This chapter established a conceptual foundation for realizing all upcoming chapters. First, we clearly identified and defined all basic key terms in networking. We showed a big-picture view of computer networks in which from one side, mainframe servers can be connected to a network backbone, and from the other side, home communication devices are connected to a backbone network over long-distance telephone lines. We illustrated how an Internet service provider (ISP) controls the functionality of networks. ISPs have become increasingly involved in supporting packet-switched networking services for carrying all sorts of data, not just voice, and the cable TV industry.
The transfer of data in packet-switched networks is organized as a multilevel hierarchy, with digital messages fragmented into units of formatted messages, or packets. In some circumstances, such as local area networks, packets must be modified further, forming a smaller or larger packet known as a frame. Two types of packet-switched networks are networks using connectionless protocol, in which no particular advanced connection is required, and networks using connection-oriented protocol, in which an advance dedication of a path is required.
A packet’s size can be optimized. Using the percentage of link utilization by data, ρd, as a main variable, we showed that the optimized packet size and the optimized packet delay depend on ρd. The total delay of packet transfer in a connectionless network may be significantly smaller than the one for a connection-oriented network since if you have a huge file to transfer, the set-up and tear-down times may be small compared to the file transfer time.
This chapter also covered a tremendous amount of fundamental networking protocol material. We presented the basic structure of the Internet network protocols and an overview of the TCP/IP layered architecture. This architectural model provides a communication service for peers running on different machines and exchanging messages.
We also covered the basics of protocol layers: the network layer and the structure of IPv4 and IPv6. IP addressing is further subdivided as either classful or classless. Classless addressing is more practical for managing routing tables. Finally, we compared the equal-sized packet networking environment to IP networks. Although packet multiplexing is easy, the traffic management is quite challenging.
The next chapter focuses on the fundamental operations of networking devices and presents an overview of the hardware foundations of our networking infrastructure. Networking devices are used to construct a computer network.