b62c84cf_inistration_Guide__IP_Services__For_Instructions
[Task] 2. Define the classes into which services on your network must be divided. [Description] Examine the types of services and SLAs that are offered by your site, and determine the discrete traffic classes into which these services fall. [For Instructions] 
How to Define the Classes for Your QoS Policy
Planning the Quality-of-Service Policy - System Administration Guide: IP Services