Re: [storm] iSCSI SAM update: login key

<Black_David@emc.com> Sat, 27 March 2010 05:51 UTC

Return-Path: <Black_David@emc.com>
X-Original-To: storm@core3.amsl.com
Delivered-To: storm@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id C788C3A689F for <storm@core3.amsl.com>; Fri, 26 Mar 2010 22:51:57 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.641
X-Spam-Level:
X-Spam-Status: No, score=-4.641 tagged_above=-999 required=5 tests=[AWL=0.828, BAYES_00=-2.599, DNS_FROM_OPENWHOIS=1.13, RCVD_IN_DNSWL_MED=-4]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3xlPyFBKyEmp for <storm@core3.amsl.com>; Fri, 26 Mar 2010 22:51:56 -0700 (PDT)
Received: from mexforward.lss.emc.com (mexforward.lss.emc.com [128.222.32.20]) by core3.amsl.com (Postfix) with ESMTP id 87AA83A67A7 for <storm@ietf.org>; Fri, 26 Mar 2010 22:51:56 -0700 (PDT)
Received: from hop04-l1d11-si04.isus.emc.com (HOP04-L1D11-SI04.isus.emc.com [10.254.111.24]) by mexforward.lss.emc.com (Switch-3.3.2/Switch-3.1.7) with ESMTP id o2R5qImt005224 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 27 Mar 2010 01:52:18 -0400
Received: from mailhub.lss.emc.com (nagas.lss.emc.com [10.254.144.15]) by hop04-l1d11-si04.isus.emc.com (RSA Interceptor); Sat, 27 Mar 2010 01:52:16 -0400
Received: from corpussmtp3.corp.emc.com (corpussmtp3.corp.emc.com [10.254.169.196]) by mailhub.lss.emc.com (Switch-3.4.2/Switch-3.3.2mp) with ESMTP id o2R5qGGR026695; Sat, 27 Mar 2010 01:52:16 -0400
Received: from CORPUSMX80B.corp.emc.com ([10.254.89.201]) by corpussmtp3.corp.emc.com with Microsoft SMTPSVC(6.0.3790.3959); Sat, 27 Mar 2010 01:52:16 -0400
X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: base64
Date: Sat, 27 Mar 2010 01:52:13 -0400
Message-ID: <C2D311A6F086424F99E385949ECFEBCB02162B43@CORPUSMX80B.corp.emc.com>
In-Reply-To: <SNT131-ds10A1204F54D78F9972EB8FA0220@phx.gbl>
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: [storm] iSCSI SAM update: login key
thread-index: AcrNFN17PQ3xD5CNTO+maRmCN0ae/gARsz8AAAVitKA=
References: <C2D311A6F086424F99E385949ECFEBCB021629C4@CORPUSMX80B.corp.emc.com> <SNT131-ds10A1204F54D78F9972EB8FA0220@phx.gbl>
From: <Black_David@emc.com>
To: <cbm@chadalapaka.com>, <storm@ietf.org>
X-OriginalArrivalTime: 27 Mar 2010 05:52:16.0381 (UTC) FILETIME=[A7CE8AD0:01CACD71]
X-EMM-EM: Active
Subject: Re: [storm] iSCSI SAM update: login key
X-BeenThere: storm@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: Storage Maintenance WG <storm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/storm>, <mailto:storm-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/storm>
List-Post: <mailto:storm@ietf.org>
List-Help: <mailto:storm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/storm>, <mailto:storm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 27 Mar 2010 05:51:57 -0000

Mallikarjun,

That makes sense (decouple from PDU structure changes), and suggests that we need a key name that doesn't use "PDUFormat" ...
... How about iSCSIProtocolLevel ?

It will be necessary to be conservative in defining new values - the requirement to publish a standards track RFC to define a new value should help with that.

Thanks,
--David

> -----Original Message-----
> From: Mallikarjun Chadalapaka [mailto:cbm@chadalapaka.com]
> Sent: Saturday, March 27, 2010 12:28 AM
> To: Black, David; storm@ietf.org
> Subject: RE: [storm] iSCSI SAM update: login key
> 
> > This will be an IETF key whose values are assigned by IETF standards action
> > (standards-track RFC); it is not linked to SAM versions (e.g., a new version
> > of SAM is not a prerequisite to assigning the value 3).
> 
> Decoupling this key from SAM numbering space is a good idea.
> 
> I also suggest decoupling it from PDU structure changes.  Any new iSCSI standards track RFC, whether
> or not it extends/changes PDU format, should be able to claim a number by WG consensus.  Reasons for
> claiming a new number could include things like:
> 1) New feature introduction (e.g. new Opcodes, new TMF Codes, new Async codes)
> 2) Major bug fix to the iSCSI protocol that affects end node processing
> 3) Change in semantics to keep up with changing SCSI semantics
> 4) A PDU Format enhancement
> 5) TBD reason by WG consensus
> 
> Reasons 1-3 may not have associated PDU format changes, unlike 4.  I suggest these should all be
> grounds for the WG to consider assigning a number.
> 
> Doing this allows implementations to negotiate a shared milestone at an RFC granularity (if that RFC
> has a number), as opposed to feature-by-feature negotiation (e.g. TaskReporting="FastAbort") with some
> gray areas that we had to resort to so far.
> 
> Thanks.
> 
> Mallikarjun
> 
> > -----Original Message-----
> > From: storm-bounces@ietf.org [mailto:storm-bounces@ietf.org] On Behalf Of
> > Black_David@emc.com
> > Sent: Friday, March 26, 2010 11:48 AM
> > To: storm@ietf.org
> > Cc: Black_David@emc.com
> > Subject: [storm] iSCSI SAM update: login key
> >
> > Based on discussion in the Anaheim meeting, here's the proposal that emerged
> > for the login key to negotiate usage of the new features in the iSCSI SAM
> > update draft (draft-ietf-storm-iscsi-sam-00).
> >
> > Past concerns (that I can recall) about this have been:
> > - Key needs to negotiate iSCSI PDU format/content changes only.
> > - Detecting device support or lack thereof for SCSI features
> > 	should be handled at the SCSI level (e.g., via SCSI commands).
> > - Using a SAM version number in this iSCSI key is not a good idea.
> > - Would like something that can accommodate future changes.
> > - Changing the key name from what's in the draft may be desired.
> >
> > The proposal that emerged is:
> >
> > The key name will be PDUFormatLevel.  It's a numeric (not boolean) key with
> > two defined values:
> > 	- 1 = Current iSCSI (all four RFCs - 3720, 3980, 4850 and 5048,
> > 		but no change to required vs. optional features).
> > 	- 2 = Current iSCSI plus features in update draft.
> > Usage is Leading Only (LO), scope is Session Wide (SW).
> > Default value is 1, result function is Minimum.
> >
> > This will be an IETF key whose values are assigned by IETF standards action
> > (standards-track RFC); it is not linked to SAM versions (e.g., a new version
> > of SAM is not a prerequisite to assigning the value 3).
> >
> > This key also provides a clean way to handle definition of iSCSI version
> > descriptors in SPC-4:
> > - 0960h would remain "iSCSI (no version claimed)"
> > - The range 0961h-097Fh would be defined as 0960h + value
> > 	of PDUFormatLevel key used by the device.
> > That results in one place (IANA registry) covering both definitions (key &
> > version descriptor).
> >
> > In order to support iSCSI version descriptors, we would ask IANA to put the
> > values of the PDUFormatLevel key into a separate registry with its own URL,
> > and then ask T10 to modify SPC-4.  The latter is not an immediate action - I
> > would not anticipate bringing the SPC-4 proposal for that to T10 until after
> > the RFC is published and the IANA registry is created.
> >
> > This was the sense of the room + WebEx in Anaheim.  Absence of objection on
> > the list will confirm the above as the approach to be taken (rough consensus
> > of the storm WG).
> >
> > Thanks,
> > --David
> > ----------------------------------------------------
> > David L. Black, Distinguished Engineer
> > EMC Corporation, 176 South St., Hopkinton, MA  01748
> > +1 (508) 293-7953             FAX: +1 (508) 293-7786
> > black_david@emc.com        Mobile: +1 (978) 394-7754
> > ----------------------------------------------------
> >
> >
> > _______________________________________________
> > storm mailing list
> > storm@ietf.org
> > https://www.ietf.org/mailman/listinfo/storm
>