Bootstrap Router

• RFC 5059
  • Similar functionality to Cisco proprietary Auto RP.
• Roles
  • RP Candidate
    • Similar to Candidate RP
    • Uses Unicast PIM to advertise itself to Bootstrap Router
  • Bootstrap Router
    • Analogous to mapping agent
    • Advertises RP info to other routers with multicast PIM on a hop by hop basis.
• By default Auto-RP and BSR messages are sent on all PIM enabled interfaces.
• For added security, these messages should be filtered on network edge.
  • Auto-RP via Multicast Boundary
  • BSR via BSR Border
• Filtering can occur via TTL as well.
  • ‘Administrative Scoping’

Configuration:

In the topology above all routers are running OSPF in area 0. They each have ip multicast enabled and we’re going to make R1 the RP via BSR.

The first two commands above will make R1 the BSR and RP Candidate. The ‘group-list 1’ is referring to an access-list numbered 1 that allows the below Multicast addresses to report into the RP.

An RP Mapping will show the same prefixes:

On R9 we can confirm that R1 is now officially the RP of the Multicast domain.

Now on R8 we’re going to create a PIM Join to the group 239.0.1.1 and and check the mroute table on R1. R8: ‘R8(config)#ip igmp join-group 239.0.1.1’

R1 now has the group setup in a (*, 239.0.1.1), meaning it not yet has a sender but knows which interface to go out for receivers/group members.

After hopping onto R9 and trying to ping the group address, R1’s mroute table looks like below:

It now has the full SPT tree completed with an (S,G) – (10.30.8.2, 239.0.1.1)

NOTE:

Command ‘show ip pim rp’ will show RP for all Multicast groups.