The Research Of TCP Protocol Based On Broadband Satellite Network Transmission Characteristic

In recent years, since the development of communications and computertechnology is so rapid that the broadband satellite communication technology alsoobtains a chance to develop and improve very fast. Multimedia, Internet access andother variety data services will replace the traditional TV, telephone and other maintransport business. The characteristics of the broadband satellite communication alsohave an effect on the development direction of the satellite Internet. Because of thecharacteristics of the satellite communication, including widely coverage, low costof construction, good mobility, disaster relief, various business types and so on,which other communication systems do not have. It makes mobile satellite systembe the part of the world’s telecommunications structure, which is more and moreimportant. We continuously invest and build new projects and hope to make it moreand more mature to serve us.At present, the development of satellite network communication and Internet is sofast that the quantity of business which is supported by the Internet is increasingvery sharply. It will affect the demand of the transmission bandwidth resourcesquantity. So it can’t already meet the requirements of the quantity of network limitedto just above the ground, already could not meet the requirements of thetransmission bandwidth resources, if only get the Internet on the ground. So a newgeneration of satellite communication network has gradually become the researchhot spot which is combined with Internet. TCP protocol plays an important role indata communication protocols, that makes it to be used in satellite communicationnetwork. However, because of the peculiar characteristics of satellite network, it hasserious influence on transmission performance when TCP protocol is used. So whenTCP protocol is used on a satellite channel, it will not perform as good as it is usedin the ground Internet. As a result, it has been a hot topic in the field of networkcommunication to improve the transmission performance when TCP protocol isused in satellite network in recent years.Firstly, the features, model analysis, influence and disadvantages of TCP Vegas protocol is introduced in detail, then Vegas dynamic improved design, an improvedalgorithm called Vegas-EA is provided to improve the ability of Vegas oftransmission performance in satellite channel. The thought of the algorithm is to fixthe congestion avoidance part by comparing the present transmission speed with thebefore and changing the value of alpha and beta according to the result. It will makethe threshold value close to the account of network data package, then Vegas willadapt to the change of network traffic. As a result, the throughput and performanceof network will be improved.In order to prove the correctness and effectiveness of the improved, we use thenetwork environment simulator NS2to simulate the algorithm. The paper simulatesthe congestion window and throughput curve of Vegas and Vegas-EA with thechange of time in the satellite network environment containing Reno protocol. Thenit compares the performance of the improved algorithm and Vegas promotion. Theresult shows that Vegas-EA performs better than Vegas when the network alsocontains Reno, and the throughput of Vegas-EA increases faster than Vegas. Thevalue calculated from the data got in the simulation environment of this paper willbe reached22.5%. In a word, Vegas-EA the improved algorithm can improve thetransmission performance of TCP in the satellite network.