Research On The Improvement Of The SRED Congestion Control Algorithm

With the rapid development of the Internet, the network congestion which is caused by competing of network resource becomes more and more critical. To improve network performance, applying effective queue management algorithm on routers become more significant.Currently active queue management (AQM) technologies are being used with TCP congestion control to avoid network congestion. Although the several present congestion control algorithms are very effective on the network congestion control and avoidance, there are some bugs on these algorithms more or less. So we need to improve them constantly.Network resources are mainly the following: link capacity, switching nodes cache and processors. High-speed backbone network set up to increase the link capacity, to some extent alleviated the low-bandwidth bottleneck caused. Hardware manufacturers continue to introduce high-speed processing capability of routers and other network equipment to ensure the CPU cache in the implementation of the queue and update the routing tables and other functions, its processing speed can match high-speed link. Increase the buffer space to some extent alleviate the sudden flow of buffer capacity due to limited groups are forced to drop the issue, but excessive if the router cache capacity, the congestion will only become worse, not better.This text firstly analyzed the reason why the congestion is caused and the methods to control the congestion, including resource control of TCP and the algorithm for routing queue. Then, stating the design principles of some classic AQM algorithms, aiming at the weakness of the SRED algorithm and providing two improved algorithms.In what follows, this text introduced the Network Simulator (NS) Simulation platform, and analyzed some functional modules on the NS and their working principles in detail. At last, testing the performance of RED, SRED, GSRED, HGSRED in the dynamic high flow environment on the NS platform, and analyzing the results of experiments.