H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 173)

24-1
24
IGMP Snooping Configuration
Support of the H3C WX series access controllers for features may vary by device model. For more
information, see "Feature Matrixes" in Compatibility Matrixes.
The sample output in this manual was created on the WX5004. The output on your device may
vary.
The grayed out functions or parameters on the Web interface indicate that they are not supported
or cannot be modified.
The models listed in this manual are not applicable to all regions. Please consult your local sales
office for the models applicable to your region.
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.
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 Figure 24-1 , when IGMP snooping is not running on the switch, multicast packets are
flooded to all devices at Layer 2. However, 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.