Many companies have a diverse collection of technologies that must work together. As a result, many corporate networks have an equally diverse collection of disparate directories as part of e-mail servers, applications, network devices, firewalls, e-commerce applications, and more. Active Directory provides a set of standard interfaces for application integration and open synchronisation mechanisms to ensure that Windows can interoperate with a wide variety of applications and devices.

Active Directory extends interoperability because it:

• Takes advantage of existing investments and ensures flexibility. Standards-based interfaces to all features make use of investments and ensure flexibility for future applications and infrastructure.
• Consolidates management of multiple application directories. Using open interfaces, connectors, and synchronisation mechanisms, organisations can consolidate directories including Novell's NDS, LDAP, ERP, e-mail, and other mission-critical applications.
• Allows organisations to deploy directory-enabled networking. Network devices from leading vendors such as Cisco and 3COM can use the directory to let administrators assign quality of service and allocate network bandwidth to users based on their role in the company.
• Allows organisations to develop and deploy directory-enabled applications. Using the fully extensible directory architecture, developers can build applications that deliver functionality tailored to the needs of the end user.

Active Directory provides a central integration point for bringing diverse systems together and for consolidating directories and management tasks. It does this by exposing all of the Windows 2000 directory features through standards-based interfaces such as LDAP, ADSI, JADSI, and MAPI so companies can consolidate existing directories and develop directory-enabled applications and infrastructure.

One example of how Microsoft is using Active Directory in its own product-line is Microsoft Exchange. The Exchange server has been integrated with Active Directory to enable companies to manage Windows 2000 user accounts and Exchange mailboxes in one place.

Figure 6: Active Directory provides a platform for integrating and extending systems through open interfaces, connectors, and synchronisation mechanisms.

For example, a directory-enabled application could reference a user's profile in the directory and provide specific menu items and functionality based on his or her job function. That way, a user in personnel could see the "Change Salary" menu item in a HR application, while a user in finance would not see that menu, even if the two users share a computer.

Just as organisations can improve the way their directory service and applications work together, so can they improve the way their network hardware and software work with their directory service. By providing a platform for directory-enabled networks, Active Directory lets companies match network resource allocation to their business-process requirements.
In particular, administrators can allocate network bandwidth to users based on their business needs. For example, an administrator could create a policy that ensures that users in the finance department are allocated additional bandwidth when they are busy closing books at the end of the month.

The benefits of Active Directory can be extended beyond the Windows environment. The open synchronization mechanisms within Active Directory ensure interoperability of the Windows platform with a wide variety of applications and devices. For example, native support for LDAP, DirSync, and ADSI interfaces enables leading vendors such as Cisco, SAP, BAAN, and 3COM to integrate with Active Directory to provide simplified and powerful management of their multi-platform products.