Novel buffer management scheme to moderate negative effects between TCP and UDP
Yoshiaki Hori, Kenji Yamane, Takeshi Ikenaga, Yuji Oie · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2001
Multiplexing both responsive and unresponsive flows, namely TCP and UDP packets, in a single FIFO queue leads both flows into having an adverse effect on each other. In order to improve characteristics of queueing delay for UDP flows, we propose active buffer management schemes in diffserv network. We focus on MRED (Multiple RED) with HOL (head-of-line) priority control as buffer management scheme. We investigate the effectiveness of the scheme by means of simulations using ns version 2. Our simulation model has a dumbbell topology, which consists of ten sender nodes, ten receiver nodes and two routers. The five of ten senders generate CBR traffic, which will be sent by UDP, and the other five ones send bulk-data with TCP. The five CBR and the five TCP traffic share a bottleneck link between two routers. In case of FIFO, MRED with FIFO, and MRED with HOL schemes, by evaluating packet transmission delay and loss probability of CBR packet and TCP throughput, we examine how performance measures are affected by some parameters such as bandwidth of bottleneck link and thresholds of MRED. From our simulation results, MRED with FIFO is better than FIFO, but its performance is sensitive to thresholds of MRED with FIFO. On the other hand, MRED with HOL keeps stable rather than MRED in our simulation scenarios. We conclude that MRED with HOL scheme leads to low delay, low jitter, low drop probability for CBR flows as well as increases TCP throughput.