Optimization of resilient packet ring networks scheduling for MPEG-4 video streaming

摘要

Resilient packet ring (RPR) is an emerging standard for the construction of local and metropolitan area networks. The priority queue (PQ) algorithm, which is recommended as the scheduling scheme for RPR always gives priority to the transit buffer. Using this scheduling scheme in single transit buffer RPR, the high priority traffic, such as video packets waiting to access the ring at congested node in the transmit buffer will suffer large delays and unsteady delay jitters. In this paper, we propose a new scheduling scheme for RPR to improve the quality of service for video traffic transmission. The proposed scheduling scheme alternately selects packets from the single transit buffer and the high priority transmit buffer using deficit round-robin (DRR) algorithm. If there is no packet in the above two buffers, low priority transmit buffer is then served. We investigate the system performance for transmission of MPEG-4 encoded bitstream as high priority traffic in an RPR network in scenario that all traffic is forwarded to a common node. We report end-to-end delay and delay jitter for I, P and B frames of several encoded video streams. Simulation results show certain improvement on overall delay and delay jitter performance for all types of video frames, especially for I frames which are the most important frames for video reconstruction.