Configuring Igmp; Overview; Igmp Versions; Introduction To Igmpv1 - HP 6125G Configuration Manual

Configuring IGMP

Overview

As a TCP/IP protocol responsible for IP multicast group member management, the Internet Group
Management Protocol (IGMP) is used by IP hosts and adjacent multicast routers to establish and maintain
their multicast group memberships.
The term "router" in this document refers to both routers and Layer 3 switches.

IGMP versions

IGMPv1 (defined in RFC 1 1 12)
•
IGMPv2 (defined in RFC 2236)
•
• IGMPv3 (defined in RFC 3376)
All IGMP versions support the Any-Source Multicast (ASM) model. In addition to the ASM model,
IGMPv3 can directly implement the Source-Specific Multicast (SSM) model. IGMPv1 and IGMPv2 must
work with the IGMP SSM mapping function to implement the SSM model.
For more information about the ASM and SSM models, see

Introduction to IGMPv1

IGMPv1 manages multicast group memberships mainly based on the query and response mechanism.
All multicast routers on the same subnet can receive IGMP membership report messages (often called
"reports") from hosts, but the subnet needs only one router to send IGMP query messages (often called
"queries"). The querier election mechanism determines which router acts as the IGMP querier on the
subnet.
In IGMPv1, the designated router (DR) elected by the working multicast routing protocol (such as PIM)
serves as the IGMP querier.
For more information about DR, see "Configuring PIM."
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"Multicast overview."