Allied Telesis AT-S63 - Manual (Page 87)

AT-S63 Management Software Features Guide
Section I: Basic Operations 87
Slave Switches
The slave switches of an enhanced stack must be connected to the master
switch through a common VLAN. A slave switch can be connected
indirectly to the master switch so long as there is an uninterrupted path of
the common VLAN from the slave switch to the master switch.
A slave switch does not need a routing interface on the common VLAN if
you use the Default_VLAN (VID 1) as the common VLAN. A routing
interface in the common VLAN is required if you use any other VLAN other
than the Default_VLAN as the common VLAN of the switches in the stack.
The routing interface in the common VLAN on a slave switch does not
have to be designated as the local interface. The only circumstance in
which you might want to designate a local interface on a slave switch is if
you want to be able to remotely manage the device independently of the
enhanced stack. However, for the switch to remain part of an enhanced
stack, the interface designated as the local interface must be in the
common VLAN.