ZyXEL Communications VES-1616 - Manual (Page 65)

ZyXEL VES-1616/24FA-5x Series Support Notes
All contents copyright 2008 ZyXEL Communications Corporation. 64
IP Multicasting
Configuring IGMP snooping in your switch
IGMP snooping is designed for scenarios with multicast traffic.
It operates on the underlying IGMP mechanism where a layer two switch
passively listens to the IGMP Query, Report and Leave (IGMP version 2) packets
transmitted between the IGMP router and clients and collects passing IGMP
messages. After that, the switch records the message’s group registration
information, and configures the multicasting information accordingly. If the
multicast group information is unknown (not recorded on the switch), the switch
discards that multicast traffic. Only the registered clients that join the group will
receive multicast stream from the IGMP router. Thus this significantly reduces the
multicast traffic forwarded down to the clients.
Another advantage of IGMP snooping is to allow the intermediate switch to learn
Receiver Receiver Receiver Not a Receiver
Video
server
IGMP
Router
Enable IGMP
Snooping
Multicast
Traffic