A new priority calculation method for sorted-priority fair queuing

The packet priority calculation method, also referred to as packet selection policy, is a necessary component for sorted priority based packet schedulers. A new packet priority calculation method, called smallest middle-point finish time first (SMFF), is proposed. An analysis model, called packet rate proportional server plus (PRPS+), based on the packet rate proportional server (PRPS) is developed to act as the start point for the discussion on the SMFF. It is shown that the packet schedulers based on sorted-priority can be modeled by the PRPS+ class, (such as weighted fair queuing, start-time fair queuing, self clocked fair queuing and worst-case fair weighted fair queuing); it is demonstrated that the scheduling fairness is improved if their priority calculation methods are replaced by SMFF.