Understanding Telecommunications Networks, (2nd Edition)
A telecommunications network is an electronic system of links, nodes and the controls that govern their operations to allow voice and data transfer among users and devices. Examples of telecommunications networks are the telephone networks, computer networks and the Internet. Understanding Telecommunications Networks provides a comprehensive explanation of how various systems and technologies link together to construct fixed and mobile telecommunications networks and provide services. It uses straightforward language supported by block-schematic diagrams so that non-engineers and engineers alike can learn about the principles. This fully revised, updated and expanded second edition covers all aspects of today's networks, including how they are planned, formed and operated. After an introductory chapter on telephony, the book describes all of today's networks and considers how they link. Individual chapters then consider the principles, technologies and network structures relating to network components; transmission systems and networks; circuit switching systems and networks; signalling and control; data (packet) switching and routeing; and mobile systems and networks. The book concludes with a chapter designed to pull everything together, considering architecture, quality of service and performance, operations, network evolution and next generation networks. This is a companion volume to "Understanding Telecommunications Business" authored by Andy Valdar & Ian Morfett (ISBN: 9781849197458).
Inspec keywords: mobile radio; telecommunication network routing; standards; telecommunication signalling; telephony
Other keywords: network components; mobile systems; telecommunications networks; signalling; transmission networks; telephony; data switching; routing; transmission systems; circuit-switching systems; standards
Subjects: Mobile radio systems; Communication network design, planning and routing; Telephony; General topics, engineering mathematics and materials science
- Book DOI: 10.1049/PBTE071E
- Chapter DOI: 10.1049/PBTE071E
- ISBN: 9781785611643
- e-ISBN: 9781785611650
- Page count: 350
- Format: PDF
-
Front Matter
- + Show details - Hide details
-
p.
(1)
-
1 An introduction to telephony
- + Show details - Hide details
-
p.
1
–19
(19)
Of course, telecommunications are now global and include not only telephony over fixed and mobile networks, but also data - the World Wide Web, e-mail, broadcast TV, video, social networking, etc. In setting out how all of this works it is helpful to understand how the basic telephone networks are structured since they form the basis of all today's telecommunications networks. We will then progressively address the full range of networks and how they link together. This first chapter introduces the principles of telephony, covering the operation of a telephone and the way that telephones are connected via a fixed (wireline) network. We will be considering telephony over mobile and data networks in subsequent chapters.
-
2 The many networks and how they link
- + Show details - Hide details
-
p.
21
–42
(22)
This chapter introduces the concept of the many other telecommunications networks that exist today and how they all interlink. Firstly, we look briefly at the two other types of network, in addition to the PSTN, that carry telephone calls, namely: mobile networks and cable TV networks. It is noted that all three networks use essentially the same type of switching system, but that the mobile networks use radio links and mobility management in place of the fixed wire access of the PSTN and cable TV networks. The necessary interconnection of all these types of networks within a country and to networks in other countries is described. We also introduce the concept of the Internet and how subscribers gain access to it via the PSTN, cable modems over Cable TV networks, xDSL broadband, mobile networks or over leased-lines using optical fibre.
-
3 Network components
- + Show details - Hide details
-
p.
43
–62
(20)
In this chapter, we looked at the basic components used in the links and nodes of telecommunication networks. Beginning with the nodes, we considered the two types of circuit switching: concentrator switching, dealing with low-occupancy subscriber lines; route switching, interconnecting routes between concentrator units and with other exchanges. Then, we considered the alternative form of switching, generally known as packet switching, which is the preferred way of conveying data. The remaining nodal functions considered include: control nodes; multiplexing (FDM, TDM, and CDM); Grooming; Consolidation A generalised view of transmission links was then described, noting that within the switched and Core Transmission networks these are four-wire systems, with Go and Return channels, whereas in the copper Access Network two-wire circuits are used for economy. Then we considered the advantages of an IDN and how it can be extended over the Access Network to the subscribers using ISDN. Finally, the important A/D conversion process was described.
-
4 Transmission systems
- + Show details - Hide details
-
p.
63
–105
(43)
This chapter describes the wide variety of transmission systems used in telecommunication networks today. In doing this, we will be drawing upon the concepts of multiplexing and analogue-to-digital (A/D) conversion introduced in the previous chapter. Earlier chapters have also introduced the important distinction between the Access Network, which serves the subscribers, and the Core Transmission Network, which provides links between network nodes only. In general, the transmission systems described in this chapter may be deployed in both the Access and the Core Transmission Networks - although they are usually more appropriate to one or the others, and this will be indicated. The previous chapter introduced the model of the networks associated with the public switched telephone network (PSTN), in which the Access and Core Transmission Networks act as a common utility for providing circuits to the various specialised networks as well as the PSTN. However, we will leave the description of how the various transmission systems are deployed in the Access and Core Transmission Networks.
-
5 Transmission networks
- + Show details - Hide details
-
p.
107
–137
(31)
This chapter considered how the various transmission systems described in Chapter 4 are used to construct transmission networks. In Section 5.2 we addressed the Access Network, covering the ubiquitous copper local loop network, as well as the use optical fibre and microwave radio. We noted that a key aspect is the ability of the Access Network to carry increasingly higher capacities to the residential and small business users - the so-called `broadband access' - as well as for the larger business customers. Some of the factors influencing the network operators' choice of broadband technology were discussed. The importance of the planning, operational and regulatory issues for the Access Network was also described. In Section 5.3 we considered the structure of the Core Transmission Network and the role of the Core Transmission Stations at the transmission nodes, looking at: PDH networks; SDH networks Finally, the various ways in which the resilience of the Core Transmission Network can be increased were identified. A simple example of dimensioning a Core Transmission Network in association with the switched telephony network is given in Chapter 6. Subsequent chapters describe intelligence, signalling, data and mobile networks.
-
6 Circuit-switching systems and networks
- + Show details - Hide details
-
p.
139
–171
(33)
In Chapter 5 we looked at how a Core Transmission Network carries a required capacity between two network nodes. But, how does a network operator determine what capacity is required to be carried? For example, are 90 circuits between Leicester and Coventry sufficient to ensure the expected volume of calls between these exchanges can be carried satisfactorily, or could the operator save money by providing just 60 circuits? Section 6.3 of this chapter considers how the size of traffic route between two exchanges is determined, and how the flow of traffic through a network of many exchanges is routed to give maximum utilisation of the capacity while achieving the appropriate level of resilience (at the switching level). Finally, we consider a simple example of how a network is dimensioned at the switching level, and how this impacts the dimensioning of the Core Transmission Network.
-
7 Signalling and control
- + Show details - Hide details
-
p.
173
–198
(26)
The concept of a telephone call being routed through a succession of exchanges was first introduced in Chapter 1, extended to the interconnection of several different operators' networks in Chapter 2, and considered from the switching systems' viewpoint in Chapter 6. We are now in a position to examine how the control of such call routeings across the networks (public switched telephone network (PSTN), mobile and others) is achieved. To this end, this chapter first considers the mechanism of signalling between nodes across the networks, and then the principal features of call switching control are introduced. In addition, we consider the broader aspects of control covering multimedia and more complex services.
-
8 Data (packet) switching and routeing
- + Show details - Hide details
-
p.
199
–246
(48)
In this chapter we looked at the variety of packet technologies providing the wide range of data services used by both business and residential customers. After considering the differences between voice and data services, we then noted that several packet systems are capable of providing voice switching. We looked at ATM in detail, noting that the VPs established enabled the QoS offered to customers to be predicted and assured. However, the main focus of the rest of the chapter addressed the various aspects of IP and why it has proved to be ubiquitous and popular as a network service as well as the main interface to user computer applications. Consideration of the Internet provided an insight into the applicability of IP and, with the advent of the WWW, the massive impact on everyday life at work and home.
-
9 Mobile systems and networks
- + Show details - Hide details
-
p.
247
–297
(51)
Mobile phones are now such an everyday feature of life throughout the world that in total they far outnumber the population of fixed telephone lines. For many, the mobile phone is the preferred means of communication. Perhaps more significantly, the mobile phone instrument is usually a smart device which enables voice, video and data services and applications to be presented together with touchscreen human interaction. The mobile networks therefore need to convey both voice and data content. This chapter explains how a mobile phone system works and the relationship between mobile and fixed networks. We begin by considering the nature of a mobile system. After a simple review of how a telephone call can be carried over a radio link, we examine the various cellular mobile network systems, and conclude by looking at how the mobile and fixed networks in the future may begin to merge.
-
10 Numbering and addressing
- + Show details - Hide details
-
p.
299
–328
(30)
This chapter confines itself to considering how numbering and addressing is defined and applied to the various types of networks (both fixed and mobile). After considering the two different approaches made in telephone and data networks, particularly IP (Internet Protocol) networks, we examine the newly introduced integrated system that allows full interworking between telephone numbers and Internet addresses. It should be appreciated that this is a surprisingly fast moving area of national regulation and there may be changes made to the establish principles of numbering and addressing, particularly as new implementation of voice services, such as voice-over IP (VoIP) are implemented.
-
11 Putting it all together
- + Show details - Hide details
-
p.
329
–360
(32)
In the first ten chapters of this book we considered various aspects of telecommunication networks: their components, how they are constructed, and the way that voice and data is carried. Now, in this final chapter we take a holistic view of how all the pieces are put together, how the end-to-end service provided to the users is managed, and how the networks are progressively enhanced and developed to take advantage of new technology. Specifically, the so-called next-generation network (NGN) concept is examined. It is hoped that by the end of this chapter readers will have gained an insight into the intriguing question raised in the Foreword to the book, that is, whether it is right to assume that all communications will eventually move onto the Internet.
-
Appendix 1 - Standards organisations
- + Show details - Hide details
-
p.
361
–362
(2)
-
Appendix 2 - List of ITU-T recommendation E.164 assigned country codes
- + Show details - Hide details
-
p.
363
–367
(5)
-
Back Matter
- + Show details - Hide details
-
p.
(1)