Subject: Re: [Models] can't query RootDSE attributes

From: "Jim Sermersheim" <[email-masked]>
Date: Tue, 12 Oct 2004 14:09:20 -0600

Right, the OID would have to change to allow this. If we changed the OID
and added matching rules, then it would cause problems for clients which
are expecting the old OIDs. I doubt there are very many clients which
use OIDs to read these attributes, but I agree it would be bad to break
those that do.

Maybe someone someday will define new attributes with new oids, and
(hopefully) new primary names, which define matching rules.

Jim

>>> "Kurt D. Zeilenga" <[email-masked]> 10/12/04 1:58:32 PM >>>
At 08:58 AM 10/12/2004, Jim Sermersheim wrote:
>Is there sufficient usefulness in allowing a client to perform a
>compare operation against some of these as its method of discovery to
>warrant an update to them to include matching rules?

No.   Changing schema definitions, even to simply add an
equality rule, can have significant interoperability
impact.  What tends to happen is that client developers
begin to assume that all servers support the new definition,
not realizing that there will be many servers operating
under the old definitions for many years to come.  This
is likely why X.501 says:

    The definition of information objects such as object
    classes, attribute types, matching rules and name forms
    which have been registered (i.e. assigned a name of type
    object identifier) are static and cannot be modified.
    Changes to the semantics of such information objects
    requires the assignment of new object identifiers.

In regards to these attributes, change could lead to a
client not being able to discover support for some
capability, such as the Start TLS extended operation or
a particular SASL mechanism of interest.

Kurt