Photon Netw Commun (2009) 17:218–225 DOI 10.1007/s11107-008-0156-8 A frequent-pattern approach for optical networks routing planning I-Shyan Hwang · Chaochang Chiu · Zen-Der Shyu Received: 4 February 2008 / Accepted: 29 July 2008 / Published online: 20 August 2008 © Springer Science+Business Media, LLC 2008 Abstract Optical burst switching (OBS) networks have been receiving much attention as a promising approach to build the next generation optical Internet. In the bufferless DWDM switching technology, burst loss that should be mini- mized is the key design parameter. One of the critical design issues in OBS network is how to plan the optimal routing path in order to minimize burst dropping due to network resource contention. This study proposes the burst frequent- pattern tree (BFP-Tree) approach to pre-determine a suitable routing path in the OBS network. The BFP-Tree approach essentially is a learning-based mechanism that is able to determine a suitable transmission path from the historical network transaction data. The experiment results show that the successful rates of routing paths obtained by the BFP- Tree approach are able to converge to those of the optimal results. Keywords Optical burst switching · Routing path · Network management I.-S. Hwang (B ) · Z.-D. Shyu Department of Computer Engineering and Science, Yuan ZeUniversity, 135Yuan-Tung Rd., Chung-Li 32026, Taiwan e-mail: ishwang@saturn.yzu.edu.tw C. Chiu Department of Information Management,Yuan Ze University, Chung-Li 32026, Taiwan e-mail: imchiu@saturn.yzu.edu.tw Z.-D. Shyu Department of General Studies, Army Academy, Chung-Li 32092, Taiwan e-mail: s949102@mail.yzu.edu.tw 1 Introduction In recent years, with advances in network technology, com- munication over networks has developed in many aspects. Optical fibers represent the preferred network transmission medium because they can support high-speed, high-capacity, and high reliability transmission with a low error rate. Wavelength division multiplex (WDM) [1] technology, which uses wavelength division, markedly increases the bandwidth of existing optical fiber networks. The advent of Dense WDM (DWDM) in optical networks has significantly increased the bandwidth available over a single optical fiber. Optical burst switching (OBS) is a promising bufferless DWDM switching technology that provides high wavelength utilization [2]. It is a technology positioned between optical circuit switching and optical packet switching. All-optical circuit switching tends to be inefficient for traffic that has not been groomed or statistically multiplexed, and optical packet switching requires the scalable implementation of optical buffering and optical header processing, which are very difficult to achieve at present. The OBS is a technical compromise that does not require optical buffering, and it is more efficient than circuit switching when the sustained traffic does not consume an entire wavelength. The structure of OBS is shown in Fig. 1 which includes core routers and edge routers. Core router configures its switch fabric according to the control information in order to switch the burst to the appropriate output port. Edge rou- ter offers the interface to the outside and to assemble and disassemble packets. The OBS is a hybrid switching tech- nology that employs electronics to control routing decisions, but keeps data in optical form as it passes through each core router. Each traffic flow in the OBS network consists of a header and a payload, and the control information is carried in the 123