HP 2500 manual The Advantage of Using Igmp

Configuring Advanced Features

Multimedia Traffic Control with IP Multicast (IGMP)

■Switch 1 ignores IGMP traffic and does not distinguish between IP multi- cast 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.

Multicast

Data Stream

Router

Router

Switch 1

Router

IGMP is NOT

Running Here

IGMP IS

Running Here

PC X

Video

Server

Router

Switch 2

PC 1
Video
Client	PC 2

PC 3
	PC 4
	Video		PC 6
	Client	PC 5

Figure 9-67. The Advantage of Using IGMP

The next figure (9-68) shows a network running IP multicasting using IGMP without a multicast router. In this case, the IGMP-configured switch runs as a querier.

PCs 2, 5, and 6 are members of the same IP multicast group.

9-99