Understanding How Rgmp Works; Configuring Rgmp - Cisco 7604 Configuration Manual

Configuring RGMP

This chapter supplements the information and procedures about Router-Port Group Management
Protocol (RGMP) in the Release 12.2 publication at this URL:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfrgmp.html
This chapter consists of these sections:
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For additional information (including configuration examples and troubleshooting information), see the
Tip
documents listed on this page:
http://www.cisco.com/en/US/products/hw/routers/ps368/tsd_products_support_series_home.html

Understanding How RGMP Works

RGMP constrains multicast traffic that exits the Cisco 7600 series router through ports to which only
disinterested multicast routers are connected. RGMP reduces network congestion by forwarding
multicast traffic to only those routers that are configured to receive it.
Note •
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All routers on the network must be RGMP-capable. RGMP-capable routers send RGMP hello messages
periodically. The RGMP hello message tells the Cisco 7600 series router not to send multicast data to
the router unless an RGMP join message has also been sent to the Cisco 7600 series router from that
router. When an RGMP join message is sent, the router is able to receive multicast data.
OL-4266-08
Understanding How RGMP Works, page 32-1
Default RGMP Configuration, page 32-2
RGMP Configuration Guidelines and Restrictions, page 32-2
Enabling RGMP on Layer 3 Interfaces, page 32-3
To use RGMP, you must enable IGMP snooping on the Cisco 7600 series router. IGMP snooping
constrains multicast traffic that exits through LAN ports to which hosts are connected. IGMP
snooping does not constrain traffic that exits through LAN ports to which one or more multicast
routers are connected.
You must enable Protocol Independent Multicast (PIM) on all routers and switches for RGMP to
work. Only PIM sparse mode is currently supported.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
C H A P T E R
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