 A side effect of increasing the rate of increase as the time since the last packet loss increases, is that flows which happen not to lose a packet when other flows do, can then take an unfair portion of the bandwidth.Techniques to overcome this are currently in the research phase.The Linux implementation of H-TCP also has an option for avoiding "RTT unfairness", which occurs in TCP Reno, but is a particular problem for most high speed variants of TCP (although not FAST TCP).