Multicast problems on Catalyst 2960

[bjitima]

We recently installed a new VoIP phone system that uses Multicasting to do phone group paging. We thought that multicasting was enabled by default on the 2960 because a multicast ghost session worked, however the phone paging appears to be blocked by the switches.

We plugged the telephones and server into a low end unmanaged switch and the paging worked fine.

Can someone tell me how to correctly enable all multicasting on the 2960? Or have any other suggestions as to why the 2960 would be filtering out this traffic?

Thanks
Ben Jitima
support@foodfairmarkets.com

 

[ADB100]

By default the 2960 has IGMP Snooping enabled, however if you don't have a multicast speaking router on each VLAN then the intelligent 'filtering' won't work and the multicast should just be flooded to all ports within the VLAN.

Use the following commands to see what youv'e got:

show ip igmp snooping mrouter
show ip igmp snooping group

HTH

Andy

 

[bjitima]

I thought it should be sent out to all ports, but something is stopping it. I can do basic setups on these and a little bit but not much more advanced setups on PIX firewalls, so I'm pretty well lost on what to do next. I'm trying to get my smartnet contracts renewed so I can call Cisco and have them take a look at it to see if they can figure out what I'm doing wrong.

 

[bjitima]

I had no ip igmp snooping on one of the switches, but not on both. That apparently is where the problem was. It appears to be working well now.

Ben