The Research Of Internet Congestion Control Algorithm

The explosion development of Internet and the surge users make the network size accretion rapidly, and the backbone congestion increasingly. Network congestion is always the main factor to affect the network performance, so congestion control algorithm have been the hotspots in the network research field.The subject of the essay analyzes the TCP source algorithm and IP link algorithm from the two parts of network congestion control. It is focused on the active queue management algorithm (AQM) of the router. We analyze the classic RED algorithm, and have a performance comparation in detail with the newly proposed algorithm BLUE. Based on BLUE and with Bloom filter, it proposed an improved AQM algorithm for enhancing the fairness between flow and flow which effectively protects the response flow to have a reliable transmission.The main research of the essay includes the following several parts:First, the background of the research and the cause of network congestion have been introduced here. The essay shows the current progress of the research about network congestion. The detail about evolution of congestion control algorithm at TCP source is discussed. And some typical TCP source algorithm is compared each other.Further, it has been done a deep research on the IP link algorithm. Some typical IP link algorithm is compared each other. A detailed description is how to add a new queue management algorithm into NS2. Then it makes a performance compared and analyzed between new added algorithm and original RED. Simulation results show that the new added algorithm BLUE is more superior than RED in the aspect of packet loss probability, link utilization, end to end delay time and jitter.At last, in view of more and more current applications don't use TCP congestion control mechanisms, and through researching the effectiveness of BLUE algorithm, it aimed at the fairness of bandwidth usage to put forward an improved algorithm named EFBLUE which is based on BLUE. It is used the NS2 network simulator for analysis and test the effectiveness. It shows the algorithm excelled to RED or BLUE in improving flow transmission fairness.On the basis of systematic summarization of up to date Internet congestion control, this thesis explores in depth the congestion control mechanisms deployed on routers and describes the author's viewpoints. The conclusions, improved algorithms and research of network simulator function extention have a special referenced value.