Residual Admission Capacity in Optical Burst Switching Networks and its Application in Routing Loss-Guaranteed Flows

Optical burst switching (OBS) is a promising technology to transmit bursty data traffic over optical networks. For QoS routing, an accurate estimation of the amount of residual capacity on a link is necessary. In IP or ATM networks, the residual bandwidth of a link can be computed as the total bandwidth subtracted by the effective bandwidth of each flow. However, this method is based on the assumption that each node has a large buffer. This method is not applicable to OBS networks, where there is no buffer at the core nodes. We propose a new metric, called residual admission capacity (RAC), to determine the amount of residual capacity on the links in OBS networks. To show the effectiveness of the new metric, we propose a routing algorithm called RAC-WSP, which is a widest shortest path (WSP) algorithm with RAC as the measurement of the residual capacity on a link. Experimental results show that RAC-WSP can admit more loss-guaranteed flows than other routing schemes, including the shortest path algorithm and other WSP algorithms where the residual capacity is evaluated by other metrics