I would suspect it's a timeout issue caused by it aging out of the arp cache and not the tcam table.
Try adding "mac-address-table aging-time 14400" to the config. This usually happens when running HSPR/GLBP or other first-hop redudancy (VSS) where the return path may be asymmetrical. ---- Matthew Huff | One Manhattanville Rd OTA Management LLC | Purchase, NY 10577 http://www.ox.com | Phone: 914-460-4039 aim: matthewbhuff | Fax: 914-460-4139 > -----Original Message----- > From: cisco-nsp-boun...@puck.nether.net [mailto:cisco-nsp- > boun...@puck.nether.net] On Behalf Of C and C Dominte > Sent: Wednesday, August 05, 2009 7:30 AM > To: cisco-nsp@puck.nether.net > Subject: [c-nsp] VSS 1440 issues > > > > > > Hi, > > > > I recently clustered 2 Catalysts 6509's into a VSS 1440 > Virtual switch. > > > > Details about the cluster: > > > > - Software version: > s72033_rp Software (s72033_rp-IPSERVICESK9_WAN-M), Version > 12.2(33)SXI1, > RELEASE SOFTWARE (fc3) > > > > - Supervisor: > VS-S720-10G with one 10G port > used as VSL link > > - Linecards Active chassis: > > 1 x > WS-X6708-10GE with one 10G used for the VSL link for redundancy > > 4 x > WS-X6748-GE-TX > > > > - Linecards Standby chassis > > 1 x > WS-X6708-10GE with one 10G used for the VSL link for redundancy > > 2 x > WS-X6748-GE-TX > > > > The 6748 line cards are used and > configured for MEC Etherchannels. > > > > At the other end of the MEC > channels there are non-Cisco edge switches. The multi chassis Ether > Channels > are configured as 2 x 1G links, and single switchport trunks are > configured as > 1 x 1G links. All vlans are allowed on the single switchport trunks and > port > channels from VSS Cluster to the edge switches. > > > > The issue is that unicast > traffic is flooded by the VSS Cluster across all trunks. The flooded > traffic > generated by the VSS cluster is between 600mbps and 1gbps, and almost > all of > the flooded traffic is unicast and has the source MAC address of the > VSS > Cluster. However, if the trunk is a MEC, the unicast traffic is flooded > only on > one switchport. All of the flooded ports in MECs are on switch 2 in the > VSS > cluster. The only ports flooded in switch 1 are the ones that have a > single > trunk instead of MEC. > > > > We tried to investigate this on > a low importance link. The VSS cluster learned only 10 MAC addresses on > one > edge trunk configured as 1 x 1G link. This edge trunk received the > flood of > unicast traffic from the VSS cluster as well. During testing, this > trunk was > modified manually on the VSS Cluster, to allow only 4 VLANS instead of > all. > Allowing only 4 vlans on this trunk stopped the flood on the edge trunk > and > stopped the flood on all other trunks as well. > > > > Does anyone have any idea about > what can cause this? > > > > Thanks > > > > Catalin > > > > > > _______________________________________________ > cisco-nsp mailing list cisco-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/
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