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PIM-SM uses the RP as the shared root of a multicast distribution tree. Only a single<br />

RP is active for a group at any point in time. There are three mechanisms for creating<br />

RPs: static RP, auto-RP (see Recipe 16.3), and bootstrap router (BSR; see Recipe<br />

16.4). Manually mapping RPs to groups is the simplest way to configure RPs in your<br />

network. A disadvantage of this method is that if an RP router becomes unavailable,<br />

no backup RP is immediately ready to take over, and multicast services will be<br />

unavailable until you manually configure another router to be the RP.<br />

The first command in this recipe, set rp local, establishes the local router, RouterA,<br />

as the RP. For the address, use the router’s loopback address. To verify the configuration,<br />

check the local router’s loopback address and then list the PIM RPs:<br />

aviva@RouterA> show interfaces terse lo0.0<br />

Interface Admin Link Proto Local Remote<br />

lo0.0 up up inet 192.168.13.1 --> 0/0<br />

aviva@RouterA> show pim rps<br />

Instance: PIM.master<br />

Address family INET<br />

RP address Type Holdtime Timeout Active groups Group prefixes<br />

192.168.13.1 static 0 None 0 224.0.0.0/4<br />

Address family INET6<br />

These commands show that the local loopback address is 192.168.13.1 and that this<br />

is the address of the RP. The Group prefixes column shows that the local RP is the RP<br />

for all groups in the range 224.0.0.0/4, which is the default for manually configured<br />

RPs.<br />

The second command, set rp static, configures the non-RP routers to know the<br />

address of the RP so they know where to send PIM Join messages. Verify the configuration<br />

on the non-RP routers in the same way:<br />

aviva@RouterB> show pim rps<br />

Instance: PIM.master<br />

Address family INET<br />

RP address Type Holdtime Timeout Active groups Group prefixes<br />

192.168.13.1 static 0 None 2 224.0.0.0/4<br />

Address family INET6<br />

The RP address column matches the RP’s address.<br />

To make the router be an RP for a more specific range than the default 224.0.0.0/4,<br />

include the range when configuring the RP:<br />

[edit protocols pim]<br />

aviva@RouterA# set rp local group-ranges 224.0.0.0/8<br />

This command sets the local router to be an RP for 224.0.0/8 instead of the default<br />

224.0.0.0/4. Different routers can be RPs for different ranges. The following command<br />

configures RouterG (192.168.19.1) is set to be the RP for the 234.0.0.0/8 range:<br />

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

584 | Chapter 16: IP Multicast<br />

This is the Title of the Book, eMatter Edition<br />

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.

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