Re: Feature discovery (Was: RFC 2596 questions)

[hahnt@us.ibm.com]

Hi all,

I like the idea of extending the schema information with the set of attribute descriptions that are known to the server.

Both approaches described so far:

1) extend the attributeTypes value to allow for additional fields to be specified within each value, add a new value that defines the OIDs used in the field
2) add a new attribute to the subschemasubentry and contain all the information here

are in the right direction.

Approach 1) has the benefit that just by looking at the attributeType value, you can get an indication if any attribute descriptions might have been used in creating/modifying entries that contain this attribute.  However, there would be the issue of whether or not the server supported the additional data in the attributeTypes value.

Approach 2) doesn't change the attributeType value definition (nice for upward compatibility).  On the downside, though, in order to see what attribute description a given attribute type can have attached to it, a not-so-easy-search of the new schema attribute would have to be performed.

After writing up this short discussion of the approaches, I think I prefer Approach 1) where the "DESCRIPTORS ( <OID> "$" ... )" clause of the attributeTypes value is an optional piece in the format of the value.

Is there agreement here?

Regards,
Tim Hahn

Internet: hahnt@us.ibm.com
Internal: Timothy Hahn/Endicott/IBM@IBMUS or IBMUSM00(HAHNT)
phone: 607.752.6388     tie-line: 8/852.6388
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To:        "Jim Sermersheim" <JIMSE@novell.com>
cc:        Timothy Hahn/Endicott/IBM@IBMUS, <ietf-ldapext@netscape.com>
Subject:        Re: Feature discovery (Was: RFC 2596 questions)




>Also, some things (like attr type options) need more than just an OID in a list. We need to specify where they can be used (which attrs or syntaxes support them).

Likely best to extend the attributeTypes and LDAPsyntaxes to include
additional fields... like X-FEATURES ( 1.2.3 $ 2.3.4 )  where 1.2.3
might indicate language tags support and 2.3.4 might indicate binary
transfer support.

Kurt