Managing Group Members - Fujitsu XG2000 Series User Manual

XG2000 series User's Guide

4.9.3 Managing Group Members

When network congestion causes Leave message loss or there is a host that uses IGMPv1, the multicast router does not
receive Leave messages. The multicast router sends out an IGMP General Query message to all hosts (IP address: 224.0.0.1)
at intervals (query interval) to determine membership information.
Upon reception of an IGMP General Query message, the host, a member of the group, returns an IGMP Report message to
maintain membership in the group.
In consideration of General Query or Report message loss caused by network congestion, it is recommended that the following
equation be used to determine the group member interval for the device.
Group member interval = (query interval for multicast router) × 2 + 10 (seconds)
Since RFC 3376 defines the default query interval for multicast routers as 125 seconds, the device uses 260 seconds for the
default group member interval.
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