SMC Networks SMCGS10C-SMART Management Manual page 135

last dynamic member port in the group, the receiving port is not a
router port, and no IGMPv1 member port exists in the group, the switch
will generate and send a group-specific (GS) query to the member port
which received the leave message, and then start the last member
query timer for that port.
When the conditions in the preceding item all apply, except that the
receiving port is a router port, then the switch will not send a GS-query,
but will immediately start the last member query timer for that port.
Leave proxy is also included in the general proxy function described
below. Therefore if Leave Proxy Enabled is not selected, but Proxy
Enabled is selected, leave proxy will still be performed.
Proxy Enabled – Enables IGMP Snooping with Proxy Reporting.
◆
(Default: Disabled)
When proxy reporting is enabled with this command, the switch
performs "IGMP Snooping with Proxy Reporting" (as defined in DSL
Forum TR-101, April 2006), including report suppression, last leave,
and query suppression.
Report suppression intercepts, absorbs and summarizes IGMP reports
coming from downstream hosts. Last leave sends out a proxy query
when the last member leaves a multicast group, and query suppression
means that neither specific queries nor general queries are forwarded
from an upstream multicast router to hosts downstream from this
device.
When proxy reporting is disabled, all IGMP reports received by the
switch are forwarded natively to the upstream multicast routers.
Port Related Configuration
◆ Port – Port identifier.
Router Port - Sets a port to function as a router port, which leads
◆
towards a Layer 3 multicast device or IGMP querier. (Default: Disabled)
If IGMP snooping cannot locate the IGMP querier, you can manually
designate a port which is connected to a known IGMP querier (i.e., a
multicast router/switch). This interface will then join all the current
multicast groups supported by the attached router/switch to ensure
that multicast traffic is passed to all appropriate interfaces within the
switch.
Fast Leave - Immediately deletes a member port of a multicast service
◆
if a leave packet is received at that port. (Default: Disabled)
The switch can be configured to immediately delete a member port of a
multicast service if a leave packet is received at that port and the Fast
Leave function is enabled. This allows the switch to remove a port from
the multicast forwarding table without first having to send an IGMP
group-specific (GS) query to that interface.
If Fast Leave is not used, a multicast router (or querier) will send a
GS-query message when an IGMPv2/v3 group leave message is
received. The router/querier stops forwarding traffic for that group only
if no host replies to the query within the specified timeout period.
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| Configuring the Switch
C 4
HAPTER
IGMP Snooping