RE: iSCSI: Representing iSCSI devices on FC fabrics

["Elliott, Robert" <Robert.Elliott@compaq.com>]

Beware than a FC WWN is not the same as an EUI-64.  They're both based
on the IEEE OUI/company_id, but the FC WWN uses the 4 most significant
bits for a "Name Address Authority" field and has 4 fewer bits available
in the vendor specified portion.

EUI-64 = (MSB) { 20-bit company_id, 
                 44-bit vendor specified } (LSB)

FC WWN = (MSB) { 4-bit NAA field, 
                 20-bit company_id, 
                 40-bit vendor specified } (LSB)
         (for the IEEE Registered NAA type)

---
Rob Elliott, Compaq Server Storage
Robert.Elliott@compaq.com



> -----Original Message-----
> From: Thanu Skariah [mailto:tskariah@npd.hcltech.com]
> Sent: Friday, November 16, 2001 1:12 AM
> To: Robert Grant
> Cc: 'ips@ece.cmu.edu'
> Subject: Re: iSCSI: Representing iSCSI devices on FC fabrics
> 
> 
> Robert,
> 
> 
>     iSCSI allows different naming formats, of which one 
> format is the EUI format  (See the example in sec 2.2 .7 and 
> the naming draft -
> http://www.ietf.org/internet-drafts/draft-ietf-ips-iscsi-name-
> disc-02.txt )
> 
>     The EUI representation  is of the form eui . <WWN>.  Each 
> FC device's WWName can be used to form the corresponding iSCSI 
> name for the  device.  This is what we are doing on a linux 
> based software FCP/iSCSI gateway that we are implementing, 
> and this is why :
> 
> (From the naming and discovery draft ):
> 
> BeginQuote "
> 
> Type "eui." (IEEE EUI format)
> 
>    The IEEE iSCSI name might be used when a manufacturer is already
>    basing unique identifiers on World-Wide Names as defined 
>    in the SCSI SPC-2 specification.
> 
>    It may also be used by a gateway representing a Fibre Channel or
>    SCSI device that is already adequately identified using a 
>    world-wide name.
> 
> " End Quote
> 
> 
> Thanks,
> Thanu