Frame Relay: Principles and Applications
Authors: Philip Smith
Venue:  (1993)

From the Book:Throughout the history of information technology there have been many changes in the way in which information is stored, retrieved, presented and used. There seem to be continual improvements in the technology is utilized and the applications to which it is put. However, the rate of change in the networking industry has never seemed to be quite as rapid. The more changes over recent years have included local area networks and the widespread digitalization of the public network infrastructure; but these changes have taken several years before being generally accepted and used.The early years of the 1990s have seen some dramatic changes in both local and wide area networking. Local area networking is becoming an all pervasive technology and is being implemented in many different applications, public network infrastructure is becoming less error-prone and more reliable, and users are generally demanding greater bandwidth over which to pass their ever increasing information transfers.These dramatic changes have required the evolution of different methods for transferring information in the wide area-methods which offer increased throughputs and lower delays. It is at this point that frame relay enters the picture.This book is about the rise of frame relay and its suitability for different networking applications. It is most definitely not an attempt to praise the technology and offer it as a paragon of networking virtue. Indeed, in some cases the book takes a completely opposite stance. Within the following pages I have tried to present rational and balanced arguments both in favour of, and against, frame relay. I have compared frame relay with other wide area technologiescurrently available and have tried not to be swayed by the 'technology for technology's sake' approach.In addition to describing the potential applications for frame relay I have also described the basic protocol and its supporting management systems in detail. Frame relay is evolving rapidly, the basic protocol is now well defined and universally implemented, and the standards for enhancements to the protocol are gradually emerging. I have explained the impact of these enhancements and the protocols which are used in their implementation.How to use this bookThe book is divided into two parts. Part I describes the evolution of the protocol, its implementations, and the process of protocol standardization. Particular emphasis is placed upon the advantages and disadvantages of other wide area communications methods, and the reasons behind the adoption of frame relay as an alternative. Part I also explains how frame relay works, placing particular emphasis on those situations which are ideally suited for frame relay as well as those areas which are not suited to the protocol. Part I is divided into five chapters covering the following topics:Chapter 1This chapter explains the evolution of IT applications and the different wide area networking solutions. This results in a description of the philosophy behind frame relay.Chapter 2This chapter explains the principles behind frame relay from a non-technical perspective. The chapter offers an introduction to the frame relay concept of committed information rates and explains the situations where frame relay will work well, as well as those applications that are not suited to frame relay.Chapter 3This chapter examines the many different implementations of frame relay, and discusses the different approaches available to the network manager. Comparisons are given between frame relay as a public network service and a s a private network solution, between packet switching and circuit switching vendors' implementations, and between different implementations of LAN routing networks. Finally, this chapter provides some simple questions for the network manager to consider when contemplating a frame relay network.Chapter 4Frame relay is not suited to all data networking requirements, and Chapter 4 discusses several protocol issues which need to be appreciated. Issues such as network performance, data delivery and congestion management are covered.Chapter 5This chapter offers a perspective on the evolution of frame relay from the ISDN standards and explains the work of the Frame Relay Forum in the development of new frame relay standards.Part II covers the detailed technical aspects of frame relay and describes the frame relay protocol in detail. As well as covering an in-depth technical description of the protocol implementation, this part also covers the enhancements to frame relay being considered and describes the implementation of the congestion control procedures and the network management requirements. Part II is divided into five chapters covering the following topics:Chapter 6This chapter includes a thorough description of the frame relay protocol, its features and its options, and discusses the local management protocol in depth. A comparison is offered between the frame relay specifications established by CCITT and ANSI.Chapter 7This chapter details the enhancements available within the frame relay protocol and describes in detail the network-to-network interface, switched virtual circuits and multi-protocol encapsulation methods. For completeness this chapter also describes a proposal for carrying voice circuits across a frame relay network.Chapter 8One of the most important aspects of a frame relay network is the way in which it handles congestion. This chapter desribes several available congestion control mechanisms explaining the recommendations laid down by the standards committees and ways in which they can be supplemented by vendors' equipment.Chapter 9The management of any network is important, and this chapter discusses some of the issues which need to be considers when managing a frame relay network. This chapter also discusses several network design considerations which may serve to improve the overall network performance.Chapter 10Frame relay is not likely to be implemented in isolation, consequently this chapter describes some of the approaches being taken to mix different traffic types across frame relay backbone networks. A description of the operations of frame relay assembler/disassemblers (FRADs) and frame relay concentrators is offered.Part I of this book can be read in total isolation from Part II by those who wish to understand the applications of frame relay without recourse to the complete protocol descriptions. Part II can be read as a supplement to Part I, or used as reference information.AcknowledgmentsMany of the ideas in this book have evolved over several years of discussions with colleagues, customers and industry specialists. The author would like to thank all those who have afforded him this discussion time, as well as those whose enthusiasm for frame relay has helped to drive the implementations to their current maturity. In particular I would like to thank my company, Telematics International Ltd., for affording me the opportunity to write this book, and my wife for her patience and understanding through the seemingly endless evenings I have spent tapping away at the word processor.Philip SmithSouthampton, EnglandAugust 1993