As shown in the figure, Windows Sockets 2 Architecture, there are two basic types of service providers: transport providers and name space providers. Examples of transport providers include protocol stacks such as TCP/IP or IPX/SPX, while an example of a name space provider would be an interface to the Internet's Domain Naming System (DNS). Separate sections of the service provider interface specification apply to each type of service provider.
Transport and name space service providers must be registered with the WS2_32.DLL at the time they are installed. This registration need only be done once for each provider as the necessary information is retained in persistent storage.