Re: iSCSI: Question about ErrorRecoveryLevel

[Bill Studenmund <wrstuden@wasabisystems.com>]

On Tue, 16 Jul 2002, Mallikarjun C. wrote:

> > Every where within-command and within-connection recovery is discussed,
> > each of them is described as optional. The quote above doesn't say that
> > level 1 MUST consist of both within-connection and within-command
> > recovery.
>
> [ The error in grammar is already fixed in the working version. ]

Cool, I still haven't grabbed -15 yet.

> The reason MUST language was not used is because the text in question is
> defining the terminology, but is not phrased in such a way as to place requirements
> on implementations.  It is similar to several terminology descriptions in chapter 2.
>
> My intent when I wrote that text was - because the negotiation of the
> ErrorRecoveryLevel follows the regular negotiation rules (i.e. don't originate
> a proposal that you cannot support, and the result function is "minimum"), no
> additional MUST/SHOULD/MAY language is necessary.  But if you recommend
> explicit text, I suggest we add the following at the end of the last para of
> text in 5.13 -

That though doesn't answer my question. :-) The main question is does
ErrorRecoveryLevel 1 imply both within-command and within-connection
support, or does it imply at least one and maybe both?

If anything, the fact that ErrorRecoveryLevel 1 implies all of 0, and 2
implies all of 1 and 0, is clear in the draft now.

> When a defined value of ErrorRecoveryLevel is proposed by an
> originator in a text negotiation, the originator MUST support the
> functionality defined for the ErrorRecoveryLevel or functionality
                                                   ^^
Is this supposed to be "and"?

> corresponding to any defined value numerically less than the proposed.
> When a defined value of ErrorRecoveryLevel is returned by a responder
> in a text negotiation, the responder MUST support the functionality
> corresponding to the ErrorRecoveryLevel it is accepting.

If "and" is appropriate, then shouldn't we add, "and all numerically lower
levels" to the end of the paragraph?

I'm happy with ErrorRecoveryLevel 1 == both within-connection and
within-command recovery. I'm also happy with ErrorRecoveryLevel 1 ==
within-command, within-connection, or both (and ErrorRecoveryLevel 2 being
both). I just think with the amount of, "optional," used in conjunction
with error recovery that it's not clear which case we want.