Analysis and implementation of look-ahead window contention resolution with QoS support in optical burst-switched networks

Optical burst switching (OBS) has been proposed as a promising switching technology to support the next-generation optical Internet. Two critical issues in OBS networks are designing effective contention resolution algorithms and implementing such algorithms in the core switch node. The first part of this paper deals with the problem of contention in OBS networks. We introduce a new contention resolution algorithm called Lookahead window Contention Resolution (LCR) that can support service differentiation. Through complexity analysis, a number of important properties of LCR and its variations are examined and verified. We also investigate the performance of LCR in a single core switch node. We show through simulation that the performance of LCR is competitive to existing contention resolution mechanisms in terms of reducing burst loss. The second part of this paper presents a practical design approach for a generic control packet processor architecture. Based on the proposed architecture, we implement the look-ahead contention resolution algorithm using a high-density field-programmable gate arrays (FPGA). Through hardware test and verification, we evaluate the performance characteristics of the look-ahead contention resolution algorithm in terms of hardware speed, scalability, and cost.