A New Adaptive Transport Protocol for Web

Today, Web interactions are frequently short, with an increasing number of responses carrying only control information and no data. On the other hand, with significant improvements in network hardware, many problems such as collision and packet loss are not as important as before. The most popular application layer protocol for the Web is the Hyper Text Transfer Protocol (HTTP), with client initiated Transmission Control Protocol (TCP) as the transport protocol. In spite of TCP´s good services to HTTP, it is poorly suited for small packets. The overhead of setting up and tearing down TCP state amortizes poorly for these small connections. In this paper, we have designed and analyzed an adaptive-hybrid scheme to address these issues. The proposed scheme uses either TCP, or the User Datagram Protocol (UDP) as the underlying transport protocol. UDP is used for short transfers (including HTTP redirection) and for lossless states, while TCP is used just in lossy and full of collision states. In this manner, we avoid the extra TCP overhead for short connections, but still benefit from the reliable delivery and congestion control that TCP provides. We ran simulations to quantify the effects of various network parameters (i.e., packet loss rates) on the performance of the hybrid scheme. We observed performance gains exceeding 25% with HTTP/1.1-style persistent connections, and over 55% without persistent connections