Multicast Anycast RP Configuration on Cisco IOS

Lessons Discussion
21

I found out that 239.1.1.1 is not a working group not sure why. I changed the group to 239.10.10.10 and it works :slight_smile:

22

That is strange but good to hear it works :slight_smile:

23

super write up thanks

1 Like
24

Very Easy to understand!

25

You are the best!

Davis

26

Your MSDP config is referring to loopback0 ? This won’t bring up MSDP as loopback0 on bough R2 and R3 are 23.23.23.23

27

Hi rene,

good article, i just noticed some mismatch :

  1. your show msdp peer is
R2#show ip msdp peer 
MSDP Peer 3.3.3.3 (?), AS ?
  Connection status:
    State: Up, Resets: 0, Connection source: Loopback1 (2.2.2.2)

and your config is

R2(config)#ip msdp originator-id Loopback 0
R2(config)#ip msdp peer 3.3.3.3 connect-source Loopback 0

it should be

R2(config)#ip msdp originator-id Loopback 0
R2(config)#ip msdp peer 3.3.3.3 connect-source Loopback 1

I think you forgot to mention that ip pim sparse-mode should be enabled in the interface loopback0

  1. your picture is showing
    R2 loopback 0 = 2.2.2.2 instead 23.23.23.23
    R3 loopback 0 = 3.3.3.3 instead 23.23.23.23
    so normally 2.2.2.2 and 3.3.3.3 should be configured in loopack 1 as loopback 0 has already its IP address.

I think we can guess it easely as your show command is correct meaning the original configuration is correct.

thank you again for this article that is very instructive

1 Like
28

Hello Rene,

I was trying to lab this topology. For some reason, I am seeing that MSDP is not coming up between the neighbors and is stuck in listening state. Any idea?

29

Hi Rene,

I found the problem, I think there is a typo in the command above “in connect-source section, it should be lo1 instead of lo0”. Overall, very good post

30

Hi all,

Just edited this post. The MSDP peering should be between the loopback 1 interfaces of R2/R3, not loopback 0.

Rene

1 Like
31

19 posts were merged into an existing topic: Multicast Anycast RP Configuration on Cisco IOS

32

i have one question…

what is the difference between msdp and anycast rp ??

thanks for your always good information

1 Like
33

Anycast RP means all our IPs are advertising the same IP address. The problem with this, is that some sources might join RP1 or RP2, and your receives also join RP1 or RP2. No single RP has information about all sources/receivers.

To fix this, we use the MSDP protocol to “sync” the information between RPs.

1 Like
34

I have question on Anycast. rfc4610 says this: extends the register mechanism in PIM so Anycast-RP functionality can be retained without using MSDP.
Why do we still need MSDP?

35

Hi @rp781,

The RFC4610 mentions that you don’t have to use MSDP for anycast within a domain. However, it also mentions that MSDP is still use for inter-domain multicast:

However, to advertise internal sources to routers outside of a PIM routing domain and to learn external sources from other routing domains, MSDP may still be required.

36

Hi Réné,
Sometile I saw ip igmp join-group or ip igmp join simply. Same effect or different?

Thank.
Ulrich

37

Hi Ulrich,

Which exact command do you mean? ip igmp join-group is an existing command but ip igmp join is not :smiley:

Rene

38

Rene,

Good to know. I saw many ine video and Mc tape this shorcut command ‘ip igmp join’
Thank o lot

39

Ah I see. They type ip igmp join, which is the abbrevation for ip igmp join-group.

40

Hi Rene
On interface loopback 0 and 1 don’t need to enable IP pim spare-mode ?