System information

126 | Chapter 4: Configuring Switching Information
GS752TXS Smart Switch Software Administration Manual
filter packets addressed to unrequested group addresses, they are unable to transmit new
packets onto the shared media for the period of time that the multicast packet is flooded. The
problem of wasting bandwidth is even worse when the LAN segment is not shared, for
example in full-duplex links.
Allowing switches to snoop IGMP packets is a creative effort to solve this problem. The
switch uses the information in the IGMP packets as they are being forwarded throughout the
network to determine which segments should receive packets directed to the group address.
IGMP Snooping Configuration
Use the IGMP Snooping Configuration page to configure the parameters for IGMP snooping,
which is used to build forwarding lists for multicast traffic.
To access the IGMP Snooping Configuration page, click Switching Multicast  IGMP
Snooping
 IGMP Snooping Configuration.
To configure IGMP Snooping:
1. Enable or disable IGMP Snooping on the switch.
• Enable. The switch snoops all IGMP packets it receives to determine which segments
should receive packets directed to the group address.
• Disable. The switch does not snoop IGMP packets.
2. Choose whether to validate the IGMP IP header.
• Enable. The switch checks the IP header of all IGMP messages for the Router Alert
option. If the option is not present, the packet is dropped.