Multicast question - CGMP

[alexng]

after reading a few pdfs, the rule of thumb is, if using legacy switches use CGMP otherwise IGMP snooping is the way to go. Is that correct?

[Reza Sharifi]

Hi Alex,

Yes,Older boxes like 2900XL/3500XL, 2948 and 1900 support CGMP.

Here is a metrix of Cat switches that support IGMP and CGMP:

http://www.cisco.com/en/US/tech/tk828/technologies_tech_note09186a0080122a70.shtml

HTH

Reza

[Peter Paluch]

Reza,

Thanks, that is a very useful link!

Also, it should be stressed that the CGMP is Cisco-proprietary protocol and must be supported both by switch AND router. In CGMP, it is the router that controls the switch using CGMP. Without a CGMP-compliant router, the switch will not provide any optimized multicast delivery, and will flood all multicast packets out every port except the inbound port.

Best regards,

Peter