Antaira Technologies - Industrial Ethernet Switches
LMP-0800G-24 Series User Manual V1.0
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5.7 IGMP Snooping
The Internet Group Management Protocol (IGMP) is a communications protocol used to manage
the membership of Internet Protocol multicast groups. IGMP is used by IP hosts and adjacent
multicast routers to establish multicast group memberships.
When IGMP snooping is enabled in a switch, it analyzes all the IGMP packets between hosts
connected to the switch and multicast routers in the network. When a switch receives an IGMP
report for a given multicast group from a host, the switch adds the host's port number to the
multicast list for that group. When the switch hears an IGMP leave, it removes the host's port from
the table entry.
IGMP snooping can reduce multicast traffic from streaming and other bandwidth intensive IP
applications more effectively. A switch using IGMP snooping will only forward multicast traffic to the
hosts in that traffic. This reduction of multicast traffic reduces the packet processing at the switch
(at the cost of needing additional memory to handle the multicast tables) and also decreases the
workload at the end hosts since their network cards (or operating system) will not receive and filter
all the multicast traffic generated in the network.
IGMP has 3 versions, IGMP v1, v2, and v3, and support query group up to 256 groups.
5.7.1 IGMP Settings
Figure 5.41
– IGMP Snooping Settings Interface
