MSDP

Used to link together multicast domains via RPs.

A source turns on, and when the first RP finds out about it, it notifies other RPs.

Details

• RPs register to each other, in different multicast domains.
• RP sends a SA (source active) message.
• Still needs PIM running for the S,G.
• TCP port 639.
• Has keepalives.

show ip msdp peer show ip msdp sa-cache

Startup

1. Multicast source starts up.

2. FHR router sends a register message to the closest RP.

3. RP registers this as a SA (Source Active).

4. Sends Source Active Messages to other RPs

(*,G) means there is an interested receiver.

Config

!
! RP1
!
int lo0
description "Only used for Anycast RP"
ip address 10.0.0.1 255.255.255.255
!
int lo1
ip add 10.1.1.1 255.255.255.255
!
ip msdp peer 10.1.1.2 connect-source loopback 1
ip msdp originator-id loopback 1
ip pim rp-address 10.0.0.1

!
! RP2
!
int lo 0
  description "Only used for Anycast RP"
  ip address 10.0.0.1 255.255.255.255
!
int lo1
  ip address 10.1.1.2 255.255.255.255
!
ip msdp peer 10.1.1.1 connect-source lo1
ip msdp originator-id loopback 1
ip pim rp-address 10.0.0.1

References

RFC 4611 - Multicast Source Discovery Protocol (MSDP) Deployment Scenarios