HTTP-MPLEX: An enhanced hypertext transfer protocol and its performance evaluation

Abstract

HTTP-MPLEX is a header compression and response encoding scheme for HTTP. It is designed to compress traditional HTTP requests to conserve bandwidth, multiplex multiple responses to a single sustained stream of data to speed response times and improve application layer use of Transmission Control Protocol (TCP) by reducing the number of parallel connections and sustaining response bursts. HTTP 1.1 uses FIFO request and response transmission that can be susceptible to head-of-line queue starvation. HTTP-MPLEX enables the simultaneous, compressed transmission of many requests with response multiplexing and prioritisation to relieve head-of-line blocking. To analyse the performance of HTTP-MPLEX relative to HTTP 1.1, a client and server was written in C ++ with plug-in implementations of both protocols. This paper analyses the effect of request compression and response multiplexing and aggregation in the simulated network environment ns (2.29-snapshot-20050921) and with experimentation results from symmetric (high bandwidth), asymmetric (ADSL) and dial-up connections to the Internet. This paper presents the result of simulation and experimentation by retrieval of four key web-pages. A comparative analysis of protocol behaviour, total page retrieval time, request/response performance and total object retrieval time is given. The results presented in this paper demonstrate the superior performance of HTTP-MPLEX over HTTP 1.1 in asymmetric bandwidth networks where a simulated improvement of greater than 10% and an experimental improvement of greater than 20% were achieved. In symmetric bandwidth networks HTTP-MPLEX does not significantly reduce page retrieval time. As bandwidth asymmetric technologies such as ADSL are commonly used for Internet connections at the user end, the superior performance of the proposed protocol in asymmetric networks is a significant contribution.