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SG71070M
Revision A3
2-9 IGMP Snooping
The function, is used to establish the multicast groups to forward the multicast packet to the
member ports, and, in nature, avoids wasting the bandwidth while IP multicast packets are
running over the network. This is because a switch that does not support IGMP or IGMP
Snooping cannot tell the multicast packet from the broadcast packet, so it can only treat them
all as the broadcast packet. Without IGMP Snooping, the multicast packet forwarding function
is plain and nothing is different from broadcast packet.
A switch supporting IGMP Snooping with the functions of query, report and leave, a type of
packet exchanged between IP Multicast Router/Switch and IP Multicast Host, can update the
information of the Multicast table when a member (port) joins or leaves an IP Multicast
Destination Address. With this function, once a switch receives an IP multicast packet, it will
forward the packet to the members who joined in a specified IP multicast group before.
The packets will be discarded by the IGMP Snooping if the user transmits multicast packets to
the multicast group that had not been built up in advance. IGMP mode enables the switch to
issue IGMP functions that you enable IGMP proxy or snooping on the switch, which connects
to a router closer to the root of the tree. This interface is the upstream interface. The router on
the upstream interface should be running IGMP.
2-9.1 Basic Configuration
The section describes how to set the basic IGMP Snooping on the switch, which connects to a
router closer to the root of the tree. This interface is the upstream interface. The router on the
upstream interface should be running IGMP.
Web Interface
To configure the IGMP Snooping Configuration in the web interface:
1.
Click Configuration, IPMC, IGMP Snooping, Basic Configuration.
2.
Evoke to select enable or disable which Global configuration.
3.
Evoke which port wants to become a Router Port or enable/ disable the Fast Leave
function.
4.
Scroll to set the Throttling parameter.
5.
Click apply to save the setting.
6.
If you want to cancel the setting then you need to click the Reset button. It will revert to
previously saved values.
Figure 2-9.1: The IGMP Snooping Configuration