Relation between IGMP join and GMRP join messages

[hostettle]

Hi,

In the document “configuring multicast services” about Catalyst 4500:

www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.5/configuration/guide/multi.html#wp1059370

…we can read this statement:

“When a host wants to join an IP multicast group, it sends an IGMP join message, which creates a corresponding GMRP join message”. How it is done?

(1) At each time, the host sends 2 different Ethernet messages, one carrying IGMP join, and the other which is GMRP join.

(2) or, at the level 2, the IGMP join message is equivalent to the GMRP join message. In this case, I don’t see this possibility in the structures of the frames.

How do you understand this?

Thanks very much for your comments,

Michel

[hostettle]

Hi,

Sorry if my question was not very sexy!

I found the solution in 802.1D-2004, Annex I section I.2.1

“GMRP-aware end stations involved in IP multicast reception must be capable of using GMRP to manage their membership of Groups as required by their use of IP multicast. For example, in order to join a given IP multicast Group using IGMP, the end station must perform a GMRP Join for that Group before issuing the IGMP Join”.

But it was in 2004. Now, I'm asking if we need MMRP with IGMP snooping. I think not. So what is the using of MMRP?

Best regards,

Michel