Description

This article provides clarification on the specific line Anycast PIM local address used in the output >show pim rps extensive

Symptoms

Using Anycast RP with MSDP the output >show pim rps extensive displays different Anycast PIM local address used.

 

 

Setup is: Switch1 peering with Switch2. Anycast IP is 1.1.1.1.

 

 

Test outputs:

 

Switch1:

set interfaces lo0 unit 0 family inet address 13.13.13.1/32 primary

set interfaces lo0 unit 0 family inet address 1.1.1.1/32

set routing-options router-id 13.13.13.1

set protocols msdp local-address 13.13.13.1

set protocols msdp peer 13.13.13.2

set protocols ospf area 0.0.0.0 interface irb.7

set protocols ospf area 0.0.0.0 interface lo0.0 passive

set protocols pim rp local address 1.1.1.1

 

 

 

 

root@SW1# run show pim rps extensive

Instance: PIM.master

 

address-family INET

 

RP: 1.1.1.1

Learned via: static configuration

Mode: Sparse

Time Active: 00:02:40

Holdtime: 150

Device Index: 26

Subunit: 32770

Interface: pimd.32770

Static RP Override: Off

Group Ranges:

    224.0.0.0/4

Anycast PIM local address used: 13.13.13.1

 

 

 

 

Switch2:

set interfaces lo0 unit 0 family inet address 13.13.13.2/32 primary

set interfaces lo0 unit 0 family inet address 1.1.1.1/32

set routing-options router-id 13.13.13.2

set protocols msdp local-address 13.13.13.2

set protocols msdp peer 13.13.13.1

set protocols ospf area 0.0.0.0 interface irb.7

set protocols ospf area 0.0.0.0 interface lo0.0 passive

set protocols pim rp local address 1.1.1.1

 

 

root@SW2# run show pim rps extensive

Instance: PIM.master

 

address-family INET

 

RP: 1.1.1.1

Learned via: static configuration

Mode: Sparse

Time Active: 00:03:13

Holdtime: 150

Device Index: 26

Subunit: 32770

Interface: pimd.32770

Static RP Override: Off

Group Ranges:

    224.0.0.0/4

Anycast PIM local address used: 13.13.13.2

 

Solution

The output is expected. The devices working as Anycast-RPs can be identified by the same logical address so that the RP is unique, in this scenario 1.1.1.1. However, the devices need to distinguish one another during the communication, so the Anycast-RP address cannot be used. To resolve this issue, the local address for the Anycast-RP is used, in this scenario 13.13.13.x.

 

 

RFC4610 Anycast RP using PIM 

Modification History

2025-06-05 : Article Created