[c-nsp] IGMP on 6500s - %MCAST-xx-GC_LIMIT_EXCEEDED

[Phil Mayers]

Tim Stevenson wrote:
> It refers to Layer 2 group MAC entries (try sh mac- mul ig or sh 
> multicast group); these are driven by IGMP join activity in host VLANs.

Although the message refers to IGMP, is it possible that MLD is 
implicated? "sh mac- mul mld" gives several 3333.0000.00xx groups per 
vlan (even though no IPv6 address is defined on those vlans) and then 
weirdly lists all active output interfaces for the 3333.0000.000d group 
for each vlan, not just the interfaces that vlan is on.

Summing up the interfaces times vlans times groups I get ~9k, which is 
getting in the right region for the 15k I'm seeing reported. But if so, 
it does rather imply that MLD snooping is very broken.

I can't come up with any other combination of multicast 
groups/sources/interfaces that gets even close to being what the error 
indicates.