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Solution<br />

Specify the group address range when you configure the RP:<br />

[edit protocols pim]<br />

aviva@RouterA# set rp local address 192.168.13.1 group-ranges 224.0.0.0/8<br />

<strong>Discussion</strong><br />

When you configure a PIM router to be an RP, by default it is eligible to be the RP<br />

for all groups. For IPv4 the default group range is 224.0.0.0/4, and for IPv6 it is<br />

FF70::/12 to FFF0::/12. If some multicast groups are sending a lot of traffic, a single<br />

RP might become overwhelmed with handling it all. To minimize router overload<br />

and congestion, configure several RPs and have each one of them act as RP only for a<br />

limited range of group addresses.<br />

This recipe shows how to limit an RP to handle only groups in the 224.0.0.0/8<br />

range. To verify that the configuration has taken effect, look at the RP routers:<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 bootstrap 150 None 4 224.0.0.0/8<br />

192.168.13.1 static 0 None 4 224.0.0.0/8<br />

Address family INET6<br />

The Group prefixes column shows that this router is now RP only for the range<br />

224.0.0.0/8. It is no longer RP for the default range of 224.0.0.0/4.<br />

You can limit the group address range serviced by the RP regardless of the method<br />

you choose to establish the RP routers in your PIM-SM domain. The show pim rps<br />

output above tells you that the RP router was configured using a bootstrap router.<br />

You can also use the set rp local address group-ranges command if you configure<br />

the RP manually, with auto-RP, or with anycast.<br />

16.9 Viewing Multicast Routes<br />

Problem<br />

You want to view the multicast routes that a router has learned.<br />

Solution<br />

The multicast protocols create a multicast forwarding cache, which the JUNOS software<br />

stores in the inet.1 routing table:<br />

aviva@RouterA> show route table inet.1<br />

inet.1: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)<br />

+ = Active Route, - = Last Active, * = Both<br />

224.1.1.1,10.0.15.1/32*[PIM/105] 00:00:08<br />

Multicast (IPv4)<br />

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

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.<br />

Viewing Multicast Routes | 599

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