Optimal Multiplexing on a Single Link: Delay and Buffer Requirements

This paper is motivated by the need to provide per session quality of service guar antees in fast packet switched networks We address the problem of characterizing and designing scheduling policies that are optimal in the sense of minimizing bu er and or delay requirements under the assumption of commonly accepted tra c constraints We investigate bu er requirements under three typical memory allocation mechanisms which represent trade o s between e ciency and complexity For tra c with delay constraints we provide policies that are optimal in the sense of satisfying the constraints if they are satis able by any policy We also investigate the trade o between delay and bu er optimality and design policies that are good optimal or close to for both Finally we extend our results to the case of soft delay constraints and address the issue of designing policies that satisfy such constraints in a fair manner Given our focus on packet switch ing we mainly concern ourselves with non preemptive policies but one class of non preemptive policies which we consider is based on tracking preemptive policies This class is introduced in this paper and may be of interest in other applications as well