Computing the loss differentiation parameters of the proportional differentiation service model

The proportional differentiation service model has emerged as a refined version of the DiffServ qualify of service (QoS) architecture. It relies on a series of parameters to enforce proportionally differentiated QoS criteria, such as queueing delay and packet loss. From the perspective of proportional loss differentiation, a large amount of work has been done on carrying out loss differentiation based on given parameters. Under certain network conditions, however, the loss differentiation cannot be met based on these hand picked parameters. While existing work focuses on enhancing dropping mechanisms themselves to honour the loss differentiation, the paper looks into calculating feasible differentiation parameters. By forming an optimisation problem based on multiple class blocking thresholds, the paper introduces a simple quantitative guideline to compute loss differentiation parameters. Derived closely related to network statuses and packet dropping mechanisms, these parameters ease the difficulty that dropping mechanisms may encounter when enforcing packet loss differentiation. Its finite computation time, moreover, makes practical implementation possible. Analytical and numerical results are given to substantiate the new approach and its merits.