Switch/Router Architectures

11Quality of Service Mechanisms in the Switch/Routers

11.1 Introduction

The QoS mechanisms discussed in this chapter are based on the Cisco Catalyst 6500 Series of switch/routers. The Catalyst 6500 family of switch/routers supports a wide range of QoS features, which makes this discussion representative of the main QoS features found in the typical switch/router in the market. This case study allows the reader to appreciate better the kind of QoS features the typical switch/router would support.

The ever-growing demands for higher network performance and bandwidth, and the greater need for smarter network applications and services, are some of the factors driving the design of today's switches, routers, switch/routers, and other network devices. Users continue to demand a wide range of performance requirements and services that include high QoS, network and service availability, and security.

These demands also drive the need to build scalable and more reliable enterprise and service provider networks. QoS mechanisms, in general, represent a collection of capabilities that provide ways to identify, prioritize, and service different classes of traffic in a network. This identification and classification allows the network to prioritize and service traffic such that end-user requirements are satisfied as best as possible.

The Catalyst 6000/6500 Series support a number of QoS tools that are used to provide preferential treatment of traffic as they pass through the switch/router. ...