Re: Protocol: control specifications.

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 01:05 PM 1/9/2004, Hallvard B Furuseth wrote:
>Kurt, I'm suddenly wondering if I've misunderstood you completely,
>and if so I don't know where.  So I need a bit of clarification
>before replying to your latest message:

After a couple of draft responses, I've concluded that there
isn't a good way to clarify my reply without taking a (big)
step back.

LDAP provides, in controls, a mechanism for extending the
semantics of an existing operation.  The extended semantics
are associated with the type of control (an OID) and
associated type-specific data (an octet string).

This mechanism also provides a facility by which a client
can indicate to the server that the extended semantics
associated with any particular control instance is critical.
That is, by marking a control critical, the client demands
that server not process the operation if it cannot make
use of the control.

Criticality was intended to be in the eye of the client
(based upon user input and/or guidance in the specification
of the particular control), not the server.

Also, the criticality field was not intended to have any
other semantic.  That is, the performance of the operation
as extended by the control is not intended to be dependent
on the criticality value.

I believe that most implementations behave as I describe
above, which I content is as intended.  I also believe
this section needs clarification to ensure future clients
and servers implement the technical specification in
a manner consistent with today's implementations.  My
suggestions are intended to do this.

I object to your suggestions are numerous grounds:
        1) that wasn't what was intended,
        2) that isn't what is implemented,
        3) that violates interoperability principles on
        which Internet is built on (be strict in what you
        send, be liberal in what you accept),
        4) that hinders subsequent revision of extension
        specifications, and
        5) it will limit how one control could extend
        an operation extended by other control(s).

(The last one is new.  For now, I'll leave it as something
for you and others to think about.)

Kurt