HP ProCurve 2810-24G, Management And Configuration Manual

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4-4
Multimedia Traffic Control with IP Multicast (IGMP)
General Operation and Features
Enabling IGMP allows detection of IGMP queries and report packets in order
to manage IP multicast traffic through the switch. If no other querier is
detected, the switch will then 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 4-10.)
N o t e
IGMP configuration on the switch operates at the VLAN context level. If you
are not using VLANs, then configure IGMP in VLAN 1 (the default VLAN)
context.
IGMP Terms
■
IGMP Device: A switch or router running IGMP traffic control
features.
■
IGMP Host: An end-node device running an IGMP (multipoint, or
multicast communication) application.
■
Querier: A required IGMP device that facilitates the IGMP protocol
and traffic flow on a given LAN. This device tracks which ports are
connected to devices (IGMP clients) that belong to specific multicast
groups, and triggers updates of this information. A querier uses data
received from the queries to determine whether to forward or block
multicast traffic on specific ports. When the switch has an IP address
on a given VLAN, it automatically operates as a Querier for that VLAN
if it does not detect a multicast router or another switch functioning
as a Querier. When enabled (the default state), the switch’s querier
function eliminates the need for a multicast router. In most cases,
ProCurve recommends that you leave this parameter in the default
“enabled” state even if you have a multicast router performing the
querier function in your multicast group. For more information, see
“How IGMP Operates” on page 4-11.