Multicast CGMP or IGMP snooping

[mkallasch]

Hello,

I have to control the multicast traffic on our LAN.

We use 2 Catalyst 6509 (with MSFC and hybrid OS) and few Catalyst 5xxx with Sup3 and NFFC.

The most "users" of the multicast traffic are connected on the Cat6509 and three other users are connected each with on a Cat5xxx.

Currently we are using multicast within one VLAN (Vlan16).

The King of the two routers (MSFC with HSRP) has CGMP enabled on the VLAN16 interfaces.

Now my 3 questions.

On the Cat6509 I can use IGMP snooping only, but on the Cat5xxx I have two options. What is the best choice in our case, IGMP snooping also or CGMP?

If I use IGMP snooping on all switches, should be CGMP disabled on the routers interfaces?

What about the "fast leave" feature. No, because the HSRP? I've read warnings in the NetPro Forum.

Thanks

Mathias

[milan.kulik]

Mathias,

if all switches in your network are IGMP-enabled you don't need CGMP. To your questions:

1) CGMP is a Cisco proprietary solution, IGMP is "standard". But some switches are not IGMP-enabled (Cat4000, e.g.). In that case you need to use IGMP to CGMP "translation" via a router. I described this solution yesterday in response to http://forums.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.ee79d3a

2) I've not tested it. But I think it should work if you disable CGMP and there would be no additional CGMP traffic in your network.

3) Don't use fast leave if using HSRP. There is a link in the response mentioned above describing this problem.

HTH,

Milan