multicast PTT in a VLAN environment

tato386 · ‎12-15-2007

I have a network based on 3750 switches and several VLANS running voice and data applications. We are deploying a 3rd party PTT (push to talk) application on our Cisco phones. In order for this to work the vendor has asked that we enable multicast routing accross the VLANS. If we are already doing L3 routing on our switches is there anything special I need to do to enable multicast traffic?

Thanks,

Diego

Jon Marshall · ‎12-15-2007

Hi Diego

At it's most basic you can just do 2 things to enable multicast routing in your network

1) Under each L3 interface (including vlan interfaces) that you want to route multicast packets type

"ip pim dense-mode"

2) On each 3750 type

"ip igmp snooping"

which allows the switch to forward multicast packets to only those clients who want it.

HTH

Jon