Can a BSR be a anycast RP ?

[gongya001]

R1 and R2 are configured to be BSR as follows:

ip pim rp-candidate Loopback0

ip pim bsr Loopback0 0 100

MSDP is also configured to let two domains to communicate as follows:

R1:

ip msdp peer 1.1.1.1 connect-source lo0 remote-as 65001

ip msdp originator-id lo0

R2:

ip msdp peer 2.2.2.2 connect-source lo0 remote-as 65002

ip msdp originator-id lo0

Everything works as expected.

I added the following to make R1 and R2 to server as anycast RP on R1 and R2

interface Loopback100

 ip address 100.100.100.100 255.255.255.255

 ip pim sparse-mode

On R3,R4,R5 and R6

access-list 10 permit host 239.100.100.100

ip pim rp-address 100.100.100.100 10 override

int lo0

  ip igmp join-group 239.100.100.100

Can I do this ?

When I join a multicast group, I got the following message:

R6

int lo0

  ip igmp join-group 239.100.100.100

R2(config-router-af)#

*Feb 16 10:23:01.622: %PIM-6-INVALID_RP_JOIN: Received (*, 239.100.100.100) Join from 172.16.2.6 for invalid RP 100.100.100.100

Even I removed the bsr configuration, I got the same thing.

Any ideas ?

appreciate any comments !

[Jose Fonseca]

Hi gongya001;

As far as I understand your Lo0 addresses are different in R1 and R2, and the idea to have Anycast RP is to use the same IP address.

With this, what is happening is that BSR is learning 2 different RP addresses depending on where they get the BSR message, so one peer will use Lo0 from R1 and other will Lo0 from R2, and that won't match all over the network for this reason you got that message:

*Feb 16 10:23:01.622: %PIM-6-INVALID_RP_JOIN: Received (*, 239.100.100.100) Join from 172.16.2.6 for invalid RP 100.100.100.100

HOW TO SOLVE THIS:

Based on the configuration you have I would change the BSR statement to the following:

ip pim rp-candidate Loopback100
ip pim bsr Loopback100 0 100

With this configuration the RP address will be the same all over the network and all the PIM neighbors will send join message to the same RP address, avoiding the issue you are reporting.

Please give it a try and let me know.

Regards,

[gongya001]

 I used lo0 for bsr.

I also configured lo100 for Anycast RP.

On R1 and R2, I configured as follows with the same IPs:

interface Loopback100

 ip address 100.100.100.100 255.255.255.255

 ip pim sparse-mode

[Jose Fonseca]

Yes and no, 

Problem is that you are using the Lo0 as RP-Candidate and that's the one that you are using as RP. 

ip pim rp-candidate Loopback0
ip pim bsr Loopback0 0 100

You can confirmed the same with the command:

show ip pim rp mapping

With this command you will know the RP you are using per device.

Regards,

[gongya001]

so I can't use one router for BSRs with different IPs and anycast with the same IPs on the same RP router, right ?

After I used loopback100 and removed loopback0 for BSR, Anycast multicast works.

thanks so much for your help !!

[Jose Fonseca · Accepted solution]

Exactly, both configurations must be consistent. 

Regarding your last statement, you can define different Anycast RP IP addresses per groups. So let's say that you want one RP device for all the 224.0.0.0/8, and other for all the other groups. 

The same will be accomplish using the following configuration: 

R7#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R7(config)#ip pim rp-candidate lo0 group-list ?
  <1-99>  Access-list reference for group prefixes
  WORD    IP Named Standard Access list

R5#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R5(config)#ip pim rp-candidate lo0 group-list ?
  <1-99>  Access-list reference for group prefixes
  WORD    IP Named Standard Access list

In this example you can see that you can have 2 different RP candidates, R7 and R5, and with this you can literally escalate this as you needed. For instance: R7 and R8 could be the Anycast RP for an specific range, while R5 and R6, can be the Anycast RP for a different range. 

This will let you scalate the network and share the load all over the network and with that been said, the sky is the limit for this config.

Happy labbing!

[gongya001]

thanks so much !!

[gongya001 · Accepted solution]

After I changed

ip pim rp-candidate Loopback100

ip pim bsr Loopback100 0 100

Anycast works. But the original BSR is also using the anycast IPs.

I am wondering whether I can use bsr with different IPs for redundancy, and anycast for some multicast groups.

BSR is configured on loopback 0, and anycast is configured on loopback 100.

Can I do this ?

thanks !!