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New Member

Multicast question about RP.

Hello all,

I'm setting up my first multicast configuration and I'm trying to find out some answers to the follwing question: When configuring auto-rp with PIM sparse mode, is it necessary to configure all routers as auto-rp?

Best regards.


New Member

Re: Multicast question about RP.

Auto-RP really works best when you're running PIM sparse-dense-mode rather than pure PIM sparse-mode.

Using sparse-dense-mode all you need to do is enable it on all router interfaces and then on your Auto-RP RP Candidates and Mapping Agent(s) you add the

ip pim send-rp-announce ...

ip pim send-rp-discovery ...


This way the two groups used by Auto-RP become dense mode groups, and you provide RP for the groups specified on your RP Candidate routers which puts them in sparse mode

For pure sparse-mode it gets a little more complicated.

You need to somehow provide a static RP for the two groups used by Auto-RP.

Alternately you can use PIM BSR which works with no further config in a pure sparse-mode network.

Just apply the following commands to your RP and BSR candidate(s):

ip pim bsr-candidate ...

ip pim rp-candidate ...

You'll find excellent examples on how to configure a PIM RP for PIM Sparse Mode and pros and cons at:

New Member

Re: Multicast question about RP.


I had a look at the documentation, but I still have a question.

These two commands:

ip pim send-rp-announce ...

ip pim send-rp-discovery ...

aren't configured on each router in the sample. Is it normal?

I assume that this command should only be configured on the routers that are candidates RP routers and ths other routers doesn't need any configuration, just the ip pim sparse-dense-mode on the interfaces that need to run multicast.



New Member

Re: Multicast question about RP.

You've got it absolutely right!

These two commands should only be configured on the candidate RP routers.

All other routers should just have "ip pim sparse-dense-mode" on the interfaces running multicast.