Study on impact of scheduling algorithm for real-time traffic on performance of TCP traffic and its improvements

摘要

For transmission of real-time traffic such as voice and video on the Internet, it is important to satisfy required QoS (Quality of Service) in terms of packet transmission delay and/or delay jitter. For this purpose, some scheduling algorithms have been proposed. DFQ (Decoupled Fair Queueing), which is one of these algorithms, can satisfy QoS of real-time traffic by assigning it to per-flow queue and by allocating more bandwidth than its transmission/required rate. Therefore, this may cause performance degradation of non real-time traffic such as TCP without per-flow control. Thus we first show the impact of DFQ on transmission of TCP traffic aggregated onto single queue. Next, by applying RED (Random Early Detection) to TCP queue, we investigate the effectiveness and parameter setting of RED depending upon the amount of real-time traffic and/or the number of TCP flows.