Table of Contents

T Commands for the LightStream 1010 ATM Switch

tacacs-server attempts

To control the number of login attempts that can be made on a line set up for TACACS verification, use the tacacs-server attempts global configuration command. To remove this feature and restore the default, use the no form of this command.

tacacs-server attempts count
no tacacs-server attempts

Syntax Description

Default

Three attempts

Command Mode

Global configuration

Usage Guidelines

Refer to the LightStream 1010 ATM Switch User Guide for more information about the tacacs-server attempts global configuration command.

Example

The following example changes the login attempt to just one try.

tacacs-server directed-request

To send only a username to a specified TACACS server when a direct request is issued, use the tacacs-server directed-request global configuration command. To disable the direct-request feature, use the no form of this command.

tacacs-server directed-request
no tacacs-server directed-request

Syntax Description

This command has no keyword or arguments.

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

This command sends only the portion of the username before the "@" symbol to the host specified after the "@" symbol. With the directed-request feature enabled, you can direct a request to any of the configured servers, and only the username is sent to the specified server.

Disabling tacacs-server directed-request causes the entire string, both before and after the "@" symbol, to be sent to the default TACACS server. When the directed-request feature is disabled, the switch queries the list of servers, starting with the first one in the list, sending the entire string, and accepting the first response that it gets from the server. The tacacs-server directed-request command is useful when you want to develop your own TACACS server software that parses the whole string and makes decisions based on the output.

When tacacs-server directed-request is enabled, only configured TACACS servers can be specified by the user after the "@" symbol. If the host name specified by the user does not match the IP address of a TACACS server configured by the administrator, the user input is rejected.

Use the no form of this command to disable the ability of the user to choose between configured TACACS servers and to cause the entire string to be passed to the default server.

Example

The following example disables directed-request so that the entire user input is passed to the default TACACS server.

tacacs dns-alias-lookup

To enable IP DNS alias lookup for TACACS+, use the tacacs dns-alias-lookup global configuration command. To disable this feature, use the no form of this command.

tacacs dns-alias-lookup
no tacacs dns-alias-lookup

Syntax Description

This command has no keywords or arguments.

Default

Disabled

Command Mode

Global Configuration

Usage Guidelines

This command enables IP Domain Name System alias lookup for TACACS servers.

tacacs-server extended

To enable extended TACACS mode, use the tacacs-server extended global configuration command. To disable the mode, use the no form of this command.

tacacs-server extended
no tacacs-server extended

Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

Refer to the LightStream 1010 ATM Switch User Guide for more information about the tacacs-server extended global configuration command.

Example

The following example enables extended TACACS mode.

tacacs-server host

To specify a TACACS host, use the tacacs-server host global configuration command. You can use multiple tacacs-server host commands to specify multiple hosts. The software searches for the hosts in the order you specify them. To delete the specified name or address, use the no form of this command.

tacacs-server host name
no tacacs-server host name

Syntax Description

Default

No TACACS host is specified.

Command Mode

Global configuration

Usage Guidelines

Refer to the LightStream 1010 ATM Switch Configuration Guide for more information about the tacacs-server host global configuration command.

Example

The following example specifies a TACACS host named SCACAT.

Related Commands

aaa authentication ppp
login
slip

tacacs-server key

To set the authentication/encryption key used for all TACACS+ communications between the access server and the TACACS+ daemon, use the tacacs-server key global configuration command. To disable the key, use the no form of the command.

tacacs-server key key
no tacacs-server key [key]

Syntax Description

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

After enabling AAA with the aaa new-model command, you must set the authentication and encryption key using the tacacs-server key command.

The key entered must match the key used on the TACACS+ daemon. All leading spaces are ignored; spaces within and at the end of the key are not. If you use spaces in your key, do not enclose the key in quotation marks unless the quotation marks themselves are part of the key.

Example

The following example shows how to set the authentication and encryption key to "dare to go".

Related Commands

aaa new-model
tacacs-server host

tacacs-server last-resort

To cause the network server to request the privileged password as verification or to force successful login without further input from the user, use the tacacs-server last-resort global configuration command. To restore the system to the default behavior, use the no form of this command.

tacacs-server last-resort {password | succeed}
no tacacs-server last-resort {password | succeed}

Syntax Description

Default

If, when running the TACACS server, the TACACS server does not respond, the default action is to deny the request.

Command Mode

Global configuration

Usage Guidelines

Use the tacacs-server last-resort command to be sure that login can occur; for example, a systems administrator must log in to troubleshoot TACACS servers that might be down.

Refer to the LightStream 1010 ATM Switch User Guide for more information about the tacacs-server last-resort global configuration command.

Example

The following example forces successful login.

Related Commands

enable password
login

tacacs-server optional-passwords

To specify that the first TACACS request to a TACACS server be made without password verification, use the tacacs-server optional-passwords global configuration command. To restore the default, use the no form of this command.

tacacs-server optional-passwords
no tacacs-server optional-passwords

Syntax Description

This command has no arguments or keywords.

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

When the user enters the login name, the login request is transmitted with the name and a zero-length password. If accepted, the login procedure completes. If the TACACS server refuses this request, the server software prompts for a password and tries again when the user supplies a password. The TACACS server must support authentication for users without passwords to make use of this feature. This feature supports all TACACS requests—login, SLIP, enable, and so on.

Refer to the LightStream 1010 ATM Switch Configuration Guide for more information about the tacacs-server optional-passwords global configuration command.

Example

The following example configures the first login to not require TACACS verification.

tacacs-server retransmit

To specify the number of times the switch software searches the list of TACACS server hosts before giving up, use the tacacs-server retransmit global configuration command. The switch software tries all servers, allowing each one to timeout before increasing the retransmit count. To restore the default, use the no form of this command.

tacacs-server retransmit retries
no tacacs-server retransmit

Syntax Description

Default

Two retries

Command Mode

Global configuration

Usage Guidelines

Refer to the LightStream 1010 ATM Switch Configuration Guide for more information about the tacacs-server retransmit global configuration command.

Example

The following example specifies a retransmit counter value of 5.

tacacs-server timeout

To set the interval that the server waits for a server host to reply, use the tacacs-server timeout global configuration command. To restore the default, use the no form of this command.

tacacs-server timeout seconds
no tacacs-server timeout

Syntax Description

Default

5 seconds

Command Mode

Global configuration

Usage Guidelines

Refer to the LightStream 1010 ATM Switch Configuration Guide for more information about the tacacs-server timeout global configuration command.

Example

The following example changes the interval timer to 10 seconds.

tag-switching atm allocation-mode

To control the mode used for handling tag binding requests on TC ATM interfaces, use the tag-switching atm allocation-mode global configuration command. To set the allocation mode to its default, use the no form of this command.

tag-switching atm allocation-mode {optimistic | conservative}
no tag-switching atm allocation-mode {optimistic | conservative}

Syntax Description

Default

Conservative

Command Mode

Global configuration

Example

The following example sets the mode for handling binding requests to optimistic on TC ATM interfaces.

tag-switching atm control-vc

To configure the VPI/VCI to be used for the initial link to the tag switching peer, use the tag-switching atm control-vc interface configuration command. This control VC is used to establish the TDP session and carry non-IP traffic. To set the control VPI/VCI to the default, use the no form of this command.

tag-switching atm control-vc vpi vci
no tag-switching atm control-vc vpi vci

Syntax Description

Default

0/32

Command Mode

Interface configuration

Usage Guidelines

On a VP tunnel, the default VPI is the tunnel number and the default VCI is 32.

Example

The following example shows how to select VPI 1 and VCI 34 as the control VC.

Related Command

tag-switching ip (interface)

tag-switching atm vc-merge

To control whether VC-merge (multipoint-to-point VCs) is supported for unicast tag VCs, use the tag-switching atm vc-merge global configuration command. To disable this feature, use the no form of this command.

tag-switching atm vc-merge
no tag-switching atm vc-merge

Syntax Description

This command has no keywords or arguments.

Default

Enabled.

Command Mode

Global configuration

Example

Since the default mode is to enable VC merge, it is not necessary to issue the tag-switching atm vc-merge command. However to disable VC merge, you must enter the no form of the command.

Related Commands

show tag-switching atm-tdp bindings
show tag-switching atm-tdp capability

tag-switching atm vpi

To configure the range of values to use in the VPI field for tag VCs, use the tag-switching atm vpi interface configuration command. To clear the interface configuration, use the no form of this command.

tag-switching atm vpi vpi [- vpi]
no tag-switching atm vpi vpi [- vpi]

Syntax Description

Default

1 - 1

Command Mode

Interface configuration

Usage Guidelines

The value will be negotiated with its peer.

You cannot enter a VPI range on a VP tunnel; the VPI is the PVP number of the tunnel.

If the TDP neighbor is a router, the VPI range cannot be larger than 2; for example, from 5 to 6 (a range of 2), not 5 to 7 (a range of 3).

Example

The following example shows you how to select a VPI range from 5 to 6.

tag-switching ip (global)

To allow tag switching of IPv4 packets, use the tag-switching ip global configuration command. To disable IP tag switching across all interfaces, use the no form of this command.

tag-switching ip
no tag-switching ip

Syntax Description

This command has no keywords or arguments.

Default

Enabled

Command Mode

Global configuration

Usage Guidelines

Dynamic tag switching (that is, the distribution of tags based on routing protocols) is allowed by this optional command, but is not actually enabled until the interface-level tag-switching ip command is issued on at least one interface. The no form of this command stops the distribution of dynamic tags and the sending of outgoing tagged packets on all interfaces. The sending of tagged packets on TSP tunnels is not affected by this command.

For TC ATM, the no form of this command prevents tag VCs beginning at, terminating at, or passing through the platform.

Example

The following example shows how to enable the distribution of dynamic tags on all interfaces.

Related Command

tag-switching ip (interface)

tag-switching ip (interface)

To enable tag switching of IPv4 packets on an interface, use the tag-switching ip interface configuration command. To disable IP tag switching on an interface, use the no form of this command.

tag-switching ip
no tag-switching ip

Syntax Description

This command has no keywords or arguments.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

The first time this command is issued on any interface, dynamic tag switching is enabled on the entire switch. TDP Hellos are issued on this interface. When an outgoing tag for a destination routed out through this interface is received, packets sent to that destination are tagged as outgoing.

The no form of this command causes packets routed out through this interface to be sent as untagged, and outgoing TDP Hellos are no longer sent.

When the no form is issued on the only interface for which tag switching is enabled, dynamic tag switching is disabled on the entire switch.

For TC ATM, the no form of this command prevents tag VCs beginning at, terminating at, or passing through the this interface.

Example

In the following example, tag switching is enabled on ATM interface 1/1/0.

Related Commands

tag-switching atm allocation-mode
tag-switching ip (global)

tag-switching tdp discovery

To configure the interval between transmission of TDP discovery Hello messages and the hold time for a TDP transport connection, use the tag-switching tdp discovery global configuration command. To set the interval and hold time to their defaults, use the no form of this command.

tag-switching tdp discovery {hello | directed-hello} {holdtime | interval} seconds
tag-switching tdp discovery {hello | directed-hello} {holdtime | interval}

Syntax Description

Default

See the syntax descriptions.

Command Mode

Global configuration

Example

In the following example, the interval for which a connection stays up if no Hello packets are received is set to 5 seconds.

Related Commands

show tag-switching interfaces
show tag-switching atm-tdp summary
show tag-switching tdp parameters

tag-switching tdp holdtime

To configure the hold time for a TDP session, use the tag-switching tdp holdtime global configuration command. To set the hold time to the default, use the no form of this command.

tag-switching tdp holdtime seconds

Syntax Description

Default

15 seconds

Command Mode

Global configuration

Usage Guidelines

When a TDP session is initiated, the hold time is negotiated to the lower of the values configured at the two ends.

This command configures the hold time determined by this tag switch.

Example

The following example configures the hold time of TDP sessions to 30 seconds.

Related Command

show tag-switching tdp parameters

tag-switching tsp-tunnels

To enable support for TSP tunnel negotiation, use the tag-switching tsp-tunnels global configuration command or interface configuration command. To disable support for TSP tunnel negotiation, use the no form of this command.

tag-switching tsp-tunnels
no tag-switching tsp-tunnels

Syntax Description

This command has no keywords or arguments.

Default

Disabled

Command Modes

Global configuration
Interface configuration

Usage Guideline

Enabling TSP tunnel negotiation using the tag-switching tsp-tunnels command in the interface configuration mode has no effect unless command is also issued in the global configuration mode.

Example

The following example shows how to enable TSP tunnel negotiation globally, then enable it at the interface.

Related Command

show tag-switching tsp-tunnels

telnet

To log on to a host that supports Telnet, use the telnet EXEC command.

telnet hostname [keyword] [port]

Syntax Description

Table 20-1   Telnet Connection Options

Default

VT100

Command Mode

Line configuration

Usage Guidelines

The argument terminal-name provides a record of the terminal type and allows terminal negotiation of display management by hosts that provide that type of service.

Example

The following example defines the terminal on the console as a type VT220.

Related Command

terminal terminal-type

test

To test the system interfaces on the modular switch, use the test EXEC command.

test

Syntax Description

This command has no arguments or keywords.

Command Mode

EXEC

Usage Guidelines

The test EXEC command is intended for the factory checkout of network interfaces. It is not intended for diagnosing problems with an operational switch. The test output does not report correct results if the switch is attached to an active network. For each network interface that has an IP address that can be tested in loopback (MCI and ciscoBus Ethernet and all serial interfaces), the test command sends a series of ICMP echoes. Error counters are examined to determine the operational status of the interface.

Example

The following example illustrates how to begin the interface test.

tftp-server

To specify that the switch or Flash device operates as a TFTP server, use the tftp-server global configuration commands. To remove a previously defined filename, use the no form of this command with the appropriate filename.

tftp-server flash [device:] filename1 [alias filename2] [rom alias filename2] [atm-accounting
filename3]
no tftp-server flash [device:] filename1 [alias filename2] [rom alias filename2]
[atm-accounting filename3]

Syntax Description

Default

Disabled

Command Mode

Global configuration

Usage Guidelines

You can specify multiple filenames by repeating the tftp-server command. The system sends a copy of the system image contained in ROM or one of the system images contained in Flash memory to any client that issues a TFTP Read Request with this filename.

If the specified filename1 or filename2 exists in Flash memory, a copy of the Flash image is sent. On systems that contain a complete image in ROM, the system sends the ROM image if the specified filename1 or filename2 is not found in Flash memory.

Images that run from ROM cannot be loaded over the network. Therefore, you should not use TFTP to offer the ROMs on these images.

The system sends a copy of the file contained on one of the Flash memory devices to any client that issues a TFTP Read Request with its filename.

Examples

In the following example, the system uses TFTP to send a copy of the version-11.1 file located in Flash memory in response to a TFTP Read Request for that file. The requesting host is checked against access list 22.

In the following example, the system uses TFTP to send a copy of the version-11.1.4 file in response to a TFTP Read Request for that file. The file is located on the Flash memory card inserted in slot 0 of the ASP card.

Related Command

access-list (extended)

timer

To configure the PNNI timers, use the timer PNNI node configuration command. To return to the default values, use the no form of this command.

timer [ack delay tenths-of-seconds] [called-integrity seconds]
[calling-integrity seconds] [hello-holddown tenths-of-seconds] [hello-interval seconds]
[hrz-link-inactivity seconds] [inactivity-factor number] [retransmit-interval seconds]
no timer [ack delay] [called-integrity] [calling-integrity] [hello-holddown] [hello-interval]
[hrz-link-inactivity] [inactivity-factor] [retransmit-interval]

Syntax Description

Default

See the syntax descriptions.

Command Mode

PNNI node configuration

Usage Guidelines

Decreasing the hello-interval allows PNNI to detect neighbor nodes that have stopped functioning more quickly. The inactivity-factor is used as a multiplier of the hello-interval in received Hello packets to determine the dead interval, the time after which the neighbor node is declared down if no Hello packets are received. The inactivity-factor can be increased on unreliable interfaces to avoid false alarms.

Decreasing the retransmit-interval causes retransmission to increase when a PNNI packet gets lost. However, this increases the risk of unnecessarily retransmitting PNNI packets that are delayed but actually reaches the neighbor. Increasing ack-delay causes more PTSEs to be acknowledged in one ack packet. Lowering hello-holddown allows another Hello packet to be sent shortly after one was sent. To avoid an overload in switch processing, you should adjust these parameters carefully.

For more information, refer to the LightStream 1010 ATM Switch Software Configuration Guide.

Example

The following script shows how to change the hello-interval to 5 seconds.

Related Command

show atm pnni local-node

traceroute (privileged)

traceroute (user)

To trace the IP routes the packets actually take when traveling from the switch to their destination, use the traceroute EXEC command.

traceroute [protocol] [destination]

Syntax Description

Default

The protocol argument is based on the switch's examination of the format of the destination argument. For example, if the switch finds a destination in IP format, the protocol defaults to ip.

Command Mode

EXEC

Usage Guidelines

The traceroute command works by taking advantage of the error messages generated by switches when a datagram exceeds its TTL value.

The traceroute command starts by sending probe datagrams with a TTL value of 1. This causes the first switch to discard the probe datagram and send back an error message. The traceroute command sends several probes at each TTL level and displays the round-trip time for each.

The traceroute command sends out one probe at a time. Each outgoing packet may result in one or two error messages. A "time exceeded" error message indicates that an intermediate switch detected and discarded the probe. A "destination unreachable" error message indicates that the destination node received and discarded the probe because it could not deliver the packet. If the timer goes off before a response comes in, traceroute prints an asterisk (*).

The traceroute command terminates when the destination responds, when the maximum TTL is exceeded, or when the user interrupts the trace with the escape sequence. By default, to invoke the escape sequence, enter ^ X.

Common Trace Problems

Due to bugs in the IP implementation of various hosts and switches, the IP trace command may behave in unexpected ways.

Not all destinations respond correctly 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 is 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 reuse the TTL of the incoming packet. Since 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 6 hops away, traceroute times out on responses 6 through 11.

Sample Display Showing Trace IP Routes

The following display shows sample IP traceroute output when a destination host name is specified.

Table 20-3 describes the fields shown in the display.

Table 20-3   Trace Field Descriptions

Default

Telnet

Command Mode

Line configuration

Usage Guidelines

Specify transport preferred none to prevent errant connection attempts.

Example

The following example sets the preferred protocol to Telnet on virtual terminal line 1.

Related Commands

terminal transport preferred
transport

tunnel

tx-queue-limit

txspeed

To set the terminal transmit baud rate (to terminal), use the txspeed line configuration command. To disable this feature, use the no form of this command.

txspeed bps
no txspeed

Syntax Description

Default

9600 bps

Command Mode

Line configuration

Usage Guidelines

Set the speed to match the baud rate of the device you have connected to the port. Some baud rates available on devices connected to the port might not be supported on the switch. The switch indicates if the speed you select is not supported. The following is a list of available line speeds, shown in bits per second:

75, 110, 134, 150, 300, 600, 1200, 2000, 2400, 4800, 1800, 9600, 19200, 38400

Example

The following example sets the auxiliary line transmit speed to 2400 bps.

Related Commands

rxspeed
speed