Cisco Systems 78-11741-02 Igmp Udlr Configuration Task List, Configuring the Igmp UDL, IPC-510

Configuring Unidirectional Link Routing

IGMP UDLR Configuration Task List

IGMP UDLR Configuration Task List

To configure IGMP UDLR, perform the tasks described in the following sections. The tasks in the first section are required; the tasks in the remaining sections are optional.

•Configuring the IGMP UDL (Required)

•Changing the Distance for the Default RPF Interface (Optional)

•Monitoring IGMP UDLR (Optional)

Prerequisites

Before configuring IGMP UDLR, ensure that the following conditions exist:

•All routers on the UDL have the same subnet address. If all routers on the UDL cannot have the same subnet address, the upstream router must be configured with secondary addresses to match all the subnets that the downstream routers are attached to.

•Multicast receivers are directly connected to the downstream routers.

Configuring the IGMP UDL

To configure an IGMP UDL, you must configure both the upstream and downstream routers to meet the following conditions:

•You need not specify whether the direction is sending or receiving; IGMP learns the direction by the nature of the physical connection.

•When the downstream router receives an IGMP report from a host, the router helpers the report to the IGMP querier associated with the UDL interface identified in the ip igmp helper-addressinterface configuration command.

To configure the IGMP UDL on the upstream router, use the following command in interface configuration mode:

Command	Purpose
Router(config-if)#ip igmp unidirectional-link	Configures IGMP on the interface to be unidirectional.

To configure the IGMP UDL on the downstream router, use the following commands in interface configuration mode:

	Command	Purpose
Step 1
	Router(config-if)# ip igmp	Configures IGMP on the interface to be unidirectional.
	unidirectional-link
Step 2
	Router(config-if)# ip igmp	Configures the interface to be an IGMP helper. Use this command
	helper-address udl type number	on every downstream router, on every interface to a potential
		multicast receiver. Specify the type and number values that identify
		the UDL interface.

Cisco IOS IP Configuration Guide

IPC-510