Data Transfer Time by HTTP 1.0/1.1 on Asymmetric Networks Composed of Satellite and Terrestrial Links

Hiroyasu OBATA
Kitsutaro AMANO

IEICE TRANSACTIONS on Communications   Vol.E85-B    No.12    pp.2895-2903
Publication Date: 2002/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Internet
web data transfer time,  asymmetric networks,  satellite links,  terrestrial links,  pipeline,  

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Asymmetric networks, which provide asymmetric bandwidth or delay for upstream and downstream transfer, have recently gained much attention since they support popular applications such as the World Wide Web (WWW). HTTP (Hypertext Transfer Protocol) is the basis of most WWW services so, evaluating the performance of HTTP on asymmetric networks is increasingly important, particularly real-world networks. However, the performance of HTTP on the asymmetric networks composed of satellite and terrestrial links has not sufficiently evaluated. This paper proposes new formulas to evaluate the performance of both HTTP1.0 and HTTP1.1 on asymmetric networks. Using these formulas, we calculate the time taken to transfer web data by HTTP1.0/1.1. The calculation results are compared to the results of an existing theoretical formula and experimental results gained from a system that combines a VSAT (Very Small Aperture Terminal) satellite communication system for satellite links (downstream) and the Internet for terrestrial links (upstream). The comparison shows that the proposed formulas yield more accurate results (compared to the measured values) than the existing formula. Furthermore, this paper proposes an evaluation formula for pipelined HTTP1.1, and shows that the values output by the proposed formula agree with those obtained by experiments (on the VSAT system) and simulations.