User manual

C HAPTER 4 | Configuring the Switch
IGMP Snooping
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specific source. For IGMPv1/v2 hosts, the source address of a channel
is always null (indicating that any source is acceptable), but for IGMPv3
hosts, it may include a specific address when requested.
Only IGMPv3 hosts can request service from a specific multicast source.
When downstream hosts request service from a specific source for a
multicast service, these sources are all placed in the Include list, and
traffic is forwarded to the hosts from each of these sources. IGMPv3
hosts may also request that service be forwarded from any source
except for those specified. In this case, traffic is filtered from sources in
the Exclude list, and forwarded from all other available sources.
◆ Leave Proxy Enabled - Suppresses leave messages unless received
from the last member port in the group. (Default: Disabled)
IGMP leave proxy suppresses all unnecessary IGMP leave messages so
that a non-querier switch forwards an IGMP leave packet only when the
last dynamic member port leaves a multicast group.
The leave-proxy feature does not function when a switch is set as the
querier. When the switch is a non-querier, the receiving port is not the
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)