Hierarchical Packet Fair Queueing (H-PFQ)algorithms have the potential to simultaneously support guaranteed realtime service, rate-adaptive best-eort, and controlled linksharing service. In this paper, we design practical H-PFQ algorithms by using one-level Packet Fair Queueing (PFQ) servers as basic building blocks, and develop techniques to analyze delay and fairness properties of the resulted H-PFQ servers. We demonstrate that, in order to provide tight delay bounds in a H-PFQ server, it is essential for the onelevel PFQ servers to have small Worst-case Fair Indices (WFI). We propose a new one-level PFQ algorithm called WF2 Q+ that is the rst to have all the following three properties: (a) providing the tightest delay bound among all PFQ algorithms; (b) having the smallest WFI among all PFQ algorithms; and (c) having a relatively low implementation complexity of O(log N). We show that practical HPFQ algorithms can be implemented by using WF2 Q+ as the basic building block and prov...
Jon C. R. Bennett, Hui Zhang