Just doing some studying on multicast and having abit of trouble.
I've lab-ed it up in GNS3 as the following:
R2 acts as a hub and connects to three routers R1, R3, and R4
I'm running OSPF on the network, with R1 and R2 being in the Area 0 and R3 and R4 are separate stub areas ... all fine and working.
The problem: i've configured PIM sparse-dense-mode on all the routers, and created a loopback interface on R1 and R3 to receive multicast traffic (ie. ip igmp join-group 18.104.22.168). I've also set the rp to R2 (this is set on all routers). My problem is when i send a ping from R4 to multicast address 22.214.171.124 it only gets a reply from R3 and not R4.
Ran the "debug ip pim" command on R2 (the hub and RP) and the only problem i am seeing is that it is only sending RP_reachability message for the 126.96.36.199 group out the link towards R3 and not R4:
*Mar 1 02:44:08.791: PIM(0): Send RP-reachability for 188.8.131.52 on FastEthernet1/0
*Mar 1 02:44:08.791: PIM(0): Send RP-reachability for 184.108.40.206 on FastEthernet0/0
*Mar 1 02:44:08.791: PIM(0): Send RP-reachability for 220.127.116.11 on FastEthernet0/1
*Mar 1 02:44:10.291: PIM(0): Send RP-reachability for 18.104.22.168 on FastEthernet0/0
why isn't it sending the reachability message to R1?