Re: LUN field in iSCSI Data PDU

[Matt Wakeley <matt_wakeley@agilent.com>]

julian_satran@il.ibm.com wrote:
> 
> Vengat,
> 
> The LUN field is mandated only if the Target Tag is valid (i.e., the data
> is sent in response to a R2T).
> This way you can get to "decentralize" the target activity as the tags can
> be issued "locally" by the LUs.

This sounds like a new "feature" that isn't required.  Fibre Channel doesn't
require LUN in any phase of it's transfer except the command - why must iSCSI
require LUN in data transfers?

-Matt

> 
> Julo
> 
> "Venkat Rangan" <venkat@rhapsodynetworks.com> on 20/11/2000 20:38:23
> 
> Please respond to "Venkat Rangan" <venkat@rhapsodynetworks.com>
> 
> To:   "IP Storage Working Group" <ips@ece.cmu.edu>
> cc:
> Subject:  LUN field in iSCSI Data PDU
> 
> Section 2.8 specifies that the SCSI Data Header contains "LUN or Reserved
> (0)" at offset 8-16 within the header. I am not clear under what
> circumstandes it contains a LUN. Note that the LUN info was already sent in
> an earlier SCSI CMD PDU. If a LUN is specified in SCSI Data PDU as well,
> what is its relationship to the one sent in SCSI CMD?
> 
> If we look at Fibre Channel FCP_DATA framing, it does not include a LUN,
> since the FCP_CMD has established the LUN for the exchange already.
> 
> Venkat Rangan
> Rhapsody Networks Inc.
> www.rhapsodynetworks.com