[c-nsp] 6500/SXI/CSCtc03951 - MS NLB packet dropping

Daniska, Tomas tomas at soitron.com
Thu Feb 25 07:37:22 EST 2010

Hello good people...



has anyone encountered CSCtc03951 - IP packets with unicast DSTIP and
multicast DMAC dropped when incoming and leaving the same distributed
etherchannel? I have customer with a large installed base of MS NLB
clusters, the setup is based around VSS and multichassis (i.e.,
distributed) etherchannels, and I'm seeking for a simple workaround
until the vendor C gets the issue fixed. It's reported with PFC3C,
downgrade to PFC3B mode is not possible as it would conflict with VSS,
and topological workarounds seem being quite complicated - there are
multiple VLANS with such clusters and I would have to isolate them to a
separate VRF each in order to make the traffic always pass some other
interface for server-to-server communications.


Any experience shared will be much appreciated






Tomas Daniska
Senior CSE/BDM

Soitron, a.s.
Plynarenska 5, 829 75 Bratislava, Slovakia
tel: +421 2 58224000, fax: +421 2 58224520

All generalizations are false, including this one.
-- Mark Twain


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