Configuring Igmp Snooping; Hardware Compatibility; Overview; Basic Concepts In Igmp Snooping - HP MSR ASM Configuration Manual

Configuring IGMP snooping

Hardware compatibility

IGMP snooping is available only on the MSR series routers with fixed Layer 2 switching interfaces or
Layer 2 switching interface modules.

Overview

IGMP snooping is a multicast constraining mechanism that runs on Layer 2 devices to manage and
control multicast groups.
By analyzing received IGMP messages, an IGMP snooping-enabled Layer 2 device establishes
mappings between ports and multicast MAC addresses, and forwards multicast data based on these
mappings.
As shown in
but the incoming port. IGMP snooping enables a Layer 2 switch to forward multicast packets destined for
a known multicast group address out of only ports that have multicast receivers. This feature improves
bandwidth efficiency, enhances multicast security, and helps per-host accounting for multicast users.
Figure 43 Before and after IGMP snooping is enabled on the Layer 2 device

Basic concepts in IGMP snooping

This section lists the basic concepts in IGMP snooping.
Figure 43, without IGMP snooping, a Layer 2 switch floods multicast packets out of all ports
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