User Manual

Table Of Contents
64
III-5-2. L2 SWITCHING IGMP SNOOPING
Internet Group Management Protocol (IGMP) is used in communicating among hosts and establishing a
multicast group membership on the IPv4 networks (Layer 3). IGMP provides the ability to prune
multicast traffic to those who need this kind of traffic and reduce the amount of traffic on the network.
However, switches work on the MAC Layer (Layer 2) and are unable to obtain IGMP information. IGMP
Snooping allows the switch to listen to the IGMP communication between hosts and routers, and
maintains a table of multicast IPs and group members. IGMP Snooping can prevent the hosts on the LAN
from receiving traffic from a non-joined multicast group and save bandwidth of the network.
Configure IGMP Snooping Information
Basic Setting
Mode
“Enable” or “Disable” the IGMP Snooping function.
Last-Member Count
The count is the number of times that the router sends IGMP query messages to receive the leave
message.
The range of the Last-Member Count is from 2 to 10.
The default Last-Member Count Interval is 2.
Last-Member Interval
The interval is the period to send IGMP query messages.
The range of the Last-Member Interval is from 1 to 25 seconds.
The default Last-Member Interval is 1 second.