[c-nsp] IGMP snooping ME6500

[Tim Stevenson]

That's not really the critical thing, so much as - you need an IGMP 
querier active in the VLAN in order for snooping to work 
correctly/reliably. Some applications may behave fine without; others 
won't. The key is periodic joins from the hosts are required to 
maintain membership state for snooping. The querier ensures that happens.

So what you really need is an SVI *with* an IP address for that vlan, 
and then enable igmp snooping querier for that vlan. The configured 
IP is used to source queries. The SVI in this case can actually be 
shutdown, it doesn't really matter.

The config is like:
int vlan 200
  ip add 10.1.1.1/24
  ip igmp snooping querier
  shut

The other option is to just enable PIM on the (admin up) SVI in the 
vlan, but you may not want to do that, depends on the network design.

int vlan 200
  ip add 10.1.1.1/24
  ip pim sparse
  no shut

HTH,
Tim



At 10:46 AM 7/12/2009, Adrian Minta remarked:

>Phil Mayers wrote:
> >
> > Config? Software version?
> >
> > If you don't already have it, try creating an un-numbered SVI e.g.:
> >
> > vlan 200
> >  name multicast
> > int Vlan200
> >  no ip address
> >
> > I seem to recall references to this being required for some multicast
> > functionality on some versions of 6500/7600 IOS
> >
> >
>Seems weird, but I will give it a try !
>
>--
>Best regards,
>Adrian Minta
>
>
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Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Cisco Nexus 7000
Cisco - http://www.cisco.com
IP Phone: 408-526-6759
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