3Com 3500 - Manual (Page 325)

bridge mpla mode 325
Procedure
1 To enable MultiPoint Link Aggregation on the switch, use the bridge
mpla mode enable
command.
To disable MultiPoint Link Aggregation on the switch, use the
bridge
mpla mode disable command.
2 Select the ports that you want to be part of the multipoint aggregated
link using the bridge trunk define command, as described in
Chapter 11 .
3 Reboot the switch to implement the multipoint aggregated link selection.
On reboot, existing trunks and VLANs are deleted, and the default VLAN
is restored.