Cisco IOS in a Nutshell, 2nd Edition

Name

ip pim — interface

Synopsis

ip pim {sparse-mode | dense-mode | sparse-dense-mode}
no ip pim

Configures

IP multicast routing on the interface

Default

Disabled

Description

This command enables PIM (Protocol-Independent Multicast) and IGMP on the interface.

sparse-mode

In this mode, the router forwards multicast packets only if it has received a join message from a downstream router or if it has group members directly connected to this interface.

dense-mode

In this mode, the router forwards multicast packets until it can determine whether there are group members or downstream routers. Unlike sparse-mode, it doesn’t wait for a join message to begin sending multicast packets.

sparse-dense-mode

This mode allows the router to operate in both sparse-mode and dense-mode, depending on what the other routers in the multicast group are using.