Cisco BPX 8600 Series Switches

Field Notice: 9.1 - 8.5 Interoperability Loop Clock Not Passing on Trunks

March 5, 1999

Products Affected





Problem Description

Pass sync can not be set on a trunk when one node is running switch software 8.5.x and the other node is running 9.1.x.

An error message is displayed indicating that you cannot set pass sync on a trunk when the other side is set for loop clock. When the other side of the trunk config is checked, however, loop clock is not configured.


The 8.5-9.1 interoperability problem is caused by inconsistent definition of data structure - UPDT_PSYNC In 9.1 - Problem to be fixed in a later release of 9.1. Please see DDTS or bug navigator to identify the fixed in release.

Problem Symptoms

You will not be able to pass clock syncronization in a network interoperating between switch software 9.1 and 8.5


The workaround is to upgrade the 8.5 nodes to 9.1 and then configure the trunks to pass sync.

A fix for this problem is planned for the 9.1.10 software release.


To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.



CSCdm05728 (registered customers only)

9.1-8.5 Interoperability Problem: Loop Clock Bit for Trunks Not Passing

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: