Re: StatSn Questions

[julian_satran@il.ibm.com]

Matt,

There are different ways to implement and use iSCSI.  If the iSCSI target
is only a "front" for a collection of
boxes - it will be  good served if the data traffic can go almost unchanged
from the LU to the initiator (even

True we loose a chance to update the StatSN.

I am ambivalent also about R2T.

Basically the same argument can be made about it and we should remove all
the counters.

Nevertheless let's hear what others have to say on this too.

regards,
Julo

Matt Wakeley <matt_wakeley@agilent.com> on 11/03/2001 10:44:21

Please respond to Matt Wakeley <matt_wakeley@agilent.com>

To:   ips@ece.cmu.edu
cc:
Subject:  Re: StatSn Questions




julian_satran@il.ibm.com wrote:

> >In Data
> >and R2T, it just transfers the previous value (except if Data is the
last
> Data
> >and conveys status).
>
> StatSN in a read data PDU is *not* the previous value.  Instead, it is a
> new (incremented) value and the field is valid only if the S-bit is set.
>
> +++ You are right - the reason I left StatSN out is that the Data PDU may
> originate close to the device where you don't know about StatRN +++

I don't understand the above statement.  The device is supposed to
communicate
through iSCSI, and iSCSI always knows what the StatSN is (not the device).
Therefore, if the "S" bit is not set in a data PDU, then the StatSN conveys
the current value.  If "S" is set, then StatSN conveys the new value.

-Matt Wakeley
Agilent Technologies