Modeling And Simulation Of Contention-Collision Cancellation Mode Type Ⅳ Double-Star Network

Contention-Collision Cancellation(C-CC) mode is an access control mode in star network. According to the working mechanism of star network, C-CC access control mode was classified six types of system model. The mathematical model of type IV system model is among the most complex at a very high computational cost so that its numerical simulation of the real network environment is hard to realized. In order to evaluate the performance of this type networks, we discuss the process of constructing the star network and implementing type IV system model using by OPNET modeler. Firstly, we compare the simulation result to the theoretical result to ensure the accuracy of the simulation model. Then in conditions close to the real network environment, we get three important performance parameters:packet delay, the queue size and throughout of central node. Finally, we analyze the impact on network performance of the value of service time in different load conditions, and provide the a basis for setting reasonable length of data packet and ACK packet, thereby optimizing the network performance.C-CC access control mode star network can be classified single-star network and multiple star network(double-star network-. triple-star network、……).We have almost finished the mathematical modeling and mathematical analysis of type Ⅰ-Ⅵ in the condition of single-star network, In the condition of double-star network, we have finished the mathematical modeling and mathematical analysis of type I, made a great breakthrough in the mathematical modeling and mathematical analysis of type Ⅲ and Ⅴ.As the complexity of the type Ⅳ C-CC control mode double-star network, its mathematical modeling was bogging down. In order to evaluate the performance of this type networks, we discuss the process of constructing the star network and implementing type IV system model double-star network using by OPNET modeler. In conditions close to the real network environment, we get three important performance parameters:packet delay, the queue size and throughout of central node. Then we compare the simulation result to the single-star network’s result to analyze the impact on network performance of the value of service time in different network conditions.