Auto-RP and Default RP Placement (workbook 1 lab question)

In the Volume 1 workbook lab, Auto-RP and Default RP Placement, I am wondering why autorp listener is not working.    Since autorp groups 224.0.1.39 and .40 are dense-mode flooded even in a PIM sparse-mode environment, why isn't R1 forwarding that to R5?  Auto-RP works fine when R1 is the Auto-RP announcer.  Why when I only configure static RP mappings for the Auto-RP groups and thereby placing those groups in a sparse-mode condition does R1 then forward it to R5.  What is it about this NBMA point to multipoint interface on R1 that I don't understand?  Does it have something to do with a split-horizon rule or something that affects dense-mode and not sparse-mode?

Thanks in advance....

Adam

Comments

  • auto-rp requires the flooding for 224.0.0.30 & 40 groups but when we enable ip pim auto rp listner no dense mode flood occurs.

    correct me If I am wrong.

     

    regards

    shivlu

     

  • NBMA mode only applies to sparse mode.  A group in dense mode cannot have the same incoming interface as the outgoing interface.  Sparse can do this in NBMA mode because the router knows that even though it's one interface the traffic is coming in and going out they are two different neighbors the traffic is coming from/going to.






    ----- Original Message -----
    From: [email protected]
    Sent: Tue, October 14, 2008 21:29
    Subject: [CCIE SP] Auto-RP and Default RP Placement (workbook 1 lab question)


    In the Volume 1 workbook lab, Auto-RP and Default RP Placement, I am wondering why autorp listener is not working.    Since autorp groups 224.0.1.39 and .40 are dense-mode flooded even in a PIM sparse-mode environment, why isn't R1 forwarding that to R5?  Auto-RP works fine when R1 is the Auto-RP announcer.  Why when I only configure static RP mappings for the Auto-RP groups and thereby placing those groups in a sparse-mode condition does R1 then forward it to R5.  What is it about this NBMA point to multipoint interface on R1 that I don't understand?  Does it have something to do with a split-horizon rule or something that affects dense-mode and not sparse-mode?

    Thanks in advance....

    Adam



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  • Brian, thanks!!!  That explains it perfectly!

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