User manual

C HAPTER 4 | Configuring the Switch
MLD Snooping
– 154 –
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.
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 MLD querier. (Default: Disabled)
If MLD snooping cannot locate the MLD querier, you can manually
designate a port which is connected to a known MLD 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 MLD
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 a 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.
If Fast Leave is enabled, the switch assumes that only one host is
connected to the interface. Therefore, Fast Leave should only be