IGMP, Globally or Locally?

[rwamstutz]

All, is IGMP Global or Locally?  The reason I ask, we are looking at an cisco ie 3000-8tc as a layer 2 switch attached to our 3750 stack.  Can the 3000 do snooping within the swtich itself, or must the 3750 stack have IGMP Snooping enabled too?

[Jon Marshall]

rwamstutz wrote:
but if i dont have IGMP Snooping enabled on the 3750, can devices on the 3750 register to the 3000?  if not, then does multi-cast traffic leave the 3000?

Your'e mixing up IGMP snooping with IGMP. If the 3000 switch is an IGMP querier then it will send out IGMP queries within vlan 199. This means the query will also go to the 3750. Now it doesn't matter whether the 3750 has IGMP snooping configured or not because if a host attached to the 3750 answers the IGMP query to say it is interested then the 3000 will register the interconnect port as a port to send the multicast traffic out on. Being able to register with IGMP has nothing to do with whether or not IGMP snooping is configured.

Edit - if you don't have any devices connected to the 3750 that are interested in the traffic then no traffic will not be sent to the 3750 for that vlan.

Jon

[Jon Marshall]

edit  - deleted, posted twice.