[Ips] Error detection responsibility
Black_David@emc.com Mon, 13 June 2005 18:42 UTC
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Date: Mon, 13 Jun 2005 14:42:09 -0400
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Subject: [Ips] Error detection responsibility
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Eddy, I agree with Mallikarjun that a blanket statement, even one like the second one you proposed, is a bad idea. I think a better approach would be to identify the specific cases for which you believe it's unreasonable for a target to make comprehensive error checks, and document what an implementation MAY choose not to check. A blanket statement like the one you proposed still leaves implementers scratching their heads about what they're supposed to do. Thanks, --David ---------------------------------------------------- David L. Black, Senior Technologist 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 ---------------------------------------------------- > -----Original Message----- > From: ips-bounces@ietf.org [mailto:ips-bounces@ietf.org] On > Behalf Of Eddy Quicksall > Sent: Monday, June 13, 2005 2:12 PM > To: Mallikarjun C.; ips@ietf.org > Subject: Re: [Ips] ABORT TASK vs ABORT TASK SET > > Actually, I was talking about a clarification of what is expected of the > target and initiator in the event that the RFC does not cover it with a > MUST. The problem is that some people think the target must check for all > protocol errors. This is not practical and sometimes not even possible for > all cases. > > Perhaps wording similar to this would be in order: > > "Except where specifically noted, the initiator and target are > not expected to catch all protocol errors introduced by the other > party and it is the implementers option as to which errors may be > caught due to internal dynamics." > > Eddy > > ----- Original Message ----- > From: "Mallikarjun C." <cbm@rose.hp.com> > To: <ips@ietf.org> > Sent: Friday, June 10, 2005 2:00 PM > Subject: Re: [Ips] ABORT TASK vs ABORT TASK SET > > > > My comment on this is that such a blanket statement will be a problem. > > > > RFC 3720 has a defined notion of protocol errors and their handling, and > > uses a fair number of MUSTs (sometimes conditional) on Rejects (as PDUs > > and in negotiation) - e.g., if you support data digests, you must discard > > a bad digest PDU with a Reject. These actions inherently require protocol > > validation and catching errors. I don't think we want to weaken any of > > that. > > > > Mallikarjun > > > > Mallikarjun Chadalapaka > > Networked Storage Architecture > > StorageWorks Division > > Hewlett-Packard MS 5668 > > Roseville CA 95747 > > cbm [at] rose.hp.com > > > > > > Eddy Quicksall wrote: > >> What do you think about this? I don't remember seeing an answer. > >> > >> Eddy > >> > >> ----- Original Message ----- From: "Eddy Quicksall" > >> <eddy_quicksall_iVivity_iSCSI@comcast.net> > >> To: <Black_David@emc.com>; <cbm@rose.hp.com>; <ips@ietf.org> > >> Sent: Friday, June 03, 2005 12:45 PM > >> Subject: Re: [Ips] ABORT TASK vs ABORT TASK SET > >> > >> > >>> If you are going to write this guide, I would like to suggest that a > >>> paragraph be added saying something like "the initiator and target are > >>> not expected to catch all protocol errors introduced by the other party > >>> and it is the implementers option as to which errors may be caught due > >>> to internal dynamics, crash dynamics or data corruption". > >>> > >>> Eddy > >>> > >>> ----- Original Message ----- From: <Black_David@emc.com> > >>> To: <cbm@rose.hp.com>; <ips@ietf.org> > >>> Sent: Friday, June 03, 2005 8:51 AM > >>> Subject: RE: [Ips] ABORT TASK vs ABORT TASK SET > >>> > >>> > >>>> Mallikarjun, > >>>> > >>>>> I am concerned that the current lack of detailed specification would > >>>>> allow targets that might even cause silent data corruptions > >>>>> to qualify as RFC 3720-compliant. > >>>>> > >>>>> Here are what I believe to be semantics applicable to all TMF requests > >>>>> that can potentially terminate multiple tasks. I do not know the IETF > >>>>> process well enough here, but I suggest that we consider this text > >>>>> replacing the existing section 10.6.2 in RFC 3720 - so the new text > >>>>> can cover all the TMFs that can impact multiple tasks. This is basically > >>>>> a superset of the current 10.6.2 semantics. > >>>> > >>>> > >>>> IETF does have an errata process, but (IMHO) it's not a great venue > >>>> for something like this that it's important for implementers to pay > >>>> attention to. What I would suggest is that we start an Internet-Draft > >>>> that is intended to become an Implementers Guide RFC (standards track) > >>>> to include both technical corrections like this one, and explanations > >>>> of subtle points such as how to deal with (what appear to be) REPORT > >>>> LUNS overruns as discussed here earlier. An available example is that > >>>> an implementers guide draft is being maintained for SCTP (see > >>>> draft-ietf-tsvwg-sctpimpguide-13.txt) although I'd like to believe that > >>>> an iSCSI implementers guide won't grow to that size. > >>>> > >>>> For this task management issue, explaining what the problem is and why > >>>> the change fixes it in an implementers guide is at least as important > >>>> as specifying the change. For the REPORT LUNS overruns, the implementers > >>>> guide text would be an explanation of why no change is needed, including > >>>> some elaboration on the (less than completely obvious) SPC-2 text that > >>>> specifies the behavior of REPORT LUNS in this circumstance. Before I > >>>> go looking for another volunteer, would you be interested in editing > >>>> an implementers guide Internet Draft? Between Julian and I, we should > >>>> be able write the REPORT LUNS explanation paragraph or two. > >>>> > >>>> Thanks, > >>>> --David > >>>> ---------------------------------------------------- > >>>> David L. Black, Senior Technologist > >>>> 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 > >>>> ---------------------------------------------------- > >>>> > >>>> _______________________________________________ > >>>> Ips mailing list > >>>> Ips@ietf.org > >>>> https://www1.ietf.org/mailman/listinfo/ips > >>> > >>> > >>> > >>> _______________________________________________ > >>> Ips mailing list > >>> Ips@ietf.org > >>> https://www1.ietf.org/mailman/listinfo/ips > > > > > > _______________________________________________ > > Ips mailing list > > Ips@ietf.org > > https://www1.ietf.org/mailman/listinfo/ips > > > _______________________________________________ > Ips mailing list > Ips@ietf.org > https://www1.ietf.org/mailman/listinfo/ips > _______________________________________________ Ips mailing list Ips@ietf.org https://www1.ietf.org/mailman/listinfo/ips
- [Ips] Error detection responsibility Black_David