H3C S3600 Series User Manual

Operation Manual – Multicast
H3C S3600 Series Ethernet Switches-Release 1510 Chapter 2 IGMP Snooping Configuration
2-1
Chapter 2 IGMP Snooping Configuration
2.1 Overview
2.1.1 IGMP Snooping Fundamentals
Internet group management protocol snooping (IGMP Snooping) is a multicast control
mechanism running on Layer 2 switches. It is used to manage and control multicast
groups.
When the IGMP messages transferred from the hosts to the router pass through the
Layer 2 switch, the switch uses IGMP Snooping to analyze and process the IGMP
messages, as shown in
Table 2-1.
Table 2-1 IGMP message processing on the switch
Received
message type
Sender Receiver Switch processing
IGMP host report
message
Host Switch
Add the host to the
corresponding multicast group.
IGMP leave
message
Host Switch
Remove the host from the
multicast group.
By listening to IGMP messages, a switch establishes and maintains IP multicast
address tables, according to which it forwards the multicast packets delivered from the
router.
As shown in
Figure 2-1, multicast packets are broadcast at Layer 2 when IGMP
Snooping is disabled and multicast (not broadcast) at Layer 2 when IGMP Snooping is
enabled.

H3C S3600 Series Specifications

General

Brand	H3C
Model	S3600 Series
Category	Switch
Language	English