User's Manual

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Chapter 72 Basic Multicast Routing
Configuration
72.1 Starting up Multicast Routing
To allow the router software to forward the multicast message, you must start up the multicast
routing. Run the following command in global configuration mode to start up the multicast
message forwarding:
Command Purpose
ip multicast-routing
Starts up the multicast routing.
72.2 Starting up the Multicast Function on the Port
When the multicast routing protocol runs on a port, the IGMP is activated on the port. The multicast routing
protocols include OLNK, PIM-DM, PIM-SM and DVMRP. Only one multicast routing protocol is allowed to run
on the same port. When the router connects multiple multicast domains, different multicast protocols can be
run on different ports.
Although the router software can function as the multicast boundary router (MBR). If possible, do not
simultaneously run multiple multicast routing protocols on the same router for some multicast routing protocols
may be badly affected. For example, when PIM-DM and BIDIR PIM-SM simultaneously run, confusion is to
occur.
72.2.1 Starting up PIM-DM
Run the following command to run PIM-DM on a port and then activate the multicast dense mode function:
Command Purpose
ip pim-dm
Enters the port where PIM-DM is running and
then activates PIM-DM multicast routing
process in port configuration mode.
72.2.2 Starting up PIM-SM
To run PIM-DM on a port and activate the PIM-DM multicast, perform the following operation:
Command Purpose
ip pim-sm
Enters a port where PIM-SM needs to run and
then activates the PIM-SM multicast routing
process in port configuration mode.
72.3 Configuring TTL Threshold
Run the command ip multicast ttl-threshold to configure the TTL threshold of the multicast message that is
allowed to pass the port. Run the command no ip multicast ttl-threshold to use the default threshold value
1.