Active Directory Design        

Active Directory (AD) service is the flagship component of Windows 2000 Server and Advanced Server. Just about everything that happens on your Microsoft Windows 2000 network will rely upon AD being installed, configured, and managed properly. Everything from the logon process to application installations can be managed through the Active Directory database.. 

Cost: Business decisions are made with an eye on return for investment, even decisions regarding something as critical as the network itself. Each choice made reflects an expected result at a given cost. When implementing a directory, we have to ensure that the perceived value outweighs the actual costs.

Security: The old maxim "Money is power" has changed to "Information is power." For many companies, the data stored on a network is their edge against the competition. This information must be secure or companies will not trust it to their networks.

Reliability: Uptime is the keyword for business networks. It does not matter what information a company obtains—if that information is not available due to a network problem, it is of no value.

Performance: A good network design, both in the physical layout of resources and in the configuration of software, can produce a system in which performance is optimized. A bad design, on the other hand, can greatly impact a user’s ability to perform their job. PC-based networks have become an integral part of the business world. They started out as simple solutions for sharing a few physical resources— hard disk space, printers, and so on. Over time, though, networks have become quite complex—often spanning multiple sites, connecting thousands of users to a multitude of resources. Today, networks control everything from payroll information to e-mail communication, from printers to fax services. As networks offer more services, they also demand more management. Easing the use and management of networks is the real goal of a directory service.

To understand and appreciate the power and convenience of a directorybased solution, you must have an understanding of the technologies that it will replace. Before the advent of directories, most network operating systems (NOSs) were server based. In other words, most account management was done on a server-by-server basis. With older NOS software, each server maintained a list of users who could access its resources (the accounts database ) and a list of the users’ permissions (the access control list , or ACL). If a system had two servers, each server had a separate accounts database, Although this system is simple and easy to understand, it becomes unwieldy once it grows beyond a certain point. Imagine trying to manage 1,000 users on 250 servers—the user and resource lists would soon overwhelm you! To get around this limitation, some NOS software, such as Microsoft NT 4, was configured so that small groups of servers could share one list of users (called a central accounts database ) for security and authentication purposes. This central accounts database gave administrators a single point of management for a section of their network, known as a domain . Once again, however, this solution becomes cumbersome after the network reaches a certain size. Network directories are just databases that hold network information. They can contain many different types of information:

• User account information (logon names, passwords, restrictions)

• User personal information (phone numbers, addresses, employee IDnumbers)

• Peripheral configuration information (printers, modems, faxes)

• Application configuration (Desktop preferences, default directories)

• Security information

• Network infrastructure configuration (routers, proxies, Internet access settings)