6500 packet forwarding problem

[neil_titchener]

I'm running fairly standard setup on a 6513 switch running a sup720-3b and IOS 12.2(18)SXF10a. One subnet appears to be randomly sending packets out all interfaces when it knows the interface it should be sending the data out of. This isn't continuous nor is it for all packets just some and only occasionally.

The CPU avergaes less than 10% utilisation and there is plenty of free memory for both processor and I/O.

The subnet in question has many portchannels associated with it and connects VMware machines.

This switch is very underutilised.

Any ideas of what the problem/solution is would be welcome. Please remember this is a 6500 switch and the subnet in question is our server subnet so I have to be very carefull about making changes.

[Edison Ortiz]

It sounds like an unicast flooding behavior. This occurs when the switch has the Layer3 information for the destination but no longer has the Layer2 information because it has aged out.

Please take a moment and read this URL

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml

HTH,

__

Edison.