Hi David,
It's the T1l FC-SW standard.
FIBRE CHANNEL SWITCH FABRIC - 5 (FC-SW-5)
http://www.t11.org/ftp/t11/pub/fc/sw-5/09-290v1.pdf
7.4.2 Domain_ID Distribution by the Principal Switch
The Principal Switch shall conduct Domain_ID distribution as indicated in figure 17 and as described
below.
State D0: Setup. At the completion of Principal Switch Selection, the Principal Switch shall assume
the role of Domain Address Manager, and perform the following setup actions:
a) The Principal Switch shall set its Switch_Priority value to 02h, if the current value of its
Switch_Priority is greater than or equal to 02h.
Regards,
David