Registration of non-LDAP schemas?

[Jim Whitehead <ejw@xxxxxxxxxxx>]

In reading through "Directory Schema Listing Requirements", 
draft-apple-schema-rqmts-list-03 (currently expired), I notice that there 
is an intentional and pervasive bais towards limiting the scope of 
registration activity to just LDAP schemas.  However, there are other 
Internet groups which are in need of schema registration services, and this 
need is likely to increase in the future.

As one major example, the Extensible Markup Language (XML) provides for the 
creation of "schema" using the Document Type Definition mechanism.  There 
is a large existing base of SGML DTDs, and hence there is an expectation 
that there will be a large base of XML DTDs in the future, especially as 
Web browsers and application programs increasingly support XML. Several 
groups are hard at work defining XML DTDs today, such as the Resource 
Description Framework, and the IETF WEBDAV working group.

It seems to me that the value of a schema repository increases with the 
amount of information available in the repository, and hence I am in favor 
of extending the scope of the schema repository to handle a much wider 
range of metadata than just LDAP schemas.

This doesn't appear to require a large change to the requirements document. 
 Requirements which would require change appear to be:

 Meta data element syntax SHALL be defined based on the concept of
 tagged attribute type-value pairs.

 Language tags as specified in [RFC1766] MUST be used in listing
 content and meta data.

 Meta data element values MUST be encoded using the UCS Transformation
 Format - 8 bit form [RFC2044].

Whether you decide to allow non-LDAP metadata to be registered or not, 
these particular requirements seem to be far too low-level compared with 
the other requirements in the document.  The real requirements here seem to 
be:

Metadata definitions must be consistent with the type of metadata (e.g., 
a-v pairs for LDAP, DTD for XML, etc.)

Listing of content and metadata must be consistent with the IETF character 
set policy [Alvestrand, 1998].

So, the question I raise is: should non-LDAP schemas be capable of 
registration and retrieval using the mechanisms defined by this working 
group?

- Jim