Re: iSCSI: not offering a key

[Luben Tuikov <luben@splentec.com>]

Excerpt of message (sent 25 January 2002) by Eddy Quicksall:
> The spec says:
>  
> Not offering a key for negotiation is not 
> equivalent to offering the current (or default) value.
>  
> Does anyone know why?

And

> Maybe I don't understand the sentence. I interpret it to mean
> that if the default value is acceptable to me then not
> offering it is somehow different than the default ... and that
> confuses me (well, actually it makes me wonder if the sentence
> is trying to say something else).

1. The sentence

``Not offering a key for negotiation is not 
  equivalent to offering the current (or default) value.''

means that one cannot assume the current (or default)
value for a key which has not been offered for
negotiation (negotiated).

I.e. you cannot assume as to the value of a key, not
the default, not the current. You always have to
negotiate it... It may turn out that both T and I
use the default, nevertheless they have to negotiate it.

This is what the sentence means from a logical point of view.
But what is meant by it the iSCSI draft, maybe someone else
will confirm.

I don't think that there is a better way to put this.
Whether that is what is meant in the draft... is another
topic.

2. Previous sentence in the draft:

``All negotiations are stateless (i.e., the result MUST be 
  based only on newly exchanged values).''

means that no keys are inherited or persistent...

_But_ the draft needs to specify a scope (connection,
session, etc) for the non-persistence of negotiations of
keys' values (just as persistence is explicitly specified
in terms of scopes in formal definitions).

There is probably a better way to put this, probably using
words like ``scope'', ``persistence'', ``session'',
``connection'', etc., which will eliminate the ``(i.e. ...)''.

-- 
-l