Competitive advance reservation with bounded path dispersion

Advance channel reservation is emerging as an important feature of ultra high-speed networks requiring the transfer of large files. In this paper, we present two new delay-competitive algorithms for advance reservation, called BatchAll and BatchLim. These algorithms are guaranteed to achieve optimal throughput performance, based on multi-commodity flow arguments. Unlike BatchAll, the BatchLim algorithm returns the completion time of a connection immediately as a request is placed, but at the expense of a slightly looser competitive ratio than that of BatchAll. We propose a simple approach that limits the number of parallel paths used by the algorithms while provably bounding the maximum reduction factor in the transmission throughput. We show that, although the number of different paths can be exponentially large, the actual number of paths needed to approximate the flow is quite small and proportional to the number of edges in the network. According to our simulations for a number of topologies, three to five parallel paths are sufficient to achieve close to optimal performance.