User's Manual

C HAPTER 4 | Configuring the Switch
MLD Snooping
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Once the table used to store multicast entries for MLD snooping is
filled, no new entries are learned. If no router port is configured in the
attached VLAN, and Unregistered IPMCv6 Flooding is disabled, any
subsequent multicast traffic not found in the table is dropped,
otherwise it is flooded throughout the VLAN.
◆ MLD SSM Range - The Source-Specific Multicast Range allows SSM-
aware hosts and routers to run the SSM service model for groups in the
specified address range. (Default: ff3e::/96)
IPv6 addresses in the range FF3x::/96 are currently designated by
RFC 4607 as SSM destination addresses and are reserved for use by
source-specific applications and protocols. SSM-aware hosts and
routers running the SSM service model can pass traffic for any group
within the specified address range.
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. MLD 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)
MLD leave proxy suppresses all unnecessary MLD leave messages so
that a non-querier switch forwards an MLD 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, and the receiving port is not a
router port, 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.
◆ Proxy Enabled - Configures the switch to issue MLD host report
messages on behalf of hosts discovered through standard MLD
interfaces. (Default: Disabled)
When MLD proxy is enabled, the switch exchanges MLD messages with
the router on its upstream interface, and performs the host portion of
the MLD task on the upstream interface as follows:
■
When queried, it sends multicast listener reports to the group.
■
When a host joins a multicast group to which no other host belongs,
it sends unsolicited multicast listener reports to that group.
■
When the last host in a particular multicast group leaves, it sends
an unsolicited multicast listener done report to the all-routers
address (FF02::2) for MLDv1.