Business Data Communications and Networking, 13th Edition

CHAPTER 8BACKBONE NETWORKS

This chapter examines backbone networks (BNs) that are used in the distribution layer (within-building backbones) and the core layer (campus backbones). We discuss the three primary backbone architectures and the recommended best practice design guidelines on when to use them. The chapter ends with a discussion of how to improve BN performance and of the future of BNs.

OBJECTIVES

• Understand the Internetworking devices used in BNs
• Understand the switched backbone architecture
• Understand the routed backbone architecture
• Understand virtual LAN architecture
• Understand the best practice recommendations for backbone design
• Be aware of ways to improve BN performance

OUTLINE

• 8.1 Introduction
• 8.2 Switched Backbones
• 8.3 Routed Backbones
• 8.4 Virtual LANs
  • 8.4.1 Benefits of VLANs
  • 8.4.2 How VLANs Work
• 8.5 The Best Practice Backbone Design
• 8.6 Improving Backbone Performance
  • 8.6.1 Improving Device Performance
  • 8.6.2 Improving Circuit Capacity
  • 8.6.3 Reducing Network Demand
• 8.7 Implications for Cyber Security
• Summary

8.1 INTRODUCTION

Chapter 6 outlined the seven major components in a network (see Figure 6-1). Chapter 7, on LANs, described how to design the LANs that provide user access to the network as well as the LANs in the data center and e-commerce edge. This chapter focuses on the next two major network architecture components: the BNs that connect the access LANs with a building (called the distribution layer) and the backbone networks that connect ...