Beyond LDAP - have a look at system.identity

LDAP (Lightweight Directory Access Protocol) is well established. It is the foundation for today's Directory Services, which support LDAP as a protocol and which usually build their data structure on the associated LDAP schema. There are many interfaces for developers to use LDAP, from the LDAP C API to high-level interfaces for many programming environments.

Even while LDAP is well established, it is somewhat limited. There are several restrictions - two important ones are:

The structure of LDAP is (more or less) hierarchical. There is one basic structure for containers - and linking leaf objects (think about the association of users and groups) is somewhat limited. That structure is a heritage of X.500, from which LDAP is derived - with LDAP originally being the lightweight version of the DAP (Directory Access Protocol) protocol. X.500 was constructed by telcos for telcos, e.g. with respect to their specific needs of structuring information. However anyone who ever has thought about structuring Novell's eDirectory or Microsoft's Active Directory knows that there is frequently more than one hierarchy, for example the location and the organizational structure. The strict hierarchy of LDAP is an inhibitor for several use cases.
LDAP is still focused on the specific, single directory. It doesn't address the need of storing parts of the information in fundamentally different stores. But the same piece of information might be found locally on a notebook, in a network directory like Active Directory, in a corporate directory and so on. How to deal with that? How to use the same information across multiple systems, exchange it, associate usage policies, and so on? That is out-of-scope for LDAP.

I could extend the list - but it is not about the limitations of LDAP. LDAP has done a great job for years but there is obviously the need to do the next big step. An interesting foundation for that next big step comes from Kim Cameron, Chief Identity Architect at Microsoft. He has developed a schema which he calls system.identity. There hasn't been much noise around before. There is a stream from last years Microsoft PDC, there is little information at the MSDN plus a blog post, there is the Keynote from this year's European Identity Conference. But it is worth to have a look at that. The approach of system.identity is to define a flexible schema for identity-related information which can cover everything - from local devices to enterprise- and internet-style directories, from internal users to customers and device identities, including all the policies. It is, from my perspective, a very good start for the evolution (compatibility to LDAP is covered) well beyond LDAP and today's directories.

I've put the concept under a stress test in a customer workshop these days. The customer is thinking about a corporate directory. Most people there are not directory guys, but enterprise IT architects. And they definitely liked the path system.identity is showing. It covers their needs much better than the LDAP schema. That proved to me that system.identity is not only for the geeks like me but obviously for the real world. Thus: Have a look at it and start thinking beyond LDAP. The concept of system.identity, despite being early stage, is a very good place to start.