Enterasys Vertical Horizon VH-2402S2, Руководство по настройке

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58 VH-2402S2 User Interface VH-2402S2
IGMP Multicast Filtering
Multicasting is used to support real-time applications such as video
conferencing or streaming audio. A multicast server does not have to
establish a separate connection with each client. It merely broadcasts its
service to the network, and any hosts which want to receive the multicast
register with their local multicast switch/router. Although this approach
reduces the network overhead required by a multicast server, the
broadcast traffic must be carefully pruned at every multicast switch/router
it passes through to ensure that traffic is only passed on the hosts which
subscribed to this service.
This switch uses IGMP (Internet Group Management Protocol) to query
for any attached hosts who want to receive a specific multicast service.
The switch looks up the IP Multicast Group used for this service and adds
any port which received a similar request to that group. It then propagates
the service request on to any neighboring multicast switch/router to
ensure that it will continue to receive the multicast service. (For more
information, see “IGMP Snooping and IP Multicast Filtering” on page
103.)