
Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
Chapter 2 IGMP Snooping Configuration
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Chapter 2 IGMP Snooping Configuration
When configuring IGMP Snooping, go to the following sections for information you are
interested in:
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IGMP Snooping Configuration Task List
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Displaying and Maintaining IGMP Snooping
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IGMP Snooping Configuration Examples
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Troubleshooting IGMP Snooping Configuration
2.1 IGMP Snooping Overview
Internet Group Management Protocol Snooping (IGMP Snooping) is a multicast
constraining mechanism that runs on Layer 2 devices to manage and control multicast
groups.
2.1.1 Principle of IGMP Snooping
By analyzing received IGMP messages, a Layer 2 device running IGMP Snooping
establishes mappings between ports and multicast MAC addresses and forwards
multicast data based on these mappings.
As shown in
, when IGMP Snooping is not running on the switch, multicast
packets are broadcast to all devices at Layer 2. When IGMP Snooping is running on the
switch, multicast packets for known multicast groups are multicast to the receivers,
rather than broadcast to all hosts, at Layer 2.
Figure 2-1
Before and after IGMP Snooping is enabled on the Layer 2 device