Multicast Stub & IGMP Helper

15 Comments

1. The following descriptions are conflicted,

   Configure dense-mode multicast between router BA and Murdock.

   You are not allowed to form a PIM neighbor relationship between router BA and murdock.

2. This might sound strange, but the lab is correct.

   This Cisco Document will give you a good idea why this is correct:

   http://www.cisco.com/en/US/customer/tech/tk828/technologies_tech_note09186a0080094821.shtml#stub

3. Please can some send me a working config of this. A text file would be ok. Kindly send to okwukaic@yahoo.com

4. I’ll add the final config soon, for now this might help you out. I’ll assume you know how the ‘normal’ multicast works and are struggling with the STUB part:

   [Murdock]
   ip multicast-routing

   int f0/0
   ip pim sparse-dense-mode
   ip igmp helper-address x.x.x.x (address of router BA)

   int s0/0
   ip pim sparse-dense-mode

   [BA]
   int s0/0
   ip pim sparse-dense-mode
   ip pim neighbor-filter 1

   access-list 1 deny y.y.y.y (IP for Murdock)

   Good luck for now 🙂

5. i still cant get the videostation router to ping 224.4.4.4 :'( the rest of the routers can ping 224.4.4.4 >:(

   1. I had the same problem till i realized that the helper address command need to be enabled on LAN interface connected to RECEIVER not the WAN interface connecting to BA

      Following is the config:
      BA
      —-
      accesss-list 1 deny host 192.168.23.3
      int ser
      ip pim neighbor-filter 1

      Mardock:
      int fa 0/0
      ip pim helper-address 192.168.23.2
      I then joined another group 225.5.5.5
      Mardock#show ip mroute 225.5.5.5
      IP Multicast Routing Table
      Flags: D – Dense, S – Sparse, B – Bidir Group, s – SSM Group, C – Connected,
      L – Local, P – Pruned, R – RP-bit set, F – Register flag,
      T – SPT-bit set, J – Join SPT, M – MSDP created entry,
      X – Proxy Join Timer Running, A – Candidate for MSDP Advertisement,
      U – URD, I – Received Source Specific Host Report,
      Z – Multicast Tunnel, z – MDT-data group sender,
      Y – Joined MDT-data group, y – Sending to MDT-data group
      Outgoing interface flags: H – Hardware switched, A – Assert winner
      Timers: Uptime/Expires
      Interface state: Interface, Next-Hop or VCD, State/Mode

      (*, 225.5.5.5), 00:04:10/stopped, RP 0.0.0.0, flags: DC
      Incoming interface: Null, RPF nbr 0.0.0.0
      Outgoing interface list:
      FastEthernet0/0, Forward/Dense, 00:04:10/00:00:00
      Serial2/0, Forward/Dense, 00:04:10/00:00:00

      (192.168.12.1, 225.5.5.5), 00:04:01/00:02:59, flags: T
      Incoming interface: Serial2/0, RPF nbr 192.168.23.2
      Outgoing interface list:
      FastEthernet0/0, Forward/Dense, 00:04:02/00:00:00
      BA#show ip mroute 225.5.5.5
      IP Multicast Routing Table
      Flags: D – Dense, S – Sparse, B – Bidir Group, s – SSM Group, C – Connected,
      L – Local, P – Pruned, R – RP-bit set, F – Register flag,
      T – SPT-bit set, J – Join SPT, M – MSDP created entry,
      X – Proxy Join Timer Running, A – Candidate for MSDP Advertisement,
      U – URD, I – Received Source Specific Host Report,
      Z – Multicast Tunnel, z – MDT-data group sender,
      Y – Joined MDT-data group, y – Sending to MDT-data group
      Outgoing interface flags: H – Hardware switched, A – Assert winner
      Timers: Uptime/Expires
      Interface state: Interface, Next-Hop or VCD, State/Mode

      (*, 225.5.5.5), 00:04:36/stopped, RP 0.0.0.0, flags: DC
      Incoming interface: Null, RPF nbr 0.0.0.0
      Outgoing interface list:
      Serial2/0, Forward/Dense, 00:04:36/00:00:00
      FastEthernet0/0, Forward/Dense, 00:04:36/00:00:00

      (192.168.12.1, 225.5.5.5), 00:04:27/00:02:57, flags: T
      Incoming interface: FastEthernet0/0, RPF nbr 0.0.0.0
      Outgoing interface list:
      Serial2/0, Forward/Dense, 00:04:29/00:00:00

      From Video Station:
      VideoStation#ping 225.5.5.5 repeat 100000 source fa 0/0

      Type escape sequence to abort.
      Sending 100000, 100-byte ICMP Echos to 225.5.5.5, timeout is 2 seconds:
      Packet sent with a source address of 192.168.12.1

      Reply to request 0 from 192.168.34.4, 120 ms
      Reply to request 1 from 192.168.34.4, 104 ms
      Reply to request 2 from 192.168.34.4, 160 ms
      Reply to request 3 from 192.168.34.4, 156 ms
      Reply to request 4 from 192.168.34.4, 172 ms
      Reply to request 5 from 192.168.34.4, 152 ms
      Reply to request 6 from 192.168.34.4, 124 ms
      Reply to request 7 from 192.168.34.4, 140 ms
      Reply to request 8 from 192.168.34.4, 168 ms
      Reply to request 9 from 192.168.34.4, 128 ms
      Reply to request 10 from 192.168.34.4, 164 ms
      Reply to request 11 from 192.168.34.4, 112 ms
      Reply to request 12 from 192.168.34.4, 128 ms
      Reply to request 13 from 192.168.34.4, 184 ms
      Reply to request 14 from 192.168.34.4, 168 ms

6. still having trouble on this one? 😉

7. I do I do!:)

8. I cant see the initial config

9. There are 2 zip files. The final config and the other one is the initial config with just the IP addresses.

10. hello Rene

    could you please tell me what are the benifit of using Multicast STUB ?

    that’s confusing me

    THANKS

    1. In short these are the reasons why we want to use multicast stub:

       – Prevent multicast traffic and enforce unicast.
       – No periodic flooding and pruning when using dense mode.
       – Less PIM control traffic.

11. http://www.cisco.com/en/US/docs/ios/ipmulti/configuration/guide/imc_stub_routing.pdf

12. "not allowed to form a PIM neighbor relationship" mean we can still enable pim on interfaces, Cool Rene (y).

13. @ rene..
    Their are no final configs also why do we need to enable sparse-dense mode as u suggested in one of the comments. The lab required to configure sparse mode. Also I m not able to ping from videostation down to receiver ..all other routers are pinging…

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