Sams Teach Yourself TCP/IP in 24 Hours, Fourth Edition

Networks and Protocols

A network is a collection of computers or computer-like devices that can communicate across a common transmission medium, as shown in Figure 1.1.

Figure 1.1. A typical local network.

In a network, requests and data from one computer pass across the transmission medium (which might be a network cable, phone line, or plain air in the case of a wireless connection) to another computer. In Figure 1.1, computer A must be able to send a message or request to computer B. Computer B must be able to understand computer A’s message and respond to it by sending a message back to computer A.

A computer interacts with the world through ...