4000 Router Series IP Multicast Configuration Guide

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Analysis

• RPs are the core of a PIM-SM domain. An RP provides services for a specific multicast group, and

multiple RPs can coexist on a network. Make sure the RP information on all routers is exactly the

same to map a specific multicast group to the same RP. Otherwise, multicast forwarding fails.

• If a static RP is configured, use the same static RP configuration on all routers on the entire network.

Otherwise, multicast forwarding fails.

Solution

1. Use display ip routing-table to verify that a unicast route to the RP is available on each router.

2. Use display pim rp-info to verify that the dynamic RP information is consistent on all routers.

3. Use display pim rp-info to verify that the same static RPs are configured on all routers on the

network.

An RPT cannot be built or multicast source registration fails in

PIM-SM

Symptom

The C-RPs cannot unicast advertisement messages to the BSR. The BSR does not advertise BSMs

containing C-RP information and has no unicast route to any C-RP. An RPT cannot be correctly established,

or the source-side DR cannot register the multicast source with the RP.

Analysis

• The C-RPs periodically send advertisement messages to the BSR by unicast. If a C-RP has no unicast

route to the BSR, it cannot send advertisement messages to the BSR, and the BSR cannot advertise

BSMs containing the information of the C-RP.

• If the BSR does not have a unicast route to a C-RP, it discards the advertisement messages from the

C-RP. Therefore, the BSR cannot advertise BSMs containing the information of the C-RP.

• RPs are the core of a PIM-SM domain. Make sure the RP information on all routers is exactly the

same to map a specific multicast group to the same RP, and a unicast route to the RP is available on

the routers.

Solution

1. Use display ip routing-table to verify that unicast routes to the C-RPs and the BSR are available on

each router and that a route is available between each C-RP and the BSR. Make sure each C-RP

has a unicast route to the BSR, the BSR has a unicast route to each C-RP, and each router on the

network has unicast routes to the C-RPs.

2. Use display pim bsr-info to verify that the BSR information exists on each router, and then use

display pim rp-info to verify that the RP information is correct on each router.

3. Use display pim neighbor to verify that PIM neighboring relationship has been correctly

established among the routers.