D-Link DGS-3308TG User Manual page 99

8-port Gigabit Ethernet Switch User's Guide
To edit a VLAN's IGMP Snooping Settings:
Switch IGMP Snooping:<
This enables or disables IGMP snooping for the selected VLAN.
Querier State:<
Non-Querier – This indicates the IGMP interface will never try to become a querier in the VLAN.
V1-Querier – If there is no querier present in the VLAN or the interface's IP address is smaller than the
current querier—whether V1-Querier or V2-Querier—the IGMP interface will become the querier for the
VLAN. An IGMPv1 query packet is sent in this mode. IGMPv2 Group Specific Query and leave packets are
not handled.
V2-Querier – In this mode, if there is one V1-Querier present in the VLAN, the IGMP interface will keep
silent. If there is no querier present in the VLAN or the interface's IP address is smaller than the current V2-
Querier, the IGMP interface will become the querier for the VLAN. When receiving an IGMPv2 leave packet,
the IGMP interface will issue an IGMPv2 Group Specific Query packet immediately and wait one second to
see if any IGMP report is received on the Ethernet port. If not, the Ethernet port will be removed from the
IGMP group member list and the group's multicast data will not be forwarded to this port until an IGMP
report is received again.
Robustness Variable – A numeric value between 2 and 255 that allows tuning for expected packet losses on a
subnet. If a subnet is expected to have high packet losses, the robustness variable maybe increased. The default is 2.
Query Interval – The time in seconds between transmission of IGMP packets.
Max Response – Sets the maximum amount of time allowed before sending an IGMP response report value
between 1 and 20 seconds can be entered, with a default of 10 seconds.
Robustness Variable, Query Interval, and Max Response values are combined to produce an IGMP age-out
timer value between 10 and 9,999 seconds. This timer determines how long a snooped multicast member's IP and MAC
Figure 6-36. IGMP Snooping screen
> – This field can be toggled between Enabled and Disabled using the space bar.
> – This field determines whether the Switch is able to send IGMP snooping queries.
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