Design And Analysis Of Effective Routing And Channel Scheduling For Wavelength Division Multiplexing Optical Networks

Optical networking, employing wavelength division multiplexing (WDM), is seen as the technology of the future for the Internet. This dissertation investigates several important problems affecting optical circuit switching (OCS) and optical burst switching (OBS) networks. Novel algorithms and new approaches to improve the performance of these networks through effective routing and channel scheduling are presented. Extensive simulations and analytical modeling have both been used to evaluate the effectiveness of the proposed algorithms in achieving lower blocking probability, better fairness as well as faster switching. The simulation tests were performed over a variety of optical network topologies including the ring and mesh topologies, the U.S. Long-Haul topology, the Abilene high-speed optical network used in Internet 2, the Toronto Metropolitan topology and the European Optical topology. Optical routing protocols previously published in the literature have largely ignored the noise and timing jitter accumulation caused by cascading several wavelength conversions along the lightpath of the data burst. This dissertation has identified and evaluated a new constraint, called the wavelength conversion cascading constraint. According to this constraint, the deployment of wavelength converters in future optical networks will be constrained by a bound on the number of wavelength conversions that a signal can go through when it is switched all-optically from the source to the destination. Extensive simulation results have conclusively demonstrated that the presence of this constraint causes significant performance deterioration in existing routing and wavelength assignment (RWA) algorithms. Higher blocking probability and/or worse fairness have been observed for existing RWA algorithms when the cascading constraint is not ignored. To counteract the negative side effect of the cascading constraint, two constraint-aware routing algorithms are proposed for OCS networks: the desirable greedy algorithm and the weighted adaptive algorithm. The two algorithms perform source routing using link connectivity and the global state information of each wavelength. Extensive comparative simulation results have illustrated that by limiting the negative cascading impact to the minimum extent practicable, the proposed approaches can dramatically decrease the blocking probability for a variety of optical network topologies. The dissertation has developed a suite of three fairness-improving adaptive routing algorithms in OBS networks. The adaptive routing schemes consider the transient link congestion at the moment when bursts arrive and use this information to reduce the overall burst loss probability. The proposed schemes also resolve the intrinsic unfairness defect of existing popular signaling protocols. The extensive simulation results have shown that the proposed schemes generally outperform the popular shortest path routing algorithm and the improvement could be substantial. A two-dimensional Markov chain analytical model has also been developed and used to analyze the burst loss probabilities for symmetrical ring networks. The accuracy of the model has been validated by simulation. Effective proactive routing and preemptive channel scheduling have also been proposed to address the conversion cascading constraint in OBS environments. The proactive routing adapts the fairness-improving adaptive routing mentioned earlier to the environment of cascaded wavelength conversions. On the other hand, the preemptive channel scheduling approach uses a dynamic priority for each burst based on the constraint threshold and the current number of performed wavelength conversions. Empirical results have proved that when the cascading constraint is present, both approaches would not only decrease the burst loss rates greatly, but also improve the transmission fairness among bursts with different hop counts to a large extent

Wavelengths switching and allocation algorithms in multicast technology using m-arity tree networks topology

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London.In this thesis, the m-arity tree networks have been investigated to derive equations for their nodes, links and required wavelengths. The relationship among all parameters such as leaves nodes, destinations, paths and wavelengths has been found. Three situations have been explored, firstly when just one server and the leaves nodes are destinations, secondly when just one server and all other nodes are destinations, thirdly when all nodes are sources and destinations in the same time. The investigation has included binary, ternary, quaternary and finalized by general equations for all m-arity tree networks. Moreover, a multicast technology is analysed in this thesis to transmit data carried by specific wavelengths to several clients. Wavelengths multicast switching is well examined to propose split-convert-split-convert (S-C-S-C) multicast switch which consists of light splitters and wavelengths converters. It has reduced group delay by 13% and 29% compared with split-convert (S-C) and split-convert-split (S-C-S) multicast switches respectively. The proposed switch has also increased the received signal power by a significant value which reaches 28% and 26.92% compared with S-C-S and S-C respectively. In addition, wavelengths allocation algorithms in multicast technology are proposed in this thesis using tree networks topology. Distributed scheme is adopted by placing wavelength assignment controller in all parents’ nodes. Two distributed algorithms proposed shortest wavelength assignment (SWA) and highest number of destinations with shortest wavelength assignment (HND-SWA) algorithms to increase the received signal power, decrease group delay and reduce dispersion. The performance of the SWA algorithm was almost better or same as HND-SWA related to the power, dispersion and group delay but they are always better than other two algorithms. The required numbers of wavelengths and their utilised converters have been examined and calculated for the researched algorithms. The HND-SWA has recorded the superior performance compared with other algorithms. It has reduced number of utilised wavelengths up to about 19% and minimized number of the used wavelengths converters up to about 29%. Finally, the centralised scheme is discussed and researched and proposed a centralised highest number of destinations (CHND) algorithm with static and dynamic scenarios to reduce network capacity decreasing (Cd) after each wavelengths allocation. The CDHND has reduced (Cd) by about 16.7% compared with the other algorithms

Towards Scalable Cost-Effective Service and Survivability Provisioning in Ultra High Speed Networks

Optical transport networks based on wavelength division multiplexing (WDM) are considered to be the most appropriate choice for future Internet backbone. On the other hand, future DOE networks are expected to have the ability to dynamically provision on-demand survivable services to suit the needs of various high performance scientific applications and remote collaboration. Since a failure in aWDMnetwork such as a cable cut may result in a tremendous amount of data loss, efficient protection of data transport in WDM networks is therefore essential. As the backbone network is moving towards GMPLS/WDM optical networks, the unique requirement to support DOE’s science mission results in challenging issues that are not directly addressed by existing networking techniques and methodologies. The objectives of this project were to develop cost effective protection and restoration mechanisms based on dedicated path, shared path, preconfigured cycle (p-cycle), and so on, to deal with single failure, dual failure, and shared risk link group (SRLG) failure, under different traffic and resource requirement models; to devise efficient service provisioning algorithms that deal with application specific network resource requirements for both unicast and multicast; to study various aspects of traffic grooming in WDM ring and mesh networks to derive cost effective solutions while meeting application resource and QoS requirements; to design various diverse routing and multi-constrained routing algorithms, considering different traffic models and failure models, for protection and restoration, as well as for service provisioning; to propose and study new optical burst switched architectures and mechanisms for effectively supporting dynamic services; and to integrate research with graduate and undergraduate education. All objectives have been successfully met. This report summarizes the major accomplishments of this project. The impact of the project manifests in many aspects: First, the project addressed many essential problems that arisen in current and future WDM optical networks, and provided a host of innovative solutions though there was no invention or patent filing. This project resulted in more than 2 dozens publications in major journals and conferences (including papers in IEEE Transactions and journals, as well as a book chapter). Our publications have been cited by many peer researchers. In particular, one of our conference papers was nominated for the best paper award of IEEE/Create-Net Broadnets (International Conference on Broadband Communications, Networks, and Systems) 2006. Second, the results and solutions of this project were well received by DOE Labs where presentations were given by the PI. We hope to continue the collaboration with DOE Labs in the future. Third, the project was the first to propose and extensively study multicast traffic grooming, new traffic models such as sliding scheduled traffic model and scheduled traffic model. Our research has sparkled a flurry of recent studies and publications by the research community in these areas. Fourth, the project has benefited a diverse population of students by motivating, engaging, enhancing their learning and skills. The project has been conducted in a manner conducive to the training of students both at graduate and undergraduate levels. As a result, one Ph.D., Dr. Abdur Billah, was graduated. Another Ph.D. student, Tianjian Li, will graduate in January 2007. In addition, four MS students were graduated. One undergraduate student, Jeffrey Alan Shininger, completed his university honors project. Fifth, thanks to the support of this ECPI project, the PI has obtained additional funding from the National Science Foundation, the Air Force Research Lab, and other sources. A few other proposals are pending. Finally, this project has also significantly impacted the curricula and resulted in the enhancement of courses at the graduate and undergraduate levels, therefore strengthening the bond between research and education

IP multicast over WDM networks

Ph.DDOCTOR OF PHILOSOPH

Multicast protection and energy efficient traffic grooming in optical wavelength routing networks.

Zhang, Shuqiang.Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.Includes bibliographical references (p. 74-80).Abstracts in English and Chinese.Abstract --- p.i摘要 --- p.ivAcknowledgements --- p.vTable of Contents --- p.viChapter Chapter 1 --- Background --- p.1Chapter 1.1 --- Routing and Wavelength Assignment --- p.1Chapter 1.2 --- Survivability in Optical Networks --- p.3Chapter 1.3 --- Optical Multicasting --- p.4Chapter 1.3.1 --- Routing and Wavelength Assignment of Optical Multicast --- p.5Chapter 1.3.2 --- Current Research Topics about Optical Multicast --- p.8Chapter 1.4 --- Traffic Grooming --- p.10Chapter 1.4.1 --- Static Traffic Grooming --- p.11Chapter 1.4.2 --- Dynamic Traffic Grooming --- p.13Chapter 1.5 --- Contributions --- p.15Chapter 1.5.1 --- Multicast Protection with Scheduled Traffic Model --- p.15Chapter 1.5.2 --- Energy Efficient Time-Aware Traffic Grooming --- p.16Chapter 1.6 --- Organization of Thesis --- p.18Chapter Chapter 2 --- Multicast Protection in WDM Optical Network with Scheduled Traffic --- p.19Chapter 2.1 --- Introduction --- p.19Chapter 2.2 --- Multicast Protection under FSTM --- p.22Chapter 2.3 --- Illustrative Examples --- p.28Chapter 2.4 --- Two-Step Optimization under SSTM --- p.37Chapter 2.5 --- Summary --- p.40Chapter Chapter 3 --- Energy Efficient Time-Aware Traffic Grooming in Wavelength Routing Networks --- p.41Chapter 3.1 --- Introduction --- p.41Chapter 3.2 --- Energy consumption model --- p.43Chapter 3.3 --- Static Traffic Grooming with Time awareness --- p.44Chapter 3.3.1 --- Scheduled Traffic Model for Traffic Grooming --- p.44Chapter 3.3.2 --- ILP Formulation --- p.44Chapter 3.3.3 --- Illustrative Numerical Example --- p.48Chapter 3.4 --- Dynamic Traffic Grooming with Time Awareness --- p.49Chapter 3.4.1 --- Time-Aware Traffic Grooming (TATG) --- p.51Chapter 3.5 --- Simulation Results of Dynamic Traffic Grooming --- p.54Chapter 3.5.1 --- 24-node USNET: --- p.55Chapter 3.5.2 --- 15-node Pacific Bell Network: --- p.59Chapter 3.5.3 --- 14-node NSFNET: --- p.63Chapter 3.5.4 --- Alternative Configuration of Simulation Parameters: --- p.67Chapter 3.6 --- Summary --- p.71Chapter Chapter 4 --- Conclusions and Future Work --- p.72Chapter 4.1 --- Conclusions --- p.72Chapter 4.2 --- Future Work --- p.73Bibliography --- p.74Publications during M.Phil Study --- p.8

Network Load Based Analysis of Blocking Probability in WDM Network

Arrangement of expansible quality of service (QoS) attestation on wavelength division multiplexing (WDM) is a crucial and perplexing problem of the cutting threshold internet. From the essential performance parameters the blocking probability (BP) computation is a QoS adept in WDM network. This method of BP computation in a wavelength routed optical network (WRON) is presented, keep in mind that blocking-probability computation used only to a network that is remain same where, traffic demands arrive, wait for a convinced time, and finally dispense, so that the total traffic intensity for a time is same i.e. remain unchanged. For an active optical network (AON), despite the fact we lag behind that traffic loads will reach, wait for a fixed time, and afterword dispense, same we taken into account that the normalized intensity of traffic existing of a network is going to increase gradually with time as the number of users receiving on the typical network and also growth in their networking essentials towards large bandwidth uses, extended holding time uses, etc. Hence, blocking probability computation try not to use meanwhile traffic is not fixed. Otherwise, we have to take into account of "exhaustion probability," having a time duration, lastly we anticipated that the network is to run into capacity exhaust. The realization traffic distribution of network performs to achieve an exact blocking performance. So the BP for each available link having a shortest path or having a large weight in a sorted order taken into account, in the network the connection and node relation for the traffic between each link is dependant. The usefulness of this technique is to be applicable in low load region, exact, faster compare to other techniques. Furthermore, this technique is more useful to calculate the estimation of blocking probability per node as well as for the network

Traffic lifetime-aware routing considering dynamic grooming in WDM networks

Master'sMASTER OF ENGINEERIN