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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 48 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 48-24.
• 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 48-26 (optional)
• Adding Auto-RP to an Existing Sparse-Mode Cloud, page 48-26 (optional)
• Preventing Join Messages to False RPs, page 48-28 (optional)
• Filtering Incoming RP Announcement Messages, page 48-28 (optional)
For overview information, see the “Auto-RP” section on page 48-7.

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 because 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 48-26. 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.