show interface counters errors UnderSize field on 3750

[nsysblh]

I have a 3750 stack with a 2 way trunked ether channel fed from a 4507r. The 4507r is not reporting any errors. However, the show interface counters errors is showing a constantly growing UnderSize field. I don't think any packets are actully being dropped. No other error indicators are evident from either side.

Sofware version is: (C3750-I5K91-M), Version 12.2(20)SE1

Anyone else seen this? Looks like SE3 is now available, but the release notes don't mention this.

[Prashanth Krishnappa · Accepted solution]

It is due to a limitation on 3750. Take a look at the following bug

http://www.cisco.com/cgi-bin/bugtool/onebug.pl?bugid=CSCec14238

Before the fix(which is in your IOS as well), runts would increment in show interface. Now it does not but undersize increments in should interface counters errors.