interdomain multicast

Unanswered Question
Jan 21st, 2009


Recently I'm implementing a project of inter-AS multicasting. Within each AS, there are two RP configured with the same IP, using the Anycast method to provide redundancy.

Between different AS, MSDP will be used to connect the RP in different AS. How should the MSDP connections be configured to provide fully resilience? Should I use a fully mesh method (i.e. each RP in one AS had MSDP sessions with every RP in the other AS )

Anyone had implemented similar solutions ?

I have this problem too.
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Mohamed Sobair Wed, 01/21/2009 - 02:29


Anycast-RP is for Intra-Domain Multicast, In Anycast RP 2 Or More routers configured with the same loopback interfaces, Anycast RP provides Redundancy along with load sharing Capabilities. In case Of a failure On a router , Normal IGP detects the failure and reconverge to the Second RP router.

In MSDP (Inter Domain Multicast), 2 Or more RP routers in Different AS's are configured to share Active Source information for every single administrative domain.



Harold Ritter Wed, 01/21/2009 - 05:56


You could simply have two MSDP sessions between the two domains (one to each RP).


Giuseppe Larosa Wed, 01/21/2009 - 06:00

Hello Gary,

you can take advantage of MSDP mesh groups and you need to use unique ip addresses to exchange messages.

As already stated Anycast RP gives you redundancy within an AS. you can use multiple MSDP sessions between the two ASes but be aware that you need to have a primary path and a secondary path between the two ASes or the RPF check can fail.

(this is for link redundancy)

MSDP requires to use also other protocols like MP-BGP address-family ipv4 multicast in order to pass the RPF check


Hope to help



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