Subject: Unsolicited Data Questions

From: "BURBRIDGE,MATTHEW (HP-UnitedKingdom,ex2)" <[email-masked]>
Date: Fri, 30 Mar 2001 13:17:53 +0100

Hi Julian

Sorry if I'm covering old ground...

Is it possible to use unsolicited data for the first burst and then request
any remaining data using R2T?  For example, if the target has a previously
allocated buffer available (length defined by FirstBurstSize) for
unsolicited data, then once the initiator has sent unsolicited data up to
and including this amount then the remaining data (if any) can be requested
using R2T once the target has the buffer space available.

Section 1.2.5 pertains to this..  "An initiator may send unsolicited data
either as immediate (up to the negotiated  maximum PDU size - DataPDULength
- disconnect-reconnect mode page) or in a separate PDU sequence (up to the
negotiated limit - FirstBurstSize - disconnect-reconnect mode page). All
subsequent data  has to be solicited"

However, Appendix D - 22 ImmediateData" appears to contradict this:   "If
ImmediateData is set to no and UseR2T is set to yes then the initiator MUST
NOT send unsolicited data and the target MUST reject them with the
corresponding response code."

Also I have some comments from my colleagues:

Page 15: Last paragraph is unclear from 2nd sentence.  The hyphens look like
minus signs. All a bit confusing.
Page 16: There are several references to initial burst. Should these not be
changed to first burst to be consistent with the terminology used
subsequently in the spec especially since this it's the "FirstBurstSize"
which defines how much data can be accepted.
page 111: The spec says that you need to set immediateData to yes so that
you can receive a first burst of immediate data, but then "only
immediate data are accepted in the first burst".  If you have immediate data
set to no and R2T set to yes you can't accept any unsolicited data: Are you
stating that immediate data and "normal" unsolicited data can not be mixed. 

1) Section 2.13.1: Is the response to a NOP-In issues by the target, always
a NOP-out?

2) Appendix D 29: KeyValueText: default value is outside of parameter range.

Cheers

Matthew Burbridge
Hewlett Packard, Bristol
Telnet: 312 7010
E-mail: [email-masked]

---

From: "Mallikarjun C." <[email-masked]>
Date: Fri, 30 Mar 2001 9:38:18 PST

Julian,

On the subject of unsolicited and immediate data: Perhaps adding
a table like this might help understand the intent of the draft
better. (InitialR2T = UseR2T, per earlier discussion)

+-------------+---------------+----------------------------------------+
| InitialR2T  | ImmediateData |   Result (upto FirstBurstSize)         |
+-------------+---------------+----------------------------------------+
|  no         |    no         | Unsolicited data in separate PDUs only |
+-------------+---------------+----------------------------------------+
|  no         |    yes        | Immediate & separate unsolicited data  |
+-------------+---------------+----------------------------------------+
|  yes        |    no         | Unsolicited data disallowed            |
+-------------+---------------+----------------------------------------+
|  yes        |    yes        | Immediate unsolicited data only        |
+-------------+---------------+----------------------------------------+

--
Mallikarjun 

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
MS 5668	Hewlett-Packard, Roseville.
[email-masked]