HP 3500YL - Manual (Page 36)

Multimedia Traffic Control with IP Multicast (IGMP)
IGMP General Operation and Features
N o t e IGMP configuration on the switches covered in this guide 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 2-12.
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