Reasons to Directory-Enable Existing Applications

By integrating existing applications with your directory service, you can do any or all of the following:

Enable new features in the applications . For example, users of an e-mail client application can access shared address books in addition to local, private address books.
Lower your data management costs . LDAP-enabling some existing applications may allow you to eliminate redundant copies of data and to decommission private directories and databases.
Simplify life for end users by leveraging your deployed directory service . For example, using a centralized directory for authentication reduces the number of distinct passwords people need to remember.
Bring the directory service to your end users . By LDAP-enabling an existing application instead of forcing people to switch to a new one, you make it easier for end users to adopt your directory service.

However, sometimes it does not make sense to integrate an application with a directory service. For example, the data the application uses may violate your directory data policy. Chapter 21, Developing New Applications, provides more information on when it does not make sense to directory-enable an application.

Each of the benefits of integrating an application with a directory service is discussed further in the following sections.

Enabling New Features in Applications

New features can increase the value of the application and expose users to your directory service in a new way. For example, suppose you have a widely used e-mail application with only local lookup capabilities for its address book; you could add LDAP lookup capabilities so that users could access other address books shared across the organization. They would thus access your directory service more because it would be closely tied to a task they perform often: addressing and sending e-mail.

Features such as a local-to-global address book upgrade are extensions of existing features, but you might add a completely new feature too. For example, modifying a server application to store its configuration information in an LDAP directory allows the configuration to be shared among a set of similar servers, thereby reducing deployment and management costs.

Lowering Data Management Costs

Directory-enabling an application that has a private, application-specific data store can reduce the cost of data management. The private data store can be taken out of service, and all the resources used to run and maintain it can be eliminated. Old, application-specific directories and databases are often more expensive to maintain than a centralized, LDAP-based directory service; expertise is harder to find, management tools are weaker, and platform choices are more limited than with an LDAP directory.

Another way data management costs can be reduced is by eliminating redundant copies of data elements; the need for synchronization between a data source and your centralized directory is eliminated with the redundant data. If some of the data used by the application is personal data, your end users will appreciate the fact that data about them is stored in one less place, therefore making changes to the data easier.

For example, Figure 22.1 shows an existing workflow system with its own database that stores information about users of the system. End users and administrators must update two separate information stores.

Figure 22.1. A Workflow Application with a Private Database

By consolidating into a directory service the information held in the private database, you eliminate redundant data and simplify the system as a whole. Figure 22.2 shows the revised, directory-enabled application.

Figure 22.2. The Directory-Enabled Workflow Application

Simplifying Life for End Users

Another reason to leverage your deployed directory service in existing applications is to simplify life for end users. Users will thank you every time you eliminate another redundant, application-specific data store. For example, if all your applications that send postal mail use a common directory service to determine a person's mailing address, employees need to change their addresses in only one place when they move.

Another way to simplify life for end users is to create a consistent view of information from within a variety of applications. All applications that use the same LDAP directory service access the same information using the same protocol. Use of a common data store and access method leads to greater consistency in the look and feel of different applications and in the terminology they use. This makes it easier for end users to carry over their knowledge of one application to another. For example, a public Web site that uses one central directory service for all of its Web-based applications may be easier for end users to use than a site that uses many different databases.

A related motivating factor is that over time, people will expect the directory service to be used when they access certain kinds of information. For example, novice users who discover your Web-based directory phone book application may assume that all contact information about them is stored in one directory service. They will be disappointed if, as shown in Figure 22.3, the same information they find in the phone book isn't returned when they execute the finger command on their Unix workstation.

Figure 22.3. Contact Information Lookup Applications That Are Not Integrated

Directory-enabling the finger service can reduce end- user confusion and frustration. Figure 22.4 shows the improved situation.

Figure 22.4. Contact Information Lookup Applications That Are Integrated and Directory-Enabled

Bringing the Directory Service to Your End Users

If one of your goals is to increase the use and visibility of your directory service, adding LDAP support to applications can be somewhat self-serving. Directory-enabled applications bring the directory service closer to your end users, making it more likely that they will use the service. By making your service an essential part of users' everyday life, you ensure future financial and political support for the directory. Data quality and data consistency across data stores also improve as more people use a common directory service.

People are more likely to try a new version of a software application they already use than they are to try a completely new application. Therefore, it is often better to add a little bit of LDAP support to an existing application than it is to invest in the development and deployment of a brand-new , richly featured directory-enabled application. The key is to add features that are valuable to your users so that they will want to use your directory service.

For example, you might have a Web-based conference room locator service running on one of your internal Web servers. Users of the application can search for a conference room on any of your campuses and view a map that shows the location of room. This application could be enhanced to locate people as well. Real value to end users can be provided by the addition of the capability to search the directory, retrieve a person's building and office number, and map the location.