CTC Union IFS-1604GSM Series, Руководство пользователя

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Chapter 4. Web Configuration & Operation
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CHAPTER 4
WEB OPERATION & CONFIGURATION
4.10 IPMC
The “IPMC” menu includes IGMP Snooping and MLD Snooping sub menu. Select the appropriate menu to set up
detailed configurations.
4.10.1 IGMP Snooping
The Internet Group Management Protocol (IGMP) is a communications protocol used to manage the membership of
Internet Protocol multicast groups. IGMP is used by IP hosts and adjacent multicast routers to establish multicast
group memberships. It can be used more efficiently when supporting activities, such as, online streaming video and
gaming.
IGMP Snooping is the process of listening to IGMP traffic. IGMP snooping, as implied by the name, is a feature that
allows the switch to “listen in” on the IGMP conversation between hosts and routers by processing the layer 3 packets
that IGMP packets sent in a multicast network.
When IGMP snooping is enabled in a switch, it analyses all the IGMP packets between hosts connected to the switch
and multicast routers in the network. When a switch receives an IGMP report for a given multicast group from a host,
the switch adds the host's port number to the multicast list for that group. When the switch hears an IGMP Leave, it
removes the host's port from the table entry.
IGMP snooping can reduce multicast traffic from streaming and other bandwidth intensive IP applications more
effectively. A switch using IGMP snooping will only forward multicast traffic to the hosts in that traffic. This reduction
of multicast traffic reduces the packet processing at the switch (at the cost of needing additional memory to handle
the multicast tables) and also decreases the workload at the end hosts since their network cards (or operating system)
will not receive and filter all the multicast traffic generated in the network.
4.10.1.1 Basic Configuration