Cisco WAN Switching Modules

Field Notice: UXM IMA With T1 Backcard Logs Trunk Failures Upon Clock Switches of Node

March 9, 1999

Products Affected

IGX UXM with T1 backcard

Problem Description

UXM IMA groups using the T1 backcard experience "IMA Group Failure" when there is a clock switch on the node. This leads to temporary Communication Breaks and clock switches on downstream nodes if failed trunk is source of clock. This may result in unreachable nodes if there are no other types of trunks to the node. The IGX has to experience a clock switch to trigger the "IMA Group Failure". This should not affect nodes using Internal Oscillator as the clock source.


Customers note network nodes going unreachable after a clock switch.

The cause is unknown and is currently under investigation.

Problem Symptoms

Unreachability if there are only IMA trunk groups to the node.


Workaround: Remove IMA trunk group(s).

Solution: UXM firmware revision AAE fixes the problem

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:

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