Objectives

Upon completion of this chapter, you should be able to

• Understand the benefits of circuit-switched vs. packet-switched networks.

• Discuss the original concept of X.25 packet switching.

• Understand the services of the Internet and intranet.

• Describe how the TCP/IP works.

• Describe how data is transferred across the IP networks.

Modes of Switching

In any given network, switching points are interconnected to a form of mesh through which voice and data calls are routed from one device to another, based on the terminal s address. The addressing methods are somewhat unique to the network being used. The network provides connectivity for every device in a way that is consistent with the infrastructure. As a user dials a call, for example, resources (circuit-switched) are allocated for the duration of the connection. Each network, however, uses a different form of switching, but could be an overlay to a different network. This is the case with many of the data networks today. These data networks are overlays to the circuit-switched telephone network regardless of the traffic they carry. GPRS is similar in that the IP-based GPRS data network is an overlay to the GSM circuit-switched network.

Circuit Switching

Circuit switching is the process of passing calls across a given path (voice, data, video, text, or multimedia) that is created on a temporary duration for the express purpose of carrying the traffic between the two endpoints. After the connection is used, the terminals are disconnected and the circuit is released and...