SMC Networks 8028L2, Management Manual

Page: 91 / 392

C
HAPTER
4
| Configuring the Switch
IGMP Snooping
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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.
VLAN Related Configuration
◆
VLAN ID - VLAN Identifier.
◆
Snooping Enabled - When enabled, the switch will monitor network
traffic on the indicated VLAN interface to determine which hosts want to
receive multicast traffic. (Default: Enabled)
When IGMP snooping is enabled globally, the per VLAN interface
settings for IGMP snooping take precedence. When IGMP snooping is
disabled globally, snooping can still be configured per VLAN interface,
but the interface settings will not take effect until snooping is re-
enabled globally.
◆
IGMP Querier - When enabled, the switch can serve as the Querier
(on the selected interface), which is responsible for asking hosts if they
want to receive multicast traffic. (Default: Disabled)
A router, or multicast-enabled switch, can periodically ask their hosts if
they want to receive multicast traffic. If there is more than one router/
switch on the LAN performing IP multicasting, one of these devices is
elected “querier” and assumes the role of querying the LAN for group
members. It then propagates the service requests on to any upstream
multicast switch/router to ensure that it will continue to receive the
multicast service. This feature is not supported for IGMPv3 snooping.
Port Related Configuration
◆
Port – Port identifier. (Range: 1-28)
◆
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.