Deadline Based Channel Scheduling

Abstract–The use of deadline based channel scheduling in sup-port of real time delivery of application data units (ADU’s) is in-vestigated. Of interest is priority scheduling where a packet with a smaller ratio of delivery deadline over number of hops to destina-tion is given a higher priority. It has been shown that a variant of this scheduling algorithm, based on head-of-the-line priority, is ef-ficient and effective in supporting real time delivery of ADU’s. In this variant, packets with a ratio smaller than or equal to a given threshold are sent to the higher priority queue. We first present a technique to select this threshold dynamically. The effectiveness of our technique is evaluated by simulation. We then study the performance of deadline based channel scheduling for large net-works, with multiple autonomous systems. For this case, accurate information on number of hops to destination may not be avail-able. A technique to estimate this distance metric is presented. The effectiveness of our algorithm with this estimated distance metric is evaluated. In addition, we study the performance of a multi-service scenario where only a fraction of the routers deploy deadline based channel scheduling. I