Quality of Service (QoS) fairness is a technique which improves the fairness of multiple virtual path flows by classifying each path into one of 16 different classes. These 16 different classes can each be categorized into one of three basic types:
- Realtime classes – paths which require prompt service
- Interactive classes – paths with lower priority than realtime, but higher priority over bulk classes
- Bulk classes – paths with lowest priority
The bandwidth requirements for each type of class are specified by the user. The virtual path scheduler then utilizes the Hierarchical Fair Service Curve (HFSC) algorithm to ensure QoS fairness is maximized.