Core Networking Technologies

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

In Microsoft Windows Server 2003, core networking tasks are accomplished by using TCP/IP. TCP/IP consists of a suite of protocols, of which TCP and IP are two. This suite of protocols was originally designed to solve a communications problem among the branches of the United States military. In the 1960s, each of the military branches obtained bids from different vendors to provide computer systems for their branch. The Army chose Digital Equipment Corporation (DEC), the Air Force chose International Business Machines (IBM), and the Navy chose Unisys. Soon after, the military branches discovered that they needed their computer systems to communicate with each other to facilitate coordination between the military branches. The Department of Defense (DoD) launched a research project in 1969 to connect the systems of various vendors together to form a network of networks. The DoD developed TCP/IP with IP version 4 (IPv4) to connect this network of networks — the collection of networks now known as the Internet. TCP/IP is still used to connect business networks across the world.


  • The word internetwork refers to multiple TCP/IP networks connected with routers. The Internet is a worldwide public IP internetwork. An intranet is a private IP internetwork.

IPv4 proved to be robust, easily implemented and interoperable. It has also stood the test of scalability from an internetwork to today’s global Internet. However, the initial design did not fully allow for the following:

  • The exponential growth of the Internet and the impending depletion of the IPv4 address space.

    The scarcity of IPv4 addresses has forced some organizations to use a network address translator to map multiple private addresses to a single public IP address. Network address translators promote reuse of the private address space, but they do not support standards-based network layer security or the correct mapping of all higher layer protocols. Moreover, the translators can create problems when connecting two organizations that use the private address space.

    Additionally, the rising prominence of Internet-connected devices and appliances ensures that the public IPv4 address space will eventually be depleted.

  • The requirement for security at the IP level.

  • Private communication over a public medium, such as the Internet, requires encryption services that protect the data being sent from being viewed or modified in transit. Although a standard now exists for providing security for IPv4 packets, known as Internet Protocol Security, or IPSec, this standard is optional.

  • The growth of the Internet and the ability of Internet backbone routers to maintain large routing tables.

    Because of the way that IPv4 network IDs have been and are currently allocated, there are often over 85,000 routes in the routing tables of Internet backbone routers. The current IPv4 Internet routing infrastructure is a combination of both flat and hierarchical routing.

  • The need for better support for real-time delivery of data, or Quality of Service (QoS).

    QoS standards exist for IPv4, but real-time traffic support relies on the IPv4 Type of Service (ToS) field and the identification of the payload, typically using either a User Datagram Protocol (UDP) or TCP port. Unfortunately, the IPv4 ToS field has limited functionality, and over time there have been various local interpretations. In addition, payload identification using a TCP and User Datagram Protocol (UDP) port is not possible when the IPv4 packet payload is encrypted.

To address these and other concerns, the Internet Engineering Task Force (IETF) developed IP version 6 (IPv6). IPv6, previously called IP next generation, incorporates the concepts of many proposed methods for updating the IPv4 protocol. The design of IPv6 is intentionally targeted for minimal impact on upper and lower layer protocols by avoiding the random addition of new features.

Windows Server 2003 supports TCP/IP with IPv4 and IPv6.

Core Networking Components

The core networking protocol, TCP/IP, which is installed by default on computers that run Windows Server 2003 is an industry-standard suite of protocols designed for large internetworks spanning wide area network (WAN) links. TCP/IP in Windows Server 2003 was designed to make it easy to integrate Microsoft systems into large-scale corporate, government and public networks, and to provide the ability to operate over those networks in a more secure manner. There are two versions of TCP/IP available for use with Windows Server 2003: TCP/IP version 4 (with IPv4) and TCP/IP version 6 (with IPv6).

TCP/IP (with IPv4)

TCP/IP in Windows Server 2003 enables enterprise networking and connectivity that have the following features:

  • A standard, routable enterprise networking protocol that is the most complete and accepted protocol available. All modern, network operating systems offer TCP/IP support, and most large networks rely on TCP/IP for much of their network traffic.

  • A technology for connecting dissimilar systems. Many standard connectivity tools are available to access and transfer data between dissimilar systems, including File Transfer Protocol (FTP) and Telnet, a terminal emulation protocol. Several of these standard tools are included with Windows Server 2003.

  • A robust, scalable, cross-platform client/server framework. TCP/IP in Windows Server 2003 offers the Windows Sockets (Winsock) interface, which is ideal for developing client/server applications that can run on Winsock-compliant TCP/IP protocol implementations from other vendors.

  • A method of gaining access to the Internet. The Internet consists of thousands of networks worldwide, connecting research facilities, universities, libraries, and private companies.

For more information about Windows Server 2003 TCP/IP, see TCP/IP Technical Reference.


The following features of the IPv6 protocol overcome the limitations of IPv4:

  • New header format

  • Large address space

  • Efficient and hierarchical addressing and routing infrastructure

  • Stateless and stateful address configuration

  • Built-in security measures

  • Better support for QoS

  • New protocol for neighboring node interaction

  • Extensibility

IPv6 includes new capabilities such as scoped addresses, stateless autoconfiguration, lowering the complexity and management burden, and mandatory IPSec, permitting end-to-end data authentication, data integrity, and privacy of connections. In addition to the new capabilities, IPv6 brings back the capability of end-to-end communications; making networking applications simpler as the network again becomes transparent


  • In IPv4, end-to-end communications have been largely replaced by a client/server model because network address translators are better behaved for client/server communications. The translators also extend the lifetime of IPv4 by enabling multiple operating systems to share a single, public IPv4 address.

IPv6 supports always-on technologies such as Digital Subscriber Line (DSL) and cable modems, personal data assistants (PDAs), and cellular Mobile Information Appliances. Windows Server 2003 supports the capability to send IPv6 traffic over existing IPv4 networks.

For more detailed information about these features, see IPv6 Technical Reference.

Core Networking Scenarios

Computers that run Windows operating systems use TCP/IP to communicate with other computers in corporate intranets, and across the Internet. As such, TCP/IP is an essential component of any Windows network configuration. Windows Server 2003 is the first release of the Windows operating system that includes IPv6. Ideally, IPv6 is used in a pure environment, meaning an environment where IPv6 is the exclusive Internet protocol used between computers. Currently, however, pure IPv6 environments are attainable only when you use computers running Windows operating systems that support IPv6 and routers that support IPv6 routing. As IPv6 replace IPv4, pure IPv6 environments will eventually replace IPv4. Until that occurs, the transition technologies described in this technical reference can be used to facilitate coexistence and provide a migration path from IPv4 to IPv6.