Chapter 1: LAN Performance Issues

This introductory chapter focuses attention on a core set of local area network (LAN) performance issues. In doing so, it discusses why such issues are important for inter- and intra-network communications in the form of questions that we will want to answer when planning or expanding a network. Although we leave it to future chapters in this book to answer questions raised in this chapter, our discussion of performance issues serves a dual purpose. First, it makes us aware of the many factors that affect the performance of individual networking devices, as well as the networks to which they are connected. Second, it makes us aware of the fact that performance can involve the trade-off of many operating characteristics. This means that in some instances the modification of the operating characteristics of a networking device to enhance its performance may require adjustments to other features of that device and other networking devices and transmission facilities. Thus, we note that LAN performance issues in many instances involve a detailed relationship between different network components , as well as the transmission facilities used to provide a connection between separate networks.

1.1 Network Basics

Readers of this book are presumed to have a degree of familiarity with the basic operation and utilization of Ethernet, Token Ring, and ATM networks. Thus, this book was written neither as an introductory text on local area networks nor on local area networking concepts. However, because Ethernet, Token Ring, and ATM network performance requires a degree of knowledge concerning the format of the frames and their composition, Chapter 2 in this book reviews both areas.

The remainder of this chapter reviews the material in succeeding chapters with respect to the performance issues they raise. Thus, Sections 1.2 through 1.13 in this chapter can be considered previews to Chapters 2 through 13, respectively.