Multicast Question

Unanswered Question
Mar 24th, 2010

Hi Guys,

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 239.3.3.3). 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 239.3.3.3 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 239.3.3.3 group out the link towards R3 and not R4:

*Mar  1 02:44:08.791: PIM(0): Send RP-reachability for 224.0.1.40 on FastEthernet1/0

*Mar  1 02:44:08.791: PIM(0): Send RP-reachability for 224.0.1.40 on FastEthernet0/0

*Mar  1 02:44:08.791: PIM(0): Send RP-reachability for 224.0.1.40 on FastEthernet0/1

*Mar  1 02:44:10.291: PIM(0): Send RP-reachability for 239.3.3.3 on FastEthernet0/0

why isn't it sending the reachability message to R1?

attached are the configs for each router. plus some show outputs, hopefully someone can see the problem.
still learning so any guidance would be great
thanks,
N
I have this problem too.
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Jon Marshall Wed, 03/24/2010 - 04:10

My problem is when i send a ping from R4 to multicast address 239.3.3.3 it only gets a reply from R3 and not R4

Can you just clarify what connectivity issues you are having ?

Jon

nqtran1979 Wed, 03/24/2010 - 04:24

My problem here is, should i not get a reply from both members of the 239.3.3.3 group (in this case being R3 and R1)?

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