Configuration: Multicast; Igmp Mode - Lancom GS-2124 User Manual

Restricted Tcn:
Same as mentioned in "Port Config"
4.16

Configuration: Multicast

The function, IGMP Snooping, is used to establish the multicast groups to for-
ward 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 can not 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 for-
warding 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 mul-
ticast packets to the multicast group that had not been built up in advance.
4.16.1

IGMP Mode

Select the IGMP operating mode IGMP for multicast.
Parameter Description
IGMP Mode
Disable: Set "Disable" mode to disable IGMP function.
Proxy: Set "Proxy" to enable the IGMP Proxy for multicast pakets.
Snooping: Set "Snooping" to enable the IGMP Snooping for multicast
pakets.
Chapter 4: Operation of Web- based Management
LANCOM GS-2124
143