RE: Feature discovery (Was: RFC 2596 questions)

["Steven Legg" <steven.legg@adacel.com.au>]

Karen,

> -----Original Message-----
> From: kgdaniec@us.ibm.com [mailto:kgdaniec@us.ibm.com]
> Sent: Tuesday, 19 September 2000 5:57
> To: ietf-ldapext@netscape.com; hahnt@us.ibm.com
> Subject: Re: Feature discovery (Was: RFC 2596 questions)
> 
> 
> Jim,
> Perhaps a combination of the approaches mentioned already 
> really is needed,
> then.  Servers could publish in their rootDSE the attributetype
> options/extensions that they support.  This would allow 
> anyone adding to or
> modifying the schema to know what the server supports.  
> However, the server
> could also publish as part of the schema what the "currently 
> active" set of
> attributetype "descriptors" (to use Tim's term) is.

I like this approach, especially when viewed from the perspective
of replication and the X.500 schema administrative model. The
information about what attribute type options a server is *capable*
of supporting is specific to that server. It is not appropriate
for that information to be replicated or held in the schema definition
for a DIT subtree that is distributed across multiple servers
(as allowed by X.500). The root DSE is a reasonable place to hold this
kind of information. The information about what attribute type
options are *permitted* to be used with what attribute types is
part of the schema configuration and it seems entirely appropriate
to me to allow this to be in the subschema subentry (where it can
be replicated).

The separation also deals with the variant uses of the attribute type
options. The options that don't imply attribute subtyping
(e.g. ;binary) have no business being described in the schema subentry
as far as I'm concerned.

Regards,
Steven

> 
> Would these be specified by syntax or by attributetype, 
> though, or both?
> Setting these by syntax allows defaults to be in effect for each
> attributetype.  I suppose this is no more confusing than  "default"
> matching rules based upon syntax.
> 
> Karen
> 
> Internet: kgdaniec@us.ibm.com
> Internal: Karen Gdaniec/Endicott/IBM@IBMUS or
>                  IBMUSM10(KGDANIEC)
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