3 – Planning
Multiple Chassis Fabrics
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A
Domain ID, Principal Priority, and Domain ID Lock
The following switch configuration settings affect multiple chassis fabrics:
 Domain ID
 Principal priority
 Domain ID lock
The domain ID is a unique number from 1–239 that identifies each switch in a 
fabric. The principal priority is a number (1–255) that determines the principal 
switch which manages domain ID assignments for the fabric. The switch with the 
highest principal priority (1 is high, 255 is low) becomes the principal switch. If the 
principal priority is the same for all switches in a fabric, the switch with the lowest 
WWN becomes the principal switch.
The domain ID lock allows (False) or prevents (True) the reassignment of the 
domain ID on that switch. Switches come from the factory with the domain ID set 
to 1, the domain ID lock set to False, and the principal priority set to 254. Refer to 
the Set Config Switch command in the SANbox 5802V Fibre Channel Switch 
Command Line Interface Guide for information about changing the default domain 
ID, domain ID lock, and principal priority parameters.
If you connect a new switch to an existing fabric with its domain ID unlocked, and 
a domain ID conflict occurs, the new switch will isolate as a separate fabric. 
However, you can remedy this by resetting the new switch or taking it offline then 
putting it back online. The principal switch will reassign the domain ID and the 
switch will join the fabric.
       
NOTE:
Domain ID reassignment is not reflected in zoning that is defined by domain 
ID/port number pair or Fibre Channel address. You must reconfigure zones 
that are affected by domain ID reassignment. To prevent zoning definitions 
from becoming invalid under these conditions, lock the domain IDs. Domain 
ID reassignment has no effect on zone members defined by WWN.