Switch/Router Architectures

12Quality of Service Configuration Tools in Switch/Routers

12.1 Introduction

The Catalyst 6500 has a rich set of QoS features and configuration tools that allow it to be used as a good reference platform for understanding the types of configuration tools available for switch/routers. The typical switch/router from other vendors in the market will support these features and configuration tools. Furthermore, devices from different vendors do interoperate very well nowadays partly due to similarities in the capabilities and feature sets built into the devices.

The QoS functions on the Cisco Catalyst 6500 running the Cisco IOS^® Software can be configured via the modular QoS command-line interface (MQC) software feature. This toolkit comes as part of the Cisco IOS Software running on Cisco routers and switch/routers. The QoS configuration process can be described by the following steps (Figure 12.1):

1. Step 1: Construct a class map that defines the relevant ACLs that identify the particular traffic of interest that QoS is to be applied. The class map defines some traffic classification criteria, essentially it specifies a set of flow matching criteria for the arriving traffic.
   • Class maps can be used to classify traffic based on, for example, Layer 3 and Layer 4 protocol information (source and destination IP address, transport protocol type, source and destination transport protocol port), Layer 7 protocol information (e.g., FTP request commands, HTTP header, HTTP URL, HTTP cookie, ...