Downloading replicated, wide-area files - a framework and empirical evaluation

The challenge of efficiently retrieving files that are broken into segments and replicated across the wide-area is of prime importance to wide-area, peer-to-peer, and grid file systems. Two differing algorithms addressing this challenge have been proposed and evaluated. While both have been successful in differing performance scenarios, there has been no unifying work that can view both algorithms under a single framework. We define such a framework, where download algorithms are defined in terms of four dimensions: the number of simultaneous downloads, the degree of work replication, the failover strategy, and the server selection algorithm. We then explore the impact of varying parameters along each of these dimensions.