Allied Telesis AT-S63 - Manual (Page 38)

Chapter 1: Overview
38 Section I: Basic Operations
Module ID Numbers
A switch has to have a unique module ID number in the range of 1 to 5 or
1 to 8 to be a member of a stack. The two ranges happen to correspond to
the maximum size of a stack, as explained in “Maximum Number of
Switches in a Stack” on page 30.
The switch assigned module ID number 1 becomes the stack’s master
switch.
The switches of a stack are identified in the boot configuration file on the
master switch by their module ID numbers. Consequently, any change to
the numbering system of the switches of an established stack can have a
significant impact on the configurations of the units.
Module ID numbers can be assigned two ways. The preferred method is to
assign the numbers yourself with the SET STACK command. Module ID
numbers assigned in this fashion are referred to as static numbers
because the switches retain their numbers even when new switches are
added or removed from a stack.
The second approach is to have the management software make the
assignments automatically during the discovery process of a stack. These
numbers are called dynamic module ID numbers because they can
change if the composition of a stack changes.
The commands for managing the module ID numbers are “SET STACK”
on page 70 and “SHOW STACK” on page 72. The SET STACK command
should only be used when a switch is functioning as a stand-alone device,
because changing a switch’s module ID number when the unit is part of a
stack can have unpredictable results.
Static Module ID
Numbers
Static module ID numbers are preferred over dynamic numbers for the
following reasons:
ˆ You can number the devices to reflect their order in the equipment
rack, making them easier to identify.
ˆ A stack with static module ID numbers stores a backup copy of the
active configuration file on the switch assigned ID number 2. For
information, refer to “Active Configuration File” on page 36.
ˆ It is easier to replace a member switch. A new switch assigned the
same module ID number of the switch that it replaces assumes the
same configuration. This will save you from having to configure the
new unit.
Static module ID numbers are assigned with the SET STACK command.
The numbers should be assigned when the switches are operating as
stand-alone devices, because there can be unpredictable results if you
assign the numbers when the switches are part of a stack.