nications, 2nd ed., West Sussex, Eng- land: John Wiley & Sons Ltd., 1999. Egyedi, T. M., "IPR Paralysis in Standardization: Is Regulatory Symmetry Desirable?" IEEE Communications Magazine, April 2001, pp. 108-144. The Telecommunications Network: An Overview This chapter describes the basic operation of a telecommunications network with the help of a conventional telephone. The operation of a conventional telephone, which is easy to understand, is used to clarify how telephone con- nections are built up in the network. We look at subscriber signaling over the subscriber loop of the telephone network. The same kind of signaling is needed in modern telecommunications networks, such as ISDN and cellular networks. We start with this simple service to lay a foundation for under- standing more complicated types of service in later chapters. In this chapter we divide the network into layers and briefly describe different network technologies that are needed to provide various kinds of service. Some of these, such as mobile and data networks, are discussed in more detail later in this book. The last topic of this chapter is an introduction to the theory of traffic engineering; that is, how much capacity we should build into the network in order to provide a sufficient grade of service for the customers. 2.1 Basic Telecommunications Network The basic purpose of a telecommunications network is to transmit user infor- mation in any form to another user of the network. These users of public networks, for example, a telephone network, are called subscribers. User Introduction to Telecommunications Network Engineering information may take many forms, such as voice or data, and subscribers may use different access network technologies to access the network, for example, fixed or cellular telephones. We will see that the telecommunications net- work consists of many different networks providing different services, such as data, fixed, or cellular telephony service. These different networks are dis- cussed in later chapters. In th