Multicast RP's - Cisco-NSP

Hey guys,

Quick question on something I am having trouble finding documentation on.

Does anyone know how a configured RP in a PIM SM implementation become aware
of all multicast groups within a particular network? Are they advertised via
PIM running on each PIM via the multicast routing table?

Thanks,

-Aaron

Aaron Riemer Tue, 22 Feb 2011 05:20:39 -0800

If I understand what you're asking, then no - RPs don't know about
"groups" in that way.

For a new multicast sender, the PIM DR on the sender vlan sends a PIM
register to the RP. The RP then performs an (s,g) join for the new
source, and and sends a register-stop telling the PIM DR to cease.

Multicast receiver state is propagated by PIM join packets.

In other words, the RP "knows" about a group when someone joins it or
sends to it.

Phil Mayers Tue, 22 Feb 2011 05:30:09 -0800

Hi,

What you need is a msdp session between all RPs that you have configured.

kind regards
Pshem

Pshem Kowalczyk Tue, 22 Feb 2011 13:26:27 -0800

So source PIM enabled routers will register the source multicast group with
the RP.

That's what I wanted to know thanks.

This link explains the registration process.

http://www.juniper.net/techpubs/software/junos/junos60/swcon[..]
html/pim-overview11.html

Thanks again,

-Aaron

Aaron Riemer Tue, 22 Feb 2011 17:15:52 -0800

Whilst not answering your question specifically, I've always found the series of article written by Peter J. Welcher of the Chesapeake Netscaftsmen a good reference for multicast (fairly easy to read and understand).

http://www.netcraftsmen.net/resources/archived-articles/436-[..] http://www.netcraftsmen.net/resources/archived-articles/376-[..] http://www.netcraftsmen.net/resources/archived-articles/424-[..] http://www.netcraftsmen.net/resources/archived-articles/375-[..]

regards,
Tony.

Tony Tue, 22 Feb 2011 18:25:00 -0800

This sounds like a use case for AutoRP/BSR to me...

Brant I. Stevens Thu, 24 Feb 2011 10:28:14 -0800