ip pim autorp listener

Answered Question
Aug 28th, 2009

please explain briefly what " ip pim autorp listener" does, and where it can be applied.

I have this problem too.
1 vote
Correct Answer by Mohamed Sobair about 7 years 3 months ago

Hi,

This command normally used when PiM Dense mode is not configured.

The IP Pim autorp listener allows the Group 224.0.0.39 & 224.0.0.40 to be densed flooded.

As the RP announces 224.0.0.39 to the mapping agent and the mapping agent announces 224.0.0.40 to all routers part of the group.

where it can be applied:

It can be applied when Dense mode is not configured, for example if you have Sparse-mode Multicast Network, and you need not to statically define your RP or use Autorp.

HTH

Mohamed

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Giuseppe Larosa Fri, 08/28/2009 - 06:04

Hello Kennie,

when using autoRP to propagate groups to RP mappings you face the following problem:

mapping messages are sent with destination address 224.0.1.40 that can travel multiple hops (not limited to local subnet).

But how to handle these messages if the links are configured for ip pim sparse-mode and no RP for 224.0.1.40 exists in the net?

or you use

ip pim sparse-dense-mode to allow group 224.0.1.40 to be treated as dense mode (no need of an RP)

or you use this ip pim autorp listener that allows the device to listen to and propagate mapping messages even if no RP for the group exists.

see

"To cause IP multicast traffic for the two Auto-RP groups 224.0.1.39 and 224.0.1.40 to be Protocol Independent Multicast (PIM) dense mode flooded across interfaces operating in PIM sparse mode, use the ip pim autorp listener command in global configuration mode. To disable this feature, use the no form of this command. "

http://www.cisco.com/en/US/docs/ios/ipmulti/command/reference/imc_04.html#wp1012925

Hope to help

Giuseppe

Correct Answer
Mohamed Sobair Fri, 08/28/2009 - 11:51

Hi,

This command normally used when PiM Dense mode is not configured.

The IP Pim autorp listener allows the Group 224.0.0.39 & 224.0.0.40 to be densed flooded.

As the RP announces 224.0.0.39 to the mapping agent and the mapping agent announces 224.0.0.40 to all routers part of the group.

where it can be applied:

It can be applied when Dense mode is not configured, for example if you have Sparse-mode Multicast Network, and you need not to statically define your RP or use Autorp.

HTH

Mohamed

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