Re: iSCSI 4.1 & 4.2

[Martins Krikis <mkrikis@yahoo.com>]

--- Luben Tuikov <luben@splentec.com> wrote:
> I don't really object to the implicit result of some
> booleans.

I do.

> 1) Couldn't find incosistencies with other things
>    I/we mentioned (states of offers, states of
> responses = states
>    of complete neg. seq.). That is, couldn't find a
>    (counter-) example.

My way of figuring out whether a value has been
negotiated is to see whether it has been sent,
whether it has been received, and of course I do
consistency checks. The ability to omit responses
for boolean values under certain conditions makes
this task more complicated. I also have to consider
the value as negotiated when it has been sent, has
not been received, but the function is OR and the 
value is Yes, or when the value is AND and the value
is No. Yes, it can be done, and it can be done also by
using more variables for values or introducing more
states, and probably by lots of other means. The
point is that this does introduce a complication,
at least in my implementation. And it certainly
does not help the clarity of the specification.

> 2) For the same reason you all considered that some
> boolean
>    responses to be optional: one can determine the
> outcome of the
>    negotiation sequence and the state of the whole
> thing
>    if one knows f(a,b) and b for certain f()'s over
> booleans.

Yes, I can determine the value. Just because I can
doesn't mean that boolean negotiations with omissions
are simpler than truly explicit boolean negotiations
(like all the others).

> Keeping the optional responses greatly simplifies
> things.

No it does not. Complicates the description and
complicates at least some (otherwise reasonable)
implementations.

> That is, the sender can safely assume a state and
> result
> of the negotiation sequence and SHOULD a reply to
> that
> key=value arrive and its value is NOT what was
> assumed,
> then the Target should close the connection with
> Initiator Error
> and the Initiator should just drop the connection.

Yes, but the same is true for explicit negotiations.
If an incorrect value is received, I can drop the
connection. But at least I know that it MUST be
eventually received. Less MAYs, less choice, less
room for misunderstandings and error. Simpler
specification as well. Let's not forget that it
still (so far incorrectly) claims that negotiations
are explicit and that the description of which value
is chosen on omissions is (in my view and nobody
has disputed it yet) incorrect.

  Martins Krikis, Intel Corp.

Disclaimer: these opinions are mine and may not be
            those of my employer.


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