Operating Systems: Concurrent and Distributed Software Design

3.7. Communications networks, interfaces and drivers

A given computer might be connected to a local area network (LAN) or a wide area network (WAN). Perhaps the most common (and most general) topology is that of interconnected LANs connected by WANs to form an internetwork. Figure 1.9 shows local networks of workstations and servers with WAN connections. For generality, it also shows some host computers directly attached to the WAN. Some concurrent systems span large-scale or even global networks, for example, electronic mail systems, information retrieval services and the private networks of companies with widely dispersed branches.

A computer's network connection is handled by the operating system in much the same way as a device. The network ...