Cisco IOS Cookbook, 2nd Edition

Routing Multicast Traffic with PIM-SM and BSR

Problem

You want to enable routing of multicasts using Sparse Mode for better efficiency and use BSR for distributing RP information.

Solution

We’ve already discussed how PIM-SM requires a Rendezvous Point (RP) router. The most reliable way to achieve this is to have the network automatically discover the RP. This way, if the RP fails, another can automatically take over for it. We recommend using the Bootstrap Router (BSR) mechanism to dynamically distribute RP information.

There are two different types of router configurations for this type of network. Most of the routers will support end devices, both group members and servers. But a small number are configured to act as candidate RP’s and candidate Bootstrap Routers (BSR). In the example, we show the RP and BSR configuration in the same router. This isn’t actually necessary, but it is convenient.

Router1 is an example of a “normal” multicast router. It forwards multicasts, takes part in PIM-SM, and may support group members or multicast servers as required:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#ip multicast-routing
Router1(config)#ip pim rp-address 192.168.15.5
Router1(config)#interface FastEthernet0/0
Router1(config-if)#ip address 192.168.1.1 255.255.255.0
Router1(config-if)#ip pim sparse-mode
Router1(config-if)#interface Serial1/0
Router1(config-if)#ip address 192.168.2.5 255.255.255.252
Router1(config-if)#ip pim sparse-mode ...