Directory Services

Because integration servers deal with distributed systems, including systems that exist in other organizations, they require directory services to locate, identify, use, and authorize network resources for those systems. Directory services provide a single point of entry for applications and middleware (e.g., integration servers). In doing so, they lend a tremendous benefit to the system. They also support the use of a shared set of standards for directory and naming services. Directory services act as guides among the thousands of resources available to applications and middleware.

Using directory services, the integration server or application integration developer can build applications that are able to intelligently locate resources anywhere on the network. Directories know where to find these resources on behalf of applications. They track them as they are reconfigured, moved, or deleted. For example, an e-mail application can locate a user group, a word processing application can find a printer, and a client/server application can find a database no matter where these resources exist on the network.

Application objects exist on the network, not on certain servers. There fore, it is essential that developers share a common infrastructure for locating objects.

At their base, directory services are nothing more than a method of classifying resources on the network in a way consistent with every other method of classification. For example, in biology, biologists classify living things according to kingdom, phylum, class, order, family, genus, and species. Directory services identify and classify all computer systems by moving down a similar hierarchy and by using a naming system to determine the direction of the branches.

A number of directory services exist, including the Domain Name System (DNS), Novell's NetWare Directory System and Directory Services, Netscape Communications' Directory Server, Microsoft's Active Directory, and X.500. DNS enables all Internet users to resolve server names. It has been a tremendous resource for years, but is, unfortunately, limited to that one simple function.