OPN05-6: Performance Enhancement in OBS Network with Flow Control and Edge Delay Method

This paper examines burst contention resolution problems in optical burst switching (OBS) networks. Since burst contentions take place (i) when the network is congested by increased input traffic, or (ii) two or more bursts demand the same wavelength exactly at the same time even though there is no congestion. From these insights, we present two novel methods that make higher throughputs and lower burst losses in the OBS network. First, from the viewpoint of flow control, we propose a burst flow control algorithm that controls the length of a burst based on the congestion price on its path. With the proposed flow control algorithm, the OBS network achieves improved efficiency and fairness compared to the case where a burst contention resolution scheme is solely used. Next, we develop an edge delay method which decreases burst losses especially when two or more bursts are overlapped in the core nodes. When some bursts need buffering to avoid contentions at core nodes, the proposed method makes them be delayed for the required buffering time at its ingress edge instead. Through extensive simulations, we demonstrate its performance.