Fair and delay adaptive scheduler for UC and NGN networks

Fair bandwidth allocation while conforming to stringent end-to-end delay constraints is a major requirement for the successful delivery of next generation QoS demanding traffic. Research has been carried out in the area of processor and scheduler sharing for decades to try to achieve the QoS requirements of network traffic. Fairness and traffic prioritization are two main objectives that many schedulers were originally designed to meet. Another important issue is how schedulers treat the delay sensitive traffic. Although the combination of fairness and prioritization is implemented in several schedulers but, to our knowledge, incorporating adaptive traffic delay treatment in fair and prioritized schedulers has not yet been successfully implemented. In this paper, we introduce a new scheduler that balances between the fairness of bandwidth allocation between flows while implementing prioritization and minimizes the number of end-to-end delay bound breaches. The scheduler combines the virtual clock concept used in well-known fair schedulers together with schedulability testing and evaluation implemented in delay sensitive schedulers. The scheduler is designed to achieve the fairness of bandwidth allocation, such as in fair schedulers, while minimizing the number of possible violation of end-to-end QoS delay of individual flows´ packets.