multicast

[carl_townshend]

Hi all, is IGMP snooping enabled by default on cisco switches, also do they use IGMP proxy function?

If so how do I turn these functions off / on

[Harold Ritter]

Carl,

IGMP snooping is enabled by default. IGMP proxy is not. To disable IGMP snooping:

(globally)

no ip igmp snooping

(per vlan)

no ip igmp snooping vlan xxx

Regards

[carl_townshend]

should this be turned off then? or should I leave it on? How can I check the group to port assignments ?

also what benefit is IGMP snooping and IGMP proxy ?

[Giuseppe Larosa]

Hello Carl,

as we discussed in another thread it is a question of implementation:

on switches supporting IGMP snooping in HW using an ASIC it is good to have it enabled.

Hope to help

Giuseppe

[aciscolook]

what if i use igmp snooping to constrain multicast traffic but don't have a router in the mix. Will this work?

Again, just one (maybe two) switch with IGMP snooping and no router.

[Joseph W. Doherty]

Many switches that support IGMP snooping will act as an IGMP Snooping Querier, if enabled.