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CHAPTER 15: IGMP IGMP
MULTILINK ML2400 ETHERNET COMMUNICATIONS SWITCH – INSTRUCTION MANUAL 15–7
The following command sequence illustrates how to display IGMP groups:
GroupIp PortNo Timer LeavePending
22.214.171.124 9 155 0
126.96.36.199 9 155 0
The output of the show-group command displays the following information:
• Group IP column shows the multicast groups.
• Port No shows the port where the multicast group is being detected.
• Timer shows the amount of time left in seconds before the group port will be
deleted (or will not be able to route multicast traffic) if the switch does not receive a
• Leave Pending column shows the number of leave messages received from this
Every port can be individually set to three different IGMP modes - auto, block and forward.
• Auto - lets IGMP control whether the port should or should not participate sending
• Block - manually configures the port to always block multicast traffic
• Forward - manually configures the port to always forward multicast traffic
To set the port characteristics, use the
set-port command in the IGMP configuration
set-port port=< port|list|range> mode=<auto|forward|block>
show-port command displays the port characteristics for IGMP.
show-router command displays detected IGMP-enabled router ports.
set-leave command enables or disables the switch to immediately process a host
sending a leave message rather that wait for the timer to expire.
set-querier command enables or disables a switch as IGMP querier.
set-qi command sets the IGMP querier router to periodically send general host-
query messages. These messages are sent to ask for group membership information. This
is sent to the all-system multicast group address, 188.8.131.52. The valid range can be from 60
to 127 seconds, with a default of 125.
set-qri command sets the query response interval representing the maximum
amount of time that can elapse between when the querier router sends a host-query
message and when it receives a response from a host. The range can be from 2 to 270
seconds, with a default of 10. Restrictions apply to the maximum value because of an
internal calculation that is dependent on the value of the query interval.