Winsock TCP/IP Annex

This section describes Transmission Control Protocol/Internet Protocol (TCP/IP) functions, data structures, and controls.

Element Description
Protocol name(s) TCP, UDP
Description Provides transport services over the IP networking layer: UDP for unreliable datagrams, TCP for reliable, connection-oriented byte streams.
Address family AF_INET, AF_INET6
Header file Ws2tcpip.h


Two basic types of transport services are offered: unreliable datagrams (UDP), and reliable connection oriented–byte streams (TCP). In addition, a raw socket is optionally supported. Raw sockets allow an application to communicate through protocols other than TCP and UDP such as ICMP. Raw sockets are supported on the AF_INET and AF_INET6 address families with some limitations.

This section covers extensions to Winsock that are specific to TCP/IP protocols. It also describes aspects of base Winsock functions that require special consideration or that may exhibit unique behavior when using TCP/IP.