Multicast DR Problem..

Hi all

I have a probelm with sparse-mode Multicast DR on a spoke point-to-point interface(R2) connecting to the FR hub on a multipoint interface(R1).

They see each other in show ip pim neighbor but R2(the spoke) sees no DR on its coonected interface to R1:

R2# sh ip pim int s0/0.1

Address          Interface                Ver/   Nbr    Query  DR     DR
                                          Mode   Count  Intvl  Prior
1.1.11.2         Serial0/0.1            v2/S   1      30     1      0.0.0.0

Both with setting R1 as DR or R2 as DR (by ip pim dr-priority) and also using (ip pm nbma) on R1,I have this problem that causes the outgoing int for all entries in ip mroute table point to null.

What is the problem that R2 doesn`t see the DR and cause all outgoing interfaces to null?

Thanks

Comments

  • Did you check to make sure its passing the RPF check?


    On Sep 22, 2009, at 6:49 AM, paydarh wrote:

    Hi all

    I have a probelm with sparse-mode Multicast DR on a spoke point-to-point interface(R2) connecting to the FR hub on a multipoint interface(R1).

    They see each other in show ip pim neighbor but R2(the spoke) sees no DR on its coonected interface to R1:

    R2# sh ip pim int s0/0.1

    Address          Interface                Ver/   Nbr    Query  DR     DR
                                              Mode   Count  Intvl  Prior
    1.1.11.2         Serial0/0.1            v2/S   1      30     1      0.0.0.0

    Both with setting R1 as DR or R2 as DR (by ip pim dr-priority) and also using (ip pm nbma) on R1,I have this problem that causes the outgoing int for all entries in ip mroute table point to null.

    What is the problem that R2 doesn`t see the DR and cause all outgoing interfaces to null?

    Thanks




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  •  

    This is the mroute table on R2 and R2 can pig all unicast addresses in whole the topology.Also (ip mroute 0.0.0.0 0.0.0.0 1.1.1.1) has no impact.


    (*, 224.0.1.39), 03:51:00/stopped, RP 0.0.0.0, flags: DP
      Incoming interface: Null, RPF nbr 0.0.0.0
      Outgoing interface list: Null

    (1.1.1.1, 224.0.1.39), 00:01:36/00:01:24, flags: PT
      Incoming interface: Serial0/0.1, RPF nbr 1.1.11.1, Mroute
      Outgoing interface list: Null

    (*, 224.0.1.40), 03:51:33/stopped, RP 0.0.0.0, flags: DCL
      Incoming interface: Null, RPF nbr 0.0.0.0
      Outgoing interface list:
        Serial0/0.1, Forward/Sparse, 02:10:01/00:02:49

    (1.1.7.7, 224.0.1.40), 01:12:23/00:02:09, flags: PLTX                            
      Incoming interface: Serial0/0.1, RPF nbr 1.1.11.1, Mroute
      Outgoing interface list: Null

    Please help!

  • I found the problem.I changed the sub int of R2 from point-to-point  to Multipoint (like R1), an now R2 sees the DR, BUT still the outgoing interface  for all groups is Null, even with (ip mroute 0.0.0.0 0.0.0.0 1.1.11.1) :

     


    (*, 224.2.2.2), 00:00:09/00:02:56, RP 200.105.101.1, flags: SP
      Incoming interface: Serial0/0.1, RPF nbr 1.1.11.1
      Outgoing interface list: Null

    (*, 224.0.1.39), 01:07:13/stopped, RP 0.0.0.0, flags: DP
      Incoming interface: Null, RPF nbr 0.0.0.0
      Outgoing interface list: Null

    (1.1.1.1, 224.0.1.39), 00:00:06/00:02:53, flags: PT
      Incoming interface: Serial0/0.1, RPF nbr 1.1.11.1
      Outgoing interface list: Null

    (*, 224.0.1.40), 01:07:58/stopped, RP 0.0.0.0, flags: DCL
      Incoming interface: Null, RPF nbr 0.0.0.0
      Outgoing interface list:
        Serial0/0.1, Forward/Sparse, 00:17:35/00:02:06

    (1.1.7.7, 224.0.1.40), 01:07:52/00:02:27, flags: PLTX
      Incoming interface: Serial0/0.1, RPF nbr 1.1.11.1
      Outgoing interface list: Null

  • Why won't mulicast work if the frame-relay interface is configured as point-to-point vs multipoint? I had the same problem, but was able to resolve it by changing it to multipoint. Thoughts?

  • Point to point should be the simplest method to do things!   No "split horizon" issues of same-interface multicast to deal with.

    You may have a forwarding problem based on which "side' of the link is DR (common placement is closer to the RP).  If so, you can use "debug ip pim" to see rejection messages related to DR.

    Scott







    ----- Original Message -----
    From: "Chosen_OnE" <[email protected]>
    Sent: Sun, September 27, 2009 10:39
    Subject: Re: [CCIE R&S] Multicast DR Problem..


    Why won't mulicast work if the frame-relay interface is configured as point-to-point vs multipoint? I had the same problem, but was able to resolve it by changing it to multipoint. Thoughts?



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