Multicast Anycast RP Configuration on Cisco IOS

Lessons Discussion
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This topic is to discuss the following lesson:

2

Awesome

3

Great post!

One small copy mistake in this configuration example:

R2(config)#interface fastEthernet 0 => probably this should be fastEthernet 0/1
R2(config-if)#ip pim sparse-mode

Thanks again for this great explanation.

Marek

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Hi Marek,

Thanks I just fixed this error!

Rene

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Also a mistake in your topology picture all interfaces f0/0. Great work on the rest.

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Thanks Diego, I just fixed it.

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Great Article Bro , knocking it out now.

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I have one question here…just consider the source is connected to one of layer 2 switch but the PIM configuration is configured in Core switch …in this case ex: vlan 90 is configured PIM sparse mode in core switch and also source connected same vlan in layer 2 switch …
1.do i need any configuration required for source connected layer 2 switch ?
2.do i want configure igmp snooping in layer 2 switch ?..

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Really thank you for all these lessons,

If you are wondering what’s the next lesson you should explain, here is a suggestion :slight_smile:
>> MSDP Mesh Groups

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Hi Mehdi,

You are welcome, glad to hear you like them! I have added MSDP Mesh Groups to my list…sounds like a good blog post :slight_smile:

Rene

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Hi Zahir,

Where are your receivers located? in the same VLAN or another one?

PIM is required when you want to route multicast traffic between different subnets.

IGMP snooping is required on your switches because the switch somehow has to know to which interfaces it has to deliver multicast traffic. It does this by listening to the IGMP report / leave / query messages between the router and host. It will learn this way which multicast traffic should go to what interfaces.

Rene

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Thanks for sharing this well written article. Don’t forget to manually set your router-id for OSPF (just like you did for MSDP) or the routing protocol might pick the anycast address as the router-id and break your unicast routing!

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That’s a good idea Tristan, thanks for sharing!

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Great work Rene. You have a great way of explaining the different technologies.

Your website is one of my go-to’s while studying.

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Thanks Keith!

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Thanks a lot Rene for your very easy to understand explanations. I just stumbled on your website and I use it as reference for my ccie study. Thanks for sharing.

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Hi Rene,

I am not able to ping the mcast address 239.1.1.1 from R1 after all configs are done.
Below are the o/p for msdp

R2#sh ip msdp peer 
MSDP Peer 3.3.3.3 (?), AS ?
  Connection status:
    State: Up, Resets: 0, Connection source: Loopback1 (2.2.2.2)
    Uptime(Downtime): 00:02:30, Messages sent/received: 4/3
    Output messages discarded: 0
    Connection and counters cleared 00:08:30 ago
  SA Filtering:
    Input (S,G) filter: none, route-map: none
    Input RP filter: none, route-map: none
    Output (S,G) filter: none, route-map: none
    Output RP filter: none, route-map: none
  SA-Requests: 
    Input filter: none
  Peer ttl threshold: 0
  SAs learned from this peer: 0
  Input queue size: 0, Output queue size: 0

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R3#sh ip msdp peer 
MSDP Peer 2.2.2.2 (?), AS ?
  Connection status:
    State: Up, Resets: 0, Connection source: Loopback1 (3.3.3.3)
    Uptime(Downtime): 00:02:35, Messages sent/received: 3/4
    Output messages discarded: 0
    Connection and counters cleared 00:08:35 ago
  SA Filtering:
    Input (S,G) filter: none, route-map: none
    Input RP filter: none, route-map: none
    Output (S,G) filter: none, route-map: none
    Output RP filter: none, route-map: none
  SA-Requests: 
    Input filter: none
  Peer ttl threshold: 0
  SAs learned from this peer: 1
  Input queue size: 0, Output queue size: 0
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Hi Sameer,

MSDP looks ok to me but did you check all the other stuff? Do you have PIM neighbors? Do you see entries in the mroute table? There’s a lot that could be wrong here.

Rene

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R3#sh ip mroute 239.1.1.1
(*, 239.1.1.1), 00:00:58/00:02:04, RP 23.23.23.23, flags: SP
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list: Null

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R2#
(*, 239.1.1.1), 00:00:05/stopped, RP 23.23.23.23, flags: SP
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list: Null

(192.168.12.1, 239.1.1.1), 00:00:05/00:02:54, flags: PTA
  Incoming interface: FastEthernet1/0, RPF nbr 0.0.0.0
  Outgoing interface list: Null

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R3#sh ip pim neighbor    
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
192.168.23.2      FastEthernet1/0          00:03:46/00:01:26 v2    1 / S
192.168.34.4      FastEthernet1/1          00:03:46/00:01:25 v2    1 / DR S

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R2#sh ip pim neighbor 
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
192.168.12.1      FastEthernet1/0          00:02:59/00:01:41 v2    1 / S
192.168.23.3      FastEthernet1/1          00:03:00/00:01:41 v2    1 / DR S

Weird thing is i don’t see any outgoing interface.

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Did you use IGMP join group on R4? As soon as you do this, R3 should show the outgoing interface for the group that you joined.

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