How many Domain IDs are reserved in the fabric in the Fibre Channel address space?

A.
16

B.
17

C.
239

D.
256

Explanation:
FC Addressing in Switched Fabric
The number of RESERVED Domain IDs = 256 – 239 = 17
An FC address is dynamically assigned when a node port logs on to the fabric. The FC address
has a distinct format, as shown in the slide.
The first field of the FC address contains the domain ID of the switch. A Domain ID is a unique
number provided to each switch in the fabric.
Although this is an 8-bit field, there are only 239 available addresses for domain ID because some
addresses are deemed special and reserved for fabric management services. For example,
FFFFFC is reserved for the name server, and FFFFFE is reserved for the fabric login service.

EMC E10-001 Student Resource Guide. Module 5: Fibre Channel Storage Area Network (FC
SAN)