1.I have read that join/prune message are sent periodically as keepalive in PIM-SM mode.Is that periodically sent on PIM-DM also,i dont see any reason for it,but just to know if anything such is there???
2. why is graft message sent???can't join message be used instead ,b'cas the message format of both join and graft message is same,except the type.(6 for graft and 3 for join).Is there any reason for that???