Dynamic bandwidth allocation

Inaccessible and isolated locations pose several problems to access scientific community onto a Grid infrastructure and satellite platforms could be the only practical way to provide connectivity. On the other hands, when an IP-based network is used to interconnect these sites, it is well known that standard Interned congestion control protocols (such as TCP and TFRC) underutilize the satellite and introduce non-negligible delays during the startup phase due to the large bandwidth-delay product of satellite links. In addition, the loss of performance is even more important when a Bandwidth on Demand (BoD) mechanism is adopted to satisfy bandwidth requirements. In this paper, we presented a novel mechanism based on quick-start, a recent IETF proposal, to enhance the performance of multimedia streaming applications at the beginning of connection or after long idle periods. Extensive simulations reveal that our modified QS algorithm (QSD) reduces significantly the initial end-to-end delay and stabilizes the queue length of source transmission buffers. Furthermore, we show that the startup delay is independent of the flow rate, which permits to support the bulk flows of grid computing applications.