Deadline based channel scheduling

The use of deadline based channel scheduling in support of real time delivery of application data units (ADU´s) is investigated. Of interest is priority scheduling where a packet with a smaller ratio of delivery deadline over number of hops to destination is given a higher priority. It has been shown that a variant of this scheduling algorithm, based on head-of-the-line priority, is efficient 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 networks, with multiple autonomous systems. For this case, accurate information on number of hops to destination may not be available. 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