Essential Guide to Computing: The Story of Information Technology, The

Getting From A To B: Circuits, Virtual Circuits, and Circuitless Approaches

Having acquired some knowledge of packets and protocols, it's necessary to return to the question of circuits. As noted earlier, while packet switching is ascendant in the networking world, circuit switching is still around and should survive for many years. Moreover, even packet-based networks can use a form of circuit switching, virtual circuits.

To frame the problem, let's take a minute to describe the A to B part of our basic network illustration (Figure 11.4). Note that there are multiple possible paths from A to B. Even as data leaves A, the system must choose between going first to Node 1 or to Node 2. Nodes in this case are just other computers on the network. ...