Talk:PIM Sparse Mode

what is the "RP?"

Rendez Vous point (the article has been updated since your question) --Cyr 10:32, 1 May 2005 (UTC)

Comment moved here (was placed in the article by 64.132.220.21).

Just an FYI... assuming "Sparse mode multicast" is referring to PIM SM, the RP does not send IGMP join messages. The hosts that wish to join the multicast group will send IGMP messages to link-local addresses. They are never routed. The routers that receive and process the IGMP requests then build the appropriate PIM message to send to the RP. Again, IGMP is never routed. A PIM-Join is a unicast IP packet to which every PIM-enabled router it traverses will adapt.