Owner's Manual

53
VLAN ID Displays the VLAN ID.
IGMP Snooping
Status
Enables or disables the IGMP Snooping feature for the specified
VLAN ID.
Version This value will affect the igmp packets type that encode and send
from switch, by the way, this value is the same as Querier Version in
the “Querier Settings” page.
Fast Leave Enables or disables the IGMP Snooping Fast Leave for the specified
VLAN
ID. Enabling this feature allows the Switch to immediately remove
the Layer 2 LAN port from its forwarding table entry upon receiving
an IGMP leave message without first sending out IGMPgroup-
specific (GS) queries to the port.
Click the Apply button to accept the changes or the Cancel button to discard them.
If Fast Leave is not used, a multicast querier will send a GS-query message when an IGMPv2/v3
group leave message is received. The 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 port. Therefore, Fast Leave should only be
enabled on a port if it is connected to only one IGMP-enabled device.
Fast Leave is supported only with IGMPv2 or IGMPv3 Snooping when IGMP Snooping is enabled.
Fast Leave does not apply to a port if the Switch has learned that a multicast querier is attached
to it.
Fast Leave can improve bandwidth usage for a network which frequently experiences many IGMP
host add and leave requests.
Querier Settings
IGMP Snooping requires that one central Switch to periodically query all end devices on the
network to announce their multicast memberships and this central device is the IGMP querier. The
snooping Switch sends out periodic queries with a time interval equal to the configured querier
query interval. The IGMP query keeps the Switch updated with the current multicast group
membership information. If the Switch does not received the updated membership information,
then it will stop forwarding multicasts to specified VLANs.