Configuring BGP Multicasting

The BGP multiprotocol extensions (MP-BGP) enable BGP to carry IP multicast routes used by the Protocol Independent Multicast (PIM) to build data distribution trees. (See JunosE Multicast Routing Configuration Guide for information about PIM.) You can configure a multicast routing topology different from your unicast topology to achieve greater control over network resources. This application of MP-BGP is often referred to as multicast BGP (MBGP).

The BGP multiprotocol extensions specify that BGP can exchange information within different types of address families:

As discussed in Understanding BGP Command Scope, BGP configuration commands fall into five categories. If you specify the multicast address family, from within the Address Family Configuration mode you can issue the commands listed in Table 7 to configure parameters that affect the multicast address family globally. You can issue the commands listed in Table 9 to configure a peer or peer group that you have activated in the multicast address family without affecting those configuration parameters for any other address family within which the peer or peer group is activated.

If you issue any of the commands listed in Table 8 from within the default IPv4 unicast address family to configure a peer or peer group, you can apply those configuration values to the same entity in the multicast address family by activating the peer or peer group in the multicast address family.

Example

To add a peer to the multicast routing table, first add the peer to the unicast routing table, and then copy it to the multicast routing table.

host1(config)#router bgp 22 host1(config-router)#neighbor 192.168.55.122 remote-as 33 host1(config-router)#address-family ipv4 multicast host1(config-router-af)neighbor 192.168.55.122 activate

address-family

exit-address-family

neighbor activate

Monitoring BGP Multicast Services

To display values from the BGP multicast routing table, use the show BGP commands with the ipv4 multicast keyword. For more information about displaying BGP parameters, see Monitoring BGP .