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This chapter describes how to manage the terminal server system. You will find information about these system processes and tasks in this chapter:
See the chapters containing information about the interfaces and protocols supported by Cisco software for descriptions of the interface- and protocol-specific debugging and monitoring commands.
Most of the system 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. Refer to the section "The EXEC Command Interpreter" in the chapter "Startup and Basic Configuration" for a description of system command levels and how to access them.
A command summary is included at the end of the chapter.
Use the privileged EXEC commands in this section to monitor and maintain the asynchronous serial lines.
To obtain the status of lines configured on the terminal server, use the show line EXEC command. The command syntax follows:
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 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 nonactivating 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 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 reset a terminal line, use the clear line command. The command syntax follows:
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.
This section describes the EXEC show commands you use to monitor the terminal server.
The show commands display information about the network and the interfaces to aid in troubleshooting and monitoring the system.
To display the list of the show command options, use the show ? EXEC command. The command syntax follows:
show ?The following is a sample output of the show ? command:
access-lists Access control lists
arp ARP cache
async-bootp Extended BOOTP information
buffers Network buffer utilization
configuration Display non-volatile configuration memory
controllers Network interface controller statistics
debugging State of debugging flags
entry Incoming queue entries
hosts Host/address cache
interfaces Network interface statistics
ip <keyword> Internet Protocol information, type ? for list
keymap [<name>] keymap data for tn3270
lat <keyword> LAT Protocol information, type ? for list
line <line> Line information, may specify a line
logging Logging information
memory Memory utilization statistics
printers Parallel printer status
processes Active system processes
sessions Telnet and rlogin connections
slip SLIP statistics
stacks Process and interrupt stack use
tcp <line> TCP information, may specify a line
terminal Terminal parameters
ttycap [<name>] ttycap data for tn3270
users Summary of active lines and connections
version Hardware configuration and software version
xremote <keyword> XRemote information, type ? for list
The terminal server has one pool of queuing elements and five pools of packet buffers of different sizes. For each pool, the terminal server keeps count 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. To display buffer pools, use the show buffers EXEC command. Enter this command at the EXEC prompt:
show buffers [interface]The optional argument interface causes 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 nonzero.
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 Middle buffers Big buffers Large buffers Huge buffers | Blocks of memory used to hold network packets. Totals indicate the number of buffers of a given size that currently exist. Buffers are dynamically allocated and the numbers increase and decrease depending upon system demand. |
| 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 in response to misses. |
| 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 that the system will create. |
| 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.
Use the show process memory command to monitor the memory utilization of processes. Enter this command at the EXEC prompt:
show process memoryThe following is a display of sample output. Table 1-2 describes the fields.
Total: 2416588, Used: 530908, Free: 1885680
PID TTY Allocated Freed Holding Process
0 0 462708 2048 460660 *Init*
0 0 76 4328 - 4252 *Sched*
0 0 82732 33696 49036 *Dead*
1 0 2616 0 2616 Net Background
2 0 0 0 0 Logger
21 0 20156 40 20116 IGRP Router
4 0 104 0 104 BOOTP Server
5 0 0 0 0 IP Input
6 0 0 0 0 TCP Timer
7 0 360 0 360 TCP Protocols
8 0 0 0 0 ARP Input
9 0 0 0 0 Probe Input
10 0 0 0 0 MOP Protocols
11 0 0 0 0 Timers
12 0 0 0 0 Net Input
13 0 2192 0 2192 TTY Background
14 0 0 0 0 TCP Driver
15 0 0 0 0 LAPB Timer
16 0 0 0 0 X25 Timer
17 0 0 0 0 HyBridge Input
22 0 108 108 0 Exec
19 0 104 0 104 IP SNMP
20 0 0 0 0 Spanning Tree
530936 Total
| Field | Description |
|---|---|
| PID | Process ID. |
| TTY | Terminal that controls the process. |
| Allocated | Sum of all memory that process has requested from the system. |
| Freed | How much memory a process has returned to the system. |
| Holding | Allocated memory minus freed memory. A value can be negative when it has freed more than it was allocated. |
| Process | Process name. |
| *Init* | System initialization. |
| *Sched* | The scheduler. |
| *Dead* | Processes as a group that are now dead. |
| Total | Total amount of memory held. |
To display the system configuration, use the show configuration EXEC command. The command syntax follows:
show configurationThis privileged command displays the contents of nonvolatile memory, if present and valid. Nonvolatile memory stores the configuration information in text form as configuration commands.
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 chapter "System Configuration" for an explanation of how to configure message logging. Following is a sample output. Table 1-3 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, the number of messages logged, and the retransmission interval. |
To display the activity statistics for the systems memory allocator, use the show memory EXEC command. The command syntax follows:
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 1-4 describes the fields and Table 1-5 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 the previous block (should match the Address on the previous line) |
| Next | Address of the next block (should match the address on the next line) |
| Free? | Tells if the block is free |
| Alloc PC | Address of the system call that allocated the block |
| What | Name of the process that owns the block |
To display the status of printers, use the show printers command. The command syntax follows:
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 show processes command output. Table 1-6 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 |
|---|---|
| CPU utilization | Provides a general idea of how busy the processor is. It is a ratio of the current idle time over the longest idle time. This information should be used as an estimate only. |
| 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 the process |
To display stack utilizations, use the show stacks command. The command syntax follows:
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.
The show version or the show hardware command displays the configuration of the system hardware, the software version, the names and sources of configuration files, and the boot images. Enter one of these commands at the EXEC prompt:
show versionThe following shows sample output from this command:
TS Software (TS3-L), Version 9.0(1)
Copyright (c) 1986-1991 by cisco Systems, Inc.
Compiled Tue 24-Mar-92 11:44 by kph
System Bootstrap, Version 4.4(0.4)
char uptime is 5 weeks, 6 days, 6 hours, 27 minutes
System restarted by power-on
System image file is "alpha.ts2", booted via tftp from 131.21.13.3
CSC3 (68020) processor with 4096K bytes of memory.
SuperLAT software (copyright 1990 by Meridian Technology Corp).
1 MCI controller (0 Ethernet, 1 Serial).
1 Serial network interface.
32 terminal lines.
32K bytes of multibus memory.
32K bytes of non-volatile configuration memory.
Configuration register is 0x2002
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. The fifth line shows the system name and uptime, or the amount of time the system has been up and running. The sixth line provides a log of how the system was last booted, both as a result of normal system startup and of system error. For example, this line may be displayed to indicate a bus error that is generally the result of an attempt to access a nonexistent address:
System restarted by bus error at PC0XC4CA address 0X210C0C0
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 nonstandard software options. The configuration register contents are displayed in hexadecimal notation.
The Flash Memory Card allows system software images to be stored, booted, and rewritten as necessary. This card, known as the CSC-MC+, is supported on the A, M, and C chassis platforms.The CSC-MC+ provides a more fault-tolerant solution to users who netboot exclusively. The CSC-MC+ reduces the effects of network failure on system netbooting. The CSC-MC+ card replaces the nonvolatile memory card (CSC-MC) used in the M and C platform systems, and connects to the Multiport Communications Interface (MCI-3) card by a 50-pin flat cable.
The following list briefly describes the features of the CSC-MC+ card:
Refer to the Hardware Installation and Reference publication for your particular communications server for the hardware requirements and step-by-step installation instructions.
Use the show flash EXEC command to display the total amount of Flash memory present on the Flash card, the type of card connected to the Flash card, any files that may currently exist in Flash memory and their size, and the amounts of Flash memory used and remaining.
Use the show flash all EXEC command to display all information displayed by show flash and also all the information about each Flash memory device.
Once you configure Flash, the show flash or show flash all commands will display the names of the system software images. The command syntax follows:
show flashFollowing is sample output of the show flash command:
TS#show flash
4096K bytes of flash memory on MC+ card (via MCI).
Contains:
ts3-rx.90-0.1 (1648952)
STS10X.45-0.4 (30444)
[835192/4194304 bytes free]
Following is sample output of the show flash all command:
TS#show flash all
4096K bytes of flash memory on MC+ card (via MCI).
ROM 0, U2 , code 0x89BD, size 0x40000, name INTEL 28F020
ROM 1, U19, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 2, U3 , code 0x89BD, size 0x40000, name INTEL 28F020
ROM 3, U20, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 4, U4 , code 0x89BD, size 0x40000, name INTEL 28F020
ROM 5, U21, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 6, U5 , code 0x89BD, size 0x40000, name INTEL 28F020
ROM 7, U22, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 8, U9 , code 0x89BD, size 0x40000, name INTEL 28F020
ROM 9, U26, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 10, U10, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 11, U27, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 12, U11, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 13, U28, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 14, U12, code 0x89BD, size 0x40000, name INTEL 28F020
ROM 15, U29, code 0x89BD, size 0x40000, name INTEL 28F020
Contains:
ts3-rx.90-0.17 (1648952) [invalidated]
ts3-rx.90-0.17 (1648952)
STS10X.45-0.4 (30444) [invalidated]
STS10X.45-0.4 (30444)
[835192/4194304 bytes free]
Note the [invalidated] flag at the end of the second example. This flag will appear when a file is rewritten (recopied) into Flash memory. A prompt will tell you that the identical file already exists and that it will be invalidated. The first (now invalidated) copy of the file is still present within Flash memory, but it is rendered unusable in favor of the newest version.
To eliminate any files from Flash (invalidated or otherwise) and free up all available memory space, the entire Flash memory must be erased; individual files cannot be erased from Flash memory.
Both examples illustrate that the Flash memory can store and display multiple, independent software images. This feature would be most useful for storing default system software as a back-up.
In the second example, ROM 0 is at location U2 on the Flash Memory Card. The code is a vendor code; size is in hex bytes; INTEL is the vendor name; and the last number is the chip part number.
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 debug EXEC commands start the console display of several classes of network events. The EXEC command show debugging displays the state of each debugging option.
Each debug command option has a corresponding undebug command that turns message logging off.
For a list and brief description of all the debug command options, enter the debug ? command at the privileged-level EXEC prompt. This section provides an overview of how to use the debugging commands and a table of the most commonly used system debugging commands. See the interface- and protocol-specific chapters for other debug command descriptions.
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 output to the line.
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 that 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: 131.108.19.5
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 131.108.19.5, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent, round-trip min/avg/max = 16/22/36 ms
| Char | Description |
|---|---|
| ! | Reply received. |
| . | Server timed out waiting for reply. |
| U | Server received a Host Unreachable message. |
| N | Server received a Network Unreachable message. |
| P | Server received a Protocol Unreachable message. |
| Q | Server received a Source Quench Received message. |
| ? | Server received an Unknown Packet Type message. |
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 that 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 follows:
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 nondefault 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:
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
| Char | Description |
|---|---|
| !N | Server received a Network Unreachable message. |
| !H | Server received a Host Unreachable message. |
| !P | Server received a Protocol Unreachable message. |
| !Q | Server received a Source Quench message. |
| ? | Server received an Unknown Packet Type message. |
| * | Server timed out. |
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 follows:
write eraseThis command erases the configuration information in nonvolatile memory. This command does not affect the configuration in use.
To save the current configuration and copy it into nonvolatile memory, use the write memory command. The command syntax follows:
write memoryThis command copies the current configuration information to nonvolatile memory.
To save the configuration to the network via TFTP, use the write network command. The command syntax follows:
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 follows:
write terminalThis command displays the current configuration information on the terminal.
Included as part of the EXEC command set are commands that allow testing of the system interface, system memory, asynchronous cards, and 16 Mbps Token Ring interfaces.
 | Caution Using these commands is not recommended, as they are intended to aid Cisco manufacturing personnel in checking system functionality. |
To test the network interfaces, use the test interfaces EXEC command. The command syntax follows:
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 follows:
test linesThis test runs software diagnostics on asynchronous serial 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.
To test system memory, use the test memory EXEC command. The command syntax follows:
test memoryThis command performs a test of Multibus memory, including nonvolatile memory.
| Caution This test will overwrite the contents of memory. You will need to rewrite nonvolatile memory after running this command. If you test Multibus memory, 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 follows:
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 provides an alphabetical list of the EXEC system management commands described in this chapter:
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.
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 debug packet command enables logging of packets received with unknown packet types.
The debug printer command enables logging of printer events.
Issues a prompt for a protocol keyword. The default protocol is IP and it is the only one needed for terminal servers.
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 nonvolatile memory, if present and valid. Nonvolatile memory stores the configuration information in the terminal server in text form as configuration commands.
Displays the current settings of the debug and undebug command options.
The show flash command displays the total amount of Flash memory present on the Flash card, the type of card connected to the Flash card, any files that may currently exist in Flash memory and their size, and the amounts of Flash memory used and remaining.
The show flash all command displays all information displayed by show flash and also all the information about each Flash memory device.
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.
show process memory
Displays memory utilization.
Displays the hardware status of any parallel printers attached to the terminal server.
Displays information about all active processes, including:
Monitors the stack utilization of processes and interrupt routines. Its display includes the reason for the last system reboot.
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 nonvolatile 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 nondefault 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 nonvolatile memory. This command does not affect the configuration in use.
Copies the current configuration information to nonvolatile 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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