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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
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Chapter42 Configuring IP Multicast Routing
Configuring IP Multicast Routing
Configuring Auto-RP
Auto-RP uses IP multicast to automate the distribution of group-to-RP mappings to all Cisco routers and
multilayer switches in a PIM network. It has these benefits:
•It is easy to use multiple RPs within a network to serve different group ranges.
•It provides load splitting among different RPs and arrangement of RPs according to the location of
group participants.
•It avoids inconsistent, manual RP configurations on every router and multilayer switch in a PIM
network, which can cause connectivity problems.
Follow these guidelines when configuring Auto-RP:
•If you configure PIM in sparse mode or sparse-dense mode and do not configure Auto-RP, you must
manually configure an RP as described in the “Manually Assigning an RP to Multicast Groups”
section on page 42-14.
•If routed interfaces are configured in sparse mode, Auto-RP can still be used if all devices are
configured with a manual RP address for the Auto-RP groups.
•If routed interfaces are configured in sparse mode and you enter the ip pim autorp listener global
configuration command, Auto-RP can still be used even if all devices are not configured with a
manual RP address for the Auto-RP groups.
These sections describe how to configure Auto-RP:
•Setting up Auto-RP in a New Internetwork, page 42-16 (optional)
•Adding Auto-RP to an Existing Sparse-Mode Cloud, page 42-16 (optional)
•Preventing Join Messages to False RPs, page 42-18 (optional)
•Filtering Incoming RP Announcement Messages, page 42-18 (optional)
For overview information, see the “Auto-RP” section on page42-6.

Setting up Auto-RP in a New Internetwork

If you are setting up Auto-RP in a new internetwork, you do not need a default RP bec ause you configure
all the interfaces for sparse-dense mode. Follow the process described in the “Adding Auto-RP to an
Existing Sparse-Mode Cloud” section on page 42-16. However, omit Step 3 if you want to configure a
PIM router as the RP for the local group.

Adding Auto-RP to an Existing Sparse-Mode Cloud

This section contains some suggestions for the initial deployment of Auto-RP into an existing
sparse-mode cloud to minimize disruption of the existing multicast infrastructure.
Beginning in privileged EXEC mode, follow these steps to deploy Auto-RP in an existing sparse-mode
cloud. This procedure is optional.