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.

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