GarrettCom Magnum MNS-6K - Manual (Page 198)

M A G N U M 6 K S W I T C H E S , M N S - 6 K U S E R G U I D E
F IGURE 113 – IGMP concepts – advantages of using IGMP
• PCs 1 and 4, switch 2, and all of the routers are members of an IP multicast group. (The
routers operate as queriers.)
• Switch 1 ignores IGMP traffic and does not distinguish between IP multicast group members
and non-members. Thus, it is sending large amounts of unwanted multicast traffic out the
ports to PCs 2 and 3.
• Switch 2 is recognizing IGMP traffic and learns that PC 4 is in the IP multicast group
receiving multicast data from the video server (PC X). Switch 2 then sends the multicast data
only to the port for PC 4, thus avoiding unwanted multicast traffic on the ports for PCs 5 and
6.
197