te destination, and forwarding, which is concerned with how to actually guide the traffic across the backbone so that it uses the physical and logical connections to best advantage. Chapter 3 Establishing Communications Channels The networking techniques that have evolved over time to handle the when and where have come about because, traditionally, relatively few high-capacity backbone cables existed. Those few backbone cables had to be manipulated to meet the needs of many individual customers, all of whom had varied bandwidth needs and varying budgets, affording (or not) higher-priority service. Two networking techniques arose: Networking modes-There are two networking modes: connection ori- ented and connectionless. Switching modes-There are two switching modes: circuit switching and packet switching. Both of these switching modes offer forms of bandwidth on demand. (But remember that the connection speed can never be greater than the speed of the customer's access line; the fastest connection you can get into the network is what your access line supports.) As you'll learn later in this chapter, circuit switching and packet switching have different ways of performing path calculations and forwarding functions. The following sections describe networking modes and switching modes in detail. Networking Modes When telecom, network, and IT professionals are evaluating a network, deciding on proper solutions to implement, they often have to consider the choice between circuit switching and packet switching. But it's also very important to consider the networking mode, which can be either connection oriented or connectionless. Connection-Oriented Networking As time-sensitive applications become more important, connection-oriented net- works are becoming increasingly desirable. In a connection-oriented network, connection setup is performed before information transfer occurs. Information about the connections in the networks helps to provide service guarantees and makes it possible to most efficiently use network ban