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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 33 Configuring IP Multicast Routing
Configuring IP Multicast Routing
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 33-23
and the
“Configuring Candidate BSRs” section
on page 33-29
.
•
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.
Monitoring the RP Mapping Information
To monitor the RP mapping information, use these commands in privileged EXEC mode:
•
show ip pim bsr displays information about the elected BSR.
•
show ip pim rp-hash group displays the RP that was selected for the specified group.
•
show ip pim rp [group-name | group-address | mapping] displays how the switch learns of the RP
(through the BSR or the Auto-RP mechanism).
Troubleshooting PIMv1 and PIMv2 Interoperability Problems
When debugging interoperability problems between PIMv1 and PIMv2, check these in the order shown:
1.
Verify RP mapping with the show ip pim rp-hash privileged EXEC command, making sure that all
systems agree on the same RP for the same group.
2.
Verify interoperability between different versions of DRs and RPs. Make sure the RPs are
interacting with the DRs properly (by responding with register-stops and forwarding decapsulated
data packets from registers).
Command
Purpose
Step 1
show ip pim rp [[group-name |
group-address] | mapping]
On any Cisco device, display the available RP mappings.
•
(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.