Allied Telesis AR400 - Manual (Page 67)

Page 67 | AlliedWare™ OS How To Note: IGMP
IGMP fast leave > Explanation of IGMP fast leave
Multiple host mode for fast leave
The previous discussion assumes that only one client is attached to the port on the Snooper.
Imagine instead a situation where multiple clients are attached to a single port on the
snooping switch, as the following figure shows.
In this situation, you need to use fast leave in multiple host mode. In multiple host mode,
the Snooper tracks which clients are joined to a given IP multicast group on a given port. The
Snooper shuts off the multicast group to that port as soon as the last client leaves the group
on the port.
Multiple host mode is available in Software Version 291-08 and later.
The alternative mode is called single host mode. In single host mode, as soon as the
Snooper receives a leave message for a group on a port, it shuts off the multicast. This mode
assumes that there are no other clients on the port that are still interested in receiving the
multicast, so is suitable only when clients are directly attached to the Snooper.
To specify multiple mode, use the command:
set igmpsnooping vlan={name|1..4094|all} fastleave=multiple
To specify single mode, use either of the commands:
set igmpsnooping vlan={name|1..4094|all} fastleave=single
set igmpsnooping vlan={name|1..4094|all} fastleave=on
Multicast Server:
TV source for
channels 1-3
AT-8948
Switch 1:
Querier
Rapier 24i
Switch 3:
Snooper
port 1
port 3
port 26
port 49
TV A
1
TV B
2
TV C
3
TV D
3 Channel:
igmp-snooper.eps