Configuring Igmp Snooping; Overview; Basic Igmp Snooping Concepts - HP 6125XLG Ip Multicast Configuration Manual

Configuring IGMP snooping

Overview

IGMP snooping runs on a Layer 2 switch as a multicast constraining mechanism to improve multicast
forwarding efficiency. It creates Layer 2 multicast forwarding entries from IGMP packets that are
exchanged between the hosts and the router.
As shown in
to all hosts. When IGMP snooping is enabled, the Layer 2 switch forwards multicast packets of known
multicast groups to only the receivers.
Figure 11 Multicast packet transmission without and with IGMP snooping

Basic IGMP snooping concepts

IGMP snooping related ports
As shown in
receivers in a multicast group.
Figure 1 1, when IGMP snooping is not enabled, the Layer 2 switch floods multicast packets
Figure 12, IGMP snooping runs on Switch A and Switch B, and Host A and Host C are
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