针对在8/16位低速处理器上实现传输控制协议(Transfer Control Protocol TCP)过于复杂的问题,通过对TCP协议进行简化,减轻了微处理器的运算负担,降低了对系统存储空间的要求,使得TCP协议能够在8/16位低速处理器上实现.嵌入式网络中大量...针对在8/16位低速处理器上实现传输控制协议(Transfer Control Protocol TCP)过于复杂的问题,通过对TCP协议进行简化,减轻了微处理器的运算负担,降低了对系统存储空间的要求,使得TCP协议能够在8/16位低速处理器上实现.嵌入式网络中大量使用长度很小的数据帧,使得网络带宽利用率极低,为此在协议中应用了Na-gle算法,减少了协议所需带宽,提高了协议的吞吐率.采用NS-2(Network Simulator-2)进行的仿真结果表明:该方案是有效的,现已经在普通8位处理器上实现,并通过了在多种宽带网络上进行的测试,在网络电能表中得到了实际应用.展开更多
A novel closed-loop feedback TCP/AQM(Transfer Control Protocol/Active Queue Management) model is proposed in this paper using a discrete-time Markov chain,and a way to calculate the equilibrium distribution of this mo...A novel closed-loop feedback TCP/AQM(Transfer Control Protocol/Active Queue Management) model is proposed in this paper using a discrete-time Markov chain,and a way to calculate the equilibrium distribution of this model is given.In the model,system time is divided into time slots,the bottleneck router queue model and TCP window size model in each slot are analyzed.Finally,by combining adjacent slots,an integrated TCP/AQM analytical model is developed.By this model,the average values of packets dropping ratio and queue length in the router and TCP sending rate can be estimated,hence,this model could be a useful tool for the analysis of AQMs and support the development of new AQM schemes theoretically.The proposed TCP/AQM model is extended to a TCP-UDP(Control User Datagram Protocol)/AQM model,to analyze the TCP/AQM system performance when UDP flows exist.By implementing this model on Matlab,we compare its solutions to NS2 simulated solutions,then the validity of the model to analyze the closed-loop feedback TCP/RED(Random Early Detection) system is verified.展开更多
Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling...Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling bifurcation and chaos in such system. Methods Based on bifurcation diagram, the effect of parameter on system performance is discussed. By using the state feedback and parameter variation strategy, a simple real time control method is proposed to modify the existing RED scheme. Results With our control method, the parametric sensitivity of RED mechanism is attenuated. Moreover, a sufficient condition on the robust stability of the system is also derived to adjust the parameters in TCP-RED system. Conclusion The proposed method has the advantages of simple implementation and unnecessary knowledge of the exact system.展开更多
为了研究Ad Hoc网络DSR(Dynamic Source Routing)、DSDV(Destination Sequenced Distance Vector Routing)、AODV(Ad hoc Dem and Distance Vector Routing)3种路由协议的TCP(Transfer Control Protocol)传输性能,在原理上对其进行了分...为了研究Ad Hoc网络DSR(Dynamic Source Routing)、DSDV(Destination Sequenced Distance Vector Routing)、AODV(Ad hoc Dem and Distance Vector Routing)3种路由协议的TCP(Transfer Control Protocol)传输性能,在原理上对其进行了分析,并通过仿真实验予以验证。结果表明,DSDV适用于跳数较少的TCP连接,DSR和AODV适用于跳数较多的TCP连接,复杂场景中DSDV总体性能最优。展开更多
文摘针对在8/16位低速处理器上实现传输控制协议(Transfer Control Protocol TCP)过于复杂的问题,通过对TCP协议进行简化,减轻了微处理器的运算负担,降低了对系统存储空间的要求,使得TCP协议能够在8/16位低速处理器上实现.嵌入式网络中大量使用长度很小的数据帧,使得网络带宽利用率极低,为此在协议中应用了Na-gle算法,减少了协议所需带宽,提高了协议的吞吐率.采用NS-2(Network Simulator-2)进行的仿真结果表明:该方案是有效的,现已经在普通8位处理器上实现,并通过了在多种宽带网络上进行的测试,在网络电能表中得到了实际应用.
基金Supported by the National Natural Science Foundation of China (No.60572093)Specialized Research Fund for the Doctoral Program of Higher Education (20050004016) of China
文摘A novel closed-loop feedback TCP/AQM(Transfer Control Protocol/Active Queue Management) model is proposed in this paper using a discrete-time Markov chain,and a way to calculate the equilibrium distribution of this model is given.In the model,system time is divided into time slots,the bottleneck router queue model and TCP window size model in each slot are analyzed.Finally,by combining adjacent slots,an integrated TCP/AQM analytical model is developed.By this model,the average values of packets dropping ratio and queue length in the router and TCP sending rate can be estimated,hence,this model could be a useful tool for the analysis of AQMs and support the development of new AQM schemes theoretically.The proposed TCP/AQM model is extended to a TCP-UDP(Control User Datagram Protocol)/AQM model,to analyze the TCP/AQM system performance when UDP flows exist.By implementing this model on Matlab,we compare its solutions to NS2 simulated solutions,then the validity of the model to analyze the closed-loop feedback TCP/RED(Random Early Detection) system is verified.
文摘Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling bifurcation and chaos in such system. Methods Based on bifurcation diagram, the effect of parameter on system performance is discussed. By using the state feedback and parameter variation strategy, a simple real time control method is proposed to modify the existing RED scheme. Results With our control method, the parametric sensitivity of RED mechanism is attenuated. Moreover, a sufficient condition on the robust stability of the system is also derived to adjust the parameters in TCP-RED system. Conclusion The proposed method has the advantages of simple implementation and unnecessary knowledge of the exact system.
文摘为了研究Ad Hoc网络DSR(Dynamic Source Routing)、DSDV(Destination Sequenced Distance Vector Routing)、AODV(Ad hoc Dem and Distance Vector Routing)3种路由协议的TCP(Transfer Control Protocol)传输性能,在原理上对其进行了分析,并通过仿真实验予以验证。结果表明,DSDV适用于跳数较少的TCP连接,DSR和AODV适用于跳数较多的TCP连接,复杂场景中DSDV总体性能最优。
