Manually Establishing a PIM-SM RP

Problem

For PIM-SM to function, the PIM domain needs to have an RP. You want to assign one of the PIM routers to be the RP.

Solution

Manually configure which router is to be the RP. Set the local router to be the RP:

[edit protocols pim] aviva@RouterA# set rp local address 192.168.13.1

On the other routers, configure the address of the RP:

[edit protocols pim] aviva@RouterB# set rp static address 192.168.13.1

Discussion

PIM-SM uses the RP as the shared root of a multicast distribution tree. Only a single RP is active for a group at any point in time. There are three mechanisms for creating RPs: static RP, auto-RP (see Recipe 16.3), and bootstrap router ( BSR; see Recipe 16.4). Manually mapping RPs to groups is the simplest way to configure RPs in your network. A disadvantage of this method is that if an RP router becomes unavailable, no backup RP is immediately ready to take over, and multicast services will be unavailable until you manually configure another router to be the RP.

The first command in this recipe, set rp local, establishes the local router, RouterA, as the RP. For the address, use the routers loopback address. To verify the configuration, check the local routers loopback address and then list the PIM RPs:

aviva@RouterA> show interfaces terse lo0.0 Interface Admin Link Proto Local Remote lo0.0 up up inet 192.168.13.1 --> 0/0 aviva@RouterA> show pim rps Instance: PIM.master Address family INET RP address Type Holdtime Timeout Active groups Group prefixes 192.168.13.1 static 0 None 0 224.0.0.0/4 Address family INET6

These commands show that the local loopback address is 192.168.13.1 and that this is the address of the RP. The Group prefixes column shows that the local RP is the RP for all groups in the range 224.0.0.0/4, which is the default for manually configured RPs.

The second command, set rp static, configures the non-RP routers to know the address of the RP so they know where to send PIM Join messages. Verify the configuration on the non-RP routers in the same way:

aviva@RouterB> show pim rps Instance: PIM.master Address family INET RP address Type Holdtime Timeout Active groups Group prefixes 192.168.13.1 static 0 None 2 224.0.0.0/4 Address family INET6

The RP address column matches the RPs address.

To make the router be an RP for a more specific range than the default 224.0.0.0/4, include the range when configuring the RP:

[edit protocols pim] aviva@RouterA# set rp local group-ranges 224.0.0.0/8

This command sets the local router to be an RP for 224.0.0/8 instead of the default 224.0.0.0/4. Different routers can be RPs for different ranges. The following command configures RouterG (192.168.19.1) is set to be the RP for the 234.0.0.0/8 range:

aviva@RouterA# set rp static address 192.168.19.1 group-ranges 234.0.0.0/8

Again, verify the configured group ranges:

aviva@RouterA> show pim rps inet detail Instance: PIM.master Address family INET RP: 192.168.13.1 Learned via: static configuration Time Active: 00:04:09 Holdtime: 0 Group Ranges: 224.0.0.0/8 RP: 192.168.19.1 Learned via: static configuration Time Active: 00:01:57 Holdtime: 0 Group Ranges: 234.0.0.0/8

The detail version of the show pim rps command shows that both routers become RPs as a result of manual configuration.

See Also

Recipes 16.3 and 16.4