Motorola 3347 - Manual (Page 212)

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• IGMP Snooping – enables the Motorola Netopia® Gateway to “listen in” to IGMP traf-
fic. The Gateway discovers multicast group membership for the purpose of restricting
multicast transmissions to only those por ts 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 mes-
sages sent by the querier gateway. The default quer y inter val 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 Quer y message. The default
quer y response inter val is 10 seconds and must be less than the quer y inter val.
• Unsolicited Report Interval – the amount of time in seconds between repetitions of a
par ticular computer’s initial repor t of membership in a group. The default unsolicited
repor t inter val is 10 seconds.
• Querier Version – select a version of the IGMP Querier: version 1, version 2, or version
3. If you know you will be communicating with other hosts that are limited to v1 or v2,
for backward compatibility, select accordingly; other wise, allow the default v3.
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NOTE:
IGMP Querier version is relevant only if the router is configured for IGMP for-
warding. If any IGMP v1 routers are present on the subnet, the querier must
use IGMP v1. The use of IGMP v1 must be administratively configured, since
there is no reliable way of dynamically determining whether IGMP v1 routers
are present on a network. IGMP for warding is enabled per IP Profile and WAN
Connection Profile.
• 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 Quer y message. The last mem-
ber quer y inter val is also the amount of time in seconds between successive Group-
Specific Quer y messages. The default last member quer y inter val 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 que-
ried on this inter face. The default last member quer y count is 2.
• Fast Leave – set to off by default, fast leave enables a non-standard expedited leave
mechanism. The querier keeps track of which client is requesting which channel by IP