SMC Networks SMC6724L3 manual Layer 3 Igmp Query used with Multicast Routing, 144

L3 - network core

( multicast routing ( and L3 IGMP query

CONFIGURING THE SWITCH

CLI – This example assigns a multicast address to VLAN 1, and then displays all the known multicast services supported on VLAN 1.

Console(config)#ip igmp snooping vlan 1 static 224.1.1.12
ethernet 1/12				4-197
Console(config)#exit
Console#show mac-address-table multicast vlan 1				4-200
VLAN	M'cast IP addr. Member ports		Type
----	--------------- ------------		-------
1	224.1.1.12	Eth1/12	USER
1	224.1.2.3	Eth1/12	IGMP

Console#

Layer 3 IGMP (Query used with Multicast Routing)

IGMP Snooping – IGMP Snooping is a Layer 2 function (page 3-137)that can be used to provide multicast filtering when no other switches in the network support multicast routing. (Note that IGMP Snooping can only be globally enabled.)

IGMP Query – Multicast query is used to poll each known multicast group for active members, and dynamically configure the switch ports which need to forward multicast traffic. Although the implementation differs slightly, IGMP Query is used in conjunction with both Layer 2 IGMP Snooping and multicast routing. Note that when using IGMP Snooping, multicast query is automatically enabled. (See “Configuring IGMP Snooping Parameters” on page 3-137.)

Layer 3 IGMP – This protocol includes a form of multicast query specifically designed to work with multicast routing. A router periodically asks its hosts if they want to receive multicast traffic. It then propagates service requests on to any upstream multicast

router to ensure that it will continue to receive the multicast service. Layer

3IGMP can be enabled for individual VLAN interfaces (page 3-144). (Note that Layer 2 snooping and query is disabled if Layer 3 IGMP is

enabled.)

3-144