That is strange but good to hear it works
super write up thanks
Very Easy to understand!
You are the best!
Your MSDP config is referring to loopback0 ? This won’t bring up MSDP as loopback0 on bough R2 and R3 are 18.104.22.168
good article, i just noticed some mismatch :
- your show msdp peer is
R2#show ip msdp peer MSDP Peer 22.214.171.124 (?), AS ? Connection status: State: Up, Resets: 0, Connection source: Loopback1 (126.96.36.199)
and your config is
R2(config)#ip msdp originator-id Loopback 0 R2(config)#ip msdp peer 188.8.131.52 connect-source Loopback 0
it should be
R2(config)#ip msdp originator-id Loopback 0 R2(config)#ip msdp peer 184.108.40.206 connect-source Loopback 1
I think you forgot to mention that ip pim sparse-mode should be enabled in the interface loopback0
- your picture is showing
R2 loopback 0 = 220.127.116.11 instead 18.104.22.168
R3 loopback 0 = 22.214.171.124 instead 126.96.36.199
so normally 188.8.131.52 and 184.108.40.206 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
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?
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
Just edited this post. The MSDP peering should be between the loopback 1 interfaces of R2/R3, not loopback 0.
19 posts were merged into an existing topic: Multicast Anycast RP Configuration on Cisco IOS
i have one question…
what is the difference between msdp and anycast rp ??
thanks for your always good information
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.
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?
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.
Sometile I saw ip igmp join-group or ip igmp join simply. Same effect or different?
Which exact command do you mean?
ip igmp join-group is an existing command but
ip igmp join is not
Good to know. I saw many ine video and Mc tape this shorcut command ‘ip igmp join’
Thank o lot
Ah I see. They type
ip igmp join, which is the abbrevation for
ip igmp join-group.
On interface loopback 0 and 1 don’t need to enable IP pim spare-mode ?
When configuring PIM sparse-mode, it is only necessary to enable this feature on the interfaces of the routers that connect to other routers that participate in PIM sparse mode. By enabling this command on the pairs of interfaces connected to each other, such as Fa0/0 on both R1 and R2, Fa0/1 on both R2 and R3 and Fa0/0 on both R3 and R4, we cause the routers to become neighbors and receive each other’s PIM hello packets. The loopbacks don’t need this config and are only used as a method of communication with each RP. For more info about PIM sparse mode, take a look at this lesson:
I hope this has been helpful!