  Nowadays, the bulk of Internet traffic uses TCP protocol for reliable
transmission. But the standard TCP's performance is very poor in High Speed
Networks (HSN) and hence the core gigabytes links are usually underutilization.
This problem has roots in conservative nature of TCP, especially in its
Additive Increase Multiplicative Decrease (AIMD) phase. In other words, since
TCP can't figure out precisely the congestion status of the network, it follows
a conservative strategy to keep the network from overwhelming. We believe that
precisely congestion estimation in the network can solve this problem by
avoiding unnecessary conservation. To this end, this paper proposes an
algorithm which considers packet loss and delay information jointly and employs
a probabilistic approach to accurately estimation of congestion status in the
network. To examine the proposed scheme performance, extensive simulations have
been performed in the NS-2 environment. Simulation results reveal that the
proposed algorithm has better performance than existing algorithms in terms of
bottleneck utilization, stability, throughput and fairness.
