Domain Id Assignment - EMC Connectrix EC-1200 Planning Manual

Domain ID
Assignment
This address becomes the Source ID (SID) on the N_Port's outbound
frames and the Destination ID (DID) on the N_Port's inbound frames.
The fabric uses the DID to route each frame to its final destination.
The Domain byte is used to determine the destination switch and the
Area byte is used to determine the destination port for each frame.
The physical address of an N_Port changes when a link is moved
from one switch port to another switch port. The WWPN of the
N_Port, however, does not change. Using the Name Server, N_Ports
can automatically adjust to changes in the fabric address by keying
off the WWPN. Not all SCSI Initiators can handle this change to a
physical address automatically. Contact your Customer Service
representative for the latest status of this functionality.
These SCSI Initiators can automatically adjust to changes in the
physical address:
JNI — Solaris Sbus & PCI
Emulex — Windows NT and Windows 2000
Symmetrix RDF
These SCSI Initiators cannot automatically adjust to changes in the
physical address:
IBM 6227 for AIX 4.3.3
HP-UX 11.0
DG-UX
Each switch in a multiswitch fabric is identified by a unique Domain
ID, in the range 1 through 31. Domain IDs are used in 24-bit Fibre
Channel addresses to identify source and destination ports in a fabric.
When adding a new switch, assign it a Preferred Domain ID that is not
in use. When the switch comes on line, it requests that it be assigned
this ID. If the ID is already in use, the principal switch assigns an
unused one. (Refer to Principal Switch Selection on page 2-7.)
Whether a new switch is going to be put onto a fabric or not, assigning it an
unused Domain ID provides for an easier, more available migration to a
fabric in the future.
Fibre Channel Switching Concepts
Fabric Addressing
2
2-5