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Just remember that only IGMP version 2 or 3 hosts can issue multicast leave messages. If a
version 1 host is receiving multicast traffic, the switch can only remove the interface from the
multicast stream after the host responds to a periodic request for a membership report.
WEB INTERFACE
To configure global and interface settings for MVR:
1. Click Configuration, MVR.
2. Enable MVR globally on the switch, and select the MVR VLAN.
3. Set each port that will participate in the MVR protocol as a source port or receiver port, and
optionally enable Immediate Leave on any receiver port to which only one subscriber is
attached.
4. Click Save.
4.10. IPMC Configurations
IGMP Snooping
Multicasting is used to support real-time applications such as videoconferencing 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 that 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 to the
hosts which subscribed to this service.
This switch can use Internet Group Management Protocol (IGMP) to filter multicast traffic.
IGMP Snooping can be used to passively monitor or
“
snoop” on exchanges between
attached hosts and an IGMP-enabled device, most commonly a multicast router. In this way,
the switch can discover the ports that want to join a multicast group, and set its filters
accordingly.
If there is no multicast router attached to the local subnet, multicast traffic and query
messages may not be received by the switch. In this case (Layer 2) IGMP Query can be
used to actively ask the attached hosts if they want to receive a specific multicast service.
IGMP Query thereby identifies the ports containing hosts requesting to join the service and
sends data out to those ports only. It then propagates the service request up to any
neighboring multicast switch/router to ensure that it will continue to receive the multicast
service.
The purpose of IP multicast filtering is to optimize a switched network's performance, so
Summary of Contents for GEP-1070
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