Multicast RP Question

Greench-cco · ‎09-02-2016

Hi,

I'm having a problem with Multicast RPs(Rendez-vous points)

We are enabling multicast in our network and run PIM-SM between a few routers. One router has to be the RP. We configured a Loopback interface and configured all the routers to that ip address:

interface Loopback0
 description multicast rp
 ip address 192.168.1.50 255.255.255.255
 ip pim sparse-mode
!

ip pim rp-address 192.168.1.50
!

All the other routers show the RP as reachable:

client#sh ip pim rp
Group: 224.0.1.40, RP: 192.168.1.50, uptime 02:09:17, expires never

But not on the router on which the above Lo0 is configured:

rtr#sh ip pim rp
Group: 239.255.255.250, RP: 192.168.1.50, next RP-reachable in 00:00:11
Group: 224.0.1.40, RP: 192.168.1.50, next RP-reachable in 00:00:11

I don't understand why this router can't reach the RP. It is a local loopback interface, so it's always up and present in the routing table.

Does anyone have a clue?

Thanks & kind regards,

Toby

dmuinoorallo · ‎09-03-2016

For multicast routing, there is this steps:

Enabling IP Multicast Routing

Router(config)# ip multicast-routing

Enabling PIM on an Interface

In populating the multicast routing table, dense mode interfaces are always added to the table. Sparse mode interfaces are added to the table only when periodic join messages are received from downstream routers, or when a directly connected member is on the interface. When forwarding from a LAN, sparse mode operation occurs if an RP is known for the group. If so, the packets are encapsulated and sent toward the RP. When no RP is known, the packet is flooded in a dense mode fashion. If the multicast traffic from a specific source is sufficient, the first hop router of the receiver may send join messages toward the source to build a source-based distribution tree.

Router(config-if)# ip pim sparse-mode

Try this, and if this don't work allright, please put the ouput of this command

show ip mroute

royalblues · ‎09-18-2016

Toby

On the RP it will mostly show like this always as it not trying to reach a RP but it itself is

this will be the case even if you have multicast traffic flowing across the router , something like this

sh ip pim rp

Group: 239.1.2.3, RP: 1.0.0.3, next RP-reachable never

Group: 224.0.1.40, RP: 1.0.0.3, next RP-reachable never

Narayan