Optimization in Congestion at Transport Layer

Existing networks with transport protocols such as TCP and UDP have limitations when fitting into new technologies, like increased heterogeneity and mobility. In order to solve this problem, our attempt is to design a self-adaptive transport protocol, which can fit into the network condition dynamically according to the parameters given by upper layer and the network layer in (wired/wireless) NGN architecture. This paper analyzes the optimization in congestion control mechanisms of nowadays transmission protocols, and does comparison among them in different aspect. We first describe the congestion control mechanism of traditional TCP, and then give out an overview and list the congestion function of transport protocols (such as TCP, UDP, DCCP, SCTP). In the end, we do a simple comparison among all the protocols above, and point out the possible advantages and limitations of these protocols under different transport performances (RTT Fairness, TCP Fairness, Utilization Ratio, Packet Loss Rate, Smoothness of throughput, Convergence Time, etc.). Future work will focus on, to implement the next-generation gateway, optimized for broadband multi-media communications over satellites. It will draw on the full power of the DVB-RCS protocol, and will merge technical advances on transport layer optimization, Quality of Service (QoS) provisioning and dynamic bandwidth allocation.