A novel buffer scheduling algorithm for burst control packet in optical burst-switched WDM networks

Abstract

This thesis presents a novel buffer scheduling algorithm, which is called as the BSCOT algorithm (Buffer Scheduling Considering Offset Time), to reduce the data loss due to early arrival problem of the burst data in optical burst-switched WDM networks. When a burst enters into the optical switching matrix before its burst control packet (BCP) has been fully processed within the predetermined processing time due to excessive delay, this event is called $\emph{early arrival}$. Early arrival problem can result in burst data loss in OBS node. Data loss due to early arrival frequently happens to BCP close to the egress node. The conventional solution is taken at the data plane by using fixed-length inlet fiber delay lines (FDLs). However, we propose a new approach taken at the control plane. In the BSCOT algorithm, a BCP with short residual offset time is sent to the scheduler prior to a BCP with long residual offset time. The BSCOT algorithm can decrease the total loss probability due to early arrival problem under a bursty environment and reduce the ratio of burst loss with short offset time to total burst loss, compared to the first-come first-served (FCFS) algorithm.