Proposal for IEEE company_id based formats for FC-PH world-wide identifiers

Larry Chen larryc at
Thu Dec 19 12:59:23 PST 1996

* From the SCSI Reflector (scsi at, posted by:
* Larry Chen <larryc at>
Hi Mike,

Assume the following configuration:

Host Computer <----FC-AL----> RAID controller + disk drives + enclosure

The host computer is attached directly to the RAID controller only
(not the disk drives). The RAID controller will manage the disk drives
and export virtual LUNs to the host computer.

At the SCSI initiator's side and level, I wanted a mechanism to associate the 
virtual LUNs with its RAID controller. This mechanism would be general enough
to work for both the simple disk drive case and for the RAID case. 

Below, I will attempt to describe the entities at the FC and SCSI layers
for my current configuration.

At the FC transport layer
Port entity is a SIM in CAM terminology.

Node entity is the RAID controller (or more specifically,
	the RAID controller's Field Replaceable Unit (FRU)).

At the SCSI layer
LUN entity is a virtual LUN.

RAID controller entity is the FRU.

In my single RAID controller configuration, the FC Node entity and the 
SCSI RAID controller entity are equivalent (and probably will have the same value).

Port name - any old WWN
Node name - IEEE Registered Format
Virtual LUN name - IEEE Registered Extended Format
RAID controller name - IEEE Registered Format

and the association field could be used to associate the Virtual LUNs
with its RAID controller.

A problem arises when multi-RAID controller complexes are introduced.
Now, the RAID controller entity is ambiguous (FRU vs. the virtual
RAID controller) and the FC Node entity and the SCSI RAID controller
entity are probably not the same.

At this point, I will not be pursuing this matter any further (unless
someone is willing to stand-up with me).

As an observation, RAID devices seem much more complex when compared to
the simple disk drive case. I hope the RAID Industry will form some
initiatives that will rectify this soon.

Please call me if there are any further questions.

On Thu, 19 Dec 1996 11:27:42 -0800  Mike Wenzel wrote:
>Hi Larry,
>I agree with a previous post, the following description is too vague to
>really follow what is happening.  Could you give a scenario, including the
>topology and node name of the controller and controlled device, then show
>what specifically would appear on the device's Device ID INQUIRY page
>(I assume that's what's involved) to correlate the devices?  If you get time
>to do this, please post it to the broader distribution list: I'm shure a
>number of people were confused and that even more didn't really understand
>the scheme.
>Best Regards and Seasons' Greetings,
>Mike Wenzel
>mw at
>>I was ready to go to Dallas and make a formal proposal but
>>fortunately, Bob Snively mentioned that I could use the 
>>24-bit company_id and 36-bit Vendor Specified Identifier 
>>fields from the virtual LUN's WWN in IEEE registered 
>>extended format to get a pseudo WWN (60-bits only) for its RAID 
>>controller node instead.

Larry Chen                 Tel: 408.383.1600 (x116)
Maximum Strategy, Inc.     Fax: 408.383.1616
801 Buckeye Court       E-mail: larryc at
Milpitas, CA 95035

* For SCSI Reflector information, send a message with
* 'info scsi' (no quotes) in the message body to majordomo at

More information about the T10 mailing list