Chapter 6. Quality of Service Design

This chapter discusses how to design quality of service into a network, and includes the following sections:

• Making the Business Case

• QoS Requirements for Voice, Data, Video, and Other Traffic

• QoS Models

• QoS Tools

• QoS Design Guidelines

This chapter introduces quality of service (QoS) models, tools, and design guidelines.

We first introduce what QoS is and why it is an important service in today's networks. The QoS-related requirements for various types of traffic are described next. Two models for deploying end-to-end QoS in a network are then examined: Integrated Services (IntServ) and Differentiated Services (DiffServ). QoS tools, including classification and marking, policing and shaping, congestion avoidance, congestion management, and link-specific tools are explained. The Cisco Automatic QoS (AutoQoS) feature on routers and switches is introduced; this tool provides a simple, automatic way to enable QoS configurations in conformance with Cisco's best-practice recommendations. We conclude with some QoS design considerations.

Note

Appendix B, "Network Fundamentals," includes material that we assume you understand before reading the rest of the book. Thus, we encourage you to review any of the material in Appendix B that you are not familiar with before reading the rest of this chapter.