Loss-free slotted OBS for ring and mesh hybrid networks

Abstract

This paper proposes a loss-free time-slot allocation (LTA) algorithm working on Optical Burst Switching (OBS) for ring and mesh hybrid networks. It preserves the number of time-slots for each source node, so that it avoids contention among time-slots fundamentally just by sacrificing acceptable delay at source nodes. In order to manipulate time-slots efficiently, it is suggested that an OBS superframe, which is a cyclic time duration. In addition, we propose a flow control scheme aiding the LTA algorithm, adjusting the number of time-slots allocated for source nodes so as to prevent loss of data bursts from buffer overflow of source nodes. Simulation results show that the LTA algorithm achieves zero blocking rate with acceptable queueing delay at moderate traffic loads. Moreover, the proposed flow control scheme supporting the LTA algorithm maintains a target upper-bound of queueing delay, and thus packet loss caused by buffer overflow is inhabited.