RE: ISCSI: LUN field in iSCSI Data PDU

[Charles Monia <cmonia@NishanSystems.com>]

Hi:

How important is this?  On the face of it, it seems marginaly easier for a
target to delegate tag assignment to the LU if the LU has the use of the
entire 32 bit tag field.

Charles
> -----Original Message-----
> From: Venkat Rangan [mailto:venkat@rhapsodynetworks.com]
> Sent: Tuesday, November 21, 2000 2:43 PM
> To: IP Storage Working Group
> Subject: Re: LUN field in iSCSI Data PDU
> 
> 
> Julo,
> 
> > 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 doesn't seem to be of significant value. If one were to 
> implement such
> decentralization, one could use certain bits of Target Tag to 
> identify the
> decentralized entity and other bits of TTT to indicate an 
> index within that
> entity. As a target, I presume I have complete flexibility in 
> how I choose
> to allocate TTTs.
> 
> Keeping the LUN only for WRITE makes iSCSI READ and WRITE 
> symmetric, and
> opens up
> the possiblity of a mismatch between the LUN in WRITE and the 
> one in CMD.
> 
> Venkat Rangan
> Rhapsody Networks Inc.
> www.rhapsodynetworks.com
>