BayStack 450 10/100/1000 Series Switches309978-D Rev 01 1-43Base UnitThe base unit is the unique stack unit that you configure with the Unit Selectswitch on the front panel of the 400-ST1 Cascade Module (see “Unit SelectSwitch” on page 1-41).One unit in the stack must be configured as the base unit; all other units in thestack must have their Unit Select switch set to Off.Normally, any single unit in a stack configuration can be assigned as the base unit,with the following restriction: In a mixed stack configuration that contains one ormore Business Policy Switch 2000 units, a Business Policy Switch 2000 must beconfigured as the base unit.The physical ordering of all of the other units in the stack is determined by theposition of the base unit within the stack. This is important for managementapplications that view the physical ordering of the units within the stack.Some characteristics of the base unit are:• Initial InstallationDuring the initial installation of the stack, the software automaticallydetermines the physical order of all units in the stack according to the positionof the base unit within the stack. Thereafter, the individual units maintain theiroriginal unit numbering, even if you change the position of one or more unitsin the stack.For example, when you initially power up the stack, the base unit becomesunit 1 and the unit that the base unit connects to (via the Cascade A Out cable)becomes unit 2 (and the next unit is unit 3 and so on), until the maximumstack configuration (up to 8 units) is reached. If you change the base unit toanother unit in the stack, the new base unit keeps its original unit number inthe stack.Note: If you do not designate a Business Policy Switch 2000 as the base unitof a mixed stack configuration, the stack configuration will not operate.Note: You can renumber the units using the Renumber Stack Units screen; see“Renumber Stack Units” on page 3-107.
