TCP/IP is a common denominator for heterogeneous networking, and Windows Sockets is a standard used by application developers. Together they provide a framework for cross-platform client-server development.
The Windows Sockets standard defines a networking API that developers use to create applications for the entire family of Microsoft Windows operating systems. Windows Sockets is an open standard that is part of the Microsoft Windows Open System Architecture (WOSA) initiative. It is a public specification based on Berkeley UNIX sockets, which means that UNIX applications can be quickly ported to Microsoft Windows and Windows NT. Windows Sockets provides a single standard programming interface supported by all major vendors implementing TCP/IP for Windows systems.
The Windows Sockets standard ensures compatibility with Windows-based TCP/IP utilities developed by many vendors. This includes third-party applications for X Windows, sophisticated terminal emulation software, NFS, electronic mail packages, and more. Because Windows NT offers compatibility with 16-bit Windows Sockets, applications created for Windows 3.x Windows Sockets run on Windows NT without modification or recompilation.
For example, third-party applications for X Windows provide strong connectivity solutions by means of X Windows servers, database servers, and terminal emulation. With such applications, a computer running Windows NT can work as an X Windows server while retaining compatibility with applications created for Windows NT, Windows 95, Windows 3.x, and MS-DOS on the same system. Other third-party software includes X Windows client libraries for Windows NT, which enable developers to write X Windows client applications on Windows NT that can be run and displayed remotely on X Windows servers.
The TCP/IP utilities for Windows NT use Windows Sockets, as do 32-bit TCP/IP applications developed by third parties. Windows NT also uses the Windows Sockets interface to support Services for Macintosh and IPX/SPX in NWLink. Under Windows NT, 16-bit Windows-based applications created under the Windows Sockets standard will run without modification or recompilation. Most TCP/IP users will use programs that comply with the Windows Sockets standard (such as ftp or telnet) or third-party applications.
The Windows Sockets standard allows a developer to create an application with a single common interface and a single executable that can run over many TCP/IP implementations. Windows Sockets is designed to:
Typical Windows Sockets applications include graphic connectivity utilities, terminal emulation software, Simple Mail Transfer Protocol (SMTP) and electronic mail clients, network printing utilities, SQL client applications, and corporate client-server applications.
Specifications for Windows Sockets are available on numerous Internet sites such as www.microsoft.com, the Microsoft Network (MSN™), and CompuServe.