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Configuring MLD snooping (available only on
the HP 3100 v2 EI)
Overview
Multicast Listener Discovery (MLD) snooping is an IPv6 multicast constraining mechanism that runs on
Layer 2 devices to manage and control IPv6 multicast groups.
By analyzing received MLD messages, a Layer 2 device that runs MLD snooping establishes mappings
between ports and multicast MAC addresses and forwards IPv6 multicast data based on these
mappings.
As shown in
, without MLD snooping enabled, the Layer 2 switch floods IPv6 multicast packets
to all devices at Layer 2. With MLD snooping enabled, the Layer 2 switch forwards IPv6 multicast packets
destined for known IPv6 multicast groups to only the receivers that require the multicast data at Layer 2.
This feature improves bandwidth efficiency, enhances multicast security, and helps per-host accounting
for multicast users.
Figure 21
Before and after MLD snooping is enabled on the Layer 2 device
Basic concepts in MLD snooping
MLD snooping related ports
As shown in
, Router A connects to the multicast source, MLD snooping runs on Switch A and
Switch B, and Host A and Host C are receiver hosts as members of an IPv6 multicast group.
