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The commands shown in this chapter apply to the Catalyst 8540 MSR, Catalyst 8510 MSR, and LightStream 1010 ATM switch routers. Where an entire command or certain attributes of a command have values specific to a particular switch or switch router, an exception is indicated by the following callouts:
Refer to Appendix D of this command reference for a detailed list of commands that have been removed, changed or replaced.
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.
Syntax Description
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Defaults
Command Modes
Command History
Examples
The following example sets the mode for handling binding requests to optimistic on TC ATM interfaces.
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.
Syntax Description
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Defaults
Command Modes
Command History
Usage Guidelines
On a VP tunnel, the default VPI is the tunnel number and the default VCI is 32.
Examples
The following example shows how to select VPI 1 and VCI 34 as the control VC.
Related Commands
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.
Syntax Description
This command has no keywords or arguments.
Defaults
Command Modes
Command History
Usage Guidelines
This feature is enabled by default.
Examples
Because this feature is enabled by default, 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
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.
Syntax Description
Defaults
Command Modes
Command History
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).
Examples
The following example shows you how to select a VPI range from 5 to 6.
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.
Syntax Description
This command has no keywords or arguments.
Defaults
Command Modes
Command History
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.
Examples
The following example shows how to enable the distribution of dynamic tags on all interfaces.
Related Commands
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.
Syntax Description
This command has no keywords or arguments.
Defaults
Command Modes
Command History
Usage Guidelines
The first time this command is issued on any interface, dynamic tag switching is enabled on the entire switch router. 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 router.
For TC ATM, the no form of this command prevents tag VCs beginning at, terminating at, or passing through the interface.
Examples
In the following example, tag switching is enabled on ATM interface 1/1/0.
Related Commands
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.
Syntax Description
Defaults
Command Modes
Command History
Examples
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
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.
Syntax Description
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Defaults
Command Modes
Command History
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.
Examples
The following example configures the hold time of TDP sessions to 30 seconds.
Related Commands
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.
Syntax Description
This command has no keywords or arguments.
Defaults
Command Modes
Global configuration
Interface configuration
Command History
Usage Guidelines
Enabling TSP tunnel negotiation using the tag-switching tsp-tunnels command in the interface configuration mode has no effect unless the command is also issued in the global configuration mode.
Examples
The following example shows how to enable TSP tunnel negotiation globally, then enable it at the interface.
Related Commands
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.
Syntax Description
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Defaults
Command Modes
Command History
Usage Guidelines
You can specify multiple filenames by repeating the tftp-server command. The system sends a copy of the system image contained in memory to any client that issues a TFTP Read Request with this filename.
If the specified filename exists in memory, a copy of the image is sent.
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 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 route processor card.
Related Commands
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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.
Syntax Description
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Defaults
Command Modes
Command History
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 reach 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 ATM Switch Router Software Configuration Guide.
Examples
The following script shows how to change the hello-interval to 5 seconds.
Related Commands
To trace the IP routes the packets actually take when traveling from the switch to their destination, use the traceroute EXEC command.
Syntax Description
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Defaults
The protocol argument is based on the switch router's examination of the format of the destination argument. For example, if the switch router finds a destination in IP format, the protocol defaults to ip.
Command Modes
Command History
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Usage Guidelines
The traceroute command works by taking advantage of the error messages generated by switch routers 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 router 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 router 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.
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 in 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 in responses 6 through 11.
Examples
The following example displays sample IP traceroute output when a destination host name is specified:
Table 19-1 describes the fields shown in the display.
Table 19-1 Trace Field Descriptions
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Table 19-2 describes the characters that can appear in traceroute output.
Table 19-2 IP Trace Text Characters
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Related Commands
To indicate to the network that this node does not allow calls to transit through, use the transit-restricted PNNI node configuration command. To allow calls to transit through the node,
use the no form of this command.
Syntax Description
This command has no keywords or arguments.
Defaults
Command Modes
Command History
Usage Guidelines
This command enables the network administrator to prevent connections from transiting nodes that only originate or terminate connections, for example, low-end edge switches that do not have the capacity to support transit calls.
For more information, refer to the ATM Switch Router Software Configuration Guide.
Examples
The following script shows how to access the transit-restricted PNNI node configuration command.
Related Commands
To configure T1 framing mode, use the t1 framing controller configuration command.
Syntax Description
Defaults
Command Modes
Command History
Usage Guidelines
Use the t1 framing controller configuration command to specify the framing mode used by the t1 line.
Examples
The following example sets the framing mode on the t1 interface on line 1 to esf and on line 2 to sf.
To configure T1 autoalarm detection and generation, use the t1 yellow controller configuration command. To disable autoalarm detection and generation, use the no form of this command.
Syntax Description
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Defaults
Yellow alarms are detected and generated on the T1 channel.
Command Modes
Command History
Usage Guidelines
A yellow alarm indicates a loss of frame alignment at the remote end. Use the t1 yellow command to turn the generation or detection of yellow alarms on or off.
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Note If you use the t1 framing command to select the sf framing mode, you should consider turning off alarm detection because the yellow alarms might be detected incorrectly with sf framing enabled. |
Examples
The following example enables autoalarm detection.
Related Commands
Posted: Tue Aug 12 17:31:19 PDT 2003
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