Regarding multicast:- if i have a hub and spoke scenario in which hub is the RP & Mapping agent, and when I ping from one spoke router to another spoke router , I got one reply and then timeout . I tried to figure out by debugs and what I understand is :- when I start sending the traffic , after one packet the traffic flow tries to be converted from Shared tree to SPT for which the receiving router sends prune to the RP ( which is hub ) because it looks another shortest path to the source router via the same DLCI which is actually the same path via hub. What I did to resolve this , I set spt-threshold infinity on the receiving router. It should solve the problem but I again faced the same problem! Can u please clarify! Did I understand the problem correctly & what is the solution of this problem ( except creating a tunnel ) ?