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'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.