Browsing by Author "Liu, Nelson X."
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Item Dynamical Properties of TCP System with AQM Routers(2003) Chen, Huigang; Baras, John S.; Liu, Nelson X.; ISR; CSHCNIn this report we discuss the dynamics of heterogeneous TCP systems with propagation delays. Instead of studying the local linearized TCP dynamics, we study the global stability conditions and obtain the stability regions. Also we provide proof of periodic behavior of a single TCP connection when stability conditions are not met.Item Global Stability of TCP with AQM Router(2004) Chen, Huigang; Baras, John S.; Liu, Nelson X.; Baras, John S.; ISRIn this study we extend the global stability results of the previous report cite{tr}. We focus on the scenario of a single TCP flow with proportional AQM controller at the router. By using Lyapunov functional method, we are able to prove the global stability of such nonlinear system with feedback delay.Item Web access over a multiple access channel: evaluations and improvements(2004) Zhou, Xiaoming; Liu, Nelson X.; Baras, John S.; Baras, John S.; ISR; CSHCNWe evaluate web browsing performance over a multiple access satellite channel for three different MAC layer protocols. A web user behavior model is used to generate realistic source traffic. A new transport layer protocol called RWBP is proposed to solve the TCP problems inside satellite networks. RWBP uses per-flow queuing, round robin scheduling and receiver window backpressure for congestion control. We compare its performance with TCP over the three multiple access protocols. Our simulation results show that RWBP can reduce the multiple access channel load and at the same time improve the web page response time when driven by realistic web traffic. For the MAC layer protocols, combined free demand assignment multiple access (CFDAMA) always performs better than the other two protocols.