packets received that would not fit on the hold queue.
MTU Current maximum transmission unit size.
Qsz Current output hold queue size.
Related Commands

async
interface async

show compress

To display compression statistics, use the show compress EXEC command.

show compress
Syntax Description

This command has no arguments or parameters.

Command Mode

EXEC

Sample Display

The following is sample output from the show compress command:

Router# show compress Serial0 uncompressed bytes xmt/rcv 10710562/11376835 1 min avg ratio xmt/rcv 2.773/2.474 5 min avg ratio xmt/rcv 4.084/3.793 10 min avg ratio xmt/rcv 4.125/3.873 no bufs xmt 0 no bufs rcv 0 resets 0

Table 6-10 describes the fields shown in the display.


Show Compress Field Descriptions
Field Description
Serial0 Name and number of the interface.
uncompressed bytes xmt/rcv Total number of uncompressed bytes sent and received.
1 min avg ratio xmt/rcv
5 min avg ratio xmt/rcv
10 min avg ratio xmt/rcv
Static compression ratio for bytes sent and received, averaged over 1, 5, and 10 minutes.
no bufs xmt Number of times buffers were not available to compress data being sent.
no bufs rcv Number of times buffers were not available to uncompress data being received.
resets Number of resets.
Related Command

compress predictor

show controllers bri

To display information about the ISDN Basic Rate Interface (BRI) on a Cisco 3000, use the show controllers bri privileged EXEC command.

show controllers bri
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show controllers bri command:

Router# show controllers bri 0 BRI unit 0 D Chan Info: Layer 1 is ACTIVATED idb 0x32089C, ds 0x3267D8, reset_mask 0x2 buffer size 1524 RX ring with 2 entries at 0x2101600 : Rxhead 0 00 pak=0x4122E8 ds=0x412444 status=D000 pak_size=0 01 pak=0x410C20 ds=0x410D7C status=F000 pak_size=0 TX ring with 1 entries at 0x2101640: tx_count = 0, tx_head = 0, tx_tail = 0 00 pak=0x000000 ds=0x000000 status=7C00 pak_size=0 0 missed datagrams, 0 overruns, 0 bad frame addresses 0 bad datagram encapsulations, 0 memory errors 0 transmitter underruns B1 Chan Info: Layer 1 is ACTIVATED idb 0x3224E8, ds 0x3268C8, reset_mask 0x0 buffer size 1524 RX ring with 8 entries at 0x2101400 : Rxhead 0 00 pak=0x421FC0 ds=0x42211C status=D000 pak_size=0 01 pak=0x4085E8 ds=0x408744 status=D000 pak_size=0 02 pak=0x422EF0 ds=0x42304C status=D000 pak_size=0 03 pak=0x4148E0 ds=0x414A3C status=D000 pak_size=0 04 pak=0x424D50 ds=0x424EAC status=D000 pak_size=0 05 pak=0x423688 ds=0x4237E4 status=D000 pak_size=0 06 pak=0x41AB98 ds=0x41ACF4 status=D000 pak_size=0 07 pak=0x41A400 ds=0x41A55C status=F000 pak_size=0 TX ring with 4 entries at 0x2101440: tx_count = 0, tx_head = 0, tx_tail = 0 00 pak=0x000000 ds=0x000000 status=5C00 pak_size=0 01 pak=0x000000 ds=0x000000 status=5C00 pak_size=0 02 pak=0x000000 ds=0x000000 status=5C00 pak_size=0 03 pak=0x000000 ds=0x000000 status=7C00 pak_size=0 0 missed datagrams, 0 overruns, 0 bad frame addresses 0 bad datagram encapsulations, 0 memory errors 0 transmitter underruns B2 Chan Info: Layer 1 is ACTIVATED idb 0x324520, ds 0x3269B8, reset_mask 0x2 buffer size 1524 RX ring with 8 entries at 0x2101500 : Rxhead 0 00 pak=0x40FCF0 ds=0x40FE4C status=D000 pak_size=0 01 pak=0x40E628 ds=0x40E784 status=D000 pak_size=0 02 pak=0x40F558 ds=0x40F6B4 status=D000 pak_size=0 03 pak=0x413218 ds=0x413374 status=D000 pak_size=0 04 pak=0x40EDC0 ds=0x40EF1C status=D000 pak_size=0 05 pak=0x4113B8 ds=0x411514 status=D000 pak_size=0 06 pak=0x416ED8 ds=0x417034 status=D000 pak_size=0 07 pak=0x416740 ds=0x41689C status=F000 pak_size=0 TX ring with 4 entries at 0x2101540: tx_count = 0, tx_head = 0, tx_tail = 0 00 pak=0x000000 ds=0x000000 status=5C00 pak_size=0 01 pak=0x000000 ds=0x000000 status=5C00 pak_size=0 02 pak=0x000000 ds=0x000000 status=5C00 pak_size=0 03 pak=0x000000 ds=0x000000 status=7C00 pak_size=0 0 missed datagrams, 0 overruns, 0 bad frame addresses 0 bad datagram encapsulations, 0 memory errors 0 transmitter underruns

Table 6-11 describes the significant fields in the display.


Show Controllers BRI Field Descriptions
Field Description
BRI unit 0 Interface type and unit number.
Chan Info D and B channel numbers
Layer 1 is ACTIVATED Status can be DEACTIVATED, PENDING ACTIVATION, or ACTIVATED.
idb
ds
reset_mask
Information about internal data structures and parameters.
buffer size Number of bytes allocated for buffers
RX ring with - entries at - Information about the Receiver Queue.
Rxhead Start of the Receiver Queue.
pak
ds
status
pak_size
Information about internal data structures and parameters.
TX ring with - entries at - Information about the Transmitter Queue.
tx_count Number of packets to transmit.
tx_head Start of the transmit list.
tx_tail End of the transmit list.
missed datagrams Incoming packets missed due to internal errors.
overruns Number of times the receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
bad frame addresses Frames received with a CRC error and noninteger number of octets.
bad datagram encapsulations Packets received with bad encapsulation.
memory errors Internal DMA memory errors.
transmitter underruns Number of times that the transmitter has been running faster than the router can handle.

show controllers cbus

Use the show controllers cbus privileged EXEC command on the AGS+ to display all information under the ciscoBus controller card. This command also shows the capabilities of the card and reports controller-related failures.

show controllers cbus
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Displays

The following is sample output from the show controllers cbus command:

Router# show controllers cbus cBus 1, controller type 3.0, microcode version 2.0 128 Kbytes of main memory, 32 Kbytes cache memory 40 1520 byte buffers, 14 4484 byte buffers Restarts: 0 line down, 0 hung output, 0 controller error --More-- HSCI 1, controller type 10.0, microcode version 129.3 Interface 6 - Hssi0, electrical interface is Hssi DTE 5 buffer RX queue threshold, 7 buffer TX queue limit, buffer size 1520 ift 0004, rql 2, tq 0000 0000, tql 7 Transmitter delay is 0 microseconds MEC 3, controller type 5.1, microcode version 130.6 Interface 18 - Ethernet2, station address 0000.0c02.a03c (bia 0000.0c02.a03c) 10 buffer RX queue threshold, 7 buffer TX queue limit, buffer size 1520 ift 0000, rql 10, tq 0000 0000, tql 7 Transmitter delay is 0 microseconds Interface 19 - Ethernet3, station address 0000.0c02.a03d (bia 0000.0c02.a03d) 10 buffer RX queue threshold, 7 buffer TX queue limit, buffer size 1520 ift 0000, rql 10, tq 0000 0000, tql 7 Transmitter delay is 0 microseconds

Table 6-12 describes the fields shown in the following lines of output from the display.

cBus 1, controller type 3.0, microcode version 2.0 128 Kbytes of main memory, 32 Kbytes cache memory 40 1520 byte buffers, 14 4484 byte buffers Restarts: 0 line down, 0 hung output, 0 controller error
Show Controllers cBus Field Descriptions--Part 1
Field Description
cBus 1 Card type and unit number (varies depending on card).
controller type 3.0 Version number of the card.
microcode version 2.0 Version number of the card's internal software (in read-only memory).
128 Kbytes of main memory Amount of main memory on the card.
32 Kbytes cache memory Amount of cache memory on the card.
40 1520 byte buffers Number of buffers of this size on the card.
14 4484 byte buffers Number of buffers of this size on the card.
Restarts
   0 line down
   0 hung output
   0 controller error
Count of restarts due to the following conditions:
   Communication line down
   Output unable to transmit
   Internal error

Table 6-13 describes the fields shown in the following lines of output from the display:

HSCI 1, controller type 10.0, microcode version 129.3 Interface 6 - Hssi0, electrical interface is Hssi DTE 5 buffer RX queue threshold, 7 buffer TX queue limit, buffer size 1520 ift 0004, rql 2, tq 0000 0000, tql 7 Transmitter delay is 0 microseconds
Show Controllers cBus Field Descriptions--Part 2
Field Description
HSCI 1 Card type and unit number (varies depending on card).
controller type 10.0 Version number of the card.
microcode version 129.3 Version number of the card's internal software (in read-only memory).
Interface 6 Physical interface number.
Hssi 0 Logical name for this interface.
electrical interface is Hssi DTE Self-explanatory.
5 buffer RX queue threshold Maximum number of buffers allowed in the receive queue.
7 buffer TX queue limit Maximum number of buffers allowed in the transmit queue.
buffer size 1520 Size of the buffers on this card (in bytes).
ift 0004 Interface type code.
0 = EIP
1 = FSIP
4 = HIP
5 = TRIP
6 = FIP
7 = AIP
rql 2 Receive queue limit. Current number of buffers allowed for the receive queue. It is used to limit the number of buffers used by a particular inbound interface. When equal to 0, all of that interface's receive buffers are in use.
tq 0000 0000 Transmit queue head and tail pointers.
tql 7 Transmit queue limit. Current number of buffers allowed for transmit queue. It limits the maximum cbus buffers allowed to sit on a particular interface's transmit queue.
Transmitter delay is 0 microseconds Transmitter delay between the packets.

The show controllers cbus command displays the internal status of the SP and each cBus interface processor (IP), including the slot location, the card hardware version, and the currently-running microcode version. It also lists each interface (port) on each IP including the logical interface number, interface type, physical (slot/port) address, and hardware (station address) of each interface. The following display shows an AIP installed in IP slot 4, the running AIP microcode is Version 170.30, the PLIM type is 4B/5B, and the available bandwidth is 100 Mbps:

Router# show controllers cbus Switch Processor 5, hardware version 11.1, microcode version 170.46 Microcode loaded from system 512 Kbytes of main memory, 128 Kbytes cache memory 60 1520 byte buffers, 91 4496 byte buffers Restarts: 0 line down, 0 hung output, 0 controller error AIP 4, hardware version 1.0, microcode version 170.30 Microcode loaded from system Interface 32 - ATM4/0, PLIM is 4B5B(100Mbps) 15 buffer RX queue threshold, 36 buffer TX queue limit, buffer size 4496 ift 0007, rql 12, tq 0000 0620, tql 36 Transmitter delay is 0 microseconds

show controllers cxbus

Use the show controllers cxbus privileged EXEC command to display information about the switch processor (SP) CxBus controller on the Cisco 7000 series. This command displays information that is specific to the interface hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.

show controllers cxbus
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output on the Cisco 7000 from the show controllers cxbus command:

Router# show controllers cxbus Switch Processor 5, hardware version 11.1, microcode version 130.2 Microcode loaded from system   512 Kbytes of main memory, 128 Kbytes cache memory 120 1520 byte buffers, 70 4484 byte buffers, 212 byte system buffer Restarts: 0 line down, 0 hung output, 0 controller error FIP 3, hardware version 6.1, microcode version 141.7 Interface 24 - Fddi3/0, station addr 0000.0c02.adf1 (bia 0000.0c02.adf1) 70 buffer RX queue threshold, 71 buffer TX queue limit, buffer size 4484 ift 0006, rql 66, tq 0000 0000, tql 70 EIP 4, hardware version 5.1, microcode version 128.10 Interface 32 - Ethernet4/0, station addr 0000.0c02.d0cc (bia 0000.0c02.d0cc) 20 buffer RX queue threshold, 28 buffer TX queue limit, buffer size 1520 ift 0000, rql 20, tq 0000 0000, tql 28 Transmitter delay is 0 microseconds Interface 33 - Ethernet4/1, station addr 0000.0c02.d0cd (bia 0000.0c02.d0cd) 20 buffer RX queue threshold, 28 buffer TX queue limit, buffer size 1520 ift 0000, rql 20, tq 0000 0000, tql 28 Transmitter delay is 0 microseconds Interface 34 - Ethernet4/2, station addr 0000.0c02.d0ce (bia 0000.0c02.d0ce) 20 buffer RX queue threshold, 28 buffer TX queue limit, buffer size 1520 ift 0000, rql 20, tq 0000 0000, tql 28 Transmitter delay is 0 microseconds Interface 35 - Ethernet4/3, station addr 0000.0c02.d0cf (bia 0000.0c02.d0cf) 20 buffer RX queue threshold, 28 buffer TX queue limit, buffer size 1520 ift 0000, rql 20, tq 0000 0000, tql 28 Transmitter delay is 0 microseconds Interface 36 - Ethernet4/4, station addr 0000.0c02.d0d0 (bia 0000.0c02.d0d0) 20 buffer RX queue threshold, 28 buffer TX queue limit, buffer size 1520 ift 0000, rql 20, tq 0000 0000, tql 28 Transmitter delay is 0 microseconds Interface 37 - Ethernet 4/5, station addr 0000.0c02.d0d1 (bia0000.0c02.d0d1) 20 buffer RX queue threshold, 28 buffer TX queue limit, buffer size 1520 ift 0000, rql 20, tq 0000 0000, tql 28 Transmitter delay is 0 microseconds

Table 6-14 describes the fields shown in the display.


Show Controllers CxBus Field Descriptions
Field Description
IP type, slot number Unit type and slot number.
hardware version Version number of the controller.
microcode version Version number of the controller's internal software (in read-only memory).
Microcode loaded from Source of microcode; can be system, ROM, or Flash.
main memory
cache memory
Amount of main and cache memory on the processor .
byte system buffer An extra buffer left over after carving the normal pools. It is used for host-generated traffic when available.
Restarts
   line down
   hung output
   controller error
Number of restarts due to the following conditions:
   Communication line down
   Output unable to transmit
   Internal error
Interface # - Names of interfaces by CxBus interface type, slot, and port number.
   RX buffers Number of buffers for received packets.
   TX queue limit Maximum number of buffers in transmit queue.
ift Interface type code.
0 = EIP
1 = FSIP
4 = HIP
5 = TRIP
6 = FIP
7 = AIP
rql Receive queue limit. Current number of buffers allowed for the receive queue. It is used to limit the number of buffers used by a particular inbound interface. When equal to 0, all of that interface's receive buffers are in use.
tq Transmit queue head and tail pointers.
tql Transmit queue limit. Current number of buffers allowed for transmit queue. It limits the maximum cbus buffers allowed to sit on a particular interface's transmit queue.
   Transmitter delay Delay between outgoing frames.
   Station address The hardware address of the interface.

show controllers ethernet

Use the show controllers ethernet EXEC command to display information on the Cisco 2500, 3000, or 4000.

show controllers ethernet interface-number
Syntax Description
interface-number Interface number of the Ethernet interface.
Command Mode

EXEC

Sample Display

The following is sample output from the show controllers ethernet command on the Cisco 4000:

Router# show controllers ethernet 0 LANCE unit 0, NIM slot 1, NIM type code 4, NIM version 1 Media Type is 10BaseT, Link State is Up, Squelch is Normal idb 0x4060, ds 0x5C80, regaddr = 0x8100000 IB at 0x600D7AC: mode=0x0000, mcfilter 0000/0001/0000/0040 station address 0000.0c03.a14f default station address 0000.0c03.a14f buffer size 1524 RX ring with 32 entries at 0xD7E8 Rxhead = 0x600D8A0 (12582935), Rxp = 0x5CF0(23) 00 pak=0x60336D0 ds=0x6033822 status=0x80 max_size=1524 pak_size=98 01 pak=0x60327C0 ds=0x6032912 status=0x80 max_size=1524 pak_size=98 02 pak=0x6036B88 ds=0x6036CDA status=0x80 max_size=1524 pak_size=98 03 pak=0x6041138 ds=0x604128A status=0x80 max_size=1524 pak_size=98 04 pak=0x603FAA0 ds=0x603FBF2 status=0x80 max_size=1524 pak_size=98 05 pak=0x600DC50 ds=0x600DDA2 status=0x80 max_size=1524 pak_size=98 06 pak=0x6023E48 ds=0x6023F9A status=0x80 max_size=1524 pak_size=1506 07 pak=0x600E3D8 ds=0x600E52A status=0x80 max_size=1524 pak_size=1506 08 pak=0x6020990 ds=0x6020AE2 status=0x80 max_size=1524 pak_size=386 09 pak=0x602D4E8 ds=0x602D63A status=0x80 max_size=1524 pak_size=98 10 pak=0x603A7C8 ds=0x603A91A status=0x80 max_size=1524 pak_size=98 11 pak=0x601D4D8 ds=0x601D62A status=0x80 max_size=1524 pak_size=98 12 pak=0x603BE60 ds=0x603BFB2 status=0x80 max_size=1524 pak_size=98 13 pak=0x60318B0 ds=0x6031A02 status=0x80 max_size=1524 pak_size=98 14 pak=0x601CD50 ds=0x601CEA2 status=0x80 max_size=1524 pak_size=98 15 pak=0x602C5D8 ds=0x602C72A status=0x80 max_size=1524 pak_size=98 16 pak=0x60245D0 ds=0x6024722 status=0x80 max_size=1524 pak_size=98 17 pak=0x6008328 ds=0x600847A status=0x80 max_size=1524 pak_size=98 18 pak=0x601EB70 ds=0x601ECC2 status=0x80 max_size=1524 pak_size=98 19 pak=0x602DC70 ds=0x602DDC2 status=0x80 max_size=1524 pak_size=98 20 pak=0x60163E0 ds=0x6016532 status=0x80 max_size=1524 pak_size=98 21 pak=0x602CD60 ds=0x602CEB2 status=0x80 max_size=1524 pak_size=98 22 pak=0x6037A98 ds=0x6037BEA status=0x80 max_size=1524 pak_size=98 23 pak=0x602BE50 ds=0x602BFA2 status=0x80 max_size=1524 pak_size=98 24 pak=0x6018988 ds=0x6018ADA status=0x80 max_size=1524 pak_size=98 25 pak=0x6033E58 ds=0x6033FAA status=0x80 max_size=1524 pak_size=98 26 pak=0x601BE40 ds=0x601BF92 status=0x80 max_size=1524 pak_size=98 27 pak=0x6026B78 ds=0x6026CCA status=0x80 max_size=1524 pak_size=98 28 pak=0x6024D58 ds=0x6024EAA status=0x80 max_size=1524 pak_size=74 29 pak=0x602AF40 ds=0x602B092 status=0x80 max_size=1524 pak_size=98 30 pak=0x601FA80 ds=0x601FBD2 status=0x80 max_size=1524 pak_size=98 31 pak=0x6038220 ds=0x6038372 status=0x80 max_size=1524 pak_size=98 TX ring with 8 entries at 0xDA20, tx_count = 0 tx_head = 0x600DA58 (12582919), head_txp = 0x5DC4 (7) tx_tail = 0x600DA58 (12582919), tail_txp = 0x5DC4 (7) 00 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 01 pak=0x000000 ds=0x602126A status=0x03 status2=0x0000 pak_size=60 02 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 03 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 04 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 05 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 06 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 07 pak=0x000000 ds=0x6003ED2 status=0x03 status2=0x0000 pak_size=126 0 missed datagrams, 0 overruns, 2 late collisions, 2 lost carrier events 0 transmitter underruns, 0 excessive collisions, 0 tdr, 0 babbles 0 memory errors, 0 spurious initialization done interrupts 0 no enp status, 0 buffer errors, 0 overflow errors 10 one_col, 10 more_col, 22 deferred, 0 tx_buff 0 throttled, 0 enabled Lance csr0 = 0x73

show controllers fddi

Use the show controllers fddi user EXEC command to display all information under the FDDI controller card on the AGS+ or FDDI Interface Processor (FIP) on the Cisco 7000.

show controllers fddi
Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Usage Guidelines

This command reflects the internal state of the chips and information the system uses for bridging and routing that is specific to the interface hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.

Sample Display

The following is sample output from the show controllers fddi command on the Cisco 7000:

Router# show controllers fddi Fddi2/0 - hardware version 2.2, microcode version 1.2 Phy-A registers: cr0 4, cr1 0, cr2 0, status 3, cr3 0 Phy-B registers: cr0 4, cr1 4, cr2 0, status 3, cr3 0 FORMAC registers: irdtlb 71C2, irdtneg F85E, irdthtt F5D5, irdmir FFFF0BDC irdtrth F85F, irdtmax FBC5, irdtvxt 5959, irdstmc 0810 irdmode 6A20, irdimsk 0000, irdstat 8060, irdtpri 0000 FIP registers ccb: 002C cmd: 0006 fr: 000F mdptr: 0000 mema: 0000 icb: 00C0 arg: 0003 app: 0004 mdpg: 0000 af: 0603     clm: E002 bcn: E016 clbn: 0198 rxoff: 002A en: 0001 clmbc: 8011 bcnbc: 8011 robn: 0004 park: 0000 fop: 8004 txchn: 0000 pend: 0000 act: 0000 tail: 0000 cnt: 0000 state: 0003 check: 0000 eof: 0000 tail: 0000 cnt: 0000 rxchn: 0000 buf0: 0534 nxt0: 0570 eof: 0000 tail: 0000 eofch: 0000 buf1: 051C nxt1: 0528 pool: 0050 err: 005C head: 0984 cur: 0000 t0: 0030 t1: 0027 t2: 000F tail: 0984 cnt: 0001 t3: 0000 rxlft: 000B used: 0000 txq_s: 0018 txq_f: 0018 Aarm: 0000 Barm: 1388 fint: 8004 Total LEM: phy-a 6, phy-b 13

The last line of output indicates how many LEM events occurred on the specific PHY.

show controllers mci

Use the show controllers mci privileged EXEC command to display all information under the Multiport Communications Interface card or the SCI. This command displays information the system uses for bridging and routing that is specific to the interface hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.

show controllers mci
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show controllers mci command:

Router# show controllers mci MCI 0, controller type 1.1, microcode version 1.8     128 Kbytes of main memory, 4 Kbytes cache memory 22 system TX buffers, largest buffer size 1520     Restarts: 0 line down, 0 hung output, 0 controller error Interface 0 is Ethernet0, station address 0000.0c00.d4a6     15 total RX buffers, 11 buffer TX queue limit, buffer size 1520     Transmitter delay is 0 microseconds Interface 1 is Serial0, electrical interface is V.35 DTE     15 total RX buffers, 11 buffer TX queue limit, buffer size 1520     Transmitter delay is 0 microseconds     High speed synchronous serial interface Interface 2 is Ethernet1, station address aa00.0400.3be4     15 total RX buffers, 11 buffer TX queue limit, buffer size 1520     Transmitter delay is 0 microseconds Interface 3 is Serial1, electrical interface is V.35 DCE     15 total RX buffers, 11 buffer TX queue limit, buffer size 1520     Transmitter delay is 0 microseconds     High speed synchronous serial interface

Table 6-15 describes significant fields shown in the display.


Show Controllers MCI Field Descriptions
Field Description
MCI 0 Card type and unit number (varies depending on card).
controller type 1.1 Version number of the card.
microcode version 1.8 Version number of the card's internal software (in read-only memory).
128 Kbytes of main memory Amount of main memory on the card.
4 Kbytes cache memory Amount of cache memory on the card.
22 system TX buffers Number of buffers that hold packets to be transmitted.
largest buffer size 1520 Largest size of these buffers (in bytes).
Restarts
   0 line down
   0 hung output
   0 controller error
Count of restarts due to the following conditions:
   Communication line down
   Output unable to transmit
   Internal error
Interface 0 is Ethernet0 Names of interfaces, by number.
electrical interface is V.35 DTE Line interface type for serial connections.
15 total RX buffers Number of buffers for received packets.
11 buffer TX queue limit Maximum number of buffers in transmit queue.
Transmitter delay is 0 microseconds Delay between outgoing frames.
Station address 0000.0c00.d4a6 Hardware address of the interface.

Note The interface type is only queried at startup. If the hardware changes subsequent to initial startup, then the wrong type is reported. This has no adverse effect on the operation of the software. For instance, if a DCE cable is connected to a dual-mode V.35 applique after the unit has been booted, then the display presented for show interfaces incorrectly reports attachment to a DTE device although the software recognizes the DCE interface and behaves accordingly.
Related Command

tx-queue-limit

show controllers pcbus

Use the show controllers pcbus privileged EXEC command to display all information about the ISA bus interface. This command is valid on LanOptics' Branchcard or Stacknet 2000 products only.

show controllers pcbus
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show controllers pcbus command:

Router# show controllers pcbus PCbus unit 0, Name = PCbus0 Hardware is ISA PCbus shared RAM IDB at 0x3719B0, Interface driver data structure at 0x3735F8 Control/status register at 0x2110008, Shared memory at 0xC000000 Shared memory is initialized Shared memory interface control block : Magic no = 0x41435A56 (valid) Version = 1.0 Shared memory size = 64K bytes, Interface is NOT shutdown Interface state is up, line protocol is up Tx buffer : (control block at 0xC000010) Start offset = 0x30, Size = 0x7FE8, Overflows = 1 GET_ptr = 0x4F6C, PUT_ptr = 0x4F6C, WRAP_ptr = 0x3BB0 Rx buffer : (control block at 0xC000020) Start offset = 0x8018, Size 0x7FE8, Overflows = 22250698 GET_ptr = 0x60, PUT_ptr = 0x60, WRAP_ptr = 0x7FD0 Interrupts received = 567

show controllers serial

Use the show controllers serial privileged EXEC command to display information that is specific to the interface hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.

show controllers serial
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

Sample output of the show controllers serial command on the Cisco 4000 follows:

Router# show controllers serial MK5 unit 0, NIM slot 1, NIM type code 7, NIM version 1 idb = 0x6150, driver structure at 0x34A878, regaddr = 0x8100300 IB at 0x6045500: mode=0x0108, local_addr=0, remote_addr=0 N1=1524, N2=1, scaler=100, T1=1000, T3=2000, TP=1 buffer size 1524 DTE V.35 serial cable attached RX ring with 32 entries at 0x45560 : RLEN=5, Rxhead 0 00 pak=0x6044D78 ds=0x6044ED4 status=80 max_size=1524 pak_size=0 01 pak=0x60445F0 ds=0x604474C status=80 max_size=1524 pak_size=0 02 pak=0x6043E68 ds=0x6043FC4 status=80 max_size=1524 pak_size=0 03 pak=0x60436E0 ds=0x604383C status=80 max_size=1524 pak_size=0 04 pak=0x6042F58 ds=0x60430B4 status=80 max_size=1524 pak_size=0 05 pak=0x60427D0 ds=0x604292C status=80 max_size=1524 pak_size=0 06 pak=0x6042048 ds=0x60421A4 status=80 max_size=1524 pak_size=0 07 pak=0x60418C0 ds=0x6041A1C status=80 max_size=1524 pak_size=0 08 pak=0x6041138 ds=0x6041294 status=80 max_size=1524 pak_size=0 09 pak=0x60409B0 ds=0x6040B0C status=80 max_size=1524 pak_size=0 10 pak=0x6040228 ds=0x6040384 status=80 max_size=1524 pak_size=0 11 pak=0x603FAA0 ds=0x603FBFC status=80 max_size=1524 pak_size=0 12 pak=0x603F318 ds=0x603F474 status=80 max_size=1524 pak_size=0 13 pak=0x603EB90 ds=0x603ECEC status=80 max_size=1524 pak_size=0 14 pak=0x603E408 ds=0x603E564 status=80 max_size=1524 pak_size=0 15 pak=0x603DC80 ds=0x603DDDC status=80 max_size=1524 pak_size=0 16 pak=0x603D4F8 ds=0x603D654 status=80 max_size=1524 pak_size=0 17 pak=0x603CD70 ds=0x603CECC status=80 max_size=1524 pak_size=0 18 pak=0x603C5E8 ds=0x603C744 status=80 max_size=1524 pak_size=0 19 pak=0x603BE60 ds=0x603BFBC status=80 max_size=1524 pak_size=0 20 pak=0x603B6D8 ds=0x603B834 status=80 max_size=1524 pak_size=0 21 pak=0x603AF50 ds=0x603B0AC status=80 max_size=1524 pak_size=0 22 pak=0x603A7C8 ds=0x603A924 status=80 max_size=1524 pak_size=0 23 pak=0x603A040 ds=0x603A19C status=80 max_size=1524 pak_size=0 24 pak=0x60398B8 ds=0x6039A14 status=80 max_size=1524 pak_size=0 25 pak=0x6039130 ds=0x603928C status=80 max_size=1524 pak_size=0 26 pak=0x60389A8 ds=0x6038B04 status=80 max_size=1524 pak_size=0 27 pak=0x6038220 ds=0x603837C status=80 max_size=1524 pak_size=0 28 pak=0x6037A98 ds=0x6037BF4 status=80 max_size=1524 pak_size=0 29 pak=0x6037310 ds=0x603746C status=80 max_size=1524 pak_size=0 30 pak=0x6036B88 ds=0x6036CE4 status=80 max_size=1524 pak_size=0 31 pak=0x6036400 ds=0x603655C status=80 max_size=1524 pak_size=0 TX ring with 8 entries at 0x45790 : TLEN=3, TWD=7 tx_count = 0, tx_head = 7, tx_tail = 7 00 pak=0x000000 ds=0x600D70C status=0x38 max_size=1524 pak_size=22 01 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2 02 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2 03 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2 04 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2 05 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2 06 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2 07 pak=0x000000 ds=0x6000000 status=0x38 max_size=1524 pak_size=0 XID/Test TX desc at 0xFFFFFF, status=0x30, max_buffer_size=0, packet_size=0 XID/Test RX desc at 0xFFFFFF, status=0x0, max_buffer_size=0, packet_size=0 Status Buffer at 0x60459C8: rcv=0, tcv=0, local_state=0, remote_state=0 phase=0, tac=0, currd=0x00000, curxd=0x00000 bad_frames=0, frmrs=0, T1_timeouts=0, rej_rxs=0, runts=0 0 missed datagrams, 0 overruns, 0 bad frame addresses 0 bad datagram encapsulations, 0 user primitive errors 0 provider primitives lost, 0 unexpected provider primitives 0 spurious primitive interrupts, 0 memory errors, 0 tr %LINEPROTO-5-UPDOWN: Linansmitter underruns mk5025 registers: csr0 = 0x0E00, csr1 = 0x0302, csr2 = 0x0704 csr3 = 0x5500, csr4 = 0x0214, csr5 = 0x0008

show controllers t1

Use the show controllers t1 privileged EXEC command on the Cisco 7000 to display information about the T1 links supported by the Multichannel Interface Processor (MIP). This command displays controller status that is specific to the controller hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.

show controllers t1 [slot/port]

Syntax Description

slot Specifies the backplane slot number and can be 0, 1, 2, 3, or 4.
port Specifies the port number of the controller and can be 0 or 1.
Command Mode

EXEC

Usage Guidelines

For the T1 interface on the Cisco 7000, the MIP can query the port adapters to determine their current status. Issue a show controllers t1 command to display statistics about the T1 link.

If you specify a slot and port number, each 15 minute period will be displayed.

Sample Display

The following is sample output from the show controllers t1 command on the Cisco 7000 series:

Router# show controllers t1 T1 0/0 is up. No alarms detected. Data in current interval (725 seconds elapsed): 0 Line Code Violations, 0 Path Code Violations 0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs Total Data (last 24 hours) 0 Line Code Violations, 0 Path Code Violations, 0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins, 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Table 6-16 describes the show controllers t1 display fields.


Show Controllers T1 Field Descriptions
Field Description
T1 0/0 is up. The T1 controller 0 in slot 0 is operating. The controller's state can be up, down, administratively down. Loopback conditions are shown by (Locally looped) or (Remotely Looped).
No alarms detected. Any alarms detected by the controller are displayed here. Possible alarms are as follows:

Transmitter is sending remote alarm.

Transmitter is sending AIS.

Receiver has loss of signal.

Receiver is getting AIS.

Receiver has loss of frame.

Receiver has remote alarm.

Receiver has no alarms.

Data in current interval (725 seconds elapsed) Shows the current accumulation period, which rolls into the 24 hour accumulation every 15 minutes. Accumulation period is from 1 to 900 seconds. The oldest 15 minute period falls off the back of the 24-hr accumulation buffer
Line Code Violations Indicates the occurrence of either a Bipolar Violation (BPV) or Excessive Zeroes (EXZ) error event.
Path Code Violations Indicates a frame synchronization bit error in the D4 and E1-noCRC formats, or a CRC error in the ESF and E1-CRC formats.
Slip Secs Indicates the replication or deletion of the payload bits of a DS1 frame. A slip may be performed when there is a difference between the timing of a synchronous receiving terminal and the received signal.
Fr Loss Secs Indicates the number of seconds an Out Of Frame (OOF) error is detected.
Line Err Secs Line Errored Seconds (LES) is a second in which one or more Line Code Violation errors are detected.
Degraded Mins A Degraded Minute is one in which the estimated error rate exceeds 1E-6 but does not exceed 1E-3.
Errored Secs In ESF and E1-CRC links, an Errored Second is a second in which one of the following are detected: one or more Path Code Violations; one or more Out of Frame defects; one or more Controlled Slip events; a detected AIS defect.

For D4 and E1-noCRC links, the presence of Bipolar Violations also triggers an Errored Second.

Bursty Err Secs A second with fewer than 320 and more than 1 Path Coding Violation error, no Severely Errored Frame defects and no detected incoming AIS defects. Controlled slips are not included in this parameter.
Severely Err Secs For ESF signals, a second with one of the following errors: 320 or more Path Code Violation errors; one or more Out of Frame defects; a detected AIS defect.

For E1-CRC signals, a second with one of the following errors: 832 or more Path Code Violation errors; one or more Out of Frame defects.

For E1-nonCRC signals, a second with 2048 Line Code Violations or more.

For D4 signals, a count of 1-second intervals with Framing Errors, or an Out of Frame defect, or 1544 Line Code Violations.

Unavail Secs A count of the total number of seconds on the interface.

show controllers token

To display information about memory management, error counters, and the CSC-R, CSC-1R, CSC-2R, C2CTR, and CSC-R16 (or CSC-R16M) Token Ring interface cards or Token Ring Interface Processor (TRIP), in the case of the Cisco 7000 series, use the show controllers token privileged EXEC command.

show controllers token
Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Usage Guidelines

Depending on the board being used, the output can vary. This command also displays information that is proprietary to Cisco Systems. Thus, the information that show controllers token displays is of primary use to Cisco technical personnel. Information that is useful to users can be obtained with the show interfaces tokenring command, described later in this chapter.

Sample Display

The following is sample output on the AGS+ from the show controllers token command:

Router# show controllers token TR Unit 0 is board 0 - ring 0 state 3, dev blk: 0x1D2EBC, mailbox: 0x2100010, sca: 0x2010000 current address: 0000.3080.6f40, burned in address: 0000.3080.6f40 current TX ptr: 0xBA8, current RX ptr: 0x800 Last Ring Status: none Stats: soft:0/0, hard:0/0, sig loss:0/0 tx beacon: 0/0, wire fault 0/0, recovery: 0/0 only station: 0/0, remote removal: 0/0 Bridge: local 3330, bnum 1, target 3583 max_hops 7, target idb: 0x0, not local Interface failures: 0 -- Bkgnd Ints: 0 TX shorts 0, TX giants 0 Monitor state: (active) flags 0xC0, state 0x0, test 0x0, code 0x0, reason 0x0 f/w ver: 1.0, chip f/w: '000000.ME31100', [bridge capable] SMT versions: 1.01 kernel, 4.02 fastmac ring mode: F00, internal enables: SRB REM RPS CRS/NetMgr internal functional: 0000011A (0000011A), group: 00000000 (00000000) if_state: 1, ints: 0/0, ghosts: 0/0, bad_states: 0/0 t2m fifo purges: 0/0 t2m fifo current: 0, t2m fifo max: 0/0, proto_errs: 0/0 ring: 3330, bridge num: 1, target: 3583, max hops: 7 Packet counts: receive total: 298/6197, small: 298/6197, large 0/0 runts: 0/0, giants: 0/0 local: 298/6197, bridged: 0/0, promis: 0/0 bad rif: 0/0, multiframe: 0/0 ring num mismatch 0/0, spanning violations 0 transmit total: 1/25, small: 1/25, large 0/0 runts: 0/0, giants: 0/0, errors 0/0 bad fs: 0/0, bad ac: 0 congested: 0/0, not present: 0/0 Unexpected interrupts: 0/0, last unexp. int: 0 Internal controller counts:     line errors: 0/0, internal errors: 0/0     burst errors: 0/0, ari/fci errors: 0/0     abort errors: 0/0, lost frame: 0/0     copy errors: 0/0, rcvr congestion: 0/0     token errors: 0/0, frequency errors: 0/0     dma bus errors: -/-, dma parity errors: -/- Internal controller smt state:     Adapter MAC: 0000.3080.6f40, Physical drop: 00000000     NAUN Address: 0000.a6e0.11a6, NAUN drop: 00000000     Last source: 0000.a6e0.11a6, Last poll: 0000.3080.6f40     Last MVID: 0006, Last attn code: 0006     Txmit priority: 0006, Auth Class: 7FFF     Monitor Error: 0000, Interface Errors: FFFF     Correlator: 0000, Soft Error Timer: 00C8     Local Ring: 0000, Ring Status: 0000     Beacon rcv type: 0000, Beacon txmit type: 0000     Beacon type: 0000, Beacon NAUN: 0000.a6e0.11a6

Table 6-17 describes the fields shown in the following line of sample output:

TR Unit 0 is board 0 - ring 0
Show Controllers Token Field Descriptions--Part 1
Field Description
TR Unit 0 Unit number assigned to the Token Ring interface associated with this output.
is board 0 Board number assigned to the Token Ring controller board associated with this interface.
ring 0 Number of the Token Ring associated with this board.

In the following output line, state 3 indicates the state of the board. The rest of this output line displays memory mapping that is of primary use to Cisco engineers.

state 3, dev blk: 0x1D2EBC, mailbox: 0x2100010, sca: 0x2010000

The following line also appears in show interface token output as the address and burned in address, respectively:

current address: 0000.3080.6f40, burned in address: 0000.3080.6f40

The following line of output displays buffer management pointers that change by board:

current TX ptr: 0xBA8, current RX ptr: 0x800

The following line of output indicates the ring status from the controller chip set. This information is used by LAN Network Manager:

Last Ring Status: none

The following lines of output show Token Ring statistics. See the Token Ring specification for more information.

Stats: soft:0/0, hard:0/0, sig loss:0/0 tx beacon: 0/0, wire fault 0/0, recovery: 0/0 only station: 0/0, remote removal: 0/0

The following line of output indicates that Token Ring communication has been enabled on the interface. If this line of output appears, the message "Source Route Bridge capable" should appear in the show interfaces tokenring display.

Bridge: local 3330, bnum 1, target 3583

Table 6-18 describes the fields shown in this line of sample output:

max_hops 7, target idb: 0x0, not local
Show Controllers Token Field Descriptions--Part 2
Field Description
max_hops 7 Maximum number of bridges.
target idb: 0x0 Destination interface definition.
not local Indicates whether the interface has been defined as a local or remote bridge.

The following line of output is specific to the hardware:

Interface failures: 0 -- Bkgnd Ints: 0

In the following line of output, TX shorts are the number of packets the interface transmits that are discarded because they are smaller than the medium's minimum packet size. TX giants are the number of packets the interface transmits that are discarded because they exceed the medium's maximum packet size.

TX shorts 0, TX giants 0

The following line of output indicates the state of the controller. Possible values include active, failure, inactive, and reset:

Monitor state: (active)

The following line of output displays detailed information relating to the monitor state shown in the previous line of output. This information relates to the firmware on the controller. This information is relevant to Cisco engineers only if the monitor state is something other than active.

flags 0xC0, state 0x0, test 0x0, code 0x0, reason 0x0

Table 6-19 describes the fields in the following line of output:

f/w ver: 1.0 expr 0, chip f/w: '000000.ME31100', [bridge capable]
Show Controllers Token Field Descriptions--Part 3
Field Description
f/w ver: 1.0 Version of the Cisco firmware on the board.
chip f/w: '000000.ME31100' Firmware on the chip set.
[bridge capable] Interface has not been configured for bridging, but that it has that capability.

The following line of output displays the version numbers for the kernel and the accelerator microcode of the Madge firmware on the board; this firmware is the LLC interface to the chip set:

SMT versions: 1.01 kernel, 4.02 fastmac

The following line of output displays LAN Network Manager information that relates to ring status:

ring mode: F00, internal enables: SRB REM RPS CRS/NetMgr

The following line of output corresponds to the functional address and the group address shown in show interfaces tokenring output:

internal functional: 0000011A (0000011A), group: 00000000 (00000000)

The following line of output displays interface board state information that is proprietary to Cisco Systems:

if_state: 1, ints: 0/0, ghosts: 0/0, bad_states: 0/0

The following output lines display information that is proprietary to Cisco Systems. Cisco engineers use this information for debugging purposes.

t2m fifo purges: 0/0 t2m fifo current: 0, t2m fifo max: 0/0, proto_errs: 0/0

Each of the fields in the following line of output maps to a field in the show source bridge display, as follows: ring maps to srn; bridge num maps to bn; target maps to trn; and max hops maps to max:

ring: 3330, bridge num: 1, target: 3583, max hops: 7

In the following lines of output, the number preceding the slash (/) indicates the count since the value was last displayed; the number following the slash (/) indicates count since the system was last booted:

Packet counts: receive total: 298/6197, small: 298/6197, large 0/0

In the following line of output, the number preceding the slash (/) indicates the count since the value was last displayed; the number following the slash (/) indicates count since the system was last booted. The runts and giants values that appear here correspond to the runts and giants values that appear in show interfaces tokenring output.

runts: 0/0, giants: 0/0

The following lines of output are receiver-specific information that Cisco engineers can use for debugging purposes:

local: 298/6197, bridged: 0/0, promis: 0/0 bad rif: 0/0, multiframe: 0/0 ring num mismatch 0/0, spanning violations 0 transmit total: 1/25, small: 1/25, large 0/0 runts: 0/0, giants: 0/0, errors 0/0

The following output lines include very specific statistics that are not relevant in most cases, but exist for historical purposes. In particular, the internal errors, burst errors, ari/fci, abort errors, copy errors, frequency errors, dma bus errors, and dma parity errors fields are not relevant.

Internal controller counts: line errors: 0/0, internal errors: 0/0 burst errors: 0/0, ari/fci errors: 0/0 abort errors: 0/0, lost frame: 0/0 copy errors: 0/0, rcvr congestion: 0/0 token errors: 0/0, frequency errors: 0/0 dma bus errors: -/-, dma parity errors: -/-

The following lines of output are low-level Token Ring interface statistics relating to the state and status of the Token Ring with respect to all other Token Rings on the line:

Internal controller smt state: Adapter MAC: 0000.3080.6f40, Physical drop: 00000000 NAUN Address: 0000.a6e0.11a6, NAUN drop: 00000000 Last source: 0000.a6e0.11a6, Last poll: 0000.3080.6f40 Last MVID: 0006, Last attn code: 0006 Txmit priority: 0006, Auth Class: 7FFF Monitor Error: 0000, Interface Errors: FFFF Correlator: 0000, Soft Error Timer: 00C8 Local Ring: 0000, Ring Status: 0000 Beacon rcv type: 0000, Beacon txmit type: 0000
Sample Display

Sample output for the show controllers token command on the Cisco 7000 follows:

Router> show controllers token Tokenring4/0: state administratively down current address: 0000.3040.8b4a, burned in address: 0000.3040.8b4a Last Ring Status: none Stats: soft: 0/0, hard: 0/0, sig loss: 0/0 tx beacon: 0/0, wire fault 0/0, recovery: 0/0 only station: 0/0, remote removal: 0/0 Monitor state: (active), chip f/w: '000000........', [bridge capable] ring mode: 0" internal functional: 00000000 (00000000), group: 00000000 (00000000) internal addrs: SRB: 0000, ARB: 0000, EXB 0000, MFB: 0000 Rev: 0000, Adapter: 0000, Parms 0000 Microcode counters: MAC giants 0/0, MAC ignored 0/0 Input runts 0/0, giants 0/0, overrun 0/0 Input ignored 0/0, parity 0/0, RFED 0/0 Input REDI 0/0, null rcp 0/0, recovered rcp 0/0 Input implicit abort 0/0, explicit abort 0/0 Output underrun 0/0, tx parity 0/0, null tcp 0/0 Output SFED 0/0, SEDI 0/0, abort 0/0 Output False Token 0/0, PTT Expired 0/0 Internal controller counts: line errors: 0/0, internal errors: 0/0 burst errors: 0/0, ari/fci errors: 0/0 abort errors: 0/0, lost frame: 0/0 copy errors: 0/0, rcvr congestion: 0/0 token errors: 0/0, frequency errors: 0/0 Internal controller smt state: Adapter MAC: 0000.0000.0000, Physical drop: 00000000 NAUN Address: 0000.0000.0000, NAUN drop: 00000000 Last source: 0000.0000.0000, Last poll: 0000.0000.0000 Last MVID: 0000, Last attn code: 0000 Txmit priority: 0000, Auth Class: 0000 Monitor Error: 0000, Interface Errors: 0000 Correlator: 0000, Soft Error Timer: 0000 Local Ring: 0000, Ring Status: 0000 Beacon rcv type: 0000, Beacon txmit type: 0000 Beacon type: 0000, Beacon NAUN: 0000.0000.0000 Beacon drop: 00000000, Reserved: 0000 Reserved2: 0000

Table 6-20 describes key show controllers token display fields.


Show Controllers Token Field Descriptions
Field Description
Tokenring4/0 Interface processor type, slot, and port.
Last Ring Status Last abnormal ring condition. Can be any of the following:

Signal Loss

HW Removal

Remote Removal

Counter Overflow

Only station

Ring Recovery

show hub

To display information about the hub on an Ethernet interface of a Cisco 2505 or Cisco 2507, use the show hub EXEC command.

show hub [ether number [port [port]]]
Syntax Description
ether (Optional) Indicates that this is an Ethernet hub.
number (Optional) Hub number, starting with 0. Since there is currently only one hub, this number is 0.
port (Optional) Port number on the hub. On the Cisco 2505, port numbers range from 1 through 8. On the Cisco 2507, port numbers range from 1 through 16. If a second port number follows, then this port number indicates the beginning of a port range.
port (Optional) Ending port number of a range.
Command Mode

EXEC

Usage Guidelines

If you do not specify a port or port range for the show hub command, the command displays all ports (for example, ports 1 through 16 on a Cisco 2507) by default. Therefore, the commands show hub, show hub ether 0, and show hub ether 0 1 16 all produce the same result.

If no ports are specified, the command displays some additional data about the internal port. The internal port is the hub's connection to Ethernet interface 0 inside the box. Ethernet interface 0 still exists; physical access to the interface is via the hub.

Sample Display

The following is sample output from the show hub command for hub 0, port 2 only:

Router# show hub ether 0 2 Port 2 of 16 is administratively down, link state is down 0 packets input, 0 bytes 0 errors with 0 collisions (0 FCS, 0 alignment, 0 too long, 0 short, 0 runts, 0 late, 0 very long, 0 rate mismatches) 0 auto partitions, last source address (none) Last clearing of "show hub" counters never Repeater information (Connected to Ethernet0) 2792429 bytes seen with 18 collisions, 1 hub resets Version/device ID 0/1 (0/1) Last clearing of "show hub" counters never

The following is sample output from the show hub command for hub 0, all ports:

Port 1 of 16 is administratively down, link state is up 2458 packets input, 181443 bytes 3 errors with 18 collisions (0 FCS, 0 alignment, 0 too long, 0 short, 3 runts, 0 late, 0 very long, 0 rate mismatches) 0 auto partitions, last source address was 0000.0cff.e257 Last clearing of "show hub" counters never . . . Port 16 of 16 is down, link state is down 0 packets input, 0 bytes 0 errors with 0 collisions (0 FCS, 0 alignment, 0 too long, 0 short, 0 runts, 0 late, 0 very long, 0 rate mismatches) 0 auto partitions, last source address (none) Last clearing of "show hub" counters never Repeater information (Connected to Ethernet0) 2792429 bytes seen with 18 collisions, 1 hub resets Version/device ID 0/1 (0/1) Last clearing of "show hub" counters never Internal Port (Connected to Ethernet0) 36792 packets input, 4349525 bytes 0 errors with 14 collisions (0 FCS, 0 alignment, 0 too long, 0 short, 0 runts, 0 late, 0 very long, 0 rate mismatches) 0 auto partitions, last source address (none) Last clearing of "show hub" counters never

Table 6-21 describes significant fields show in the display.


Show Hub Field Descriptions
Field Description
Port ... of ... is administratively down Port number out of total ports; indicates whether the interface hardware is currently active, or down due to one of the following:

  • The link state test failed.

  • The MAC address mismatched when source address configured.

  • It has been taken down by an administrator.

link state is up

Indicates whether port has been disabled by the link test function. If the link test function is disabled by the user, nothing will be shown here.
packets input Total number of error-free packets received by the system.
bytes Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
errors Sum of FCS, alignment, too long, short, runts, very long, and rate mismatches.
collisions Number of messages retransmitted due to Ethernet collisions.
FCS Counter for the number of frames detected on the port with an invalid frame check sequence.
alignment Counter for the number of frames of valid length (64 bytes to 1518 bytes) that have been detected on the port with an FCS error and a framing error.
too long Counter for the number of frames that exceed the maximum valid packet length of 1518 bytes.
short Counter for the number of instances when activity is detected with duration less than 74-82 bit times.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size. For example, any Ethernet packet that is less than 64 bytes is considered a runt.
late Counter for the number of instances when a collision is detected after 480-565 bit times in the frame.
very long Counter for the number of times the transmitter is active in excess of 4ms to 7.5 ms.
rate mismatches Counter for the number of occurrences when the frequency, or data rate of incoming signal is detectably different from the local transmit frequency.
auto partitions Counter for the number of instances where the repeater has partitioned the port from the network.
last source address Source address of last packet received by this port. Indicates "none" if no packets have been received since power on or a hub reset.
Last clearing of "show hub" counters Elapsed time since clear hub counter command. Indicates "never" if counters have never been cleared.
Repeater information (Connected to Ethernet0) Indicates that the following information is about the hub connected to the Ethernet interface shown.
... bytes seen with ... collisions, ... hub resets Hub resets is the number of times the hub has been reset by network management software or by the clear hub command.
Version/device ID 0/1 (0/1) Hub hardware version. IMR+ version device of motherboard (daughter board)
Internal Port (Connected to Ethernet0) Set of counters for the internal AUI port connected to the Ethernet interface.
Related Command

hub

show interfaces

Use the show interfaces EXEC command to display statistics for all interfaces configured on the router. The resulting output varies, depending on the network for which an interface has been configured.

show interfaces [type {unit}] [first] [last] [accounting]
show interfaces [type slot/port] [accounting] (for the Cisco 7000 series)
Syntax Description
type unit (Optional) Specify that information for a particular interface controller be displayed. Allowed values for type include async, bri0, ethernet, fddi, hssi, loopback, null, serial, tokenring, and tunnel.

For the Cisco 7000 series, type can be atm, ethernet, fddi, serial, or tokenring.

The argument unit must match a port number on the selected interface controller.

first last (Optional) The Cisco 2500 and 3000 support the ISDN Basic Rate Interface (BRI). The argument first can be either 1 or 2. The argument last can only be 2, indicating B channels 1 and 2. D-channel information is obtained by using the command without the optional arguments.
accounting (Optional) Displays the number of packets of each protocol type that has been sent through the interface. You can show these numbers for all interfaces, or you can specify a specific type and unit.
slot Specifies the backplane slot number and can be 0, 1, 2, 3, or 4.
port Specifies the port number of the interface and can be 0, 1, 2, 3, 4, or 5 depending on the type of interface, as follows:

  • AIP (ATM Interface Processor) 0

  • EIP (Ethernet Interface Processor) 0, 1, 2, 3, 4, or 5

  • FIP (FDDI Interface Processor) 0

  • FSIP (Fast Serial Interface Processor) 0, 1, 2, 3, 4, 5, 6, or 7

  • HIP (HSSI Interface Processor) 0

  • TRIP (Token Ring Interface Processor) 0, 1, 2, or 3

Command Mode

EXEC

Usage Guidelines

The show interfaces command displays statistics for the network interfaces. The resulting display on the Cisco 7000 series will show the interface processors in slot order. If you add interface processors after booting the system, they will appear at the end of the list, in the order in which they were inserted.

If you use the show interfaces command on the Cisco 7000 series without the slot/port arguments, information for all interface types will be shown. For example, if you type show interfaces ethernet you will receive information for all ethernet, serial, Token Ring, and FDDI interfaces. Only by adding the type slot/port argument can you specify a particular interface.

If you enter a show interfaces command for an interface type that has been removed from the router, interface statistics will be displayed accompanied by the following text: "Hardware has been removed."

You will use the show interfaces command frequently while configuring and monitoring routers. The various forms of the show interfaces commands are described in detail in the sections immediately following this command.

Sample Display

The following is sample output from the show interfaces command. Because your display will depend on the type and number of interface cards in your router, only a portion of the display is shown.

Router# show interfaces Ethernet 0 is up, line protocol is up Hardware is MCI Ethernet, address is 0000.0c00.750c (bia 0000.0c00.750c) Internet address is 131.108.28.8, subnet mask is 255.255.255.0 MTU 1500 bytes, BW 10000 Kbit, DLY 100000 usec, rely 255/255, load 1/255 Encapsulation ARPA, loopback not set, keepalive set (10 sec) ARP type: ARPA, ARP Timeout 4:00:00 Last input 0:00:00, output 0:00:00, output hang never Last clearing of "show interface" counters 0:00:00 Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 2000 bits/sec, 4 packets/sec 1127576 packets input, 447251251 bytes, 0 no buffer Received 354125 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 5332142 packets output, 496316039 bytes, 0 underruns 0 output errors, 432 collisions, 0 interface resets, 0 restarts ---More---
Sample Display with Accounting Option

To display the number of packets of each protocol type that have been sent through all configured interfaces, use the show interfaces accounting EXEC command. When you use the accounting option, only the accounting statistics are displayed.


Note Except for protocols that are encapsulated inside other protocols, such as IP over X.25, the accounting option also shows the total of all bytes sent and received, including the MAC header. For example, it totals the size of the Ethernet packet or the size of a packet that includes HDLC encapsulation.

Table 6-22 lists the protocols for which per-packet accounting information is kept.


Per-Packet Counted Protocols
Protocol Notes
Apollo no note
AppleTalk no note
ARP For IP, Apollo, Frame Relay, SMDS.
CLNS no note
DEC MOP The routers use MOP packets to advertise their existence to DEC machines that use the MOP protocol. A router periodically broadcasts MOP packets to identify itself as a MOP host. This results in MOP packets being counted, even when DECnet is not being actively used.
DECnet no note
HP Probe no note
IP no note
LAN Manager LAN Network Manager and IBM Network Manager.
Novell no note
Serial Tunnel SDLC.
Spanning Tree no note
SR Bridge no note
Transparent Bridge no note
VINES no note
XNS no note
Sample Display

The following is sample output from the show interfaces accounting command:

Router# show interfaces accounting Interface TokenRing0 is disabled Ethernet0 Protocol Pkts In Chars In Pkts Out Chars Out IP 873171 735923409 34624 9644258 Novell 163849 12361626 57143 4272468 DEC MOP 0 0 1 77 ARP 69618 4177080 1529 91740 Interface Serial0 is disabled Ethernet1 Protocol Pkts In Chars In Pkts Out Chars Out IP 0 0 37 11845 Novell 0 0 4591 275460 DEC MOP 0 0 1 77 ARP 0 0 7 420 Interface Serial1 is disabled Interface Ethernet2 is disabled Interface Serial2 is disabled Interface Ethernet3 is disabled Interface Serial3 is disabled Interface Ethernet4 is disabled Interface Ethernet5 is disabled Interface Ethernet6 is disabled Interface Ethernet7 is disabled Interface Ethernet8 is disabled Interface Ethernet9 is disabled Fddi0 Protocol Pkts In Chars In Pkts Out Chars Out Novell 0 0 183 11163 ARP 1 49 0 0

When the output indicates an interface is "disabled," the router has received excessive errors (over 5000 in a keepalive period).

show interfaces async

Use the show interfaces async privileged EXEC command to display information about the serial interface.

show interfaces async [unit] [accounting]
Syntax Description
unit (Optional) Must be 1.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show interfaces async command:

Router# show interfaces async 1 Async 1 is up, line protocol is up     Hardware is Async Serial Internet address is 1.0.0.1, subnet mask is 255.0.0.0 MTU 1500 bytes, BW 9 Kbit, DLY 100000 usec, rely 255/255, load 56/255 Encapsulation SLIP, keepalive set (0 sec) Last input 0:00:03, output 0:00:03, output hang never Last clearing of "show interface" counters never Output queue 0/3, 2 drops; input queue 0/0, 0 drops Five minute input rate 0 bits/sec, 1 packets/sec Five minute output rate 2000 bits/sec, 1 packets/sec 273 packets input, 13925 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 221 packets output, 41376 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts 0 carrier transitions

Table 6-23 describes the fields shown in the display.


Show Interfaces Async Field Descriptions
Field Description
Async... is {up | down}
...is administratively down
Indicates whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol think the line is usable (that is, whether keepalives are successful).
Hardware is Hardware type.
Internet address is Internet address and subnet mask, followed by packet size.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. The calculation uses the value from the bandwidth interface configuration command.
Encapsulation Encapsulation method assigned to interface.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds
24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing The time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, drops
input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.
packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
input errors Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum may not balance with the other counts.
CRC Cyclic redundancy checksum generated by the originating LAN station or far end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRC's is usually the result of collisions or a station transmitting bad data. On a serial link, CRC's usually indicate noise, gain hits or other transmission problems on the data link.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be incremented.
abort Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment.
packets output Total number of messages transmitted by the system.
bytes Total number of bytes, including data and MAC encapsulation, transmitted by the system.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.
carrier transitions Number of times the carrier detect signal of a serial interface has changed state. Indicates modem or line problems if the carrier detect line is changing state often.
Protocol Protocol that is operating on the interface.
Pkts In Number of packets received for that protocol.
Chars In Number of characters received for that protocol.
Pkts Out Number of packets transmitted for that protocol.
Chars Out Number of characters transmitted for that protocol.
Sample Display with Accounting Option

The following is a sample display from the show interfaces async accounting command:

Router# show interfaces async 0 accounting Async 0    Protocol   Pkts In    Chars In   Pkts Out    Chars Out     IP         7344       4787842    1803        1535774     DEC MOP 0   0        127     9779     ARP    7    420      39       2340

The show line and show slip commands can also be useful in monitoring asynchronous interfaces.

show interfaces atm

Use the show interfaces atm privileged EXEC command to display information about the ATM interface.

show interfaces atm [slot/port]
Syntax Description
slot/port (Optional) Slot on the 7000 can be 0, 1, 2, 3, or 4. On the 7010, slot can be 0, 1, or 2. Port must be 0.
Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show interfaces atm command:

Router# show interfaces atm4/0 ATM4/0 is up, line protocol is up Hardware is cxBus ATM Internet address is 131.108.97.165, subnet mask is 255.255.255.0 MTU 4470 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255 Encapsulation ATM, loopback not set, keepalive set (10 sec) Encapsulation(s): AAL5, PVC mode 256 TX buffers, 256 RX buffers, 1024 Maximum VCs, 1 Current VCs Signalling vc = 1, vpi = 0, vci = 5 ATM NSAP address: BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.13 Last input 0:00:05, output 0:00:05, output hang never Last clearing of "show interface" counters never Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 144 packets input, 3148 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 154 packets output, 4228 bytes, 0 underruns 0 output errors, 0 collisions, 1 interface resets, 0 restarts

Table 6-24 describes the fields shown in the display.


Show Interfaces ATM Field Descriptions
Field Description
ATM... is {up | down}
...is administratively down
Indicates whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol think the line is usable (that is, whether keepalives are successful).
Hardware is Hardware type.
Internet address is Internet address and subnet mask.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. The calculation uses the value from the bandwidth interface configuration command.
Encapsulation Encapsulation method assigned to interface.
Encapsulation(s) AAL5, PVC or SVC mode.
TX buffers Number of buffers configured with the atm txbuff command.
RX buffers Number of buffers configured with the atm rxbuff command.
Maximum VCs Maximum number of virtual circuits.
Current VCs Current number of virtual circuits.
Signaling VC Number of the signaling PVC.
vpi Virtual path identifier number.
vci Virtual channel identifier number.
ATM NSAP address NSAP address of the ATM interface.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds
24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing The time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, drops
input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.
packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffer Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
input errors Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum may not balance with the other counts.
CRC Cyclic redundancy checksum generated by the originating LAN station or far end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRC's is usually the result of collisions or a station transmitting bad data. On a serial link, CRC's usually indicate noise, gain hits or other transmission problems on the data link.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be incremented.
abort Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment.
packets output Total number of messages transmitted by the system.
bytes Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the transmitter has been running faster than the router can handle. This may never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.

show interfaces bri

Use the show interfaces bri privileged EXEC command to display information about the BRI D and B channels.

show interfaces bri [first] [last] [accounting]
Syntax Description
first last (Optional) The argument first can be either 1 or 2. The argument last can only be 2, indicating B channels 1 and 2. D-channel information is obtained by using the command without the optional arguments.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show interfaces command for BRI:

Router# show interfaces bri 0 BRI0 is up, line protocol is up (spoofing)     Hardware is BRI     Internet address is 150.136.190.203, subnet mask is 255.255.255.0    MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255    Encapsulation HDLC, loopback not set, keepalive set (10 sec)    Last input 0:00:07, output 0:00:00, output hang never    Output queue 0/40, 0 drops; input queue 0/75, 0 drops    Five minute input rate 0 bits/sec, 0 packets/sec    Five minute output rate 0 bits/sec, 0 packets/sec        16263 packets input, 1347238 bytes, 0 no buffer        Received 13983 broadcasts, 0 runts, 0 giants        2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort        22146 packets output, 2383680 bytes, 0 underruns        0 output errors, 0 collisions, 2 interface resets, 0 restarts        1 carrier transitions

Table 6-25 describes the fields shown in the display.


Show Interfaces BRI Field Descriptions
Field Description
BRI ... is {up | down}
...is administratively down
Indicates whether the interface hardware is currently active (whether line signal is present) and if it has been taken down by an administrator.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol consider the line usable (that is, whether keepalives are successful).
Hardware is Hardware type.
Internet address is Internet address and subnet mask, followed by packet size.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
loopback Indicates whether loopback is set or not.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Output queue, drops
Input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.
packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
input errors Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors also can increment the count, so this sum may not balance with the other counts.
CRC Cyclic redundancy checksum generated by the originating station or far-end device does not match the checksum calculated from the data received. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. Broadcast storms and bursts of noise can cause the ignored count to be increased.
abort Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment.
packets output Total number of messages transmitted by the system.
bytes Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the transmitter has been running faster than the router can handle. This may never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.
carrier transitions Number of times the carrier detect signal of a serial interface has changed state. Indicates modem or line problems if the carrier detect line is changing state often.
Protocol Protocol that is operating on the interface.
Pkts In Number of packets received for that protocol.
Chars In Number of characters received for that protocol.
Pkts Out Number of packets transmitted for that protocol.
Chars Out Number of characters transmitted for that protocol.

show interfaces ethernet

Use the show interfaces ethernet privileged EXEC command to display information about an Ethernet interface on the router.

show interfaces ethernet unit [accounting]
show interfaces ethernet slot/port [accounting] (for the Cisco 7000 series)
Syntax Description
unit Must match a port number on the selected interface.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
slot On the Cisco 7000 series, optional slot location of the interface processor.
port On the Cisco 7000 series, optional port number on interface.
Command Mode

Privileged EXEC

Usage Guidelines

If you do not provide values for the argument unit (or slot and port on the Cisco 7000 series), the command will display statistics for all network interfaces. The optional keyword accounting displays the number of packets of each protocol type that have been sent through the interface.

Sample Display

The following is sample output from the show interfaces command for the Ethernet 0 interface:

Router# show interfaces ethernet 0 Ethernet 0 is up, line protocol is up     Hardware is MCI Ethernet, address is aa00.0400.0134 (bia 0000.0c00.4369)    Internet address is 131.108.1.1, subnet mask is 255.255.255.0    MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255    Encapsulation ARPA, loopback not set, keepalive set (10 sec)     ARP type: ARPA, PROBE, ARP Timeout 4:00:00    Last input 0:00:00, output 0:00:00, output hang never    Output queue 0/40, 0 drops; input queue 0/75, 2 drops    Five minute input rate 61000 bits/sec, 4 packets/sec    Five minute output rate 1000 bits/sec, 2 packets/sec        2295197 packets input, 305539992 bytes, 0 no buffer        Received 1925500 broadcasts, 0 runts, 0 giants        3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort        0 input packets with dribble condition detected        3594664 packets output, 436549843 bytes, 0 underruns        8 output errors, 1790 collisions, 10 interface resets, 0 restarts

Table 6-26 describes significant fields shown in the display.


Show Interfaces Ethernet Field Descriptions
Field Description
Ethernet ... is up
...is administratively down
Indicates whether the interface hardware is currently active and if it has been taken down by an administrator. "Disabled" indicates the router has received over 5000 errors in a keepalive interval, which is 10 seconds by default.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol believe the interface is usable (that is, whether keepalives are successful) or if it has been taken down by an administrator.
Hardware Hardware type (for example, MCI Ethernet, SCI, cBus Ethernet) and address.
Internet address Internet address followed by subnet mask.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
ARP type: Type of Address Resolution Protocol assigned.
loopback Indicates whether loopback is set or not.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output Number of hours, minutes, and seconds since the last packet was successfully transmitted by the interface. Useful for knowing when a dead interface failed.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds
24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, input queue, drops Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes. If the interface is not in promiscuous mode, it senses network traffic it sends and receives (rather than all network traffic).

The 5-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average will be within two percent of the instantaneous rate of a uniform stream of traffic over that period.

packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
Received ... broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size. For instance, any Ethernet packet that is less than 64 bytes is considered a runt.
giants Number of packets that are discarded because they exceed the medium's maximum packet size. For example, any Ethernet packet that is greater than 1,518 bytes is considered a giant.
input error Includes runts, giants, no buffer, CRC, frame, overrun, and ignored counts. Other input-related errors can also cause the input errors count to be increased, and some datagrams may have more than one error; therefore, this sum may not balance with the sum of enumerated input error counts.
CRC Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a LAN, this is usually the result of collisions or a malfunctioning Ethernet device.
overrun Number of times the receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased.
input packets with dribble condition detected Dribble bit error indicates that a frame is slightly too long. This frame error counter is incremented just for informational purposes; the router accepts the frame.
packets output Total number of messages transmitted by the system.
bytes Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the transmitter has been running faster than the router can handle. This may never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
collisions Number of messages retransmitted due to an Ethernet collision. This is usually the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). A packet that collides is counted only once in output packets.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times a Type 2 Ethernet controller was restarted because of errors.
Sample Display on Cisco 7000

The following sample output illustrates the show interfaces ethernet command on the Cisco 7000:

> show interfaces ethernet 4/2 Ethernet4/2 is up, line protocol is up Hardware is cxBus Ethernet, address is 0000.0c02.d0ce (bia 0000.0c02.d0ce) Internet address is 131.108.7.1, subnet mask is 255.255.255.0 MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255 Encapsulation ARPA, loopback not set, keepalive set (10 sec) ARP type: ARPA, ARP Timeout 4:00:00 Last input 0:00:00, output 0:00:09, output hang never Last clearing of "show interface" counters 0:56:40 Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 3000 bits/sec, 4 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 4961 packets input, 715381 bytes, 0 no buffer Received 2014 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 567 packets output, 224914 bytes, 0 underruns 0 output errors, 168 collisions, 0 interface resets, 0 restarts
Sample Display with Accounting Option

The following is sample output from the show interfaces ethernet command with the accounting option on the Cisco 7000:

Router# show interfaces ethernet 4/2 accounting Ethernet4/2 Protocol Pkts In Chars In Pkts Out Chars Out IP 7344 4787842 1803 1535774 Appletalk 33345 4797459 12781 1089695 DEC MOP 0 0 127 9779 ARP 7 420 39 2340

show interfaces fddi

Use the show interfaces fddi EXEC command to display information about the FDDI interface.

show interfaces fddi unit [accounting]
show interfaces fddi slot/port [accounting] (for the Cisco 7000 series)
Syntax Description
unit Must match a port number on the selected interface.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
slot On the Cisco 7000 series, optional slot location of the interface processor.
port On the Cisco 7000 series, optional port number on interface.
Command Mode

EXEC

Sample Display

The following is a sample partial display of FDDI-specific data from the show interfaces fddi command on a Cisco 7000:

Router> show interfaces fddi 3/0 Fddi3/0 is up, line protocol is up Hardware is cxBus Fddi, address is 0000.0c02.adf1 (bia 0000.0c02.adf1) Internet address is 131.108.33.14, subnet mask is 255.255.255.0 MTU 4470 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255 Encapsulation SNAP, loopback not set, keepalive not set ARP type: SNAP, ARP Timeout 4:00:00 Phy-A state is active, neighbor is B, cmt signal bits 008/20C, status ILS Phy-B state is active, neighbor is A, cmt signal bits 20C/008, status ILS CFM is thru A, token rotation 5000 usec, ring operational 21:32:34 Upstream neighbor 0000.0c02.ba83, downstream neighbor 0000.0c02.ba83 Last input 0:00:05, output 0:00:00, output hang never Last clearing of "show interface" counters 0:59:10 Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 69000 bits/sec, 44 packets/sec Five minute output rate 0 bits/sec, 1 packets/sec 113157 packets input, 21622582 bytes, 0 no buffer Received 276 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 4740 packets output, 487346 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts 0 transitions, 2 traces, 3 claims, 2 beacons

The following is an example that includes the accounting option. When you use the accounting option, only the accounting statistics are displayed.

> show interfaces fddi 3/0 accounting Fddi3/0 Protocol Pkts In Chars In Pkts Out Chars Out IP 7344 4787842 1803 1535774 Appletalk 33345 4797459 12781 1089695 DEC MOP 0 0 127 9779 ARP 7 420 39 2340

Table 6-27 describes the show interfaces fddi display fields.


Show Interfaces FDDI Field Descriptions

Field

Description
Fddi is {up |down}
...is administratively down
Gives the interface processor unit number and tells whether the interface hardware is currently active and can transmit and receive or if it has been taken down by an administrator. "Disabled" indicates the router has received over 5000 errors in a keepalive interval, which is 10 seconds by default.
line protocol
is {up | down |
administratively down}
Indicates whether the interface hardware is currently active and can transmit and receive or if it has been taken down by an administrator.
Hardware Provides the hardware type, followed by the hardware address.
Internet address Internet address, followed by subnet mask.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
loopback Indicates whether or not loopback is set.
keepalive Indicates whether or not keepalives are set.
ARP type: Type of Address Resolution Protocol assigned.
Phy-{A | B} Lists the state the Physical A or Physical B connection is in; one of: off, active, trace, connect, next, signal, join, verify, or break.
neighbor State of the neighbor:

· A--Indicates that the CMT process has established a connection with its neighbor. The bits received during the CMT signaling process indicate that the neighbor is a Physical A type dual-attachment station or concentrator that attaches to the primary ring IN and the secondary ring OUT when attaching to the dual ring.

· S--Indicates that the CMT process has established a connection with its neighbor and that the bits received during the CMT signaling process indicate that the neighbor is one Physical type in a single-attached station (SAS).

· B--Indicates that the CMT process has established a connection with its neighbor and that the bits received during the CMT signaling process indicate that the neighbor is a Physical B dual-attached station or concentrator that attaches to the secondary ring IN and the primary ring OUT when attaching to the dual ring.

· M--Indicates that the CMT process has established a connection with its neighbor and that the bits received during the CMT signaling process indicate that the router's neighbor is a Physical M-type concentrator that serves as a Master to a connected station or concentrator.

· unk--Indicates that the network server has not completed the CMT process, and as a result, does not know about its neighbor. See the section "Setting Bit Control" for an explanation of the bit patterns.

cmt signal bits Shows the transmitted/received CMT bits. The transmitted bits are 0x008 for a Physical A type and 0x20C for Physical B type. The number after the slash (/) is the received signal bits. If the connection is not active, the received bits are zero (0); see the line beginning Phy-B earlier in this display.
status Status value displayed is the actual status on the fiber. The FDDI standard defines the following values:

· LSU--Line State Unknown, the criteria for entering or remaining in any other line state have not been met.

· NLS--Noise Line State is entered upon the occurrence of 16 potential noise events without satisfying the criteria for entry into another line state.

· MLS--Master Line State is entered upon the reception of eight or nine consecutive HQ or QH symbol pairs.

· ILS--Idle Line State is entered upon receipt of four or five idle symbols.

· HLS--Halt Line State is entered upon the receipt of 16 or 17 consecutive H symbols.

· QLS--Quiet Line State is entered upon the receipt of 16 or 17 consecutive Q symbols or when carrier detect goes low.

· ALS--Active Line State is entered upon receipt of a JK symbol pair when carrier detect is high.

· OVUF--Elasticity buffer Overflow/Underflow. The normal states for a connected Physical type are ILS or ALS. If the report displays the QLS status, this indicates that the fiber is disconnected from Physical B, or that it is not connected to another Physical type, or that the other station is not running.

Off Indicates that the CMT is not running on the Physical Sublayer. The state will be off if the interface has been shutdown or if the cmt disconnect command has been issued for Physical A or Physical B.
Brk Break State is the entry point in the start of a PCM connection.
Tra Trace State localizes a stuck beacon condition.
Con Connect State is used to synchronize the ends of the connection for the signaling sequence.
Nxt Next State separates the signaling performed in the Signal State and transmits Protocol Data Units (PDUs) while MAC Local Loop is performed.
Sig Signal State is entered from the Next State when a bit is ready to be transmitted.
Join Join State is the first of three states in a unique sequence of transmitted symbol streams received as line states--the Halt Line State, Master Line State, and Idle Line State, or HLS-MLS-ILS--that leads to an active connection.
Vfy Verify State is the second state in the path to the Active State and will not be reached by a connection that is not synchronized.
Act Active State indicates that the CMT process has established communications with its physical neighbor.
The transition states are defined in the X3T9.5 specification. You are referred to the specification for details about these states.
CFM is ... Contains information about the current state of the MAC connection. The Configuration Management (CFM) state can be one of the following:
· Isolated--The MAC is not attached to any Physical type.
· Wrap A--The MAC is attached to Physical A. Data is received on    Physical A and transmitted on Physical A.
· Wrap B--The MAC is attached to Physical B. Data is received on    Physical B and transmitted on Physical B.
· Thru A--The MAC is attached to Physical A and B. Data is    received on Physical A and transmitted on  Physical B. This is the    normal mode for a dual attachment station (DAS) with one MAC.    The ring has been operational for 1 minute and 42 seconds.
token rotation Token rotation value is the default or configured rotation value as determined by the fddi token rotation-time command. This value is used by all stations on the ring. The default is 5000 microseconds.
ring operational When the ring is operational, the displayed value will be the negotiated token rotation time of all stations on the ring. Operational times are displayed by the number of hours:minutes:seconds the ring has been up. If the ring is not operational, the message "ring not operational" is displayed.
Upstream | downstream neighbor Displays the canonical MAC address of outgoing upstream and downstream neighbors. If the interface is not up, these values will be zero (0).
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, Input Queue, drops Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five-minute input rate
Five-minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.

The five-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average will be within two percent of the instantaneous rate of a uniform stream of traffic over that period.

packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
CRC Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data.
frame Number of packets received incorrectly that have a CRC error and a noninteger number of octets. On a LAN, this is usually the result of collisions or a malfunctioning Ethernet device. On an FDDI LAN, this also may be the result of a failing fiber (cracks) or a hardware malfunction.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased.
packets output Total number of messages transmitted by the system.
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of transmit aborts (when the router cannot feed the transmitter fast enough).
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, because some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
collisions Because an FDDI ring cannot have collisions, this statistic is always zero.
interface resets Number of times an interface has been reset. The interface may be reset by the administrator or automatically when an internal error occurs.
restarts Should always be zero for FDDI interfaces.
transitions The number of times the ring made a transition from ring operational to ring nonoperational, or vice versa. A large number of transitions indicates a problem with the ring or the interface.
traces Trace count applies to both the FCI, FCIT, and FIP. Indicates the number of times this interface started a trace.
claims Pertains to FCIT and FIP only. Indicates the number of times this interface has been in claim state.
beacons Pertains to FCIT and FIP only. Indicates the number of times the interface has been in beacon state.
Protocol Protocol that is operating on the interface.
Pkts In Number of packets received for that protocol.
Chars In Number of characters received for that protocol.
Pkts Out Number of packets transmitted for that protocol.
Chars Out Number of characters transmitted for that protocol.

show interfaces hssi

Use the show interfaces hssi privileged EXEC command to display information about the HSSI interface.

show interfaces hssi unit [accounting]
show interfaces hssi slot/port [accounting] (for the Cisco 7000 series)
Syntax Description
unit Must match a port number on the selected interface.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
slot On the Cisco 7000 series, optional slot location of the interface processor.
port On the Cisco 7000 series, optional port number on interface.
Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show interfaces hssi command when HSSI is enabled:

Router# show interfaces hssi 0 HSSI 0 is up, line protocol is up Hardware is cBus HSSI Internet address is 150.136.67.190, subnet mask is 255.255.255.0 MTU 4470 bytes, BW 45045 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation HDLC, loopback not set, keepalive set (10 sec) Last input 0:00:03, output 0:00:00, output hang never Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec      0 packets input, 0 bytes, 0 no buffer      Received 0 broadcasts, 0 runts, 0 giants 0 parity, 0 rx disabled 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 17 packets output, 994 bytes, 0 underruns 0 output errors, 0 applique, 4 interface resets, 0 restarts 2 carrier transitions

Table 6-28 describes significant fields shown in the display.


Show Interfaces HSSI Field Descriptions
Field Description
HSSI is {up | down}
...is administratively down
Indicates whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator. "Disabled" indicates the router has received over 5000 errors in a keepalive interval, which is 10 seconds by default.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol considers the line usable (that is, whether keepalives are successful).
Hardware Specifies the hardware type.
Internet address Lists the Internet address followed by subnet mask.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
loopback Indicates whether loopback is set and type of loopback test.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, drops
Input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.
packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
parity Report of the parity errors on the HSSI.
rx disabled Indicates the HSSI could not find a free buffer on the ciscoBus controller to reserve for use for the HSSI receiver. When this happens, the HSSI shuts down its receiver and waits until a buffer is available. Data is not lost unless a packet comes in and overflows the HSSI FIFO. Usually, the receive disables are frequent but do not last for long, and the number of dropped packets is less than the count in the "rx disabled" field. A receive disabled condition can happen in systems that are under heavy traffic load and that have shorter packets. In this situation, the number of buffers available on the ciscoBus controller is at a premium. One way to alleviate this problem is to reduce the mtu on the HSSI interface from 4500 (FDDI size) to 1500 (Ethernet size). Doing so allows the software to take the fixed memory of the ciscoBus controller and divide it into a larger number of smaller buffers, rather than a small number of large buffers. Receive disables are not errors, so they are not included in any error counts.
input errors Sum of all errors that prevented the receipt of datagrams on the interface being examined. This may not balance with the sum of the enumerated output errors, because some datagrams may have more than one error and others may have errors that do not fall into any of the specifically tabulated categories.
CRC Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link. CRC errors are also reported when a far-end abort occurs, and when the idle flag pattern is corrupted. This makes it possible to get CRC errors even when there is no data traffic.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased.
abort Number of packets whose receipt was aborted.
packets output Total number of messages transmitted by the system.
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. This may never happen (be reported) on some interfaces.
congestion drop Number of messages discarded because the output queue on an interface grew too long. This can happen on a slow, congested serial link.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
applique Indicates an unrecoverable error has occurred on the HSA applique. The system then invokes an interface reset.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.
carrier transitions Number of times the carrier detect signal of a serial interface has changed state. Indicates modem or line problems if the carrier detect line is changing state often.
Protocol Protocol that is operating on the interface.
Pkts In Number of packets received for that protocol.
Chars In Number of characters received for that protocol.
Pkts Out Number of packets transmitted for that protocol.
Chars Out Number of characters transmitted for that protocol.

The following is an example of the show interfaces hssi command on a Cisco 7000:

Router# show in hssi 1/0 Hssi1/0 is up, line protocol is up Hardware is cxBus HSSI Internet address is 131.108.38.14, subnet mask is 255.255.255.0 MTU 1500 bytes, BW 45045 Kbit, DLY 1000000 usec, rely 255/255, load 1/255 Encapsulation HDLC, loopback not set, keepalive set (10 sec) Last input 0:00:00, output 0:00:08, output hang never Last clearing of "show interface" counters never Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 1000 bits/sec, 2 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 630573548 packets input, 2077237628 bytes, 0 no buffer Received 2832063 broadcasts, 0 runts, 0 giants 0 parity, 1970 rx disabled 113 input errors, 20 CRC, 93 frame, 0 overrun, 0 ignored, 0 abort 629721628 packets output, 1934313295 bytes, 0 underruns 0 output errors, 0 applique, 62 interface resets, 0 restarts 309 carrier transitions

The following is an example of the show interfaces hssi command with the accounting option on a Cisco 7000:

Router# show interfaces hssi 1/0 accounting HIP1/0 Protocol Pkts In Chars In Pkts Out Chars Out IP 7344 4787842 1803 1535774 Appletalk 33345 4797459 12781 1089695 DEC MOP 0 0 127 9779 ARP 7 420 39 2340

show interfaces loopback

Use the show interfaces loopback privileged EXEC command to display information about the dialer interface.

show interfaces loopback [unit] [accounting]
Syntax Description
unit (Optional) Must match a port number on the selected interface.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
Command Mode

Privileged EXEC

Sample Displays

The following is sample output from the show interfaces loopback command:

Router# show int loop 0 Loopback0 is up, line protocol is up Hardware is Loopback MTU 1500 bytes, BW 1 Kbit, DLY 50 usec, rely 255/255, load 1/255 Encapsulation UNKNOWN, loopback not set, keepalive set (10 sec) Last input never, output never, output hang never Last clearing of "show interface" counters never Output queue 0/0, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec

                          0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort      0 packets output, 0 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts

The following is sample output when the accounting keyword is included:

Router# show int loop 0 acc Loopback0 Protocol Pkts In Chars In Pkts Out Chars Out No traffic sent or received on this interface. Router#

Table 6-29 describes significant fields shown in the displays.


Show Interfaces Loopback Descriptions
Field Description
Loopback is {up | down}
...is administratively down
Indicates whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator. "Disabled" indicates the router has received over 5000 errors in a keepalive interval, which is 10 seconds by default.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol considers the line usable (that is, whether keepalives are successful).
Hardware Hardware is Loopback.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
loopback Indicates whether loopback is set and type of loopback test.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, drops
Input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.
packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffer Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
input errors Sum of all errors that prevented the receipt of datagrams on the interface being examined. This may not balance with the sum of the enumerated output errors, because some datagrams may have more than one error and others may have errors that do not fall into any of the specifically tabulated categories.
CRC Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link. CRC errors are also reported when a far-end abort occurs, and when the idle flag pattern is corrupted. This makes it possible to get CRC errors even when there is no data traffic.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased.
abort Number of packets whose receipt was aborted.
packets output Total number of messages transmitted by the system.
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. This may never happen (be reported) on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
collisions A loopback interface does not have collisions.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.
Protocol Protocol that is operating on the interface.
Pkts In Number of packets received for that protocol.
Chars In Number of characters received for that protocol.
Pkts Out Number of packets transmitted for that protocol.
Chars Out Number of characters transmitted for that protocol.

show interfaces pcbus

Use the show interfaces pcbus privileged EXEC command to display information about an ISA bus interface. This command is valid on LanOptics' Branchcard or Stacknet 2000 products only.

show interfaces pcbus number [accounting | stats]
Syntax Description
number Number of the interface port.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
stats (Optional) Displays packets sent and received.
Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show pcbus command:

Router# show interfaces pcbus 0 PCbus0 is up, line protocol is up Hardware is ISA PCbus shared RAM Internet address is 198.135.1.43, subnet mask is 255.255.255.0 MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation HDLC, loopback not set, keepalive set (10 sec) Last input 0:00:00, output never, output hang never Last clearing of "show interface" counters never Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 135 packets input, 2918 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 135 packets output, 3776 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts 0 carrier transitions

show interfaces serial

Use the show interfaces serial privileged EXEC command to display information about a serial interface.

show interfaces serial unit [accounting]
show interfaces serial slot/port [accounting] (for the Cisco 7000 series)
Syntax Description
unit Must match the interface port number.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
slot On the Cisco 7000 series, optional slot location of the interface processor.
port On the Cisco 7000 series, optional port number on interface.
Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show interfaces command for a synchronous serial interface:

Router# show interfaces serial Serial 0 is up, line protocol is up     Hardware is MCI Serial    Internet address is 150.136.190.203, subnet mask is 255.255.255.0    MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255    Encapsulation HDLC, loopback not set, keepalive set (10 sec)    Last input 0:00:07, output 0:00:00, output hang never    Output queue 0/40, 0 drops; input queue 0/75, 0 drops    Five minute input rate 0 bits/sec, 0 packets/sec    Five minute output rate 0 bits/sec, 0 packets/sec        16263 packets input, 1347238 bytes, 0 no buffer        Received 13983 broadcasts, 0 runts, 0 giants        2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort 1 carrier transitions 22146 packets output, 2383680 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets, 0 restarts

Table 6-30 describes significant fields shown in the display.


Show Interfaces Serial Field Descriptions
Field Description
Serial ... is {up | down}
...is administratively down
Indicates whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator. "Disabled" indicates the router has received over 5000 errors in a keepalive interval, which is 10 seconds by default.
line protocol
is {up | down}
Indicates whether the software processes that handle the line protocol consider the line usable (that is, whether keepalives are successful) or if it has been taken down by an administrator.
Hardware is Specifies the hardware type.
Internet address is Specifies the Internet address and subnet mask.
MTU Maximum Transmission Unit of the interface.
BW 1544 Kbit Indicates the value of the bandwidth parameter that has been configured for the interface (in kilobits per second). The bandwidth parameter is used to compute IGRP metrics only. If the interface is attached to a serial line with a line speed that does not match the default (1536 or 1544 for T1 and 56 for a standard synchronous serial line), use the bandwidth command to specify the correct line speed for this serial line.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
loopback Indicates whether loopback is set or not.
keepalive Indicates whether keepalives are set or not.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Output queue, drops

input queue, drops

Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.

The 5-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average will be within two percent of the instantaneous rate of a uniform stream of traffic over that period.

packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
Received ... broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
input error Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum may not balance with the other counts.
CRC Cyclic redundancy checksum generated by the originating station or far-end device does not match the checksum calculated from the data received. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. Broadcast storms and bursts of noise can cause the ignored count to be increased.
abort Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment.
packets output Total number of messages transmitted by the system.
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the transmitter has been running faster than the router can handle. This may never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
collisions Number of messages retransmitted due to an Ethernet collision. This usually is the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). Some collisions are normal. However, if your collision rate climbs to around 4 or 5%, you should consider verifying that there is no faulty equipment on the segment and/or moving some existing stations to a new segment. A packet that collides is counted only once in output packets.
interface resets Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds' time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.
carrier transitions Number of times the carrier detect signal of a serial interface has changed state. For example, if data carrier detect (DCD) goes down and comes up, the carrier transition counter will increment two times. Indicates modem or line problems if the carrier detect line is changing state often.

The following is sample output of the show interfaces serial command for the HDLC synchronous serial interface on a Cisco 7000:

Router# show interfaces serial 1/0 Serial1/0 is up, line protocol is up Hardware is cxBus Serial Internet address is 150.136.190.203, subnet mask is 255.255.255.0 MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation HDLC, loopback not set, keepalive set (10 sec) Last input 0:00:07, output 0:00:00, output hang never   Last clearing of "show interface" counters 2w4d Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 16263 packets input, 1347238 bytes, 0 no buffer Received 13983 broadcasts, 0 runts, 0 giants 2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort      22146 packets output, 2383680 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets, 0 restarts 1 carrier transitions
Sample Display with Frame Relay Encapsulation

When using the Frame Relay encapsulation, use the show interfaces command to display information on the multicast DLCI, the DLCI of the interface, and the LMI DLCI used for the local management interface.

The multicast DLCI and the local DLCI can be set using the frame-relay multicast-dlci and the frame-relay local-dlci configuration commands, or provided through the local management interface. The status information is taken from the LMI, when active.

The following is sample output from the show interfaces serial command when using Frame Relay encapsulation:

Router# show interfaces serial Serial 2 is up, line protocol is up     Hardware type is MCI Serial     Internet address is 131.108.122.1, subnet mask is 255.255.255.0    MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255    Encapsulation FRAME-RELAY, loopback not set, keepalive set (10 sec)    multicast DLCI 1022, status defined, active    source DLCI 20, status defined, active    LMI DLCI 1023, LMI sent 10, LMI stat recvd 10, LMI upd recvd 2    Last input 7:21:29, output 0:00:37, output hang never    Output queue 0/100, 0 drops; input queue 0/75, 0 drops    Five minute input rate 0 bits/sec, 0 packets/sec    Five minute output rate 0 bits/sec, 0 packets/sec        47 packets input, 2656 bytes, 0 no buffer        Received 5 broadcasts, 0 runts, 0 giants        5 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 57 abort        518 packets output, 391205 bytes         0 output errors, 0 collisions, 0 interface resets, 0 restarts        1 carrier transitions

In this display, the multicast DLCI has been changed to 1022 with the frame-relay multicast-dlci interface configuration command.

The display shows the statistics for the LMI are the number of status inquiry messages sent (LMI sent), the number of status messages received (LMI recvd), and the number of status updates received (upd recvd). See the Frame Relay Interface specification for additional explanations of this output.

Sample Display with ANSI LMI

For a serial interface with the ANSI LMI enabled, use the show interfaces command to determine the LMI type implemented.

The following is a sample display from the show interfaces output for a serial interface with the ANSI LMI enabled:

Router# show interfaces serial Serial 1 is up, line protocol is up     Hardware is MCI Serial    Internet address is 131.108.121.1, subnet mask is 255.255.255.0    MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255    Encapsulation FRAME-RELAY, loopback not set, keepalive set    LMI DLCI 0, LMI sent 10, LMI stat recvd 10    LMI type is ANSI Annex D    Last input 0:00:00, output 0:00:00, output hang never    Output queue 0/40, 0 drops; input queue 0/75, 0 drops    Five minute input rate 0 bits/sec, 1 packets/sec    Five minute output rate 1000 bits/sec, 1 packets/sec        261 packets input, 13212 bytes, 0 no buffer        Received 33 broadcasts, 0 runts, 0 giants        0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort        238 packets output, 14751 bytes, 0 underruns        0 output errors, 0 collisions, 0 interface resets, 0 restarts

Notice that the show interfaces output for a serial interface with ANSI LMI shown in this display is very similar to that for encapsulation set to Frame Relay, as shown in the previous display.
Table 6-31 describes the few differences that exist.


Show Interfaces Serial Field Description with ANSI LMI
Field Description
LMI DLCI 0 Identifies the DLCI used by the LMI for this interface. Default: 1023.
LMI sent 10 Number of LMI packets the router sent.
LMI type is ANSI Annex D Indicates that the interface is configured for the ANSI-adopted Frame Relay specification T1.617 Annex D.
Sample Display with LAPB Encapsulation

Use the show interfaces command to display operation statistics for an interface using LAPB encapsulation.

The following is sample output from the show interfaces command for a serial interface using LAPB encapsulation:

Router# show interfaces LAPB state is DISCONNECT, T1 3000, N1 12000, N2 20, K7, TH 3000 Window is closed IFRAMEs 12/28 RNRs 0/1 REJs 13/1 SABMs 1/13 FRMRs 3/0 DISCs 0/11

Table 6-32 shows the fields relevant to all LAPB connections.


Show Interfaces Serial Fields and Descriptions when LAPB is Enabled
Parameter Description
LAPB state is DISCONNECT State of the LAPB protocol.
T1 3000, N1 12000, ... Current parameter settings.
Window is closed Indicates that no more frames can be transmitted until some outstanding frames have been acknowledged.
IFRAMEs 12/28 RNRs 0/1 ... Count of the different types of frames in the form of
sent/received.
Show Interfaces Serial with PPP

An interface configured for synchronous PPP encapsulation differs from the standard show interface serial output. An interface configured for PPP might include the following information.

lcp state = OPEN ncp ipcp state = OPEN ncp osicp state = NOT NEGOTIATED ncp ipxcp state = NOT NEGOTIATED ncp xnscp state = NOT NEGOTIATED ncp vinescp state = NOT NEGOTIATED ncp deccp state = NOT NEGOTIATED  ncp bridgecp state = NOT NEGOTIATED ncp atalkcp state = NOT NEGOTIATED

Table 6-33 show the fields relevant to PPP connections.


Show Interfaces Serial Fields and Descriptions with PPP Encapsulation
Field Description
lcp state Link Control Protocol
ncp ipcp state Network Control Protocol Internet Protocol Control Protocol
ncp osicp state Network Control Protocol OSI (CLNS) Control Protocol
ncp ipxcp state Network Control Protocol IPX (Novell) Control Protocol
ncp xnscp state Network Control Protocol XNS Control Protocol
ncp vinescp state Network Control Protocol VINES Control Protocol
ncp deccp state Network Control Protocol DECnet Control Protocol
ncp bridgecp state Network Control Protocol Bridging Control Protocol
ncp atalkcp state Network Control Protocol AppleTalk Control Protocol
Sample Display with SDLC Connections

Use the show interfaces command to display the SDLC information for a given SDLC interface. The following is sample output from the show interfaces command for an SDLC primary interface supporting the SDLLC function.

Router# show interfaces Serial 0 is up, line protocol is up Hardware is MCI Serial MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255 Encapsulation SDLC-PRIMARY, loopback not set      Timers (msec): poll pause 100 fair poll 500. Poll limit 1      [T1 3000, N1 12016, N2 20, K 7] timer: 56608 Last polled device: none      SDLLC [ma: 0000.0C01.14--, ring: 7 bridge: 1, target ring: 10 largest token ring frame 2052] SDLC addr C1 state is CONNECT       VS 6, VR 3, RCNT 0, Remote VR 6, Current retransmit count 0       Hold queue: 0/12 IFRAMEs 77/22 RNRs 0/0 SNRMs 1/0 DISCs 0/0       Poll: clear, Poll count: 0, chain: p: C1 n: C1       SDLLC [largest SDLC frame: 265, XID: disabled]   Last input 00:00:02, output 00:00:01, output hang never   Output queue 0/40, 0 drops; input queue 0/75, 0 drops  Five minute input rate 517 bits/sec, 30 packets/sec  Five minute output rate 672 bits/sec, 20 packets/sec       357 packets input, 28382 bytes, 0 no buffer       Received 0 broadcasts, 0 runts, 0 giants       0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort      926 packets output, 77274 bytes, 0 underruns      0 output errors, 0 collisions, 0 interface resets, 0 restarts      2 carrier transitions

Table 6-34 shows the fields relevant to all SDLC connections.


Show Interfaces Serial Fields and Descriptions when SDLC is Enabled
Parameter Description
Timers (msec): poll pause, fair poll, Poll limit Current values of these timers, as described in the configuration section, for this interface.
T1, N1, N2, K Values for these parameters, as described in the configuration section, for this interface.

Table 6-35 shows other data given for each SDLC secondary configured to be attached to this interface.


SDLC Secondary Descriptions
SDLC Secondary Description
addr Address of this secondary.
state is

  DISCONNECT

  CONNECT

  DISCSENT

  SNRMSENT

  THEMBUSY

  USBUSY

  BOTHBUSY

  ERROR

Current state of this connection, which is one of the following:

No communication is being attempted to this secondary.

A normal connect state exists between this router and this secondary.

This router has sent a disconnect request to this secondary and is awaiting its response.

This router has sent a connect request (SNRM) to this secondary and is awaiting its response.

This secondary has told this router that it is temporarily unable to receive any more information frames.

This router has told this secondary that it is temporarily unable to receive any more information frames.

Both sides have told each other that they are temporarily unable to receive any more information frames.

This router has detected an error and is waiting for a response from the secondary acknowledging this.

VS Sequence number of the next information frame this station sends.
VR Sequence number of the next information frame from this secondary that this station expects to receive.
Remote VR Last frame transmitted by this station that has been acknowledged by the other station.
Current retransmit count: Number of times the current I-frame or sequence of I-frames has been retransmitted.
Hold Queue Number of frames in hold queue/Maximum size of hold queue.
IFRAMEs, RNRs, SNRMs, DISCs Sent/received count for these frames.
Poll "Set" if this router has a poll outstanding to the secondary; "clear" if it does not.
Poll Count Number of polls in a row that have been given to this secondary at this time.
Chain Shows the previous (p) and next (n) secondary address on this interface in the round robin loop of polled devices.
Sample Display with SDLLC

Use the show interfaces serial command to display the SDLLC statistics for SDLLC configured interfaces.

The following is sample output from the show interfaces serial command for an a serial interface configured for SDLLC:

Router# show interfaces serial Serial 0 is up, line protocol is up     Hardware is MCI Serial    MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255    Encapsulation SDLC-PRIMARY, loopback not set        Timers (msec): poll pause 100 fair poll 500. Poll limit 1        [T1 3000, N1 12016, N2 20, K 7] timer: 56608 Last polled device: none        SDLLC [ma: 0000.0C01.14--, ring: 7 bridge: 1, target ring: 10 largest token ring frame 2052]    SDLC addr C1 state is CONNECT        VS 6, VR 3, RCNT 0, Remote VR 6, Current retransmit count 0        Hold queue: 0/12 IFRAMEs 77/22 RNRs 0/0 SNRMs 1/0 DISCs 0/0        Poll: clear, Poll count: 0, chain: p: C1 n: C1        SDLLC [largest SDLC frame: 265, XID: disabled]    Last input 00:00:02, output 00:00:01, output hang never    Output queue 0/40, 0 drops; input queue 0/75, 0 drops    Five minute input rate 517 bits/sec, 30 packets/sec    Five minute output rate 672 bits/sec, 20 packets/sec        357 packets input, 28382 bytes, 0 no buffer        Received 0 broadcasts, 0 runts, 0 giants        0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort        926 packets output, 77274 bytes, 0 underruns        0 output errors, 0 collisions, 0 interface resets, 0 restarts        6608 Last polled device: none        SDLLC [ma: 0000.0C01.14--, ring: 7 brid2 carrier transitions

Most of the output shown in the display is generic to all SDLC encapsulated interfaces and is described in the chapter entitled "LLC2 and SDLC Commands." Table 6-36 shows the parameters specific to SDLLC.


SDLLC Parameters
Parameter Description
SDLLC ma Lists the MAC address configured for this interface. The last byte is shown as "--" to indicate that it is filled in with the SDLC address of the connection.
ring, bridge, target ring Lists the parameters as configured by the sdllc traddr command.
largest token ring frame Shows the largest Token Ring frame that is accepted on the LLC2 side of the connection.
largest SDLC frame Shows the largest SDLC frame that is accepted and will be generated on the SDLC side of the connection.
XID Enabled or disabled: Shows whether XID processing is enabled on the SDLC side of the connection. If enabled, it will show the XID value for this address.
Sample Display with Accounting Option

The following example illustrates the show interfaces serial command with the accounting option on a Cisco 7000:

Router# show interfaces serial 1/0 accounting Serial1/0 Protocol Pkts In Chars In Pkts Out Chars Out IP 7344 4787842 1803 1535774 Appletalk 33345 4797459 12781 1089695 DEC MOP 0 0 127 9779 ARP 7 420 39 2340

show interfaces tokenring

Use the show interfaces tokenring privileged EXEC command to display information about the Token Ring interface and the state of source route bridging.

show interfaces tokenring unit [accounting]
show interfaces tokenring
slot/port [accounting] (for the Cisco 7000 series)
Syntax Description
unit Must match the interface port line number.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
slot On the Cisco 7000 series, optional slot location of the interface processor. On the 7000, value can be 0, 1, 2, 3, or 4. On the 7010, value can be 0, 1, or 2.
port On the Cisco 7000 series, optional port number on interface. Value can be 0, 1, 2, or 3.
Command Mode

Privileged EXEC

Usage Guidelines

If you do not provide values for the parameters slot and port, the command will display statistics for all the network interfaces. The optional keyword accounting displays the number of packets of each protocol type that have been sent through the interface.

Sample Display

The following is sample output from the show interfaces tokenring command:

Router# show interfaces tokenring TokenRing 0 is up, line protocol is up Hardware is 16/4 Token Ring, address is 5500.2000.dc27 (bia 0000.3000.072b)     Internet address is 150.136.230.203, subnet mask is 255.255.255.0    MTU 8136 bytes, BW 16000 Kbit, DLY 630 usec, rely 255/255, load 1/255     Encapsulation SNAP, loopback not set, keepalive set (10 sec)    ARP type: SNAP, ARP Timeout 4:00:00    Ring speed: 16 Mbps   Single ring node, Source Route Bridge capable    Group Address: 0x00000000, Functional Address: 0x60840000     Last input 0:00:01, output 0:00:01, output hang never     Output queue 0/40, 0 drops; input queue 0/75, 0 drops     Five minute input rate 0 bits/sec, 0 packets/sec     Five minute output rate 0 bits/sec, 0 packets/sec    16339 packets input, 1496515 bytes, 0 no buffer         Received 9895 broadcasts, 0 runts, 0 giants         0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 32648 packets output, 9738303 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets, 0 restarts 5 transitions

Table 6-37 describes significant fields shown in the display.


Show Interfaces Tokenring Field Descriptions
Field Description
Token Ring is up | down Interface is either currently active and inserted into ring (up) or inactive and not inserted (down).

On the Cisco 7000 series, gives the interface processor type, slot number, and port number.

"Disabled" indicates the router has received over 5000 errors in a keepalive interval, which is 10 seconds by default.

Token Ring is Reset Hardware error has occurred.
Token Ring is Initializing Hardware is up, in the process of inserting the ring.
Token Ring is
Administratively Down
Hardware has been taken down by an administrator.
line protocol
is {up | down |
administratively down}
Indicates whether the software processes that handle the line protocol believe the interface is usable (that is, whether keepalives are successful).
Hardware Hardware type. "Hardware is Token Ring" indicates that the board is a CSC-R board. "Hardware is 16/4 Token Ring" indicates that the board is a CSC-R16 board. Also shows the address of the interface.
Internet address Lists the Internet address followed by subnet mask.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method assigned to interface.
loopback Indicates whether loopback is set or not.
keepalive Indicates whether keepalives are set or not.
ARP type: Type of Address Resolution Protocol assigned.
Ring speed: Speed of Token Ring--4 or 16 Mbps.
{Single ring/multiring node} Indicates whether a node is enabled to collect and use source routing information (RIF) for routable Token Ring protocols.
Group Address: Interface's group address, if any. The group address is a multicast address; any number of interfaces on the ring may share the same group address. Each interface may have at most one group address.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, drops
Input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.

The 5-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average will be within two percent of the instantaneous rate of a uniform stream of traffic over that period.

packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
CRC Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of a station transmitting bad data.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased.
packets output Total number of messages transmitted by the system.
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. This may never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
collisions Since a Token Ring cannot have collisions, this statistic is nonzero only if an unusual event occurred when frames were being queued or dequeued by the system software.
interface resets Number of times an interface has been reset. The interface may be reset by the administrator or automatically when an internal error occurs.
Restarts Should always be zero for Token Ring interfaces.
transitions Number of times the ring made a transition from up to down, or vice versa. A large number of transitions indicates a problem with the ring or the interface.

The following is sample output from the show interfaces tokenring command on a Cisco 7000:

Router# show interfaces tokenring 2/0 TokenRing2/0 is administratively down, line protocol is down Hardware is cxBus Token Ring, address is 0000.3040.8b4a (bia 0000.3040.8b4a) MTU 8136 bytes, BW 16000 Kbit, DLY 630 usec, rely 255/255, load 1/255 Encapsulation SNAP, loopback not set, keepalive set (10 sec) ARP type: SNAP, ARP Timeout 4:00:00 Ring speed: 0 Mbps Single ring node, Source Route Transparent Bridge capable Ethernet Transit OUI: 0x0000F8 Last input never, output never, output hang never Last clearing of "show interface" counters never Output queue 0/40, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 0 packets output, 0 bytes, 0 underruns 0 output errors, 0 collisions, 1 interface resets, 0 restarts 1 transitions

The following example on the Cisco 70000 includes the accounting option.When you use the accounting option, only the accounting statistics are displayed.

Router# show interfaces tokenring 2/0 accounting TokenRing2/0 Protocol Pkts In Chars In Pkts Out Chars Out IP 7344 4787842 1803 1535774 Appletalk 33345 4797459 12781 1089695 DEC MOP 0 0 127 9779 ARP 7 420 39 2340

show interfaces tunnel

To list tunnel interface information, use the show interfaces tunnel privileged EXEC command.

show interfaces tunnel unit [accounting]
Syntax Description
unit Must match the interface port line number.
accounting (Optional) Displays the number of packets of each protocol type that have been sent through the interface.
Command Mode

EXEC

Sample Display

The following is sample output from the show interface tunnel command:

Router# show interfaces tunnel 4 Tunnel4 is up, line protocol is down Hardware is Routing Tunnel MTU 1500 bytes, BW 9 Kbit, DLY 500000 usec, rely 255/255, load 1/255 Encapsulation TUNNEL, loopback not set, keepalive set (10 sec) Tunnel source 0.0.0.0, destination 0.0.0.0 Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled Last input never, output never, output hang never Last clearing of "show interface" counters never Output queue 0/0, 0 drops; input queue 0/75, 0 drops Five minute input rate 0 bits/sec, 0 packets/sec Five minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort      0 packets output, 0 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts

Table 6-38 describes significant fields shown in the display.


Show Interfaces Tunnel Field Descriptions
Field Description
Tunnel is up | down Interface is currently active and inserted into ring (up) or inactive and not inserted (down).

On the Cisco 7000 series, gives the interface processor type, slot number, and port number.

line protocol is {up | down | administratively down} Shows line protocol up if a valid route is available to the tunnel destination. Shows line protocol down if no route is available, or if the route would be recursive.
Hardware Specifies the hardware type.
MTU Maximum Transmission Unit of the interface.
BW Bandwidth of the interface in kilobits per second.
DLY Delay of the interface in microseconds.
rely Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.
load Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation Encapsulation method is always TUNNEL for tunnels.
loopback Indicates whether loopback is set or not.
keepalive Indicates whether keepalives are set or not.
Tunnel source IP address used as the source address for packets in the tunnel.
destination IP address of the host destination.
Tunnel protocol Tunnel transport protocol (the protocol the tunnel is using). This is based on the tunnel mode command, which defaults to GRE.
key ID key for the tunnel interface, unless disabled.
sequencing Indicates whether the tunnel interface drops datagrams that arrive out of order. Can be disabled.
Last input Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.
Last output Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Last clearing Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared.
*** indicates the elapsed time is too large to be displayed.
0:00:00 indicates the counters were cleared more than 231ms (and less than 232ms) ago.
Output queue, drops
Input queue, drops
Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.
Five minute input rate,
Five minute output rate
Average number of bits and packets transmitted per second in the last 5 minutes.

The 5-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average will be within two percent of the instantaneous rate of a uniform stream of traffic over that period.

packets input Total number of error-free packets received by the system.
bytes input Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.
no buffers Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.
broadcasts Total number of broadcast or multicast packets received by the interface.
runts Number of packets that are discarded because they are smaller than the medium's minimum packet size.
giants Number of packets that are discarded because they exceed the medium's maximum packet size.
CRC Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of a station transmitting bad data.
frame Number of packets received incorrectly having a CRC error and a noninteger number of octets.
overrun Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be increased.
abort Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment.
packets output Total number of messages transmitted by the system.
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. This may never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.
collisions Number of messages retransmitted due to an Ethernet collision. This usually is the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). Some collisions are normal. However, if your collision rate climbs to around 4 or 5%, you should consider verifying that there is no faulty equipment on the segment and/or moving some existing stations to a new segment. A packet that collides is counted only once in output packets.
interface resets Number of times an interface has been reset. The interface may be reset by the administrator or automatically when an internal error occurs.
Restarts Number of times the controller was restarted because of errors.
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

show interfaces
show ip route
+
show route +

show ip interface

To list a summary of an interface's IP information and status, use the show ip interface privileged EXEC command.

show ip interface [brief] [type] [number]
Syntax Description
brief (Optional) Displays a brief summary of IP status and configuration.
type (Optional) Specifies that information be displayed about that interface type only. The possible value depends on the type of interfaces the system has. For example, it could be ethernet, null, pcbus, serial, tokenring, and so on. (The pcbus keyword is valid on LanOptics' Branchcard or Stacknet 2000 products only.)
number (Optional) Interface number.
Command Mode

Privileged EXEC

Sample Displays

The following is sample output from the show ip interface command:

Router# show ip interface Ethernet0 is administratively down, line protocol is down Internet address is 1.0.46.10, subnet mask is 255.0.0.0 Broadcast address is 255.255.255.255 Address determined by setup command MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is enabled Multicast groups joined: 224.0.0.1 224.0.0.2 Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP SSE switching is disabled Router Discovery is disabled IP accounting is disabled TCP/IP header compression is disabled Probe proxy name replies are disabled Gateway Discovery is disabled PCbus0 is administratively down, line protocol is down Internet address is 198.135.1.43, subnet mask is 255.255.255.0 Broadcast address is 255.255.255.255 Address determined by setup command MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is enabled Multicast groups joined: 224.0.0.1 224.0.0.2 Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP SSE switching is disabled Router Discovery is disabled IP accounting is disabled TCP/IP header compression is disabled Probe proxy name replies are disabled Gateway Discovery is disabled Serial0 is administratively down, line protocol is down Internet address is 198.135.2.49, subnet mask is 255.255.255.0 Broadcast address is 255.255.255.255 Address determined by setup command MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is enabled Multicast groups joined: 224.0.0.1 224.0.0.2 Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP SSE switching is disabled Router Discovery is disabled IP accounting is disabled TCP/IP header compression is disabled Probe proxy name replies are disabled Gateway Discovery is disabled

The following is sample output from the show ip interface brief command:

Router# show ip interface brief Interface IP-Address OK? Method Status Protocol Ethernet0 1.0.46.10 YES manual administratively down down PCbus0 198.135.1.43 YES manual administratively down down Serial0 198.135.2.49 YES manual administratively down down

The following is sample output from the show ip interface brief pcbus 0 command:

Router# show ip interface brief pcbus 0 Interface IP-Address OK? Method Status Protocol PCbus0 198.135.1.43 YES manual administratively down down
Related Command

show interfaces

show rif

Use the show rif EXEC command to display the current contents of the RIF cache.

show rif
Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Sample Display

The following is sample output from the show rif command:

Router# show rif Codes: * interface, - static, + remote Hardware Addr How Idle (min) Routing Information Field 5C02.0001.4322 rg5 - 0630.0053.00B0 5A00.0000.2333 TR0 3 08B0.0101.2201.0FF0 5B01.0000.4444 - - - 0000.1403.4800 TR1 0 - 0000.2805.4C00 TR0 * - 0000.2807.4C00 TR1 * - 0000.28A8.4800 TR0 0 - 0077.2201.0001 rg5 10 0830.0052.2201.0FF0

In the display, entries marked with an asterisk (*) are the router/bridge's interface addresses. Entries marked with a dash (-) are static entries. Entries with a number are cached entries. If the RIF timeout is set to something other than the default of 15 minutes, the timeout is displayed at the top of the display.

Table 6-39 describes significant fields shown in the display.


Show RIF Cache Display Field Descriptions
Field Description
Hardware Addr Lists the MAC-level addresses.
How Describes how the RIF has been learned. Possible values include a ring group (rg), or interface (TR).
Idle (min) Indicates how long, in minutes, since the last response was received directly from this node.
Routing Information Field Lists the RIF.

shutdown (hub configuration)

To shut down a port on an Ethernet hub of a Cisco 2505 or Cisco 2507, use the shutdown hub configuration command. To restart the disabled hub, use the no form of this command.

shutdown
no shutdown
Syntax Description

This command has no arguments or keywords.

Command Mode

Hub configuration

Example

The following example shuts down hub 0, ports 1 through 3:

hub ether 0 1 3 shutdown
Related Command

hub

shutdown (interface configuration)

To disable an interface, use the shutdown interface configuration command. To restart a disabled interface, use the no shutdown command.

shutdown
no shutdown
Syntax Description

This command has no arguments or keywords.

Default

Enabled

Command Mode

Interface configuration

Usage Guidelines

The shutdown command disables all functions on the specified interface. On serial interfaces, this command causes the DTR signal to be dropped. On Token Ring interfaces, this command causes the interface to be deinserted from the ring. On FDDI interfaces, this command causes the optical bypass switch, if present, to go into bypass mode.

This command also marks the interface as unavailable. To check whether an interface is disabled, use the EXEC command show interfaces. An interface that has been shut down is shown as administratively down in the display from this command.

Examples

The following example turns off interface Ethernet 0:

interface ethernet 0 shutdown

The following example turns the interface back on:

interface ethernet 0 no shutdown
Related Command

show interfaces

slip

To make a SLIP connection on the auxiliary port, use the slip user EXEC command.

slip [default | client [@tacacs-server]] [/routing] [/compressed]
Syntax Description
default (Optional) Makes a SLIP connection when a default address has been configured.
client (Optional) IP address or the name of the client workstation or PC.
@tacacs-server (Optional) IP address or IP hostname of the TACACS server to which the user's TACACS authentication request is sent.
/routing (Optional) Indicates routing is enabled. Interface async 1 must be configured for async dynamic routing.
/compressed (Optional) Indicates IP header compression should be used on
the link.
Command Mode

User EXEC

Usage Guidelines

The IP address (indicated by the client and tacacs-server arguments) is the IP address of the system dialing in. This parameter can only be specified if the line is set for dynamic addresses using the line configuration command async address dynamic.

If you do not specify an address or enter default, you will be prompted for an IP address or host name. You can enter default at this point to use the default address configured for the line.

Using the tacacs-server argument, you can specify a TACACS server. If you do not specify a TACACS server for SLIP address authentication, the TACACS server specified at login (if any) will be used for the SLIP address query.

The /routing switch indicates that the remote system is a router and that routing messages should be exchanged over the link. The /routing switch can only be used if the line is configured for async dynamic routing.

The /compressed switch indicates that IP header compression should be used on the link. This switch can only be specified if the underlying asynchronous interface has been configured for ip tcp header-compression passive. Compression is always used if the interface is configured for ip tcp header-compression on and it is never used if the interface is configured for ip tcp
header-compression off
.

Examples

The following example illustrates how to make a connection when a permanent SLIP address has been assigned. Once a correct password is entered, you are placed in SLIP mode, and the IP address is displayed.

Router> slip Password: Entering SLIP mode. Your IP address is 192.31.7.28, MTU is 1524 bytes

The following example illustrates the prompts displayed and the response required when dynamic addressing is used to assign the SLIP address:

Router> slip IP address or hostname? 192.31.6.15 Password: Entering SLIP mode Your IP address is 192.31.6.15, MTU is 1524 bytes

In the following example, the address 192.31.6.15 has been assigned as the default. Password verification is still required before SLIP mode can be enabled.

Router> slip default Password: Entering SLIP mode Your IP address is 192.31.6.15, MTU is 1524 bytes

The following example illustrates the implementation of header compression on the interface with the IP address 128.66.2.1:

Router> slip /compressed 128.66.2.1 Password: Entering SLIP mode. Interface IP address is 128.66.2.1, MTU is 1500 bytes. Header compression is On.

When a line is configured for slip header-compression passive, and you use the slip EXEC command to enter SLIP mode, you will see that the interface is set to match compression status indicated at the EXEC level.

The message "Header compression will match your system" indicates that the router starts compressing when it first receives a compressed packet. You can override this and force compression with /compression. If the line was configured for slip header-compression on, this line would read "Header compression is On." TACACS server check is specified for address authentication.

Router> slip 1.0.0.1@check Password: Entering SLIP mode. Interface IP address is 1.0.0.1, MTU is 1500 bytes Header compression will match your system.
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

async default ip address
async dynamic address

async dynamic routing
async mode dedicated

async mode interactive

encapsulation ppp
interface async 1
tacacs-server +

smt-queue-threshold

To set the maximum number of unprocessed FDDI station management (SMT) frames that will be held for processing, use the smt-queue-threshold global configuration command. Use the
no smt-queue-threshold command to restore the queue to the default.

smt-queue-threshold number
no smt-queue-threshold
Syntax Description
number Number of buffers used to store unprocessed SMT messages that are to be queued for processing. Acceptable values are positive integers.
Default

The default threshold value is equal to the number of FDDI interfaces installed in the router.

Command Mode

Global configuration

Usage Guidelines

This command helps ensure that the routers keep track of FDDI upstream and downstream neighbors, particularly when a router includes more than one FDDI interface.

In FDDI, upstream and downstream neighbors are determined by transmitting and receiving SMT Neighbor Information Frames (NIFs). The router can appear to lose track of neighbors when it receives an SMT frame and the queue currently contains an unprocessed frame. This occurs because the router discards incoming SMT frames if the queue is full. Discarding SMT NIF frames can cause the router to lose its upstream or downstream neighbor.


Note Use this command carefully, because the SMT buffer is charged to the inbound interface (input hold queue) until the frame is completely processed by the system. Setting this value to a high limit can impact buffer usage and the ability of the router to receive routable packets or routing updates.
Example

The following example specifies that the SMT queue can hold ten messages. As SMT frames are processed by the system, the queue is decreased by one:

smt-queue-threshold 10

source-address

To configure source address control on a port on an Ethernet hub of a Cisco 2505 or Cisco 2507, use the source-address hub configuration command. To remove a previously defined source address, use the no form of this command.

source-address [mac-address]
no source-address
Syntax Description
mac-address (Optional) MAC address in the packets that the hub will allow to access the network.

If you omit the MAC address, the hub uses the value in the last source address register, and if the address register is invalid, it will remember the first MAC address it receives on the previously specified port, and allow only packets from that MAC address onto that port.

Default

Disabled

Command Mode

Hub configuration

Usage Guidelines

On an Ethernet hub only, you can configure a security measure so that a hub port accepts packets only from a specific MAC address. For example, suppose your workstation is connected to port 3 on a hub, and source address control is enabled on port 3. Your workstation has access to the network because the hub accepts from port 3 any packet bearing your workstation's MAC address. Any packets arriving with a different MAC address cause the port to be disabled. The port is then re-enabled after 1 minute and again the MAC address of incoming packets is checked.

Examples

The following example configures the hub (repeater) to allow only packets from MAC address 1111.2222.3333 on port 2 of hub 0:

hub ether 0 2 source-address 1111.2222.3333

The following example configures the hub use the value of the last source address register. If the address register is invalid, it will remember the first MAC address it receives on port 2, and allow only packets from the learned MAC address on port 2:

hub ether 0 2 source-address
Related Command

hub

squelch

To extend the Ethernet twisted-pair 10BaseT capability beyond the standard 100 meters on the
Cisco 4000 platform, use the squelch interface configuration command.

squelch {normal | reduced}
no squelch {normal | reduced}
Syntax Description
normal Allows normal capability.
reduced Allows extended 10BaseT capability.
Default

Normal range

Command Mode

Interface configuration

Example

The following example extends the twisted-pair 10BaseT capability on the cable attached to interface Ethernet 2:

interface ethernet 2 squelch reduced

transmit-clock-internal

When a DTE does not return a transmit clock, use the transmit-clock-internal interface command to enable the internally generated clock on a serial interface on a Cisco 7000. Use the no form of this command to disable the feature.

transmit-clock-internal
no transmit-clock-internal
Syntax Description

This command has no keywords or arguments.

Default

Disabled

Command Mode

Interface configuration

Example

In the following example, the internally generated clock is enabled on serial interface 3/0:

interface serial 3/0 transmit-clock-internal

transmitter-delay

To specify a minimum dead-time after transmitting a packet, use the transmitter-delay interface configuration command. The no transmitter-delay command restores the default.

transmitter-delay {microseconds | hdlc-flags}
no transmitter-delay
Syntax Description
microseconds Approximate number of microseconds of minimum delay after transmitting a packet on the MCI and SCI interface cards.
hdlc-flags Minimum number of HDLC flags to be sent between each packet on the HIP, HSCI, FSIP, or HSSI. The valid range on the HSSI is 2 to 128000.
Default

0 microseconds

Command Mode

Interface configuration

Usage Guidelines

This command is especially useful for serial interfaces that can send back-to-back data packets over serial interfaces faster than some hosts can receive them.

The transmitter delay feature is implemented for the following Token Ring cards: CSC-R16,
CSC-R16M, CSC-1R, CSC-2R, and CSC-CTR. For the first four cards, the command syntax is the same as the existing command and specifies the number of milliseconds to delay between sending frames that are generated by the router. Transmitter delay for the CSC-CTR uses the same syntax, but specifies a relative time interval to delay between transmission of all frames.

Example

The following example specifies a delay of 300 microseconds on interface serial 0:

interface serial 0 transmitter-delay 300

tunnel checksum

To enable encapsulator-to-decapsulator checksumming of packets on a tunnel interface, use the tunnel checksum interface configuration command. To disable checksumming, use the no form of the command.

tunnel checksum
no tunnel checksum
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command currently applies to generic route encapsulation (GRE) only. Some passenger protocols rely on media checksums to provide data integrity. By default, the tunnel does not guarantee packet integrity. By enabling end-to-end checksums, the routers will drop corrupted packets.

Example

In the following example, all protocols will have encapsulator-to-decapsulator checksumming of packets on the tunnel interface:

tunnel checksum

tunnel destination

To specify a tunnel interface's destination, use the tunnel destination interface configuration command. To remove the destination, use the no form of this command.

tunnel destination {hostname | ip-address}
no tunnel destination
Syntax Description
hostname Name of the host destination
ip-address IP address of the host destination expressed in decimal in four-part, dotted notation.
Default

No tunnel interface destination is specified.

Command Mode

Interface configuration

Usage Guidelines

You cannot have two tunnels using the same encapsulation mode with exactly the same source and destination address. The workaround is to create a loopback interface and source packets off of the loopback interface.

Examples

The following example enables Cayman tunneling:

interface tunnel0 tunnel source ethernet0 tunnel destination 131.108.164.19 tunnel mode cayman

The following example enables GRE tunneling:

interface tunnel0 appletalk cable-range 4160-4160 4160.19 appletalk zone Engineering tunnel source ethernet0 tunnel destination 131.108.164.19 tunnel mode gre ip
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

appletalk cable-range+
appletalk zone+
tunnel mode
tunnel source

tunnel key

To enable an ID key for a tunnel interface, use the tunnel key interface configuration command. To remove the ID key, use the no form of this command.

tunnel key key-number
no tunnel key
Syntax Description
key-number Integer from 0 to 4294967295
Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command currently applies to generic route encapsulation (GRE) only. Tunnel ID keys can be used as a form of weak security to prevent misconfiguration or injection of packets from a foreign source.


Note When using GRE, the ID key is carried in each packet. We do not recommend relying on this key for security purposes.
Example

In the following example, the tunnel key is set to 3:

tunnel key 3

tunnel mode

To set the encapsulation mode for the tunnel interface, use the tunnel mode interface configuration command. To set to the default, use the no form of the command.

tunnel mode {cayman | eon | gre ip | nos}
no tunnel mode
Syntax Description
cayman Cayman TunnelTalk AppleTalk encapsulation
eon EON compatible CLNS tunnel
gre ip Generic route encapsulation (GRE) protocol over IP
nos KA9Q/NOS compatible IP over IP
Default

GRE tunneling

Command Mode

Interface configuration

Usage Guidelines

You cannot have two tunnels using the same encapsulation mode with exactly the same source and destination address. The workaround is to create a loopback interface and source packets off of the loopback interface.

Cayman tunneling implements tunneling as designed by Cayman Systems. This enables our routers to interoperate with Cayman GatorBoxes. With Cayman tunneling, you can establish tunnels between two routers or between our router and a GatorBox. When using Cayman tunneling, you must not configure the tunnel with an AppleTalk network address. This means that there is no way to ping the other end of the tunnel.

Generic Route Encapsulation (GRE) tunneling can be done between our routers only. When using GRE tunneling for AppleTalk, you configure the tunnel with an AppleTalk network address. This means that you can ping the other end of the tunnel.

Examples

The following example enables Cayman tunneling:

interface tunnel0 tunnel source ethernet0 tunnel destination 131.108.164.19 tunnel mode cayman

The following example enables GRE tunneling:

interface tunnel0 appletalk cable-range 4160-4160 4160.19 appletalk zone Engineering tunnel source ethernet0 tunnel destination 131.108.164.19 tunnel mode gre ip
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

appletalk cable-range+
appletalk zone+
tunnel destination
tunnel source

tunnel sequence-datagrams

To configure a tunnel interface to drop datagrams that arrive out of order, use the tunnel sequence-datagrams interface configuration command. To disable this function, use the no form of this command.

tunnel sequence-datagrams
no tunnel sequence-datagrams
Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

This command currently applies to generic route encapsulation (GRE) only. This command is useful when carrying passenger protocols that behave poorly when they receive packets out of order (for example, LLC2-based protocols).

Example

In the following example, the tunnel is configured to drop datagrams that arrive out of order:

tunnel sequence-datagrams

tunnel source

To set a tunnel interface's source address, use the tunnel source interface configuring command. To remove the source address, use the no form of the command.

tunnel source {ip-address | interface-type interface-number}
no tunnel source
Syntax Description
ip-address IP address to use as the source address for packets in the tunnel.
interface-type All types.
interface-number Specifies the port, connector, or interface card number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed with the show interfaces command.
Default

No tunnel interface's source address is set.

Command Mode

Interface configuration

Usage Guidelines

You cannot have two tunnels using the same encapsulation mode with exactly the same source and destination address. The workaround is to create a loopback interface and source packets off of the loopback interface.

When using tunnels to Cayman boxes, you must set the tunnel source to an explicit IP address on the same subnet as the Cayman box, not the tunnel itself.

Examples

The following example enables Cayman tunneling:

interface tunnel0 tunnel source ethernet0 tunnel destination 131.108.164.19 tunnel mode cayman

The following example enables GRE tunneling:

interface tunnel0 appletalk cable-range 4160-4160 4160.19 appletalk zone Engineering tunnel source ethernet0 tunnel destination 131.108.164.19 tunnel mode gre ip
Related Commands

A dagger (+) indicates that the command is documented in another chapter.

appletalk cable-range+
appletalk zone+
tunnel destination
tunnel source

tx-queue-limit

To control the number of transmit buffers available to a specified interface on the MCI and SCI cards, use the tx-queue-limit interface configuration command.

tx-queue-limit number
Syntax Description
number Maximum number of transmit buffers that the specified interface can subscribe.
Default

Defaults depend on the total transmit buffer pool size and the traffic patterns of all the interfaces on the card. Defaults and specified limits are displayed with the show controllers mci EXEC command.

Command Mode

Interface configuration

Usage Guidelines

This command should be used only under the guidance of a technical support representative.

Example

The following example sets the maximum number of transmit buffers on the interface to 5:

interface ethernet 0 tx-queue-limit 5
Related Command

show controllers mci

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