Asynchronous Transfer Mode - IEEE Xplore

ATM - Foundation for Broadband Networks Uyless D. Black, Prentice Hall, ISBN 013-297178-X, 1995, 426 pages REVIEWER:SIGMUND HANDELMAN Networking professionals have to keep up with technological changes that are constantly occurring. Today’s needs in networking include requirements for increased bandwidth, guaranteed quality of service, support for multimedia streams, and the need to continue to support traditional telephony. T h e world community has worked on a set of standards in the ITU, ATM Forum, ANSI, and IETF to create a networking structure: ATM. ATM is not a physical network, it is actually an implementation of several levels of the OS1 stack, optimized to perform the services mentioned previously. At this point in time, ATM implementation and deployment has started. Uyless Black has written a book which describes the technologies that make up ATM for the networking professional. In this book, Black not only describes the technologies but writes several tutorials, for example, on analog and digital systems, Internet and OS1 networks, A T M basics, and A T M switching. Black’s treatment of this work makes reference to his earlier work, Emerging Communications Technologies. H e builds on this base and explains how T l / E l , X.25, ISDN, SS7, and SONET have influenced the development of ATM. In this development Black points o u t t h e standards t h a t have guided ATM, and goes into several examples from ITU’s B-ISDN, and t h e A T M Forum. H e does not spare details and in the analysis of the adaptation layer (AAL 1-5) and switching operations, and the other chapters he gives the status of current work and outlines future research. The extensive amount of material presented here has some interesting points to consider. A short list includes: (1) Parts of ATM are not standard, such as switching. (2) The rationale for t h e 48-octet cell is based on the tolerable delay on a phone line if one cell is lost. (3) The details of ATM setup a r e based o n call management: setup, release, restart, status inquiry, add party, and more. One overriding concern of ATM is found several times; that is, a highspeed network has to be perfect for the

user, such that it does not carry extra user traffic for management. Thus, ATM management is found in several areas such as call admittance, bandwidth and congestion control, and traffic shaping. The ending chapters of this book go into an important part of ATM that is often overlooked: ATM implementation on various networks. There is a chapter explaining the default network, SONET. The book ends with a description of the ATM market, and includes companies’ and countries’ efforts. I t ends with a statement of t h e flux of ATM: ”Since ATM is changing so rapidly, you shall probably see a second edition of this book in the near future.” This book is valuable because it serves as a key to other reference works on ATM, such as the ATM Forum UserNetwork Interface Specifi’cation, and the numerous articles that are published in journals on ATM. In summary, Black‘s book performs an important function for network planners and workers, who need to understand the growing area of ATM. In particular, the treatment of ATM in this book shows that one can view it from the perspective of the ITU as B-ISDN, o r as a d a t a network as does t h e I E T F ; above all, with t h e deployment of the various AALs, ATM is the network on which multimedia can be built in the future.

Asynchronous Transfer Mode: Solution for Broadband ISDN Martin De Prycker, Prentice Hall, 380 pages, 1995, 3rd edition, ISBN 0- 13342 1 7 1-6 REVIEWER:CHUNG-SHENG Lr Not to be overshadowed by the great success of its first two editions, the third edition of Asynchronous Transfer Mode: Solution for Broadband ISDN is a n excellent update of the fast-evolving ATM technology. For many of us who have fond memories of t h e first two editions, this one definitely will not be disappointing. I t has included many new discussions on available bit rate (ABR) and video on demand (VOD). This book is definitely “the choice” for those who a r e interested in gaining more comprehensive knowledge about ATM. This book i s divided into nine chapters. The first chapter defines the envir o n m e n t in which A T M o p e r a t e s . (Continued on page 18)

IEEE Communications Magazine June 1996

BOOK REVIEWS (Continued from page 16) Chapter 2 briefly discusses the history of various data transfer mechanisms circuit switching, multirate circuit switching, fast circuit switching, packet switching, and fast packet switching. This chapter also describes the evolution of the ATM standard, in particular the field length. Chapters 3 t o 5 of this edition stay relatively unchanged from the previous edition. The details of the ATM standard from the physical layer to the AAL layer are described in Chapter 3. Various ATM switching mechanisms such as input queuing, output queuing, and central queuing are discussed and analyzed in Chapter 4. These two chapters give a very good introduction t o t h e basic principles of ATM standards and ATM switching. Chapter 5 describes the impact of A T M o n terminals and services. O n one hand, ATM offers flexibility within acceptable complexity; on t h e other hand, ATM introduces cell losses and cell delay jitters that have to be handled by the terminals and services. Therefore, several cell loss protection and

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synchronization mechanisms are introduced in this chapter. Due to the standardization of both 25 and 51 Mbls user-network interface (UNI) within the ATM Forum, ATM LANs in which ATM switches are used to interconnect workstations directly or serve as backbones t o interconnect legacy LANs have received growing popularity. These issues are covered in Chapt e r 6. Several types of metropolitan area network (MAN), such as FDDI. FDDI-11, DQDB, and Orwell. are also introduced in this chapter. These networks seem to be losing favor recently in anticipation of the impending introduction of ATM LANs. Therefore, most of these discussions can be shortened or eliminated in the next edition. Chapter 7 of this edition has been significantly revised to describe traffic and congestion control in A T M networks. The most significant new development in the ATM Forum for the past two years has been t h e adoption of a rate-based (as opposed to credit-based) flow control mechanism and the introduction of ABR traffic. This flow control mechanism is captured by t h e specification of the generic cell rate

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algorithm (GCRA) - virtual scheduling and continuous-state leaky bucket algorithms. A connection is catalogued as compliant as long as the proportion of nonconforming cells does not exceed a certain positive threshold, whose value is specified by the network operators. Both constant bit rate (CBR) and variable bit rate (VBR) traffic require the network t o guarantee some f o r m of quality of service (QoS) (such as t h e cell loss rate, cell transfer delay, and cell delay variation), provided the peak and sustainable data rates of the stream are compliant to the contract negotiate d a t connection setup time. In contrast, ABR traffic allows the ATM layer transfer characteristics t o be changed subsequent t o connection establishment. It is expected that a user adapts its traffic to the changing A T M layer transfer characteristics. T h e QoS for this type of connection will only include cell loss rate, while cell transfer delay and cell loss r a t e a r e not controlled. T h e A B R traffic control mechanism includes the injection of resource management (RM) cells by the source end system. These RM cells are subsequent(Continued on page 20)

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BOOK REVIEWS (Continued from page 18) ly returned by the destination end system. As a result, this flow control mechanism can enable t h e source end system to dynamically adjust its cell sending rate based on the feedback control information received from the network. The introduction strategies of ATM a r e described in Chapter 8. These strategies can be divided into three categories:

(1) A T M LANs - where ATMbased intelligent hubs will be used to interconnect legacy LANs (Ethernet or token ring) and private ATM eventually ( 2 ) Access networks - where enabling technologies such as fiber in the loop are necessary in order to provide sufficient bandwidth (3) Switching networks - w h e r e existing services and service interface are converted to ATM at the customer in the service multiplexer

Chapter 9, which is brand new in this edition, describes how VOD can be supported by ATM through either existing infrastructures (copper or coaxial cable) or new access cables (fiber or hybrid fiberlcoaxial). Although it is a short chapter, it gives a very inspirational description of several possible VOD over ATM architectures. In summary, this is an excellent book for anyone who is interested in acquiring up-to-date or even up-to-the-minute descriptions of the ATM standards. It is written in such a way that both beginning and sophisticated readers will greatly benefit from reading this book. This book is thus highly recommended.

ISDN and ISDN with and ATM

and Relay

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After the technology has matured for more than a decade, ISDN and frame relay services seem to have finally taken off. This phenomenon can be partially attributed to the recent exploding growth of I n t e r n e t access. As a result, people can no longer tolerate the crawling speed of a regular modem at 28.8 kbis, and ISDN seems to offer immediate, albeit temporary, relief, even though fiber to the home is still the ultimate solution. Similarly, frame relay is also providing temporary relief for interconnections between bridges and high-speed data network services. Furthermore, t h e r e a r e numerous changes in the ATM standards, mostly advanced by the ATM Forum, since the last edition of this book was published in 1992. Therefore, this book is definitely a timely update of an already popular textbook in the field of ISDN and broadband ISDN. This edition of the book is divided into five parts. The current structure of this book puts the emphasis on frame relay and ATM, which have both gained independence since the previous edition. Part I, which contains two chapters, introduces the basic concepts of digital transmission and communication networks such as digital carrier systems, circuit switching, and packet switching. T h e ISDN network is covered in detail in Part 11, which remains essentially unchanged from the previous edi(Continued on page 22)

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IEEE Communications Magazine June 1996