Igmp Multicast Filtering; Configuring Igmp - Alcatel OmniStack 8008 User Manual

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 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
that 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 "IP Multicast Filtering" in the Users
Guide.)

Configuring IGMP

This protocol allows a host to inform its local switch/router that it wants to receive
transmissions addressed to a specific multicast address group. Use the IGMP
Configuration screen to set key parameters for multicast filtering as shown below.
Parameter
IGMP Status
IGMP Query Count
IGMP Report Delay
Note: The default values are indicated in the sample screen.
Description
If enabled, the switch will monitor network traffic to determine which hosts
want to receive multicast traffic.
The maximum number of queries issued for which there has been no
response before the switch takes action to solicit reports.
The time (in seconds) between receiving an IGMP Report for an IP multicast
address on a port before the switch sends an IGMP Query out that port and
removes the entry from its list.
IGMP Multicast Filtering
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