Specifications

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The IGMP page appears.
You can set the following options:
•IGMP Snooping – checking this checkbox enables the
Motorola Netopia® Gateway to “listen in” to IGMP traffic.
The Gateway discovers multicast group membership for
the purpose of restricting multicast transmissions to only
those ports which have requested them. This helps to
reduce overall network traffic from streaming media and
other bandwidth-intensive IP multicast applications.
•Robustness – a way of indicating how sensitive to lost
packets the network is. IGMP can recover from robustness
minus 1 lost IGMP packet. The default value is 2.
•Query Interval– the amount of time in seconds between
IGMP General Query messages sent by the querier gate-
way. The default query interval is 125 seconds.
•Query Response Interval – the maximum amount of
time in tenths of a second that the IGMP router waits to
receive a response to a General Query message. The
default query response interval is 10 seconds and must
be less than the query interval.
•Unsolicited Report Interval – the amount of time in
seconds between repetitions of a particular computer’s initial report of membership in a group. The
default unsolicited report interval is 10 seconds.
• Querier Version – Select a version of the IGMP Querier from the pull-down menu: v1, v2, or v3. The
default v3 allows for backward compatibility mode with the earlier versions, and should not need to be
changed. However, for administrative purposes you may select either v1 or v2.
• Last Member Query Interval – the amount of time in tenths of a second that the IGMP gateway waits
to receive a response to a Group-Specific Query message. The last member query interval is also the
amount of time in seconds between successive Group-Specific Query messages. The default last mem-
ber query interval is 1 second (10 deci-seconds).
• Last Member Query Count – the number of Group-Specific Query messages sent before the gateway
assumes that there are no members of the host group being queried on this interface. The default last
member query count is 2.
• Fast Leave – Checking this checkbox enables a non-standard expedited leave mechanism. The querier
keeps track of which client is requesting which channel by IP address. When a leave message is
received, the querier can check its internal table to see if there are any more clients on this group. If
there are none, it immediately sends an IGMP leave message to the upstream querier. By default, Fast
Leave is set to Off.
• Log Enable – If you check this checkbox, all IGMP messages on both the LAN and the WAN will be
logged.
• Wireless Multicast to Unicast conversion – This checkbox only appears if IGMP Snooping is
enabled. If you check this checkbox, the Gateway replaces the multicast MAC-address with the physical
MAC-address of the wireless client. If there is more than one wireless client interested in the same mul-
ticast group, the router will revert to multicasting the stream immediately. When one or more wireless
clients leave a group, and the router determines that only a single wireless client is interested in the
stream, it will once again unicast the stream.
Click the
Submit button. Click the Alert icon, and in the resulting page, click the Save and Restart link.