Network applications in the UNIX world usually follow the client-server model using the communications facilities provided by the UNIX kernel. These facilities are commonly built upon the TCP/IP protocol suite and the Ethernet local area network. A quick overview of the network protocols is given, leading into a discussion of the programmer interface to the network ing functions. Topics covered include making daemon processes, inter-process communications (IPC), network addressing, the Berkeley socket interface, the System V transport layer interface (TLI), and the differences between sockets and TU. Several versions of an echo client and server are examined to show the differences between the various interfaces.
ESC_1992_Vol1_Page367_Hyman – UNIX Network Programming- Sockets & Streams.pdf