Configuring an RP Router for PIM Sparse Mode and PIM Sparse-Dense Mode for IPv4
When you use the router for PIM sparse mode or PIM sparse-dense mode, some VRs must act as RP routers. You can configure static RP routers or configure the router to assign RP routers automatically.
To configure the router to assign RP routers automatically, you must define several VRs as RP routers and one VR as an RP mapping agent. RP routers send their announcement messages to the RP mapping agent, which assigns groups to RP routers and resolves any conflicts. The RP mapping agent notifies neighbors of the RP assigned to each group.
![]() | Note: You can configure PIM on IPv4 and IPv6 interfaces. However, IPv6 does not support all PIM configuration options. For information about configuring PIM on IPv6 interfaces, see Configuring PIM for IPv6 Multicast. |
The following subsections explain how to configure an RP router for PIM sparse mode and PIM sparse-dense mode:
- Configuring a Static RP Router
- Configuring an Auto-RP Router for PIM Sparse Mode
- Configuring an Auto-RP Router for PIM Sparse-Dense Mode
Configuring a Static RP Router
If you want to control PIM more tightly, you can configure a static RP router. To do so:
- Configure an access list that specifies the multicast
groups that can use the static RP router.host1(config)#access-list boston permit 228.0.0.0 15.255.255.255
- Specify a static RP router.host1(config)#ip pim rp-address 122.0.0.1 1 boston
Configuring an Auto-RP Router for PIM Sparse Mode
Two multicast groups, 224.0.1.39 and 224.0.1.40, are reserved for forwarding auto-RP messages through the network. When you configure an auto-RP router for PIM sparse mode, you must assign a static RP router to these two groups. You can then specify an RP mapping agent for other multicast groups.
To configure an auto-RP router for PIM sparse mode:
- Configure a static RP to have priority over the auto-RP
for the groups that send auto-RP multicast messages.host1(config)#access-list 11 permit 224.0.1.39 0.0.0.0 host1(config)#access-list 11 permit 224.0.1.40 0.0.0.0 host1(config)#ip pim rp-address 192.48.1.22 11 override
- Assign an RP mapping agent.host1(config)#ip pim send-rp-discovery scope 23 loopback 1
- Configure routers to send auto-RP announcement messages
to the mapping agent.host1(config)#ip pim send-rp-announce loopback 2 scope 16 group-list 1
Configuring an Auto-RP Router for PIM Sparse-Dense Mode
In PIM sparse-dense mode, you must prevent routers from advertising auto-RP messages to the multicast groups 224.0.1.39 and 224.0.1.40, which are reserved for forwarding auto-RP messages through the network. To configure an auto-RP router for PIM sparse-dense mode:
- Assign an RP mapping agent.host1(config)#ip pim send-rp-discovery scope 23 loopback 1
- Configure an access list that details the multicast groups
that can use the static RP router.host1(config)access-list boston permit 224.0.0.0 15.255.255.255
- Prevent routers from advertising auto-RP messages to the
multicast groups that are reserved for forwarding auto-RP messages
through the network.host1(config)#access-list 1 deny 224.0.1.39 host1(config)#access-list 1 deny 224.0.1.40
- Configure routers to send auto-RP announcement messages
to the mapping agent.host1(config)#ip pim send-rp-announce loopback 2 scope 23 group-list boston interval 200
Related Documentation
- Understanding PIM for IPv4 Multicast
- Configuring the PIM for IPv4 Join/Prune Message Interval
- Configuring BSR and RP Candidates for PIM Sparse Mode for IPv4
- Monitoring RP Routers and the RP Mapping Agent in a PIM Sparse Mode Environment for IPv4
- Monitoring PIM Group-to-RP Mappings for IPv4
- Monitoring the RP Router that a Multicast Group Uses for IPv4
- access-list
- ip pim rp-address
- ip pim send-rp-discovery scope
- ip pim send-rp-announce