The socket components let you create an application that can communicate with other systems using TCP/IP and related protocols. Using sockets, you can read and write over connections to other machines without worrying about the details of the underlying networking software. Sockets provide connections based on the TCP/IP protocol, but are sufficiently general to work with related protocols such as User Datagram Protocol (UDP), Xerox Network System (XNS), Digital's DECnet, or Novell's IPX/SPX family. 

Using sockets, you can write network servers or client applications that read from and write to other systems. A server or client application is usually dedicated to a single service such as Hypertext Transfer Protocol (HTTP) or File Transfer Protocol (FTP). Using server sockets, an application that provides one of these services can link to client applications that want to use that service. Client sockets allow an application that uses one of these services to link to server applications that provide the service. 

To write applications that use sockets, you should understand

• Implementing services
• Types of socket connections
• Describing sockets
• Using socket components
• Responding to socket events
• Reading and writing over socket connections