Performance Analysis of a Dynamic Parallel Downloading Scheme from Mirror Sites Throughout the Internet
Allen Miu · 2000
In this paper, we describe paraloading, a novel approach to retrieving files from the Internet by establishing parallel connections with multiple mirror sites. This method contrasts with the conventional download method where the client retrieves data from a single source. The advantages of paraloading over single-connection downloading include improved performance gained from aggregating the bandwidths of the parallel connections, increased efficiency gained from load balancing download requests among the parallel connections. and increased resilience against congestion or failures on any one path, In order for paraloading to work, servers must be mirrored throughout the Internet. However, as mirror sites become more widespread and as end users upgrade to higher connection speeds, we believe that paraloading—if implemented properly— will offer significant performance gain over the traditional singlesource file accesses. Paraloading is a subject that has not been extensively studied by the research community. This paper examines the performance and the design of a paraloading scheme proposed in [21]. We have developed a paraloader application in Java that uses HTTP 1.1 for its range-request and persistent connection features. We have conducted a series of experiments using our paraloader at MIT and at UC Berkeley, and we have found that the performance gains of paraloading are not as good as those claimed in [21]. This suggests that paraloading may not fair well in different network environments. Nevertheless, we believe that there are a number of enhancements that can be made to the paraloader to improve its performance in different network environments. We will outline some of these enhancement techniques and discuss some open research issues on