C
HAPTER
17
| IGMP Commands
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Leave function is enabled. This allows the switch to remove a port from
the multicast forwarding table without first having to send an IGMP
group-specific (GS) query to that interface.
◆ If Fast Leave is not used, a multicast router (or querier) will send a
GS-query message when an IGMPv2/v3 group leave message is
received. The router/querier stops forwarding traffic for that group only
if no host replies to the query within the specified time-out period.
◆ If Fast Leave is enabled, the switch assumes that only one host is
connected to the interface. Therefore, Fast Leave should only be
enabled on an interface if it is connected to only one IGMP-enabled
device, either a service host or a neighbor running IGMP snooping.
◆ Fast Leave is only effective if IGMP snooping is enabled, and IGMPv2 or
IGMPv3 snooping is used.
◆ Fast Leave does not apply to a port if the switch has learned that a
multicast router is attached to it.
◆ Fast Leave can improve bandwidth usage for a network which
frequently experiences many IGMP host add and leave requests.
EXAMPLE
IGMP>fastleave 6-10 enable
IGMP>
igmp throttling This command displays or sets IGMP group throttling for specified ports
SYNTAX
igmp throttling [port-list] [group-limit]
port-list - A specific port or a range of ports. (Range: 1-28, or all)
group-limit - The number of multicast groups to which a port can
belong. (Range: 1-10, or 0 to indicate unlimited)
DEFAULT SETTING
unlimited
COMMAND USAGE
IGMP throttling sets a maximum number of multicast groups that a port
can join at the same time. When the maximum number of groups is
reached on a port, any new IGMP join reports will be dropped.
EXAMPLE
IGMP>throttling 9 5
IGMP>
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