LDAP Extension

Charter LDAP Extension WG (ldapext)
Title LDAP Extension
Last updated 2003-04-04
State Approved
State Concluded
Responsible AD (None)
Send notices to (None)


LDAPv3 defines an information model and an authentication model,
allowing information to be protected via access control. But LDAPv3
defines no standard representation or semantic for this access
control information. This work item will be to define such a
standard access control model.

- Server-side sorting of search results - Paged retrieval of search

In order to more efficiently support the assumptions of users
viewing search results as a sorted, scrollable list, servers sort
and provide a paged view onto search results. This work item will
define the LDAPv3 message controls to allow a client to request a
particular sort order, and to allow a client to retrieve search
results one page at a time. The group will base its work on the
following drafts:


- Language tags

LDAPv3 carries character data in UTF-8 format, allowing the full
range of international characters to be represented. This work item
will be to define attribute descriptions allowing the data returned
from or input to an LDAPv3 directory to be tagged identifying the
language of the data, and to define an LDAP message control allowing
a client to specify a preferred language. The group will base its
work on the following draft:


- Dynamic directories

LDAPv3 supports static directory information that persists in its
value over a relatively long period of time until it is removed.
Some applications (e.g., Internet conferencing) require dynamic
information that changes often and persists only as long as it is
being refreshed. The deliverable from this work item will be LDAPv3
message controls and extended operations allowing the specification
and refresh of dynamic directory information. The group will base
its work on the following drafts:

draft-ietf-asid-ldapv3ext-04.txt draft-ietf-asid-ldap-dynatt-nn.txt

- Referral and knowledge reference maintenance

LDAPv3 is defined as an access protocol in which referrals may be
returned directing a client from one directory server to others. It
does not specify how this referral information is represented in the
directory. The deliverable from this work item is a document
defining the mechanisms by which referrals (sometimes known as
knowledge references) may be maintained in a server. The group will
base its work on the following draft:


- LDAP server discovery

Like most other Internet protocols, LDAPv3 is silent on the
bootstrapping issue of how a client locates an LDAP server to talk
to. Yet this step is necessary for any client to successfully use
the directory without a priori knowledge of the directory server
address it should use. The group will work in conjunction with the
SVRLOC group on defining the method by which LDAP clients discover
LDAP servers, based on the following document:



LDAP has an associated de facto standard C API, defined in RFC 1823.
The existence of this API has proved to be of great value in
spurring LDAP client development. As new features are added in
LDAPv3 and the extensions discussed elsewhere in this charter, the
API will need to be updated to make these new protocol features
available to clients. As application development in other languages,
Java in particular, occurs, the need for a standard API increases.
The deliverable from this work item will be documents updating RFC
1823 for LDAPv3, documents defining API extensions to support
protocol extensions, and a document defining a similar API for Java.
The group will base its work on the following documents:



LDAPv3 defines transport over TCP. In some situations, the overhead
involved in setting up and tearing down TCP connections is
prohibitive, requiring a lighter-weight transport. The deliverable
from this work item will be a document defining transport of the
LDAPv3 protocol over connectionless UDP transport. The group will
expand on the work developed for LDAPv2 in RFC 1798.

- Signed directory information

In many environments clients require the ability to validiate the
source and integrity of information provided by the directory. The
deliverable will be a document describing an LDAP message control
which allows for the retrieval of digitally signed information.

Other areas such as deployment and schema definition and review will
be handled by other groups. Other areas may be added after approval
by the area directors if and when they turn out to be necessary for
the deployment of LDAP and feasible for the group to tackle. In
particular, replication may be considered for addition to the
group's charter if and when a viable approach to the problem is