X.500 Still Important

Those who started the X.500 work in the 1980s envisaged a global directory that would have broad use, including provision of a global white pages and support of the sister X.400 messaging specification. By measure of this ambitious goal, the technology failed. However, this technology has been a tremendous success, but not exactly in the way its originators intended.

X.500 spawned two technologies that have very broad commercial adoption. The first of these is LDAP, which is based on and requires conformance to the core X.500 standards. It is not widely realized how closely the key X.500 and LDAP protocol authors worked together. LDAP is a stable and widely used protocol for directory access. Many systems have been built around this -- for example, X.509 PKI (Public Key Infrastructure) was developed with X.500 and is very widely used, generally in conjunction with LDAP.

The core X.500 protocols also have an important ongoing role. Attempts in the 1990s to build a full directory specification around LDAP (with replication and access control) were abandoned. If you want to build a distributed directory based on open standards, X.500 is the only game in town. Where systems have a requirement for open directory interconnect, X.500 DSP (Directory System Protocol) is still specified. Highly replicated directories are needed for reliability in many situations. X.500 DISP (Directory Information Shadowing Protocol) is the obvious and only open choice here. As well as being chosen by those who understand the requirements, some industries mandate X.500 as the basis for directory services, notably military directories (with ACP 133) and aviation (with the ATN directory).

... Steve Kille

One Trackback

  1. By IT Blogwatch on October 31, 2006 at 3:25 AM

    IE7: bad, Firefox 2.0: good? (and ultimate Coke+Me

    Woah there, it’s IT Blogwatch, in which another IE7 vulnerability rears its ugly head, prompting the inevitable comparisons with Firefox 2.0. Not to mention more amazing experiments with Diet Coke and Mentos…

Post a comment

You must be logged in to post a comment. To comment, first join our community.