ECS3510-26P_Management Guide R02

C HAPTER 17 | Multicast Filtering
Layer 2 IGMP (Snooping and Query)
– 485 –
◆ Interface Version – Sets the protocol version for compatibility with
other devices on the network. This is the IGMP Version the switch uses
to send snooping reports. (Range: 1-3; Default: 2)
This attribute configures the IGMP report/query version used by IGMP
snooping. Versions 1 - 3 are all supported, and versions 2 and 3 are
backward compatible, so the switch can operate with other devices,
regardless of the snooping version employed.
◆ Query Interval – The interval between sending IGMP general queries.
(Range: 2-31744 seconds; Default: 125 seconds)
An IGMP general query message is sent by the switch at the interval
specified by this attribute. When this message is received by
downstream hosts, all receivers build an IGMP report for the multicast
groups they have joined.
This command applies when the switch is serving as the querier
(page 474), or as a proxy host when IGMP snooping proxy reporting is
enabled (page 474).
◆ Query Response Interval – The maximum time the system waits for
a response to general queries. (Range: 10-31744 tenths of a second;
Default: 10 seconds)
This command applies when the switch is serving as the querier
(page 474), or as a proxy host when IGMP snooping proxy reporting is
enabled (page 474).
◆ Last Member Query Interval – The interval to wait for a response to
a group-specific query message. (Range: 1-31740 tenths of a second in
multiples of 10;
Default: 1 second)
When a multicast host leaves a group, it sends an IGMP leave message.
When the leave message is received by the switch, it checks to see if
this host is the last to leave the group by sending out an IGMP group-
specific query message, and starts a timer. If no reports are received
before the timer expires, the group record is deleted, and a report is
sent to the upstream multicast router.
A reduced value will result in reduced time to detect the loss of the last
member of a group or source, but may generate more burst traffic.
This attribute will take effect only if IGMP snooping proxy reporting is
enabled (see page 474) or IGMP querier is enabled (page 474).
◆ Last Member Query Count – The number of IGMP proxy group-
specific or query messages that are sent out before the system
assumes there are no more local members. (Range: 1-255; Default: 2)
This attribute will take effect only if IGMP snooping proxy reporting or
IGMP querier is enabled.