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Community Member

Out-discards between 6509 & 5500's

I've recently moved the uplinks for all of my access layer 5500's & 5509's from my old dist/core switches (5500's) to my new dist/core switches (6509's). All connections are 100basefx, 2port etherchannel.

Once the connections were moved onto the 6509's I began seeing Out-Discards on the ports on the 6509's that connect to the 5500/5509's. I've checked and double checked the connections and settings between the switches and everything looks fine.

Any idea's what might me causing this? Traffic on the links is very light. Less than 10Mb/s in most cases

Community Member

Re: Out-discards between 6509 & 5500's

I have the same setup here where i work and i don't have those conditions with 400mb trunks between the 6509 and the 5500 can you provide a little more detail as to your configuration and i can look at the difference between yours and mine.

Community Member

Re: Out-discards between 6509 & 5500's

when you do a "show mac" on the 100basefx ports on your 6509 do you see any unicast traffic on those trunk links?

I'm seeing a large amount of unicasts on my trunks on the 6509's but was under the impression that that a trunk link should only be carrying multicast traffic since it is an Interswitch communication type link.

Looking back at my old core 5500's (I've not cleared the counters yet) I can see that there was no unicast traffic between the core/dist switches and the access layer switches when the access layers were connected to the 5500's

Looking at the access layer switch port stat's, I see no unicasts being either received or sent. Only multicast

Finally, while watching the port with Ciscoview, I can see that the packet discards only occur when the port is being hit with this large amount of unicast traffic.

Does this make any sense or am I barking up the wrong tree here?


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