[c-nsp] multicast on layer 2

[Tim Stevenson]

Yes, that's exactly what we do. But IGMP snooping is on by default, so this 
won't happen naturally - you have to disable snooping first.

The desire of most people trying to do multicast in a VLAN though is: I 
want source & receivers in a single VLAN, no multicast routing, BUT, I want 
to still constrain the multicast to only the ports w/interested receivers.

And that's where you need a querier of some sort: PIM on an interface, or 
the switch querier feature.

Tim

At 09:36 AM 6/29/2005, Tantsura, Jeff noted:
>Without IGMP snooping configured every switch should flood a
>multicast frame out all ports that are in the same VLAN as source.
>It's kinda stupid to ask you again but :) I'd really like to understand
>logic behind it.



Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Catalyst 6500
Cisco Systems, http://www.cisco.com
IP Phone: 408-526-6759
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