Re: [storm] iSER - problem with unsolicited NOP-IN right after final Login Response

<david.black@emc.com> Tue, 12 June 2012 18:01 UTC

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From: <david.black@emc.com>
To: <Paul_Koning@Dell.com>
Date: Tue, 12 Jun 2012 14:01:11 -0400
Thread-Topic: [storm] iSER - problem with unsolicited NOP-IN right after final Login Response
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Cc: storm@ietf.org
Subject: Re: [storm] iSER - problem with unsolicited NOP-IN right after final Login Response
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Hi Paul,

We're in violent agreement, and I wasn't clear in what I wrote.

I'm proposing 200ms unless someone on the list has a better idea ... 

Thanks,
--David


> -----Original Message-----
> From: Paul_Koning@Dell.com [mailto:Paul_Koning@Dell.com]
> Sent: Tuesday, June 12, 2012 9:57 AM
> To: Black, David
> Cc: cbm@chadalapaka.com; storm@ietf.org
> Subject: Re: [storm] iSER - problem with unsolicited NOP-IN right after final
> Login Response
> 
> 
> On Jun 11, 2012, at 9:44 PM, <david.black@emc.com>
>  <david.black@emc.com> wrote:
> 
> >> FWIW, I did not believe both sides were compliant in this case.
> >
> > There's an additional consideration here - one of the goals of the iSER
> > update is to match "running code", and we have already made a number of
> > changes that diverge from RFC 5046 for this reason, including in this
> > area of iSER start-up (see Appendix A of the iSER draft for details).
> > As a result, we are  already well into non-compliance territory, as
> > omission of the Hello messages does not comply with RFC 5046, but those
> > messages are simply not implemented in practice.
> >
> > The implementation under discussion is (I believe) the predominant iSER
> > implementation and hence I think the new iSER RFC needs to explain what
> > that implementation has done (even if it may not be what should have been
> > done), and (more importantly) explain how to interoperate.  The key
> > requirement is the following (IMHO, a fine example of "be conservative
> > in what you send"):
> >
> >>> 2) The target MUST wait at least 200ms (use some other number if 200ms
> >>> isn't a good choice) or until it receives a full feature mode PDU from
> >>> the initiator before sending a second unsolicited PDU in order to ensure
> >>> that initiator has sufficient time to allocate the full feature buffer
> >>> resources for the connection.
> 
> I don't understand how a protocol standard can have such language.  "200 ms
> (use some other number if...") is not a testable property.  If you delete the
> "(use...)" then you have  standard, or if you delete "at least... or" but as
> written, an implementer has no clue what is expected.
> 
> 	paul
>