Computer and communication networks to provide a wide range of services, from simple networks of computers to remote-file access, digital libraries, videoconferencing, and networking billions of users and devices. Before exploring the world of computer and communication networks, we need to study the fundamentals of packet-switched networks as the first step. Packet-switched networks are the backbone of the data communication infrastructure. Therefore, our focus in this chapter is on the big picture and the conceptual aspects of this backbone:
We start with the basic definitions and fundamental concepts, such as messages , packets , and frames , and packet switching versus circuit switching . We learn what the Internet is and how Internet service providers (ISPs) are formed . We then proceed to types of packet-switched networks and how a message can be handled by either connection-oriented networks or connectionless networks . Because readers must get a good understanding of packets as data units, packet size and optimizations are also discussed. |