A Novel Scheduler For a Low Delay Service Within Best-Effort

We present a novel scheduling algorithm, Duplicate Scheduling with Deadlines (DSD). This algorithm implements the ABE service which allows interactive, adaptive applications, that mark their packets green, to receive a low bounded delay at the expense of maybe less throughput. ABE retains the best-effort context by protecting flows that value higher throughput more than low bounded delay, whose packets are marked blue. DSD optimises green traffic performance while satisfying the constraint that blue traffic must not be adversely affected. Using a virtual queue, deadlines are assigned to packets upon arrival, and green and blue packets are queued separately. At service time, the deadlines of the packets at the head of the blue and green queues are used to determine which one to serve next. It supports any mixture of TCP, TCP Friendly and non TCP Friendly traffic. We motivate, describe and provide an analysis of DSD, and show simulation results.