This chapter provides a (necessarily) brief introduction to computer networking concepts. For many applications of gawk to TCP/IP networking, we hope that this is enough. For more advanced tasks, you will need deeper background, and it may be necessary to switch to lower-level programming in C or C++.
There are two real-life models for the way computers send messages to each other over a network. While the analogies are not perfect, they are close enough to convey the major concepts. These two models are the phone system (reliable byte-stream communications), and the postal system (best-effort datagrams).