Re: Fw: iSCSI: FirstBurstSize and unsolicited data

["Julian Satran" <Julian_Satran@il.ibm.com>]

In your example (even before the correction) nothing bad would have happened (the behavior is correct).
If you would have decided to send (and had InitialR2T=No) some amount of unsolicited data but not all
the target could have answered with error.
The error explanation is (was) a residue from when FirstBurtSize was only a limit (not also a mandated to send value).

Julo

"Nandakumar Ramamurthy" <nramamur@npd.hcltech.com> 06/21/2002 12:50 PM Please respond to "Nandakumar Ramamurthy"

To:        Julian Satran/Haifa/IBM@IBMIL         cc:                 Subject:        Fw: iSCSI: FirstBurstSize and unsolicited data

Julian,

This was my mail to the IPS alias which started discussions on this thread.

Thanks,
Nandakumar.


----- Original Message ----- 
From: "Nandakumar Ramamurthy" <nramamur@npd.hcltech.com>
To: <ips@ece.cmu.edu>
Sent: Friday, June 14, 2002 4:45 PM
Subject: iSCSI: FirstBurstSize and unsolicited data


> Hi All,
> 
> Consider the case where InitialR2T=yes and ImmediateData=yes.
> All other values are the defaults.
> 
> The expected data transfer length for a SCSI write
> operation is a value exceeding FirstBurstSize (64KB).
> 
> In the above case, the initiator will send immediate
> unsolicited data (MaxRecvPDULength=8192 bytes).
> After that it has to wait for an R2T from the target.
> 
> In this scenario, FirstBurstSize of data will not be sent
> to the target as unsolicited data-out's cannot be sent here.
> 
> My understanding is that the remaining data can be
> sent only through solicited Data-out PDUs,
> and this is the expected way according to the draft.
> 
> What does the following statement(in Section 9.4.6.2 Sense Data) mean in
> this context ?
> 
> <quote>
> 
> The target reports the "Not enough unsolicited data" condition only
> if it does not support output (write) operations in which the total
> 
> data length is greater than FirstBurstSize, but the initiator sent
> 
> less than FirstBurstSize amount of unsolicited data, and out-of-order
> 
> R2Ts cannot be used.
> 
> </quote>
> 
> If this is specific to the SCSI layer at the target,
> what is the dependency on FirstBurstSize?
> 
> Please clarify.
> 
> Thanks,
> Nandakumar
> Member Technical Staff
> HCL Technologies, Chennai, INDIA.
> http://san.hcltech.com
> 
>