N o t e

Multimedia Traffic Control with IP Multicast (IGMP)

Terminology

network). Switches in the network (that support IGMP) can then be config­ ured to direct the multicast traffic to only the ports where needed. If multiple VLANs are configured, you can configure IGMP on a per-VLAN basis.

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 then also function as the querier. (If you need to disable the querier feature, you can do so by using the no ip igmp querier command. Refer to “Configuring the Querier Capability” on page 12-9.)

IGMP configuration on the Series 5300XL switches operates at the VLAN context level. If you are not using VLANs, then configure IGMP in VLAN 1 (the default VLAN) context.

Terminology

IGMP: Internet Group Management Protocol. This is an internal protocol of the Internet Protocol (IP) suite. IP manages multicast traffic by using switches, multicast routers, and hosts that support IGMP.

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.

Leave Group: A message sent by a host to the querier to indicate that the host has ceased to be a member of a specific multicast group.

Multicast Group: A set of hosts, routers, and/or switches that send or receive multicast data streams to or from the same source(s). All devices in the group use the same multicast group address.

Report: A message sent by a host to the querier to indicate that the host wants to be or is a member of a given group indicated in the report message.

Query: A message sent from the querier (multicast router or switch) asking for a response from each host belonging to the multicast group. For more information, refer to “More on IGMP Operation” on page 12-10.

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

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