Cisco Catalyst 5000 Series Switches

November 10, 1999

Products Affected

Problem Description

When amending the Token Ring virtual local-area network (VLAN) CRF configuration on the Supervisor module, changing the ring number can cause communication to source-route bridged devices within the VLAN to be lost.

A software fix for this problem is available. Please see the Catalyst Software Versions section below for more information.

Background

When the ring number for an existing Token Ring CRF is modified, the Token Ring card does not properly update the table used to determine the destination VLAN for source-route traffic. The destination color lookup table is consulted only while switching source-route frames. Consequently, only source-route frames will be switched incorrectly.

Problem Symptoms

Devices using source routing that are assigned to the Token Ring CRF where the change was made will be unable to communicate with other devices in the network. The affected devices range from end stations located on Token Ring interfaces within the Token Ring CRF, to virtual rings configured on the Route Switch Module (RSM).

This problem does not affect non-source-route bridged devices.

Workaround/Solution

If it becomes necessary to alter a Token Ring CRF ring number configuration, there are two methods available to ensure that the described problem is not experienced. Both options are explained below.

Option 1: Make the required changes and the reset then entire chassis. This will of course cause connectivity failure for all devices connected via this switch during the reset process.

Option 2. Erase the VLAN(s) requiring change that are configured in the Supervisor and assign the ports from these VLANs to the default Token Ring CRF (1003). Recreate the modified VLAN(s) and reassign the ports to the required VLAN(s).

DDTS

If you are a registered CCO user and you have logged in, you can view the bug details by navigating to the Bug Navigator on CCO, and then entering the bug ID number below to view details.

Catalyst Software Versions

This problem was discovered in Catalyst 5000 supervisor software versions 4.5.2 and later. The current release exhibiting the problem is 5.1.1.

The fix to the problem has been implemented in the Token Ring line card image. The fix is available in release 3.3(2). No modification to Supervisor code is required, and therefore, any Catalyst 5000 running Supervisor Software 4.5.2 or later will require Token Ring module release 3.3(2) or later.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

• Open a service request on Cisco.com
• By email
• By telephone

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