Re: 2119bis
2011-08-31 02:37:12
My interpretation of what you wrote is that in your mind there is absolutely no
difference between a SHOULD and a MAY. They are both optional, and you
implement whatever you have time to implement, with SHOULD's prioritized higher
than MAY's.
Even if that is not what you mean, it is what many implementors do.
I would offer this highlights the problem with today's SHOULD. Some think
SHOULD means something is OK to implement, but life does not end if you do not
do it. Others think SHOULD means something HAS to be implemented, unless the
environment indicates the protocol will not work in some corner case.
On Aug 30, 2011, at 3:08 PM, hector wrote:
When I approach a protocol to implement, the first thing I typically do is
extract and develop the basic wiring of the protocol, the minimum
requirements. Make sure the basic framework is correct 100%, then I look for
the SHOULDs and also MAYS which are the easiest to add. I look at the SHOULD
by order of importance and also complexity. How much "CANDY" is it? It is a
security feature? What are the other implementation requirements, tools,
APIs, etc. Generally I want to get security out the way. Its like SMTP AUTH
- its not required but anyone cleaning up and rewriting an SMTP spec today,
might include the AUTH extension as a SHOULD. And implementators are keen to
the importance of it. But nothing won't break down if you don't, less
functionality but the basic structure is still there.
Its the same approach used for all the protocols we support. Start with the
basics and then add on as necessary.
Eric Burger wrote:
What is the difference in this case between SHOULD or MAY?
On Aug 30, 2011, at 2:49 PM, Adam Roach wrote:
On 8/29/11 9:44 PM, Eric Burger wrote:
Yes, and...
I would offer that for most cases, If Y then MUST X or If Z then MUST NOT
X *are* what people usually mean when they say SHOULD. In the spirit of
Say What You Mean, a bare SHOULD at the very least raise an ID-nit,
suggesting to the author to turn the statement into the if Y then MUST X
or if Z then MUST NOT X form. Being pedantic and pedagogic:
SHOULD send a 1 UNLESS you receive a 0
really means
UNLESS you receive a 0, one MUST send a 1.
My vision of the UNLESS clause is not necessarily a protocol state, but an
environment state. These are things that I can see fit the SHOULD/UNLESS
form:
SHOULD send a 1 UNLESS you are in a walled garden
SHOULD flip bit 27 UNLESS you have a disk
SHOULD NOT explode UNLESS you are a bomb
are all reasonable SHOULD-level statements.
I would offer that ANY construction of SHOULD without an UNLESS is a MAY.
Eric. Put down the axe and step away from the whetstone. Here, I'll give
you some text from RFC 3265 to mull.
deactivated: The subscription has been terminated, but the subscriber
SHOULD retry immediately with a new subscription. One primary use
of such a status code is to allow migration of subscriptions
between nodes.
Let's examine this use of "SHOULD." If the subscriber doesn't re-subscribe,
is it an interop issue? No.
Is it in the interest of the implementation to re-subscribe? Yes. At least,
under most circumstances. Otherwise, they won't get the state change
notifications they want.
Are there cases in which it makes sense for the subscriber _not_ to
re-subscribe? Yes, I'm sure there are. It's conceivable that the client
happens to be shutting down but hasn't gotten around to terminating this
particular subscription yet. But any such exceptions are highly
implementation-dependent. Listing them would be useless noise to the
reader, and senseless text creation for the author.
Does "SHOULD" get abused by some authors in some documents? Of course it
does. But your crusade to throw out a useful tool just because it has been
misused on occasion is an extreme over-reaction. I like this tool. I use
this tool. If you see people misusing it, slap them.
But don't ban the tool.
/a
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- Re: 2119bis, (continued)
- Re: 2119bis, Adam Roach
- Re: 2119bis, Eric Burger
- Re: 2119bis, hector
- Re: 2119bis,
Eric Burger <=
- Re: 2119bis, Hector
- Re: 2119bis, Keith Moore
- Re: 2119bis, Hector
- Re: 2119bis, Keith Moore
- Re: 2119bis, hector
- Re: 2119bis, Keith Moore
- Re: 2119bis, Hector
- Re: 2119bis, Keith Moore
- RE: 2119bis, Murray S. Kucherawy
- Re: 2119bis, Hector
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