excessive giant frame reported on Supervisor 720 RJ45 interface

[marklatham1]

I have a Supervisor 720 installed in a Cat 6509. 10% of incoming frames on it's RJ45 interface are reported as giants (and presumably discarded?). We are not using jumbo frames across our network. Setting the MTU to 9216 on this interface has no effect. The Supervisor 720 is running on IOS 12.2(17a)SX1. The interface is configured as SWITCHPORT ACCESS and not a trunk port. Any ideas?

[Roberto Salazar]

I believe this is a cosmetic bug on this asics counter. I would try the 12.2(17b)SXA or above. It has many fix on many counter issues.

[sundar.palaniappan]

Roberto is correct. You are hitting the following bug.

CSCec62587 Bug Details

Headline giants on dot1q trunk with sup720 uplink ports

Product IOS

Feature OTHERS Components Duplicate of

Severity 3 Severity help Status Resolved Status help

First Found-in Version 12.2(14)SX01, 12.2(17a)SX All affected versions First Fixed-in Version 8.3(0.45)BOC, 12.2(17b)SXA Version help

Release Notes

Symptoms :

A Catalyst 6000 series switch running 12.2(14)SX or 12.2(17)SX codes may

report giants for packet size above 1496 bytes received tagged on a trunk over

the sup720 ports.

The issue is cosmetic.

Pls. rate all helpful posts.

HTH,

Sundar

[marklatham1]

Thankyou both for your help, the bug report does sound like our fault. We have a planned outage on this switch in 2 weeks time. I shall try an IOS upgrade then.

Thanks again