Chapter 1 - Differences in Data and Voice Traffic

Abstract

This chapter discusses the difference between data and voice traffic. Circuit switching is a technique in which a system seeks out the physical copper path from the caller's telephone to the receiver's telephone. Packet switching is a type of network where small units of data are routed through a network based on the destination address in each packet. Compared to circuit switching, which statically reserves the required bandwidth in advance, packet switching acquires and releases bandwidth as and when it is needed. This type of communication between sender and receiver is known as connectionless. The data layering of communications gives rise to situations where the lower layers of a network are connectionless, but the higher layers establish a connection. In a system that has a layered architecture, a process communicates only with its peer processes on the same layer. Peers communicate with a common protocol, appropriate to the services they provide. Each level may require a protocol that is different and layers of processes have corresponding layers of protocols. The lower layers communicate across a single link, while the upper layers must communicate with peers to which the link is indirect, that is, through other nodes. It is observed that in a system with a layered architecture, programs at a high level deal with more complicated data but do not have to deal with implementation details and routine tasks.