The traditional TCP transport protocol has many drawbacks on Fast Long Distance Networks (FLDnet), and its transfer performance can not satisfy the requirement of increasing bulk data transfer applications. The UDP transport protocol has high transfer speed on FLDnet, but its reliability can not be guaranteed. This paper firstly analyzes the drawbacks of the traditional transport protocols on FLDnet, then, classifies and summarizes the main design principles of all kinds of enhanced transport protocols proposed in recently years and the research work on performance evaluation of transport protocols. Finally, some open issues and further research directions are proposed.