[Xorp-users] Change in RP vs change in next-hop for RP

[Vikram KAUL]

Hi Pavlin,

 Please see below..

pavlin>>   Specifically, where are the conditions addressed when the RP itself 
pavlin>> changes for the (*,G) and (*,*,RP) state. Not the next hop changes, but 
pavlin>> the RP changes when the group is active. Is the protocol designed to 
pavlin>> handle this ?
pavlin>> 
pavlin>>From the perspective of transmitting the Join/Prune messages toward
pavlin>the RP it is important to send the messages in the right direction
pavlin>(i.e., next-hop router), and the downstream routers don't really
pavlin>care about the particular RP address. In fact, if we ignore the PIM
pavlin>Register mechanism, then the RP address doesn't even have to belong
pavlin>to a real host, and this is exactly how Bidir-PIM works.
pavlin>
pavlin>That said, it is important to notice only if the next-hop router
pavlin>toward the RP changes, regardless whether the change is because the
pavlin>underlying RPF information changed or because the RP address was
pavlin>changed. In other words, the RP change will translate eventually in
pavlin>same handling as the RPF(*,G) change.
pavlin>
pavlin>Note that even though the (*,G) Join message conains the RP address
pavlin>for group G, there is no need to trigger immediately a new (*,G)
pavlin>Join message with the new RP address if the next-hop router hasn't
pavlin>changed. The new RP address will be included with the next periodic
pavlin>(*,G) Join message.

Is this the current handling in XORP ? Can you point to the section of the 
code where I can see this happen ? Thanks for your help in advance

regards..
Vikram