Lantronix
SM12XPA Web User Guide
33848 Rev. A
Page
147
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473
9. Multicast
IGMP Snooping
This 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 supported 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 function that you
enable IGMP proxy or snooping on the switch, which connects to a router closer to the root of the tree.
Basic Configuration
This page lets you set 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 must be running IGMP
Web Interface
To configure IGMP Snooping parameters in the web UI:
1.
Click Multicast, IGMP Snooping, and Basic Configuration.
2.
Set the IGMP Snooping Global Configuration parameters.
3.
Set the Port Related Configuration parameters.
4.
Click the Apply button to save the settings or to cancel the settings click the Reset button.
Figure 9-1.1: IGMP Snooping Basic Configuration
