Cisco Systems 3750E Using Auto-RP and a BSR, Show ip pim rp group-name, Group-address mapping

Chapter 42 Configuring IP Multicast Routing

Configuring IP Multicast Routing

This example shows how to configure the switch to advertise itself as a candidate RP to the BSR in its PIM domain. Standard access list number 4 specifies the group prefix associated with the RP that has the address identified by a port. That RP is responsible for the groups with the prefix 239.

Switch(config)# ip pim rp-candidate gigabitethernet1/0/2 group-list 4

Switch(config)# access-list 4 permit 239.0.0.0 0.255.255.255

Using Auto-RP and a BSR

If there are only Cisco devices in you network (no routers from other vendors), there is no need to configure a BSR. Configure Auto-RP in a network that is running both PIMv1 and PIMv2.

If you have non-Cisco PIMv2 routers that need to interoperate with Cisco PIMv1 routers and multilayer switches, both Auto-RP and a BSR are required. We recommend that a Cisco PIMv2 router or multilayer switch be both the Auto-RP mapping agent and the BSR.

If you must have one or more BSRs, we have these recommendations:

•Configure the candidate BSRs as the RP-mapping agents for Auto-RP. For more information, see the “Configuring Auto-RP” section on page 42-16and the “Configuring Candidate BSRs” section on page 42-22.

•For group prefixes advertised through Auto-RP, the PIMv2 BSR mechanism should not advertise a subrange of these group prefixes served by a different set of RPs. In a mixed PIMv1 and PIMv2 domain, have backup RPs serve the same group prefixes. This prevents the PIMv2 DRs from selecting a different RP from those PIMv1 DRs, due to the longest match lookup in the RP-mapping database.

Beginning in privileged EXEC mode, follow these steps to verify the consistency of group-to-RP mappings. This procedure is optional.

	Command	Purpose
Step 1 show ip pim rp [[group-name		On any Cisco device, display the available RP mappings.
	group-address] mapping]	• (Optional) For group-name, specify the name of the group about which to
		display RPs.
		• (Optional) For group-address, specify the address of the group about which
		to display RPs.
		• (Optional) Use the mapping keyword to display all group-to-RP mappings
		of which the Cisco device is aware (either configured or learned from
		Auto-RP).
Step 2 show ip pim rp-hash group		On a PIMv2 router or multilayer switch, confirm that the same RP is the one that
		a PIMv1 system chooses.
		For group, enter the group address for which to display RP information.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
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