Users Guide

Internet Group Management

Protocol (IGMP)

Internet group management protocol (IGMP) is a Layer 3 multicast protocol that hosts use to join or leave a

multicast group.

Multicast is premised on identifying many hosts by a single destination IP address; hosts represented by the

same IP address are a multicast group. Multicast routing protocols (such as protocol-independent multicast

[PIM]) use the information in IGMP messages to discover which groups are active and to populate the

multicast routing table.

IGMP Implementation Information

• The Dell Networking OS supports IGMP versions 1, 2, and 3 based on RFCs 1112, 2236, and 3376,

respectively.

• The system does not support IGMP version 3 and versions 1 or 2 on the same subnet.

• Dell Networking switches cannot serve as an IGMP host or an IGMP version 1 IGMP Querier.

• The system automatically enables IGMP on interfaces on which you enable a multicast routing protocol.

Topics:

• IGMP Protocol Overview

• Configure IGMP

• Viewing IGMP Enabled Interfaces

• Selecting an IGMP Version

• Viewing IGMP Groups

• Enabling IGMP Immediate-Leave

• IGMP Snooping

• Fast Convergence after MSTP Topology Changes

• Designating a Multicast Router Interface

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