3Com Switch 8800 Advanced Software V5 Configuration Guide

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MLD SNOOPING CONFIGURATION
When configuring MLD Snooping, go to these sections for information you are
interested in:
■ “MLD Snooping Overview” on page 649
■ “MLD Snooping Configuration Task List” on page 653
■ “Displaying and Maintaining MLD Snooping” on page 664
■ “MLD Snooping Configuration Examples” on page 664
■ “Troubleshooting MLD Snooping” on page 669
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For details about MLD and IPv6 PIM, refer to “MLD Configuration” on page 637
and “IPv6 PIM Configuration” on page 671.
MLD Snooping
Overview
Multicast Listener Discovery Snooping (MLD Snooping) is an IPv6 multicast
constraining mechanism that runs on Layer 2 devices to manage and control IPv6
multicast groups.
How MLD Snooping
Works
By analyzing received MLD messages, a Layer 2 device running MLD Snooping
establishes mappings between ports and multicast MAC addresses and forwards
IPv6 multicast data based on these mappings.
As shown in Figure 196, when MLD Snooping is not running on the switch (Layer
2 device), IPv6 multicast packets are broadcast to all Layer 2 ports. When MLD
Snooping runs, multicast packets for known IPv6 multicast groups are forwarded
to only those Layer 2 ports with receivers attached to them.