Output Discards

Unanswered Question
Jul 28th, 2008

Cat6509- lots of output drops on a group of 1GB interface (all on same module).

Utilization is low and no other errors are logged on the ports.

Any thoughts on this are appreciated.

I have this problem too.
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Giuseppe Larosa Mon, 07/28/2008 - 08:48

Hello Joseph,

I faced a similar issue.

In my case the output drops were made by the broastorm-control feature that worked during a bridging loop to discard output broadcast frames in excess of configured threshold.

I would verify if you have configured broadcast storm-control or any other form of storm-control (multicast or unknown unicast)

Another aspect to verify is what type of linecard you have, depending on the type of module, bigger or smaller groups of ports share same resources (on 48 GE linecards). This would lead to a traffic peak in the past on the group of GE ports.

Hope to help


jrabener Mon, 07/28/2008 - 10:37

Thanks Giuseppe,

I'll investigate the broadcast storm control aspect.




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