Hi Sebastian, There is a solution for your problem for 4500 switches which is called per-vlan capture mode. You can enable it with the 'access-list hardware capture mode vlan' command. This will make sure special multicast traffic is punted to CPU only in case there's an SVI for that vlan.
Refer to the "Selecting Mode of Capturing Control Packets" section on the following link: http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/54sg/configuration/guide/secure.html#wp1128851 Best regards, Andras On Fri, Jan 21, 2011 at 12:09 AM, Sebastian Wiesinger <[email protected]> wrote: > * Pete Lumbis <[email protected]> [2011-01-20 22:26]: >> Devin, >> >> I did a bunch of testing and checking in the lab and here is the scoop: >> Any multicast mac that is received on an SVI will be punted. The short >> reason is because we only look for the "01" in the MAC to indicate >> that this is multicast then we flood to the VLAN. Unlike a unicast > > Hi Pete, > > I had something like this occur on a Catalyst 4500. It seems that all > "Link-local" Multicast (224.0.0.0/24) is ALWAYS punted even without an > SVI (only L2). There is no way to say "This is only a switch, just > flood it and don't send it to the CPU." > > CoPP doesn't really help because then the packet is dropped and not > forwarded at all which is a bad thing(tm) for stuff like OSPF, HSRP, > VRRP, etc. > > I don't know if the platform could support a feature to keep multicast > from being punted to the CPU but if so I could really use it. > > Regards, > > Sebastian > > -- > New GPG Key: 0x93A0B9CE (F4F6 B1A3 866B 26E9 450A 9D82 58A2 D94A 93A0 B9CE) > Old GPG Key-ID: 0x76B79F20 (0x1B6034F476B79F20) > 'Are you Death?' ... IT'S THE SCYTHE, ISN'T IT? PEOPLE ALWAYS NOTICE THE > SCYTHE. > -- Terry Pratchett, The Fifth Elephant > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
