Igmp Settings - Motorola 2200 Administrator's Handbook

IGMP Settings

NOTE: IGMP Version 3 is supported beginning with Firmware Version 7.7.
See "IGMP (Internet Group Management Protocol)" on page 100
You can set the following options:
• IGMP Snooping – 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 gateway. 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 sec-
onds and must be less than the query interval.
• Unsolicited Report Interval – the amount of time in seconds between repetitions of a particular com-
puter'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: 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; otherwise, allow the default v3.
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NOTE:
IGMP Querier version is relevant only if the router is configured for IGMP forwarding. 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 forwarding 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 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 – 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 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.
•
Log Enable – If set to on, all IGMP messages on both the LAN and the WAN will be logged.
•
Wireless Multicast to Unicast conversion – Only available if IGMP Snooping is enabled. If set to on,
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 multicast group, the router will revert to
multicasting the stream immediately. When one or more wireless clients leave a group, and the router
for detailed explanation.
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