5 Configuration
D-Link Web Smart Switch User Manual
Figure 56 – Configuration > IGMP Snooping Configuration
By default, IGMP is disabled. If enabled, the IGMP Global Settings will need to be entered:
Querier State:
D-Link Smart Switch is able to send out the IGMP Queries to check the status of multicast
clients. Default is disabled.
Query Interval (60-600 sec):
The Query Interval is the interval between General Queries sent. By adjusting
the Query Interval, the number of IGMP messages can increase or decrease; larger values cause IGMP
Queries to be sent less often. Default is 125 seconds.
Max Response Time (10-25 sec):
The Max Response Time specifies the maximum allowed time before
sending a responding report. Adjusting this setting effects the "leave latency", or the time between the
moment the last host leaves a group and when the IGMP protocol is notified that there are no more members.
It also allows adjustments for controlling the frequency of IGMP traffic on a subnet. Default is 10 seconds.
Robustness Variable (2-255 sec):
The Robustness Variable allows adjustment for the expected packet loss
on a subnet. If a subnet is expected to be lossy, the Robustness Variable may be increased. The
Robustness Variable can not be set zero, and SHOULD NOT be one. Default is 2 seconds.
Last Member Query Interval (1-25 sec):
The Last Member Query Interval is the Max Response Time
inserted into Group-Specific Queries sent in response to Leave Group messages, and is also the amount of
time between Group-Specific Query messages. This value may be adjusted to modify the "leave latency" of
the network. A reduced value results in reduced time to detect the loss of the last member of a group. Default
is 1 second.
Host Timeout (System assigned):
This is the interval after which a learnt host port entry will be purged. For
each host port learnt, a 'Port Purge Timer' runs for 'Host Port Purge Interval'. This timer will be restarted
whenever a report message from host is received over that port. If no report messages are received for 'Host
Port Purge Interval' time, the learnt host entry will be purged from the multicast group. After entering Max
Response Time, Robustness Variable and Last Member Query Interval, system will auto assign the value of
Host Timeout.
Router Timeout (60-600 sec):
This is the interval after which a learnt router port entry will be purged. For
each router port learnt, a 'Router Port Purge Timer' runs for 'Router Port Purge Interval'. This timer will be
restarted whenever a router control message is received over that port. If no router control messages are
received for 'Router Port Purge Interval' time, the learnt router port entry will be purged. Default is 260
seconds.
Leave Timer (0-25 sec):
This is the interval after which a Leave message is forwarded on a port. When a
leave message from a host for a group is received, a group-specific query is sent to the port on which the
leave message is received. A timer is started with a time interval equal to Igs Leave Process Interval. If a
report message is received before above timer expires, the Leave message is dropped. Otherwise the Leave
message is either forwarded to the port. Default is 1 second.
To enable IGMP snooping for a given VLAN, select enable and click on the
Apply
button. Then press the
Edit
button under
Router Port Setting
, and select the ports to be assigned for IGMP snooping for the VLAN,
and press
Apply
for changes to take effect.
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