Key Components of an Enterprise Network

Although an enterprise network has many functional layers, this chapter focuses on three key components that are critical to the functionality of a Windows Server 2003 environment. These three aspectsnetwork addressing, name resolution, and directory integrationprovide for the base-level functionality expected of any modern enterprise network and provide the backbone for the Windows Server 2003 infrastructure.

Network Addressing

The first critical component of a network is addressing, or allowing clients to assume a logical place in a network so that packets of information can be forwarded to and from the clients. This component was historically accomplished by proprietary network protocols, one for each network operating system (NOS). This gave NOS designers a great deal of flexibility in tailoring the communications components of their network to their specific design needs but made it difficult to exchange information between networks.

The Transmission Control Protocol/Internet Protocol (TCP/IP) was designed to interoperate between different varieties of networks, allowing them to speak a common language. The rise of this protocol coincided with the widespread adoption of the Internet itself, and it was this popularity and ubiquitous use of this protocol that led Microsoft to choose it as the standard protocol for Windows 2000. Windows Server 2003 continues to use TCP/IP as the default network protocol, expanding its place within the Microsoft NOS world.

TCP/IP requires that each node on a network be addressed by a unique IP address, such as 10.23.151.20. Each IP address must be assigned to every node on a network, either manually or by automatic methods. The automatic addressing component is the place where the DHCP service comes in with Windows Server 2003.

DHCP provides the automation of the critical TCP/IP addressing in Windows Server 2003 and makes administration of a network more palatable. You can find more details on DHCP in the "Dynamic Host Configuration Protocol (DHCP)" section later in this chapter.

Name Resolution

The second critical aspect in networks is name resolution. Because humans understand the concept of names better than they do IP addresses, the need arises to translate those sets of numbers into common names.

Windows Server 2003 supports two types of name resolution. The first type, the Domain Name System (DNS), translates IP addresses into fully qualified domain name (FQDN) addresses, which allows them to be addressed in an Active Directory or Internet DNS structure. This type of name resolution, the default (and required) type in Windows Server 2003, is covered in more detail in Chapter 9, "The Domain Name System."

The second type of name resolution, mapping legacy Microsoft NetBIOS names into IP addresses, is provided by WINS. Although it is technically possible (and ideal) to create a Windows Server 2003 environment free of NetBIOS name resolution, the truth is that divorcing a network from WINS dependency is very difficult, so it will remain an active part of network services in most organizations, at least for a few more years. You can find more information on WINS in the "Windows Internet Naming Service" section later in this chapter.

Directory Integration

The final important service that is supplied by a functional enterprise network is directory placement and lookup capability. Having a centralized directory that controls access to resources and provides for centralized administration is a vital function in modern networks.

Active Directory is the directory service that is provided with Windows Server 2003 and is built into many of the operating system components. The servers that handle the login requests and password changes and contain directory information are the domain controllers and global catalog domain controllers, which will be explained in more detail in the "Understanding the Role of the Active Directory Global Catalog" section later in this chapter.

Subsequently, domain controller and global catalog placement is a critical piece of a Windows Server 2003 environment. Special considerations must be made regarding this concept because access to directory lookup and registration is key for client functionality on a network.

Outlining Network Services Changes in Windows Server 2003

Windows Server 2003 introduces several functional improvements to network services. These improvements allow for increased administrative functionality, greater reliability, and an overall increase in value for an organization's network infrastructure.

DHCP improvements such as DHCP Backup and Restore, migration improvements, and WINS advanced database search and filtering enhance the basic capabilities of these networking services and provide for a richer set of tools in configuring a network environment. You can find more information about these capabilities later in the "Automating DHCP Database Backup and Restore" section of this chapter.