Tcp Congestion Control, Active Queue Scheduling Algorithm

The network congestion remains to be unavoidable due to its own nature and the increasing application of new network technology. Therefore, the adoption of a feasible mechanism would serve to be the only effective way of preventing the network from collapse at the moment.The mechanism of congestion control can be widely classified based on different standardizations. The algorithm of active queue management (AQM) applied in the inter node of the network is an active close-loop link algorithm while the algorithm of random early disposed is the primary candidate algorithm introduced by IETF in management algorithm, which the latter seems to have defects in some aspects such as response speed and stability.This thesis focuses on the current congestion control algorithm and a few kinds of typical active queue management (AQM) algorithm. Furthermore, I will put forward a non-linear higher order and dropping probability function, as well as the rapid convergence RCRED algorithm based on the analysis of primitive RED algorithm and insufficient algorithm, including the explanation of the thought of the algorithm. Finally, the NS2 network simulator to the algorithm would be experimented.The simulation experiment indicated, when the low utilization of the buffer zone, the NLRED algorithm discards the packets by the low probability, to ensure high network throughput and higher link utilization, and when the utilization of the buffer zone is higher, the probability of packets discard of rapidly rising, the network can quickly ease the congestion, thereby effectively improve network performance.The improved RCRED algorithm, which routers average queue length is more gentle, less oscillation, will help improve the utilization of network links and networks running stability, greatly increasing the network's robustness. In a more serious network congestion, while packet discard probability, link utilization, such as a decrease in performance, and effective throughput and a higher division greatly reduce queuing time delay, which some real-time requirements more stringent application of the network Such as video conferencing is more appropriate.