Multicast Advanced


In an effort to load balance various multicast responsibilities across your routers, you decide to implement Cisco’s AutoRP feature along with MSDP and SSM so you can use the same IP addresses as RPs for the same multicast groups while increasing security. Only problem is, your boss tells you that you cannot use sparse-dense mode as he never wants multicast traffic to be flooded unnecessarily. Additionally, responsibilities are being distributed to all (5) backbone routers in your network.


  • Nothing has been preconfigured for you! Configure IP addresses and interface assignments in accordance with the diagram.
  • Enable EIGRP on all routers and all interfaces for basic connectivity. Do NOT enable EIGRP on R1 and R7 as those devices simulate hosts. Instead, configure a default route on each one.
  • Enable multicast-routing and PIM-SM on all interfaces, including loopbacks.
  • Configure AutoRP on all (5) routers. R4 should be both the mapping agent and the RP using Lo0 for AutoRP’s discovery group using Lo1. R5 should be the RP for AutoRP’s announcement group using Lo0.
  • Ensure all routers know these two RP addresses so they can receive AutoRP information.
  • Configure R2 Lo0 to be the RP for only.
  • Configure R5 Lo1 to be the RP for only.
  • Configure R3 Lo0 to be the RP for only.
  • Configure R6 Lo1 to be the RP for only.
  • Configure MSDP so RPs can share appropriate RP-related information. You are only allowed to create (2) peerings.
  • R7 needs to tell R6 that it wants to receive multicast traffic on groups and Use SSM to ensure that only multicast traffic on these groups is forwarded by R6. Do not use the “ip access-group” command or any explicit filtering mechanisms.
  • R1 should be able to ping and and receive responses from R7.




mcast advanced

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Written by René Molenaar - CCIE #41726

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About the Author: Nicholas Russo


  1. Please, the final config!!!.. I need a few details to look at!!!…. currently doing something similar with a client…

    1. Hi phyohtetaung!

      Couple of notices of your final configs:
      – you shouldn’t enable multicast routing on R1 nor R7 as they simulate hosts
      – Why do you have SSM-mapping in R2 as there is no need for IGMPv2 to IGMPv3 conversion ? (And there is no multicast subsribers behind R2 neither)
      – SSM Range is not changed in any router

      And yes, multicast restriction is little bit confusing.

      Also MSDP doesn’t make any sense in this lab. There is basically one single Auto-RP domain so where do we need MSDP? What does it give to us? Doesn’t matter where do you put those 2 allowed MSDP sessions, they are useless! They can’t be used to deliver SA (source active) information anyhow. Please explain NICK!

      1. It has been a long time since I made this lab, so I will try my best to recall. The goal here was anycast RP. R2 and R6 both agree that is an RP that services some groups, but have different routes to reach it. R2 is connected, while R6 has an IGP route to R5. MSDP is necessary so that the RP that receives the register message from the DR about a source can turn around and originate an SA message towards all MSDP peers.

        Don’t be so fast to dismiss MSDP simply because you have a single homogenous domain. Anycast RP is a valid use as well.

        Think about it this way. If R1 sent traffic, R2 has to tell the RP about it via register. R2 is the RP! So how will R5 know about the active source? R5 received the (*,G) join from R6, who thought R5 was the RP.

        I will have to look into what the heck I was thinking when I wrote this lab 🙂 Thanks to everyone for being patient with it.

  2. Hi. Will a video solution be posted for this? I am new to multicast and trying to learn it on my own.
    I agree with Kaag…from my reading MSDP is used between domains. Maybe is was thrown in here for us to just get a feel for it!

    1. Again, don’t be so fast to dismiss the other uses of MSDP. It allows different group to RP mappings to exist. No one said anything about routing domains 🙂

  3. General comment: Most of you are right, this lab is a bit sloppy. The idea was to show you how MSDP works with Anycast RP, and to get a feel for SSM as well. My group ranges were poorly designed. I apologize for that.

  4. “Configure AutoRP on all (5) routers. R4 should be both the mapping agent and the RP using Lo0 for AutoRP’s discovery group using Lo1. R5 should be the RP for AutoRP’s announcement group using Lo0.”

    This is just a poorly worded sentence. What?

    1. Poorly worded indeed. The diagram reminded me of what I wanted to say.

      R4 should be the mapping agent using Lo0.
      R4 should also be the RP for the AutoRP control groups using Lo1.

  5. topology file and startup configs appear to be missing… I am logged in, but do not see the files to download…

  6. Rene,
    Can you please revisit the topology and rephrase the requirements as I dont understand the wordings .

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