Configuring Igmp Snooping; Overview; Basic Concepts In Igmp Snooping - HP 5920 series Configuration Manual

Configuring IGMP snooping

Overview

IGMP snooping enables Layer 2 switches to establish a Layer 2 multicast forwarding table instead of
flooding all multicast packets. To populate the Layer 2 multicast forwarding table, IGMP snooping listens
to IGMP messages exchanged between a Layer 3 multicast device and hosts.
As shown in
all devices. With IGMP snooping enabled, the Layer 2 switch forwards multicast packets of known
multicast groups to only the receivers that require the data at Layer 2. This feature improves bandwidth
efficiency, enhances multicast security, and helps per-host accounting for multicast users.
Figure 10 Multicast packet transmission without and with IGMP snooping

Basic concepts in IGMP snooping

IGMP snooping related ports
As shown in
receiver hosts as members of a multicast group.
Figure 10, without IGMP snooping enabled, the Layer 2 switch floods multicast packets to
Figure 1 1, IGMP snooping runs on Switch A and Switch B, and Host A and Host C are
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