Cisco IOS Cookbook, 2nd Edition

Exchanging Multicast Routing Information with MBGP

Problem

You want to exchange multicast routing information between two networks using MBGP.

Solution

Before setting up MBGP, you should set up multicast-routing on the Autonomous System Boundary Router (ASBR) and configure it to block multicast traffic that you know is only intended for the local network:

Router-ASBR1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router-ASBR1(config)#ip multicast-routing
Router-ASBR1(config)#access-list 15 deny 239.0.0.0 0.255.255.255
Router-ASBR1(config)#access-list 15 deny 224.0.1.39
Router-ASBR1(config)#access-list 15 deny 224.0.1.40
Router-ASBR1(config)#access-list 15 permit any
Router-ASBR1(config)#interface Serial0/0
Router-ASBR1(config-if)#ip multicast boundary 15
Router-ASBR1(config-if)#ip multicast ttl-threshold 64
Router-ASBR1(config-if)#ip pim dense-mode
Router-ASBR1(config-if)#end
Router-ASBR1#

Then you need to set up the MBGP configuration:

Router-ASBR1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router-ASBR1(config)#router bgp 65530
Router-ASBR1(config-router)#network 10.0.0.0 mask 255.0.0.0 
Router-ASBR1(config-router)#neighbor 10.15.32.1 remote-as 65531
Router-ASBR1(config-router)#address-family ipv4 multicast
Router-ASBR1(config-router-af)#neighbor 10.15.32.1 activate
Router-ASBR1(config-router-af)#end
Router-ASBR1#

Discussion

Usually when people talk about using BGP, they immediately think of the public Internet. Since ...