Improvement Of The Fred Algorithm And Its Implementation

The congestion control mechanism of the main internet protocol, TCP/IP, has especially important meaning to the controlling the congestion problem. congestion control is the key factor in guaranteeing the QOS of Internet, and also is the base of all the administration controlling mechanism and application(for example, the QOS controlling and diff-Service in multimedia communication),so it has been a hotspot problem in networking technology research. The key reason that results in the network congestion lies in the overload that users(end-system) put on the network, this overload results in the increase of datagram delay, the increase of packet drop probability, the performance in application system in upper layer getting worse ,etc. At present, almost all the research focuses on TCP congestion control field and IP congestion control field . This paper focuses on the congestion control in IP layer,.we classify flows by the character of packet arriving gap of each flow,which means we think two flows are different if the inter-packet arriving time of the two flows are different,and the flow could be hardworking flow,idle flow,outburst flow(variable flow speed),etc.Different kinds of flows will be interactional when fight for the same network resource.This paper put much emphasis on analysising and comparing present main queueing scheduling algorithm,RED,FRED,and put forward a new algorithm to solve the interactional problem,this new algorithm is 28FRED.28FRED not only has the merit that forbiden some of the burst flows occupy the Buffer space which RED and FRED have,but also solve the interactional problem in different kinds of flow.Besides,I realized the 28FRED module in Linux2.4.20,make it can be configured using TC(Traffic control).We also made some experiments to prove that 28FRED could make a difference between different kinds of flows,alleviate the interactional problem exists among the flows. In the end, some application foreground and some other place could be done in 28FRED are also introduced in this paper, and we made some experiment to compare RED,FRED,28FRED.