6-34
Configuring the Switch
IP Multicast (IGMP) Service Features—Multimedia Traffic Control
Configuring the Switch
IP Multicast (IGMP) Service Features—
Multimedia Traffic Control
In a network where IP multicast traffic is transmitted for various multimedia 
applications, you can use the switch to reduce unnecessary bandwidth usage 
on a per-port basis by configuring IGMP (Internet Group Management Proto-
col). In the factory default state IGMP is disabled—the switch forwards all 
IGMP traffic to all ports, which can cause unnecessary bandwidth usage on 
ports not belonging to multicast groups. Enabling IGMP allows the ports to 
detect IGMP queries and report packets and manage IP multicast traffic 
through the switch. 
IGMP is useful in multimedia applications such as LAN TV, desktop confer-
encing, and collaborative computing, where there is multipoint communica-
tion; that is, communication from one to many hosts, or communication 
originating from many hosts and destined for many other hosts. In such 
multipoint applications, IGMP will be configured on the hosts, and multicast 
traffic will be generated by one or more servers, inside or outside of the local 
network. Switches in the network that support IGMP can then be configured 
to direct the multicast traffic to only the ports where needed. In addition to 
the Switch 212M and Switch 224M, other HP switches that support IGMP 
include:
Enabling IGMP allows the ports to detect IGMP queries and report packets 
and manage IP multicast traffic through the switch. If no other querier is 
detected, the switch will also function as the querier. (If you need to disable 
the querier feature, you can do so through the IGMP configuration MIB. Refer 
to “Changing the Querier Configuration Setting” on page page 6-42.)
Note
In order for IGMP service to take effect, an IP address must be configured on 
the switch. Refer to “IP Configuration” on page page 6-5. 
For more information on IGMP operation, refer to “How IGMP Operates” on 
page 6-38.
• HP Switch 1600M
• HP Switch 2400M
• HP Switch 4000M
• HP Switch 8000M
• HP Switch 2000 (B-version)
• HP Switch 800T
Sraswb.book : SIER_SW6.FM  Page 34  Tuesday, June 30, 1998  12:20 PM