Smoothly estimate the RTT of Fast TCP by ARMA function model

An inherent problem of Fast TCP with delay-based congestion control algorithms is pointed out in this paper. The problem is, if the actual round-trip-time is inaccurately estimated by base RTT, for certain flows relative to other concurrent flows, this will subsequently result in an unfair share of the resources. A smooth function of RTT with exponential weighted by ARMA models was designed in this paper. This congestion control algorithm called CNFAST TCP is elaborated in detail. It improves the smooth estimation of round-trip delay and eliminates the fluctuations of the queue throughput and queuing delay. Packet level ns2 simulations are used to verify the theoretical claims.