Research On TCP Congestion Control For Aerospace Network

Aerospace network is a integrated space communications network, includingaerial platforms, LEO and MEO satellites, geostationary satellites, which has a widerange of communications coverage, rich spectrum resource and not the terrainconditions, etc., suitable for some scenes such as worldwide communications andemergency communications. The demand for reliable transport service with aerospacenetwork is increasing. To design a network for aerospace reliable and efficienttransmission protocol while ensuring the fairness of the agreement each connectionhas become a hot research.TCP is the most widely used ground network reliabletransmission control protocol and TCP transport with high efficiency in terrestrialnetwork. However,compared with the traditional terrestrial networks, aerospacenetwork has long round trip delay, high link error rate, limited processing resourceswith the satellite. All these features make the aerospace network faces tra nsmissioninefficiencies and bandwidth allocation inequities for reliable transport network.Therefore, according to the characteristics of aerospace network, for the existingTCP congestion control algorithm is optimized so that it can adapt to improve a ir andspace network, improving transmission efficiency and to ensure the transmissionfairness of the transport layer.In this paper, with the lack of existing research of improving the efficiency ofTCP transmission, combined with the characteristics of aerospace network, wedesigned slow start algorithm based on the forecast revision and packet lossdiscrimination algorithm. The design idea of slow start algorithm based on thepredicted and adjusted is to start slow start phase with a larger growth rate of thecongestion window and a more reasonable threshold. With the growth of thecongestion window, based on the current available bandwidth and slow start phase inwhich the congestion window is adjusted accordingly, so that it can quickly andsmoothly into the congestion avoidance phase. In addition, the high error aerospacenetwork environment transmission inefficiencies. In addition, for transmissioninefficiencies with higher bit error rate for aerospace network environment. In thispaper, combined ECN and RED, based on the type and number of received ACKmake the distinguish packet loss with congestion from packet loss with bit error, thealgorithm is simple and can be well on the distinction between congestion and error,so that the send window reach quickly and stabilize at higher transmission rate,thereby improving transmission efficiency.Meanwhile, there are businesses with long delay and short delay in the aerospacenetwork shared bottleneck link situation. In this case, short delay business competefor bandwidth capacity is strong, long delay business compete for bandwidth capacity is poor, resulting in unfair in bandwidth allocation. In this paper, a congestion controlalgorithms based on double parameter adjust to ensure fairness with high efficiencyhave been proposed. Algorithm make the initial adjustment to bandwidth capacity oncompetition with the respective delay per link, establish the TCP transport model withmathematical method, Combine equitable formulas and optimal efficiency equationsobtain optimum theoretical optimum transmission parameters, which make furtheradjustments for bandwidth for per link. Thus, ensure the fairness of sharing bandwidthfor each link taking into account the transmission efficiency as well.Finally, NS2network simulation environment was constructed to,verify theprediction based on the slow start and loss adjustment congestion control algorithmcan distinguish between a good application in aerospace network, enabling thetransport layer to obtain higher transmission efficiency;verify that the two-parameteradjustment to ensure fair congestion control algorithm can guarantee fairness for eachshared connection while taking into account the bandwidth utilization in aerospacenetwork.