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This chapter describes the EXEC commands used to monitor and troubleshoot a terminal server. Most of the network management commands are executed at the privileged level prompt, although there is a subset of monitoring (show) commands that may be entered at the user level prompt. User level commands are noted in the descriptions.
The following information is provided in this chapter:
Refer to "Using the EXEC Command Interpreter" in the "Using the Terminal Server" chapter for a description of system command levels and how to access them.
This section describes how to change the terminal parameters using the terminal commands. The new settings temporarily override those made with the line subcommands, remaining in effect only until the user exits the system. All terminal commands are available at the user level prompt (>).
To obtain information about the terminal configuration parameter settings for the current terminal line, use the show terminal command. The command syntax is:
show terminalTo display information about the active ports of the server, use the show users command. The command syntax is:
show users [all]The information displayed includes the line number, connection name, idle time, and terminal location. The optional keyword, all, requests information for both active and inactive ports.
Some terminal commands use the decimal representation of an ASCII character as an argument. Refer to Appendix A, "ASCII Character Set," for ASCII-to-decimal conversion information.
To display a list of commands that you can enter to change the hardware and software parameters of the current terminal line, use the terminal command. The command syntax is:
terminal ?To record the current terminal type, use the terminal terminal-type command. The command syntax is:
terminal terminal-type terminal-nameThe type in the argument terminal-name is passed as information to the remote host of the terminal type. The text terminal-name is used by TN370 for display management.
To set the number of lines on the screen of the current terminal, use the terminal length command. The command syntax is:
terminal length screen-lengthThe argument screen-length is the desired number of lines.
The terminal server uses this value to determine when to pause during multiple-screen output. The default length is 24 lines. A value of 0 (zero) disables pausing between screens of output. The screen length specified can be learned by hosts.
To set the number of characters (columns) on a single line of the current terminal screen, use the terminal width command. The command syntax is:
terminal width columnsThe rlogin protocol uses the argument columns to set up terminal parameters on a remote UNIX host. Hosts can learn the specified width specified with this command.
To set the escape character for the current terminal line, use the terminal escape-character command. The command syntax is:
terminal escape-character decimal-numberThe argument decimal-number is the ASCII decimal representation of the desired escape character or an escape character (Ctrl-P, for example).
Typing the escape character followed by the X key returns you to the EXEC when you are connected to another computer. The default escape characters are Ctrl-^.
To make the Break key function as the escape sequence, use the terminal no escape-character command. The command syntax is:
terminal no escape-characterThe Break need not be followed by an "X". However, you cannot set the console escape character to Break, because the operating software interprets Break on the console as an attempt to halt the system. Depending upon the configuration register setting, console breaks will either be ignored or cause the server to shut down.
Refer to "Entering the Configuration Commands" in the "Configuring the System" chapter for a complete list of escape character sequences supported by the terminal server.
To set or change the hold character, use the terminal hold-character command. The command syntax is:
terminal hold-character decimal-numberThe terminal hold-character command sets the hold character for the current terminal line.
The argument decimal-number is either the ASCII decimal representation of the desired hold character or else a control sequence (for example, Ctrl-C). Typing the hold character temporarily halts the output at the terminal. To continue the output, type any other character. To send the hold character to the host, precede it with the escape character. By default, no local hold character is set.
The terminal no hold-character command clears the hold character.
To change the terminal parity, use the terminal parity command. The command syntax is:
terminal parity {none | even | odd | space | mark}The terminal parity command defines the generation of the parity bit for the current terminal line.
The default setting is none.
To change the speed of the terminal, use the terminal speed command. The command syntax is:
terminal speed baudThe terminal speed command sets the transmit and receive speeds of the current terminal line.
When used, argument baud is typically specified as 300, 1200, 2400, 4800, 9600, 19200, or 38400, but can be set to any user-defined speed in a range from 75 to 57600.
The default speed is 9600 baud.
To change the start-character of the data transmission, use the terminal start-character command. The command syntax is:
terminal start-character decimal-numberThe terminal start-character command sets the character that signals the start of data transmission when software flow control is in effect.
The argument decimal-number is the ASCII decimal representation of the desired start character.
The default start character is Ctrl-Q (ASCII character 17).
To change the stop-character of data transmission, use the terminal stop-character command. The command syntax is:
terminal stop-character decimal-numberThe terminal stop-character command sets the character that signals the end of data transmission when software flow control is in effect.
The argument decimal-number is the ASCII decimal representation of the desired stop character.
The default stop character is Ctrl-S (ASCII character 19).
To change the character data bits, use the terminal stopbits command. The command syntax is:
terminal stopbits {1 | 1.5 | 2}The terminal stopbits command sets the number of stop bits transmitted per byte by the current terminal line.
The default is 2 stop bits.
To set the character padding on the current terminal line, use the terminal padding command. The command syntax is:
terminal padding decimal-number countThe argument decimal-number is the ASCII decimal representation of the character. It can be any of the 127 ASCII characters, up to 255 padding characters in length.
The argument count is the number of NUL bytes sent after that character.
The terminal no padding command ends this padding after the character represented by decimal-number.
The terminal telnet-transparent command causes the current terminal line to send a Return (CR) as a CR followed by a NUL instead of a CR followed by a Line Feed (LF). This scheme permits interoperability with different interpretations of end-of-line handling in the Telnet protocol specification. It has the following syntax:
terminal telnet-transparentTo set up the terminal flow control, use the terminal flowcontrol command. The command syntax is:
terminal flowcontrol {none | software [in | out] | hardware}The terminal flowcontrol command sets the method of data flow control for the current terminal line.
The keyword software sets software flow control. An additional keyword specifies the direction: in causes the terminal server to listen to flow control from the attached device, and out causes the terminal server to send flow control information to the attached device. If you do not specify a direction, both directions are assumed.
The keyword hardware sets hardware flow control. For information about setting up the RS-232 line, see the relevant Cisco Hardware Installation and Reference publication.
By default, no flow control method is set for a line.
To set up the packet dispatch character, use the terminal dispatch-character EXEC command. The command syntax is:
terminal dispatch-character decimal-number1 [decimal-number2 ... decimal-numberx]The terminal dispatch-character command defines a character or string that causes a packet to be sent. The argument decimal-number is the ASCII decimal representation of the character or string.
This command causes the terminal server to attempt to buffer characters into larger-sized packets for transmission to the remote host. The terminal server normally dispatches each character as it is typed.
To establish input notification, use the terminal notify commands. The command syntax is:
terminal notifyWhen you have multiple concurrent connections, you may want to know when output is pending on a connection other than the current connection. For example, you may want to know when another connection receives mail or a message. The terminal notify command causes the terminal server to notify you of pending output. The terminal no notify command ends such notifications.
To set the line to maximum transparency for file transfers, use the terminal download command. The command syntax is:
terminal downloadThe terminal download command is used when running a program such as KERMIT, XMODEM, or CrossTalk that downloads a file across a terminal server line. It sets up the terminal line as a transparent pipe that can be used to transmit data, and is equivalent to entering all the following commands:
terminal telnet-transparent
terminal no escape-character
terminal no hold-character
terminal no pad 0
.
.
.
terminal no pad 128
terminal parity none
terminal databits 8
The terminal no download command restores the line's original parameter settings.
To select a preferred remote terminal protocol, use the terminal transport command. The command syntax is:
terminal transport [telnet|lat|rlogin|none]This EXEC command sets the preferred protocol for the duration of the current session.
For details on the parameters of this command, refer to "Defining the Transport Protocol for a Specific Line" in the "Configuring the System" chapter.
This section includes sample screen outputs for the terminal transport commands.
The following example makes a connection using Telnet, after rlogin is refused as a preferred protocol by the remote host Eng2:
ts>terminal transport rlogin
ts>Eng2
Trying Eng2.Cisco.com (121.108.145.12)...
ts>Eng2
Trying Eng2.Cisco.com (121.108.145.12)...Open
login:
The following example sets the preferred transport to none and then attempts to make a connection without specifying a protocol. A Telnet connection is made successfully once telnet is specified.
ts>terminal transport none
ts>Eng2
% unknown command "Eng2"
ts>telnet Eng2
Trying Eng2.Cisco.com (121.108.145.12)...Open
login:
To display system debugging and event messages on the current terminal, use the terminal monitor command. The command syntax is:
terminal monitorThe terminal monitor command copies the system debugging and event messages to the current terminal. To use this command, you must first issue the enable command and enter the password to access the privileged command mode.
Use the privileged EXEC commands in this section to clear interface counters, reset hardware logic, and clear all activity on a line.
To clear the interface counters shown with the EXEC show interface command, use the following command:
clear counters [type unit]The command clears all the current interface counters from the interface unless the optional arguments type and unit are specified to clear only a specific interface type (serial, ethernet, tokenring) from a specific unit or card number.
Use the clear interface EXEC command to reset the hardware logic on a network interface. The syntax for this command is as follows:
clear interface type unitThe arguments type and unit specify the interface type and unit or card number (such as, Ethernet 0, Serial 0, or Token Ring 0).
To reset a terminal line, use the clear line command. The command syntax is:
clear line line-numberThis command aborts any connections, terminates the associated processes, and resets the data structures associated with a terminal line.
The argument line-number specifies the terminal line number.
To maintain the Routing Information Field (RIF) cache for terminal servers with Token Ring interfaces, use the clear rif-cache command. The command syntax is:
clear rif-cacheThis command clears all entries from the RIF cache. It applies only to terminal servers with Token Ring interfaces.
This section describes the EXEC show commands you use to monitor the terminal server.
To display a list of the show command options, show ? command at the EXEC prompt. The command syntax is:
show ?The show commands display information about the network and the interfaces to aid in troubleshooting and monitoring the system.
To display the utilization statistics for the network packet buffer allocator, use the show buffers EXEC command. The command syntax is:
show buffers interfaceThis command displays utilization statistics for the network packet buffer allocator. For each pool, the network server keeps counts of the number of buffers outstanding, the number of buffers in the free list, and the maximum number of buffers allowed in the free list.
The optional argument interface will cause a search of all buffers that have been associated with that interface for longer than one minute. The contents of these buffers will be printed to the screen. This option is useful in diagnosing problems where the input queue count on an interface is consistently non-zero.
Following is sample output without the optional interface argument. Table 1-1 describes the fields seen.
Buffer elements:
250 in free list (250 max allowed)
10816 hits, 0 misses, 0 created
Small buffers, 104 bytes (total 120, permanent 120):
120 in free list (0 min, 250 max allowed)
26665 hits, 0 misses, 0 trims, 0 created
Middle buffers, 600 bytes (total 90, permanent 90):
90 in free list (0 min, 200 max allowed)
5468 hits, 0 misses, 0 trims, 0 created
Big buffers, 1524 bytes (total 90, permanent 90):
90 in free list (0 min, 300 max allowed)
1447 hits, 0 misses, 0 trims, 0 created
Large buffers, 5024 bytes (total 0, permanent 0):
0 in free list (0 min, 100 max allowed)
0 hits, 0 misses, 0 trims, 0 created
Huge buffers, 12024 bytes (total 0, permanent 0):
0 in free list (0 min, 30 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
Field Description
Buffer elements Blocks of memory used in internal operating system queues
Small buffers Blocks of memory used to hold network packets
Middle buffers
Big buffers
Large buffers
Huge buffers
hits Count of successful attempts to allocate a buffer when needed
misses Count of allocation attempts which failed for lack of a free
buffer in the pool
created Count of new buffers created
trims Count of buffers destroyed
in free list Number of buffers of a given type which are not
currently allocated and are available for use
max allowed The maximum number of buffers of a given type
allowed in the system
failures The total number of allocation requests that have
failed for lack of a free buffer
no memory Number of failures due to a lack of memory to create a
new buffer
misses specified are not necessarily indicative of a system problem. They essentially reflect packets that are dropped.
To display the system configuration, use the show configuration command. The command syntax is:
show configurationThe privileged show configuration command displays the contents of the non-volatile memory, if present and valid. The non-volatile memory stores the configuration information in text form as configuration commands.
The following is a sample output from the show configuration command:
Using 3150 out of 32768 bytes
!
!
!
interface Ethernet 0
address 192.31.7.18 255.255.255.240
!
boot network network-confg 255.255.255.255
boot host VFsystem-confg 255.255.255.255
boot system alpha.ts2 255.255.255.255
!
name-server 255.255.255.255
domain-name VF.COM
ip host FOO 513 131.108.1.27
ip host NATASHA 192.31.7.27
ip host CGS 192.31.7.114 192.31.7.145
ip host NOC-A-GW 130.128.1.1
ip host TGW 192.31.7.99 1.0.0.2
snmp-server community
tacacs-server host 131.108.1.27
tacacs-server host 192.31.7.24
access-list 1 deny 192.31.7.18
access-list 1 deny 192.31.7.50
access-list 1 permit 0.0.0.0 255.255.255.255
banner +
Welcome to VeryFast Communications Server, Inc. Use of this system
requires a user login name and password.
Please report any problems to engineering@fast.com.
+
hostname VFsystem
logging 192.31.7.19
!
line console 0
location VFsystem console
password secret
line 1
location joe x123
notify
stopbits 1
dispatch-timeout 200
slip address 192.31.7.23
line 22
location jim x124
flowcontrol software in
flowcontrol software out
txspeed 38400
rxspeed 38400
line 25
location lab x125
autobaud
line 41
location 555-1126
access-class 1 out
autobaud
login tacacs
modem callin
modem answer-timeout 16
line vty 0
login
password secret
telnet speed 2400 9600
line vty 1
login
password secret
line vty 2
login
password secret
The show controllers command displays current internal status information for different interface cards. Enter this command at the EXEC prompt:
show controllers {serial|token|mci}Use the following keywords to display the information about that card:
Sample output for the MCI controller card follows. Table 1-2 describes the fields displayed.
MCI 0, controller type 1.1, microcode version 1.5
64 Kbytes of main memory, 4 Kbytes cache memory
5 system TX buffers, largest buffer size 1520
Restarts: 0 line down, 0 hung output, 0 controller error
Interface 1 is Serial0, electrical interface is RS-232 DTE
36 total RX buffers, 5 buffer TX queue limit, buffer size 1520
Transmitter delay is 0 microseconds
High speed synchronous serial interface
Field Description
MCI (number) The unit number of the MCI card
controller type The version number of the MCI card
microcode version The version number of the MCI card's internal
software (in read-only memory)
main memory The amounts of main and cache memory on the card
cache memory
system TX buffers Number of buffers that hold packets to be transmitted
Restarts Count of restarts due to the following conditions:
line down Communication line down
hung output Output unable to transmit
controller error Internal error
Interface...is Names of interfaces, by number
electrical interface Line interface type for serial connections
RX buffers Number of buffers for received packets
TX queue limit Maximum number of buffers in transmit queue
Transmitter delay Delay between outgoing frames
Station address The hardware address of the interface
Use the command show interfaces to display information about the Ethernet interface. Enter this command at the EXEC prompt:
show interfaces [type unit]Where type is the ethernet keyword and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces.
Sample output of this command is provided below. Table 1-3 describes the fields seen.
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
3594664 packets output, 436549843 bytes, 0 underruns
8 output errors, 1790 collisions, 10 interface resets, 0 restarts
Field Descriptions
Ethernet...is up Tells whether the interface hardware is currently active
...is administratively down and if it's been taken down by an administrator.
line protocol Tells whether the software processes that handle the line
is {up | down | protocol believe the interface is usable (are keepalives
administratively down} successful?).
Hardware Specifies the hardware type (for example, MCI Serial,
MCI Ethernet) and address.
Internet address Lists the Internet address followed by subnet mask.
Encapsulation Encapsulation method assigned to interface.
ARP type: Type of Address Resolution Protocol assigned.
Last input The number of hours, minutes, and seconds since the
last packet was successfully received by an interface.
Useful for knowing when a dead interface failed.
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 The 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, Input queue, Number of packets in output and input queues. Each
drops 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, The average number of bytes and packets transmitted
Five minute output rate per second in the last five minutes.
packets input The total number of error-free packets received by the
system.
Received...broadcasts The total number of broadcast or multicast packets
received by the interface.
runts The number of packets which are discarded because
they are smaller than the medium's minimum packet size.
For instance, any Ethernet packet which is less than 64
bytes is considered a runt.
giants The number of packets which are discarded because
they exceed the medium's maximum packet size. For
example, any Ethernet packet which is greater than
1518 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 The 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 The number of packets received incorrectly having a
CRC error and a non-integer number of octets. On a
LAN, this is usually the result of collisions or a
malfunctioning Ethernet device.
overrun The 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 The 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 An 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
happen (be reported) on some interfaces.
output errors The sum of all errors which 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 The 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 The 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 which 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 The number of times a Type 2 Ethernet controller was
restarted because of errors.
Use the command show interfaces to display information about the serial interface and the state of source bridging. Enter this command at the EXEC prompt:
show interfaces [type unit]Where type is the keyword serial and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces.
Sample output of this command for Cisco's synchronous serial interfaces is provided below:
Serial 0 is up, line protocol is up
Hardware is MCI Serial
Internet address is 192.31.7.50, subnet mask is 255.255.255.240
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 0:00:00, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 2000 bits/sec, 4 packets/sec
Five minute output rate 1000 bits/sec, 2 packets/sec
1131427 packets input, 87088176 bytes, 2 no buffer
Received 312429 broadcasts, 0 runts, 0 giants
8 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 8 abort
753820 packets output, 41586176 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets, 0 restarts
19 carrier transitions
Table 1-4 describes the fields seen.
Field Descriptions
Serial ... is {up |down} Tells whether the interface hardware is currently active
...is administratively down (whether carrier detect is present) and if it's been taken
down by an administrator.
line protocol Tells whether the software processes that handle the line
is {up | down | protocol thinks the line is usable (are keepalives
administratively down} successful?).
Hardware Specifies the hardware type (for example, MCI Serial,
MCI Ethernet).
Encapsulation Encapsulation method assigned to interface.
loopback Tells whether loopback is set or not.
keepalive Tells whether keepalives are set or not.
Last input The 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 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.
Output queue, Input queue, Number of packets in output and input queues. Each
drops 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, The average number of bytes and packets transmitted
Five minute output rate per second in the last five minutes.
packets input The total number of error-free packets received by the
system.
broadcasts The total number of broadcast or multicast packets
received by the interface.
runts The number of packets which are discarded because
they are smaller than the medium's minimum packet size.
giants The number of packets which are discarded because
they exceed the medium's maximum packet size.
CRC The 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 The number of packets received incorrectly having a
CRC error and a non-integer number of octets. On a
serial line, this is usually the result of noise or other
transmission problems.
overrun The 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 The 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 An 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
happen (be reported) on some interfaces.
congestion drop The 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 The sum of all errors which 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 The 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 which 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 The number of times the controller was restarted
because of errors.
carrier transitions The 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.
Use the command show interface to display information about the Token Ring interface and the state of source bridging. Enter this command at the EXEC prompt:
show interface [type unit]Where type is the keyword tokenring and unit is the interface unit number. If you do not provide values for the parameters type and unit, the command will display statistics for all the network interfaces. Sample output of this command is provided below. Table 1-5 describes the fields seen.
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
Field Descriptions
Token Ring is up | down The interface is currently active and inserted
into ring (up) or inactive and not inserted (down).
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 Hardware has been taken down by an administrator.
Administratively Down
line protocol Tells whether the software processes that handle the line
is {up | down | protocol believe the interface is usable (are keepalives
administratively down} successful?).
Hardware Specifies the hardware type (Token Ring or 16/4
Token Ring) and provides the address.
Internet address Lists the Internet address followed by subnet mask.
Encapsulation Encapsulation method assigned to interface.
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: The 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 The number of hours, minutes, and seconds since the
last packet was successfully received by an interface.
Useful for knowing when a dead interface failed.
Output queue, Input queue, Number of packets in output and input queues. Each
drops 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, The average number of bytes and packets transmitted
Five minute output rate per second in the last five minutes.
packets input The total number of error-free packets received by the
system.
broadcasts The total number of broadcast or multicast packets
received by the interface.
runts The number of packets which are discarded because
they are smaller than the medium's minimum packet
size.
giants The number of packets which are discarded because
they exceed the medium's maximum packet size.
CRC The 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 The number of packets received incorrectly having a
CRC error and a non-integer number of octets. On a
LAN, this is usually the result of collisions or a
malfunctioning Ethernet device. On a serial line, this is
usually the result of noise or other transmission
problems.
overrun The 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 The 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 An 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.
congestion drop The 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 The sum of all errors which 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 The 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 The 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.
To obtain the status of lines configured on the terminal server, use the show line EXEC command. The command syntax is:
show line [line-number]The show line command entered with no argument displays a summary status of the terminal lines on the terminal server.
The following is a sample command output of the show line command:
Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise
1 TTY 9600/9600 - - - - - 5 0
2 TTY 9600/9600 - - - - - 13 1
3 TTY 9600/9600 - - - - - 0 0
4 TTY 9600/9600 - - - - - 2 0
5 TTY 9600/9600 - - - - - 0 0
6 TTY 9600/9600 - - - - - 0 0
7 TTY 9600/9600 - - - - - 0 0
10 TTY 9600/9600 - - - - - 0 0
11 TTY 9600/9600 - - - - - 0 0
12 TTY 2400/2400 F callin - - - 26 5
*13 TTY 2400/2400 F callin - - - 14 10
14 TTY 9600/9600 - - - - - 0 0
15 TTY 38400/38400 - - - - - 0 0
16 TTY 4800/4800 - - - - - 0 0
17 TTY 9600/9600 - - - - - 0 0
20 TTY 9600/9600 - - - - - 0 0
*21 VTY - - - - - 2 0
22 VTY - - - - - 0 0
23 VTY - - - - - 0 0
In the output, the Tty column lists the line number in octal or decimal (depending on the setting of the service decimal-tty global configuration command; an asterisk (*) indicates an active line. The Typ column identifies the line type:
The Tx/Rx column lists the current transmit and receive baud rates. The A column indicates the autobaud detect range; F specifies full range, and a hyphen (-) specifies no autobaud detection. The Modem column identifies the handling, if any, of RS-232 modem control signals. The Roty column lists the rotary group number, if any.
The AccO and AccI columns indicate the access classes for outgoing (Telnet and rlogin) and incoming (rotary and virtual terminal) connections, respectively. The Uses column shows the total number of connections made to or from the terminal line since the system was booted. This count helps you evaluate terminal line use. The Noise column lists the total number of "noise" characters received. (A noise character is a non-activating character received as a framing error or when the line is inactive. The default activating character is Return.)
The show line command entered with the argument line-number displays detailed parameter information about a particular line. The show terminal command displays the same information for the current line. The following is a sample command output:
Line 42, Location: "", Type: ""
Length: 24 lines, Width: 80 columns
Baud rate (TX/RX) is 9600/9600
The escape character is "^^", followed by "x"
The local hold character is disabled
No flowcontrol in effect.
Status: Ready, Active, No Exit Banner
Capabilities: none
Idle EXEC timeout is not set.
Idle session timeout is not set.
Session limit is not set.
Modem answer timeout is 15 seconds
Dispatch timeout is not set.
Allowed transports are telnet rlogin. Preferred is telnet
Disconnect character is not set
Activation character is ^M (13)
No output characters are padded
Characters causing immediate data dispatching:
Char ASCII
To show the state of logging (syslog), use the following EXEC command:
show loggingThis command displays the state of syslog error and event logging, including host addresses and whether console logging is enabled. This command also displays SNMP configuration parameters and protocol activity. See the section "Redirecting System Error Messages" in the "Configuring the System" chapter for an explanation of how to configure message logging. Following is a sample output. Table 1-6 describes the fields seen.
Syslog logging: enabled
Console logging: disabled
Monitor logging: level debugging, 18 messages logged.
Trap logging: level informational, 18 messages logged.
Logging to 192.31.7.19
SNMP logging: enabled, retransmission after 30 seconds
741 messages logged
Logging to 131.108.1.27, 0/10
Logging to 131.108.1.111, 0/10
Logging to 131.108.2.63, 0/10
Field Description
Syslog logging When enabled, system logging messages are sent to
a UNIX host which acts as a syslog server, that is,
it captures and saves the messages.
Console logging If enabled, states the level; otherwise this field displays
disabled.
Monitor logging The minimum level of severity required for a log message
to be sent to a monitor terminal (not the console).
Trap logging The minimum level of severity required for a log
message to be sent to syslog server.
SNMP logging Shows whether SNMP logging is enabled and the
number of messages logged, and the retransmission
interval.
To display the system memory, use the show memory command. The command syntax is:
show memoryThis command displays memory free pool statistics. These statistics include summary information about the activities of the system memory allocator, and a block-by-block listing of memory use. Sample output follows.
Head Free Start Total Bytes Used Bytes Free Bytes
Processor AA0A8 E42D8 3497816 308700 3189116
Multibus 2000000 2000000 32768 0 32768
--More--
Address Bytes Prev. Next Free? PrevF NextF Alloc PC What
AA0A8 916 0 AA43C 7ACE *Init*
AA43C 2024 AA0A8 AAC24 AD2E *Init*
AAC24 536 AA43C AAE3C AD58 *Init*
AAE3C 2024 AAC24 AB624 49BC *Init*
AB624 72 AAE3C AB66C 248E0 *Init*
AB66C 44 AB624 AB698 3614C *Init*
AB698 152 AB66C AB730 1CFC *Init*
AB730 2024 AB698 ABF18 1D20 *Init*
ABF18 152 AB730 ABFB0 1CFC *Init*
ABFB0 2024 ABF18 AC798 1D20 *Init*
AC798 100 ABFB0 AC7FC 3F2FE Logger
AC7FC 152 AC798 AC894 y E2568 D74E8 74E12 TCP Protocols
AC894 44 AC7FC AC8C0 4BCC *Sched*
AC8C0 1880 AC894 AD018 y D74E8 D7134 74E3C TCP Protocols
AD018 104 AC8C0 AD080 5126 *Init*
AD080 2024 AD018 AD868 67E6 *Init*
AD868 348 AD080 AD9C4 54BA *Init*
AD9C4 348 AD868 ADB20 54BA *Init*
ADB20 348 AD9C4 ADC7C 54BA *Init*
ADC7C 348 ADB20 ADDD8 54BA *Init*
ADDD8 348 ADC7C ADF34 54BA *Init*
Table 1-7 describes the fields seen; Table 1-8 lists the characteristics of each block of memory in the system.
Field Description
Head The hexadecimal address of the head of the memory
allocation chain
Free Start The hexadecimal address of the base of the free list
Total Bytes The total amount of system memory
Used Bytes The amount of memory in use
Free Bytes The amount of memory not in use
Field Description
Address Hexadecimal address of block
Bytes Size of block in bytes
Prev Address of previous block (should match Address on
previous line)
Next Address of next block (should match address on next
line)
Free? Tells if the block is free
Alloc PC Address of the system call that allocated the block
What Name of process that owns the block
To display the status of printers, use the show printers command. The command syntax is:
show printersThis command displays the hardware status of any parallel printers attached to the terminal server.
To see information about the active processes, use the following EXEC command:
show processesFollowing is a partial display of the command output. Table 1-9 describes the fields seen.
CPU utilization for one minute: 38%; for five minutes: 37%
PID Q T PC Runtime (ms) Invoked uSecs Stacks TTY Process
1 M E 122DE 62812 4897 12826 780/1000 0 Net Background
2 M E 22842 8 19 421 804/1000 0 Logger
809 M E 74AF0 272808 489888 556 1504/2000 36 Exec
4 H E 67C0 373540 630248 592 628/900 0 IP Input
5 M E 3E124 26044 630201 41 824/1000 0 IP Protocols
6 M E 46BA2 592 255178 2 794/1000 0 TCP Timer
7 L E 47CE6 1736 1635 1061 776/1000 0 TCP Protocols
8 L E 67C0 0 1 0 958/1000 0 ARP Input
813 M * 768 384 93 4129 1456/2000 42 Virtual Exec
10 M E 3F51E 0 1 0 894/1000 0 BOOTP Server
11 H E 67C0 25096 194823 128 426/500 0 Net Input
12 M T 36FA 5420 277303 19 850/1000 0 TTY Background
13 L E 5444E 65996 24907 2649 686/1000 0 SNMP Server
14 M E 6E842 0 1 0 966/1000 0 Serial Line IP
Field Description
PID Process ID
Q Queue priority (high, medium, low)
T Scheduler test (Event, Time, Suspended)
PC Current program counter
Runtime (ms) CPU time the process has used, in milliseconds
Invoked Number of times the process has been invoked
uSecs Microseconds of CPU time for each invocation
Stacks Low water mark/Total stack space available
TTY Process Terminal that controls the process and name of process
To display information about your active terminal sessions, use the show sessions EXEC command. This command has the following syntax:
show sessions
Conn Host Address Byte Idle Conn Name
* 1 GUN 131.222.3.11 0 0 GUN
2 BIG 131.222.3.14 0 5 BIG
The information it displays includes the host name, address, number of characters waiting to be sent to the terminal, idle time, and connection name. An asterisk (*) indicates the users's current session.
To display stacks utilizations, use the show stacks command. The command syntax is:
show stacksThis command monitors the stack utilization of processes and interrupt routines. The command output is of use only to Cisco Systems engineers analyzing software problems. The command is described here in case you need to issue it and read the displayed statistics to an engineer over the phone.
To display the settings of the terminal, use the show terminal command. The command syntax is:
show terminalThis command displays the configuration parameter settings for the current terminal. The privileged show line command entered with a line number displays the same information for other lines.
The following is a sample command output:
Line 42, Location: "", Type: ""
Length: 24 lines, Width: 80 columns
Baud rate (TX/RX) is 9600/9600
The escape character is "^^", followed by "x"
The local hold character is disabled
No flowcontrol in effect.
Status: Ready, Active, No Exit Banner
Capabilities: none
Idle EXEC timeout is not set.
Idle session timeout is not set.
Session limit is not set.
Modem answer timeout is 15 seconds
Dispatch timeout is not set.
Allowed transports are telnet rlogin. Preferred is telnet
Disconnect character is not set
Activation character is ^M (13)
No output characters are padded
Characters causing immediate data dispatching:
Char ASCII
To display the line statistics of terminal server, use the show users command or the systat command. The syntax of these commands are:
show users [all]or
systat [all]The show users or systat command displays information about the active ports of the terminal server, including the line number, connection name, idle time, and terminal location. Specify the keyword all to display information about both active and inactive ports.
The following is a sample command output:
TTY Host(s) Idle Location
tty16 MATHOM 14:38 Maggie Peters x245
tty23 DUSTBIN 22:54 Engineering Lab
tty41 DUSTBIN 0 Dialup line # 1
tty42 HEAP 0 Dialup line # 2
tty43 MILANO 0 Dialup line # 3
To display the system version, use the show version command. The command syntax is:
show versionThis command displays the software version and the hardware configuration of the system.
The following is a sample command output:
TS Software (TS3-L), Version 8.3
Copyright (c) 1986-1991 by cisco Systems, Inc.
Compiled Thu 01-Aug-91 13:00 by kph
System Bootstrap, Version 4.3(2)
char uptime is 2 weeks, 23 hours, 25 minutes
System restarted by reload
System image file is unknown, booted via tftp from 131.108.13.111
CSC3 (68020) processor with 4096K bytes of memory.
1 MCI controller.
1 Serial network interface.
32 terminal lines.
32K bytes of multibus memory.
32K bytes of non-volatile configuration memory.
Configuration register is 0x2
In the output, the first line is the bootstrap version string. The second through fourth lines list information about the system software; the version number is on the second line. Always specify the complete version number when reporting a possible software problem. In the sample output, the version number is 8.3, initial release.
The fifth line shows the system name and uptime. The sixth line indicates the reason the system was restarted, including in response to an error.
If the software was booted over the network, the seventh line shows the Internet address of the boot host; if the software was loaded from onboard ROM, this line reads "running default software." The eighth and ninth lines identify the names and sources of the host and network configuration files.
The remaining lines of output show the hardware configuration and any non-standard software options. The configuration register contents are displayed in hexadecimal notation.
Cisco Systems terminal servers include hardware and software to aid in tracking down problems with the terminal server or with other hosts on the network. The privileged EXEC command debug starts the console display of several classes of network events. The EXEC command show debugging displays the state of each debugging option.
The privileged EXEC command undebug turns off the console display. Each debug command option has a corresponding undebug command.
Normally, the debug command output goes only to the console terminal. To send a copy of this output to the current terminal, use the privileged EXEC command terminal monitor; use the terminal no monitor command to stop copying debug output to the line.
The debug ? command displays a list of the debug command options.
The debug all command enables logging of all possible debugging options.
The debug broadcast command enables logging of all broadcast traffic.
The debug modem command enables logging of modem control events, such as signal transitions and autobaud progress. The command syntax is:
The debug packet command enables logging of packets received with unknown packet types.
The debug printer command enables logging of printer events.
The debug rif command enables logging of information about the route information fields (RIF) in Token Ring packets.
The debug serial-interface command enables logging of serial-interface hardware events for protocol translators equipped with serial network interfaces.
The debug token-event command enables logging of Token Ring events, providing low-volume output.
The debug token-ring command enables logging of Token Ring behavior, providing high-volume output.
As an aid to diagnosing basic network connectivity, many network protocols support an echo mechanism. This involves sending a special datagram to the destination host, then waiting for a reply datagram from that host. Results from this echo protocol can help in evaluating the path-to-host reliability, delays over the path, and whether the host can be reached or is functioning.
To implement these features, use the privileged EXEC command:
pingThe ping command is the Cisco user interface to a number of echo protocols.
When the ping command is entered, the system issues a prompt for a protocol keyword. The default protocol is IP and it is the only one supported for the terminal server.
After determining the protocol type, the ping command prompts for an address or host name, repeat count (default is 5), datagram size (default is 100 bytes), timeout interval (default is 2 seconds), and extended commands (default is none). The precise dialogue varies from protocol to protocol.
If a host name or address is typed on the same line as the EXEC ping command, the default actions will be taken as appropriate for the protocol type of that name or address.
The ping command uses the exclamation point (!) and period (.) in its display. Each exclamation point indicates receipt of a reply. A period (.) indicates the network server timed out while waiting for a reply. Other characters may appear in the ping output display, depending on the protocol type. The output concludes with the success rate and minimum, average, and maximum round-trip times.
To abort a ping session, type the escape sequence (by default, Ctrl-^, X).
A sample display and tips for using the ping protocol follows.
For IP, the ping command sends ICMP Echo Request messages and waits for ICMP Echo Reply messages. The following example shows the ping command output for IP:
Protocol [ip]:
Target IP address: 192.31.7.17
Repeat count [5]: 50
Datagram size [100]: 500
Timeout in seconds [2]:
Extended commands [n]:
Type Ctrl^X to abort.
Sending 50, 500-byte ICMP Echos to 192.31.7.17, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent, round-trip min/avg/max = 16/22/36 ms
If the terminal server receives an ICMP Host Unreachable message during the ping session, the letter "U" will be printed out rather than a "!" or ".". The letter "N" indicates receipt of an ICMP Network Unreachable message, and the letter "P" indicates receipt of a Protocol Unreachable message. The letter "Q" indicates source quench received, and the character "?" indicates an unknown packet type.
The IP ping command, in verbose mode, accepts a data pattern. The pattern is specified as a 16-bit hexadecimal number. The default pattern is 0xABCD. Patterns such as all ones or all zeros can be used to debug data sensitivity problems on CSU/DSUs.
The trace command is a useful debugging command which allows the network administrator to discover the routes packets will actually take when travelling to their destination. The trace command supports IP route tracing. The command syntax is:
trace [destination]To invoke a simple trace test, enter the destination address or host name on the command line. The default parameters for the appropriate protocol are assumed and the tracing action begins.
To use non-default parameters and invoke an extended trace test, enter the command without a destination argument. You will be stepped through a dialogue to select the desired parameters.
Typing the escape sequence (by default, Ctrl-^, X) terminates a trace command.
The trace command works by taking advantage of the error messages generated by routers when a datagram exceeds its time-to-live (TTL) value.
The trace command starts by sending probe datagrams with a TTL value of one. This causes the first router to discard the probe datagram and send back an error message. The trace command sends several probes at each TTL level and displays the round trip time for each.
The trace command sends out one probe at a time. Each outgoing packet may result in one of two error messages. A time exceeded error message indicates that an intermediate router has seen and discarded the probe. A destination unreachable error message indicates that the destination node has received the probe and discarded it because it could not deliver the packet. If the timer goes off before a response comes in, trace prints an asterisk (*).
The trace command terminates when the destination responds, when the maximum TTL was exceeded, or when the user interrupts the trace with the escape sequence.
Due to bugs in the IP implementations of various hosts and routers, you may notice one or more of the following behaviors when using the trace command.
Not all destinations will correctly respond to a probe message by sending back an ICMP port unreachable message. A long sequence of TTL levels with only asterisks, terminating only when the maximum TTL has been reached, may indicate this problem.
There is a known problem with the way some hosts handle an ICMP TTL exceeded message. Some hosts generate an ICMP message but they re-use the TTL of the incoming packet. As this is zero, the ICMP packets do not make it back. When you trace the path to such a host, you may see a set of TTL values with asterisks (*). Eventually the TTL gets high enough that the ICMP message can get back. For example, if the host is six hops away, trace will time-out on responses six through 11. Response 12 and after should be fine.
When tracing IP routes, the following trace command parameters may be set:
Target IP address. You must enter a host name or an IP address. There is no default.
Source Address. One of the interface addresses of the terminal server to use as a source address for the probes. The terminal server will normally pick what it feels is the best source address to use.
Numeric Display. The default is to have both a symbolic and numeric display; however, you may suppress the symbolic display.
Timeout in seconds. The number of seconds to wait for a response to a probe packet. The default is three seconds.
Probe count. This is the number of probes to be sent at each TTL level. The default count is 3.
Minimum Time to Live [1]: The TTL value for the first probes. The default is 1, but may be set to a higher value to suppress the display of known hops.
Maximum Time to Live [30]: This is the largest TTL value which may be used. The default is 30. The trace command terminates when the destination is reached or when this value is reached.
Port Number. This is the destination port used by the UDP probe messages. The default is 33,434.
Loose, Strict, Record, Timestamp, Verbose. These are IP header options. You may specify any combination. The trace command issues prompts for the required fields. Note that trace will place the requested options in each probe; however, there is no guarantee that all routers (or end-nodes) will process the options.
Loose Source Routing. You may specify a list of nodes which must be traversed when going to the destination.
Strict Source Routing. You may specify a list of nodes which must be the only nodes traversed when going to the destination.
Record. You may specify the number of hops to leave room for.
Timestamp. You may specify the number of timestamps to leave room for.
Verbose. If you select any option, the verbose mode is automatically selected and trace prints the contents of the option field in any incoming packets. You can prevent verbose mode by selecting it again, toggling its current setting.
The following is an example of the simple use of the trace command with IP:
chaos#trace nic.ddn.mil
Type escape sequence to abort.
Tracing the route to NIC.DDN.MIL (26.0.0.73)
1 DEBRIS.CISCO.COM (131.108.1.6) 1000 msec 8 msec 4 msec
2 BARRNET-GW.CISCO.COM (131.108.16.2) 8 msec 8 msec 8 msec
3 EXTERNAL-A-GATEWAY.STANFORD.EDU (192.42.110.225) 8 msec 4 msec 4 msec
4 BB2.SU.BARRNET.NET (131.119.254.6) 8 msec 8 msec 8 msec
5 SU.ARC.BARRNET.NET (131.119.3.8) 12 msec 12 msec 8 msec
6 MOFFETT-FLD-MB.DDN.MIL (192.52.195.1) 216 msec 120 msec 132 msec
7 NIC.DDN.MIL (26.0.0.73) 412 msec 628 msec 664 msec
The following is an example going through the extended dialogue of the trace command:
chaos#trace
Protocol [ip]:
Target IP address: mit.edu
Source address:
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to MIT.EDU (18.72.2.1)
1 DEBRIS.CISCO.COM (131.108.1.6) 1000 msec 4 msec 4 msec
2 BARRNET-GW.CISCO.COM (131.108.16.2) 16 msec 4 msec 4 msec
3 EXTERNAL-A-GATEWAY.STANFORD.EDU (192.42.110.225) 16 msec 4 msec 4 msec
4 NSS13.BARRNET.NET (131.119.254.240) 112 msec 8 msec 8 msec
5 SALT_LAKE_CITY.UT.NSS.NSF.NET (129.140.79.13) 72 msec 64 msec 72 msec
6 ANN_ARBOR.MI.NSS.NSF.NET (129.140.81.15) 124 msec 124 msec 140 msec
7 PRINCETON.NJ.NSS.NSF.NET (129.140.72.17) 164 msec 164 msec 172 msec
8 ZAPHOD-GATEWAY.JVNC.NET (128.121.54.72) 172 msec 172 msec 180 msec
9 HOTBLACK-GATEWAY.JVNC.NET (130.94.0.78) 180 msec 192 msec 176 msec
10 CAPITAL1-GATEWAY.JVNC.NET (130.94.1.9) 280 msec 192 msec 176 msec
11 CHEESESTEAK2-GATEWAY.JVNC.NET (130.94.33.250) 284 msec 216 msec 200 msec
12 CHEESESTEAK1-GATEWAY.JVNC.NET (130.94.32.1) 268 msec 180 msec 176 msec
13 BEANTOWN2-GATEWAY.JVNC.NET (130.94.27.250) 300 msec 188 msec 188 msec
14 NEAR-GATEWAY.JVNC.NET (130.94.27.10) 288 msec 188 msec 200 msec
15 IHTFP.MIT.EDU (192.54.222.1) 200 msec 208 msec 196 msec
16 E40-03GW.MIT.EDU (18.68.0.11) 196 msec 200 msec 204 msec
17 MIT.EDU (18.72.2.1) 268 msec 500 msec 200 msec
In the output, an "!N" represents ICMP network unreachable, "!H" represents ICMP host unreachable, "!P" represents ICMP protocol unreachable, and "!Q" represents source quench received. The asterisk "*" represents time-out, and "?" represents unknown packet type.
All Cisco internetworking products include a server which implements a subset of DEC's Maintenance Operation Protocol (MOP) for Ethernet interfaces. The MOP server supports the request ID message, periodic system ID messages, and the remote console carrier functions.
The MOP server periodically multicasts a system ID message, which is used by DEC's Ethernet configurator to determine what stations are present in an Ethernet network. The configurator is controlled by the Network Control Program (NCP) command define module configurator. For more information on this command, consult DECnet or VAX documentation.
The Cisco internetworking products use a MOP communication device code of 121. This code has been assigned to Cisco by DEC, although some versions of DECnet-VAX software may report the code numerically, rather than with a device name. The DEC Ethernet product also makes use of receipt of system ID messages when building network maps.
The MOP server supports the DEC remote console function. Using this capacity, a system manager on a DECnet system can create a virtual terminal connection to a Cisco terminal server. Due to the nature of the MOP server, only a single inbound connection per Ethernet interface is supported. The MOP protocol does not contain the necessary mechanisms for supporting more than one connection at a time.
MOP is not a routable protocol. To bridge the MOP console carrier and system ID functions, you must enable bridging for protocol type 6002. The periodic system ID messages are sent to the multicast address AB00.0002.0000.
The EXEC command debug mop reports interesting events occurring within the MOP server, including reception of request ID messages, transmission of system ID messages, and reservation and release of the remote console.
To control whether MOP is enabled for an interface, use the mop enabled command. The command syntax is:
[no] mop enabledThe default is enabled.
Use the no mop enabled command to disable the MOP if you do not want to run it at all.
To control whether MOP periodic sysids messages are sent out to an interface, use the mop sysid command. The command syntax is:
[no] mop sysidYou can still run MOP without having the background sysid messages sent out. This lets you use the MOP remote console, but does not generate messages used by the configurator.
Use the no mop sysid command to disable MOP from sending the sysid messages.
As configured at the factory, the operating system software executes instructions in the onboard EPROM. If you have a CSC/3 CPU card, you need not change the system EPROMs with each software update. Instead, you can download the latest software over the network. This process is called netbooting.
Netbooting works as follows: when you power up your Cisco communication server product for the first time, it checks the processor configuration register or the non-volatile memory for special netbooting instructions. If the system finds no special instructions, it executes the default EPROM software.
If the system finds netbooting instructions, it determines its interface address and then runs a special process to load the new software into memory.
You can specify boot loading in two ways. The first way involves setting the low four bits of the processor configuration register; refer to the relevant Cisco Modular Products Hardware Installation and Reference publication for details. If no bits are set, you must manually boot the system using the System Bootstrap program.
If only the low bit is set, the system runs the default software. The system interprets any other binary bit combination as an octal number for use in forming the boot file name. The system forms the boot filename by starting with the word cisco and then appending the octal number, a hyphen, and the processor type name. The System Bootstrap program displays the processor type name at system startup.
For example, if bit one in the four-bit field is set and the processor type is CSC/3, the boot file name formed is cisco2-csc3. Assuming no other information is available, the system would try to TFTP-load the file cisco2-csc3 by first sending a broadcast TFTP read request to determine which server host had the file.
The second way to specify boot loading uses the non-volatile memory option, which enables you to provide more detailed instructions for software downloading. You can use the boot configuration command to specify both the boot file name and the IP address of the server host.
By default, the terminal server continues sending TFTP Read Request messages until it receives a response. The terminal server remains unusable as long as the network or the host with the specified file is unavailable. To limit the number of netbooting attempts, set bit 13 in the processor configuration register to 1. The terminal server then gives up after five netbooting attempts and returns to the ROM operating software.
The terminal server can use any network interface, regardless of the media type or encapsulation method, to load operating software. If the interface does not support broadcasts (for example, a terminal server using the X.25 interface does not), you must use the non-volatile memory to specify the address of the server host with the desired file.
To display the Internet address of the server host that provided the current operating software, use the EXEC command show version.
To reload the operating system, use the reload EXEC command. The command syntax is:
reloadThe reload command halts the terminal server. If the system is set to restart on error, it reboots itself.
This section describes the privileged write commands used to manage the system configuration information.
To erase the configuration information, use the write erase EXEC command. The command syntax is:
write eraseThis command erases the configuration information in the non-volatile memory. This command does not affect the configuration in use.
To save the configuration into non-volatile memory, use the write memory command. The command syntax is:
write memoryThis command copies the current configuration information to the non-volatile memory.
To save the configuration to the network via TFTP, use the write network command. The command syntax is:
write networkThis command sends a copy of the current configuration information to a server host. You are prompted for a destination host and a file name.
To write the configuration on the terminal, use the write terminal command. The command syntax is:
write terminalThis command displays the current configuration information on the terminal.
To send messages to one or all lines, use the privileged send EXEC command. The syntax for the command is:
send {line-number| *}To send a message to a particular line, use the argument line-number to specify the line. To send a message to all lines, use an asterisk (*). The system prompts for the message, which may be several text lines long. End the message by typing the Ctrl-Z key sequence. Type Ctrl-C to abort the command. This command can be used to inform users of an impending shutdown.
cisco-prompt# send all
Enter message, end with CTRL/Z; abort with CTRL/C:
System shutdown in 10 minutes.
<Ctrl-Z>
Send message? [confirm] yes
***
***
*** Message from tty56, cube CE10, to all terminals:
***
System shutdown in 10 minutes.
Included as part of the EXEC command set are commands that allow testing of system interface, system memory, asynchronous cards, and 16 Mbps Token Ring interfaces.
 | Caution Use of these commands is not recommended, as they are intended to aid Cisco manufacturing personnel in checking out system functionality. |
To test the network interface, use the test interfaces EXEC command. The command syntax is:
test interfacesThis command is intended for the factory checkout of network interfaces. It is not intended for diagnosing problems with an operational terminal server. The test interfaces output will not report correct results if the system is attached to a "live" network. For each network interface that has an IP address that can be tested in loopback (MCI Ethernet and all serial interfaces), the test interfaces command sends a series of ICMP echoes. Error counters are examined to determine the operational status of the interface.
To test the asynchronous cards for ASM and MSM systems, use the test lines EXEC command. The command syntax is:
test linesThis test runs software diagnostics on asynchronous serial interface cards that can be useful when analyzing hardware failures and suspected hardware failures. The command is not designed to be used on a system while the system is in use. This test should be used only at the direction of your Cisco technical support representative.
To test the system memory, use the test memory EXEC command. The command syntax is:
test memoryThis command performs a test of Multibus memory, including the non-volatile memory.
| Caution This test will overwrite the contents of memory. You will need to rewrite non-volatile memory after running this command. If you test Multibus memory, for example, the memory used by a CSC-R Token Ring interface, you will need to reload the system to restore correct operation of the network interfaces. |
To test the CSC-R16 16 Mbps Token Ring cards for ASM and MSM systems, use the test sbe EXEC command. The command syntax is:
test sbeThis test runs software diagnostics on 16 Mbps Token Ring interface boards that can be useful when analyzing hardware failures and suspected hardware failures. The command is not designed to be used on a system while the system is in use. This test should be used only at the direction of your Cisco technical support representative.
This section lists all system management interface subcommands in alphabetic order:
Controls whether MOP is enabled for an interface or disabled.
The default is enabled.
Use the no mop enabled to disable the MOP if you do not want to run it at all.
Controls whether MOP periodic sysids messages are sent out to an interface.
Use the no mop sysid to disable the MOP from sending the sysid messages.
This section lists all of the EXEC system management and user commands in alphabetic order.
Resets all interface counters listed in show interface statistics. The arguments type and unit specify the interface type and unit or card number (such as, Ethernet 0, Serial 0, or Token Ring 0).
Resets the hardware logic on an interface. The arguments type and unit specify the interface type and unit or card number (such as, Ethernet 0, Serial 0, or Token Ring 0).
This command aborts any connections, terminates the associated processes, and resets the data structures associated with a terminal line. The argument line-number specifies the terminal line number.
Maintains the Routing Information Field (RIF) cache for terminal servers with a Token Ring interface. This command clears all entries from the RIF cache. It applies only to terminal servers with Token Ring interfaces.
Issues a prompt for a protocol keyword. The default protocol is IP and it is the only one needed for terminal servers.
Halts the terminal server. If the system is set to restart on error, it reboots itself.
Sends messages to one or all lines. To send a message to a particular line, use the argument line-number to specify the line. To send a message to all lines, use an asterisk (*). The system prompts for the message, which may be several text lines long. End the message by typing the Ctrl-Z key sequence. Type Ctrl-C to abort the command.
Lists all the show command options. Two lists may be displayed, one at the user level prompt, and one at the enabled, privileged level prompt.
Displays statistics for the buffer pools on the terminal server. The terminal server has one pool of queuing "elements" and four pools of packet buffers of different sizes. The interface argument displays all the buffers for the specified interface.
Displays the contents of the non-volatile memory, if present and valid. The non-volatile memory stores the configuration information in the terminal server in text form as configuration commands.
show controllers {serial|token|mci}
Displays current internal status information for different interface cards. Use the keywords mci, serial or token to display the information about those cards.
Displays the current settings of the debug and undebug command options.
Displays statistics for the network interfaces on the network server.
Displays a summary status of terminal lines on the terminal server. Include the optional argument line-number to display detailed information about a particular line.
Displays the state of syslog error and event logging, including host addresses and whether console logging is enabled. This command also displays SNMP (Simple Network Monitoring Protocol) configuration parameters and protocol activity.
Displays memory free pool statistics. These statistics include summary information about the activities of the system memory allocator, and a block-by-block listing of memory use.
Displays the hardware status of any parallel printers attached to the terminal server.
Displays information about all active processes, including:
Displays information about your active terminal sessions. The information it displays includes the host name, address, number of characters waiting to be sent to the terminal, idle time, and connection name. An asterisk (*) indicates the users's current session.
Monitors the stack utilization of processes and interrupt routines. Its display includes the reason for the last system reboot.
Displays the configuration parameter settings for the current terminal. This command may be issued at the user level prompt.
Display information about the active lines of the network server, including the line number, connection names, and terminal location. Specify the keyword all to display information for both active and inactive lines. These commands enable monitoring of virtual terminal use. These commands may be issued at the user level prompt.
Displays the configuration of the system hardware, the software version strings, the names and sources of configuration files and/or boot images, and the Internet addresses of the interfaces.
terminal dispatch-character decimal-number1 [decimal-number2 ... decimal-numberx]
Sets up the packet dispatch character. Defines a character or string that causes a packet to be sent. The argument decimal-number is the ASCII decimal representation of the character or string.
Sets the line to maximum transparency file transfers. The terminal download command is used when running a program such as KERMIT, XMODEM, or CrossTalk that downloads a file across a terminal server line. It sets up the terminal line as a transparent pipe that can be used to transmit data:
The terminal no download command restores the line's original parameter settings.
terminal escape-character decimal-number
terminal no escape-character
Sets the escape character for the current terminal line. The argument decimal-number is the ASCII decimal representation of the desired escape character or an escape character (Ctrl-P, for example).
terminal flowcontrol {none | software [in | out] | hardware}
Sets the method of data flow control for the current terminal line.
The keyword software sets software flow control. An additional keyword specifies the direction: in causes the terminal server to listen to flow control from the attached device, and out causes the terminal server to send flow control information to the attached device. If you do not specify a direction, both directions are assumed.
The keyword hardware sets hardware flow control. For information about setting up the RS-232 line, see your respective Hardware Installation and Reference publication.
By default, no flow control method is set for a line.
terminal hold-character decimal-number
terminal no hold-character
Sets or changes the hold character for the current terminal line.
The argument decimal-number is either the ASCII decimal representation of the desired hold character or else a control sequence (for example, Ctrl-C). Typing the hold character temporarily halts the output at the terminal. To continue the output, type any other character. To send the hold character to the host, precede it with the escape character. By default, no local hold character is set.
The terminal no hold-character command clears the hold character.
Sets the number of lines on the screen of the current terminal. The argument screen-length is the desired number of lines. The default length is 24 lines. A value of 0 (zero) disables pausing between screens of output. The screen length specified can be learned by hosts.
Enables logging of system debugging and event messages on the current terminal. The terminal monitor command copies the system debugging and event messages to the current terminal. To use this command, you must first issue the enable command and enter the password to access the privileged command mode.
Establishes input notification. The terminal notify command causes the terminal server to notify you of pending output. The terminal no notify command ends such notifications.
terminal padding decimal-number count
terminal no padding decimal-number
Sets the character padding on the current terminal line. The argument decimal-number is the ASCII decimal representation of the character. It can be any of the 127 ASCII characters, up to 255 padding characters in length.
The argument count is the number of NUL bytes sent after that character.
The terminal no padding command ends this padding after the character represented by decimal-number.
terminal parity {none | even | odd | space | mark}
Defines the generation of the parity bit for the current terminal line.
The default setting is none.
Changes the transmit and receive speeds of the current terminal line.
When used, argument baud is typically specified as 300, 1200, 2400, 4800, 9600, 19200, or 38400, but can be set to any user-defined speed in a range from 75 to 57600.
The default speed is 9600 baud.
terminal start-character decimal-number
Sets the character that signals the start of data transmission when software flow control is in effect. The argument decimal-number is the ASCII decimal representation of the desired start character.
The default start character is Ctrl-Q (ASCII character 17).
terminal stopbits {1 | 1.5 | 2}
Sets the number of stop bits transmitted per byte by the current terminal line.
The default is 2 stop bits.
terminal stop-character decimal-number
Sets the character that signals the end of data transmission when software flow control is in effect. The argument decimal-number is the ASCII decimal representation of the desired stop character.
The default stop character is Ctrl-S (ASCII character 19).
Causes the current terminal line to send a Return (CR) as a CR followed by a NUL instead of a CR followed by a Line Feed (LF). This scheme permits interoperability with different interpretations of end-of-line handling in the Telnet protocol specification.
terminal terminal-type terminal-name
Records the current terminal type. The type in the argument terminal-name is passed as information to the remote host. The type specified in terminal-name is used by TN3270 for display management.
terminal transport [telnet|pad|rlogin|none]
Selects a preferred remote terminal protocol. This EXEC command sets the preferred protocol for the duration of the current session.
Sets the number of characters (columns) on a single line of the current terminal screen. The rlogin protocol uses the argument columns to set up terminal parameters on a remote UNIX host.
Sends a series of ICMP echoes. Error counters are examined to determine the operational status of the interface.
Runs software diagnostics on asynchronous serial interface boards.
Performs a test of Multibus memory, including the non-volatile memory.
Runs software diagnostics on 16 Mbps Token Ring interface boards.
Allows the network administrator to discover the routes packets will actually take when travelling to their destination. The command supports IP route tracing.
To invoke a simple trace test, enter the destination address or host name on the command line. The default parameters for the appropriate protocol are assumed and the tracing action begins.
To use non-default parameters and invoke an extended trace test, enter the command without a destination argument. You will be stepped through a dialogue to select the desired parameters.
Typing the escape sequence (by default, Ctrl-^, X) terminates a trace command.
Erases the configuration information in the non-volatile memory. This command does not affect the configuration in use.
Copies the current configuration information to the non-volatile memory.
Sends a copy of the current configuration information to a server host. You are prompted for a destination host and a file name.
Displays the current configuration information.
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