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Command Usage
•IGMP Snooping – This switch can passively snoop on IGMP
Query and Report packets transferred between IP multicast
routers/switches and IP multicast host groups to identify the IP
multicast group members. It simply monitors the IGMP packets
passing through it, picks out the group registration information,
and configures multicast filters accordingly.
•IGMP Query – A router, or multicast-enabled switch, can
periodically ask their hosts if they want to receive multicast
traffic. If there is more than one router/switch on the LAN
performing IP multicasting, one of these devices is elected
“querier” and assumes the role of querying the LAN for group
members. It then propagates the service requests on to any
adjacent multicast switch/router to ensure that it will continue
to receive the multicast service.
Note: Multicast routers use this information, along with a
multicast routing protocol such as DVMRP or PIM, to
support IP multicasting across the Internet.
Command Attributes
•IGMP Status — When enabled, the switch will monitor
network traffic to determine which hosts want to receive
multicast traffic. This is also referred to as IGMP Snooping.
(Default: Disabled)
•Act as IGMP Querier — When enabled, the switch can serve
as the Querier, which is responsible for asking hosts if they
want to receive multicast traffic. (Default: Disabled)
b_mgmt.book Page 114 Tuesday, July 8, 2003 5:24 PM