A High-Performance Online Cooperative File-Transfer Mechanism over Lambda Grids

Abstract – A lambda grid is characterized by nodes connected by high speed optical infrastructure in which lightpaths can be set dynamically between end nodes. In this paper, we investigate the problem of downloading very large files requested by end nodes from data repositories connected to the lambda grid. To optimize the download time we propose to exploit a cooperative data-transfer mechanism in which a file downloaded by one end node is used to serve subsequent requests for the same file. The proposed algorithm requires multipath routing, intelligent replication, and fragmentation of the downloaded files. We design an online file-transfer scheme FFToG (Fast File Transfers over Grids) that offers a significant performance enhancement over the traditional file transfer mechanisms. Through detailed simulation analysis, performance of FFToG is compared with an end-to-end file transfer method OPNB (One Path No Buffering) and we find that the download time is significantly lower for FFToG. We also compared FFToG with a multipath file transmission model, with no file replication- MPNB (Multi-Path No Buffering) and achieved better results. Finally, we performed a detailed sensitivity analysis with respect to the various parameters of FFToG. Index Terms—lambda grid, online scheduling, high-performance, lightpath, replication, fragmentation, routing, cooperative download I