Inside all-optical networks

Imagine a world where lightning speed Internet is as common as telephones today. Imagine when light, the fastest moving thing in the universe, is the signal-carrying transport medium. Imagine when bandwidth no more remains a constraint for any application. Imagine when imagination is the only limit! This all can be made possible with only one technology and that is optical communication. Optical networks have thus far provided a realization to a greater extent to the unlimited bandwidth dreams of this era, but as the demands are increasing, the electro-optic conversions seem to become bottlenecks in blended optical networks. The only answer to this is a complete migration to `All-Optical Networks\u27 (AONs) which promise an end-to-end optical transmission. This thesis will investigate various aspects of all-optical networks and prove that AONs perform better than currently existing electro-optical networks. In today\u27s\u27 electro-optical networks, routing and switching is performed in electronic domain. Performance analysis of electro-optical and all-optical networks would include node utilization, link utilization and percentage of traffic routed. It will be shown through Opnet Transport Planner simulations that AONs work better under various traffic conditions. The coming decade will see a great boom in demands on telecommunications networks. The development in bandwidth-hungry applications like real-time video transmission, telemedicine, distance learning and video on demand require both an unlimited amount of bandwidth and dependable QoS. It is well understood that electrically switched networks and copper cables will not be able to meet the future network demands effectively. The world has already agreed to move towards optical communication techniques through the introduction of fiber in access parts of the networks replacing copper. Now the race is to bring optics in higher layers of OSI reference model. Optical communication is on the horizon, and new discoveries are still underway to add to the value of available bandwidth through this technology. My research thesis will primarily focus on the design, architecture and network properties of AONs and challenges being faced by AONs in commercial deployment. Optical components required in AONs will be explored. A comparison between AONs and electro-optical networks will also be shown through optical transport planner simulations

Design and provisioning of WDM networks for traffic grooming

Wavelength Division Multiplexing (WDM) is the most viable technique for utilizing the enormous amounts of bandwidth inherently available in optical fibers. However, the bandwidth offered by a single wavelength in WDM networks is on the order of tens of Gigabits per second, while most of the applications\u27 bandwidth requirements are still subwavelength. Therefore, cost-effective design and provisioning of WDM networks require that traffic from different sessions share bandwidth of a single wavelength by employing electronic multiplexing at higher layers. This is known as traffic grooming. Optical networks supporting traffic grooming are usually designed in a way such that the cost of the higher layer equipment used to support a given traffic matrix is reduced. In this thesis, we propose a number of optimal and heuristic solutions for the design and provisioning of optical networks for traffic grooming with an objective of network cost reduction. In doing so, we address several practical issues. Specifically, we address the design and provisioning of WDM networks on unidirectional and bidirectional rings for arbitrary unicast traffic grooming, and on mesh topologies for arbitrary multipoint traffic grooming. In multipoint traffic grooming, we address both multicast and many-to-one traffic grooming problems. We provide a unified frame work for optimal and approximate network dimensioning and channel provisioning for the generic multicast traffic grooming problem, as well as some variants of the problem. For many-to-one traffic grooming we propose optimal as well as heuristic solutions. Optimal formulations which are inherently non-linear are mapped to an optimal linear formulation. In the heuristic solutions, we employ different problem specific search strategies to explore the solution space. We provide a number of experimental results to show the efficacy of our proposed techniques for the traffic grooming problem in WDM networks

Framework for waveband switching in multigranular optical networks: part I-multigranular cross-connect architectures

Optical networks using wavelength-division multiplexing (WDM) are the foremost solution to the ever-increasing traffic in the Internet backbone. Rapid advances in WDM technology will enable each fiber to carry hundreds or even a thousand wavelengths (using dense-WDM, or DWDM, and ultra-DWDM) of traffic. This, coupled with worldwide fiber deployment, will bring about a tremendous increase in the size of the optical cross-connects, i.e., the number of ports of the wavelength switching elements. Waveband switching (WBS), wherein wavelengths are grouped into bands and switched as a single entity, can reduce the cost and control complexity of switching nodes by minimizing the port count. This paper presents a detailed study on recent advances and open research issues in WBS networks. In this study, we investigate in detail the architecture for various WBS cross-connects and compare them in terms of the number of ports and complexity and also in terms of how flexible they are in adjusting to dynamic traffic. We outline various techniques for grouping wavelengths into bands for the purpose of WBS and show how traditional wavelength routing is different from waveband routing and why techniques developed for wavelength-routed networks (WRNs) cannot be simply applied to WBS networks. We also outline how traffic grooming of subwavelength traffic can be done in WBS networks. In part II of this study [Cao , submitted to J. Opt. Netw.], we study the effect of wavelength conversion on the performance of WBS networks with reconfigurable MG-OXCs. We present an algorithm for waveband grouping in wavelength-convertible networks and evaluate its performance. We also investigate issues related to survivability in WBS networks and show how waveband and wavelength conversion can be used to recover from failures in WBS networks

Dynamic grooming in IP over WDM networks: A study with realistic traffic based on GANCLES simulation package

Abstract — Dynamic grooming capabilities lies at the hearth of many envisaged scenarios for IP over Optical networks, but studies on its performance are still in their infancy. This work addresses two fundamental aspects of the problem. First of all it presents a novel tool for the study of IP over Optical networks. The tool, freely available on-line, is a network level simulator named GANCLES that includes several innovative features allowing the study of realistic scenarios in IP over Optical networking, making it an ideal tool for Traffic Engineering purposes. GANCLES architecture enables the simulation of dynamic traffic grooming on top of a realistic network model that correctly describes the logical interaction between the optical and the IP layer, i.e., the mutual relationship between routing algorithms and lightpath assignment procedures at the optical layer and routing at th

Performance analysis on multi-dimensional optical routing networks.

Zhang Yu.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 67-72).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Overview of Optical Networking --- p.1Chapter 1.2 --- Mechanism in Optical Routing Networks --- p.3Chapter 1.3 --- Related Work on Optical Routing Networks --- p.4Chapter 1.4 --- The Motivation of This Thesis --- p.7Chapter 1.5 --- Thesis Structure --- p.8Chapter 2 --- Technologies for Multi-dimensional Optical Routing Networks --- p.10Chapter 2.1 --- Background --- p.10Chapter 2.2 --- Multi-fiber WDM Networks --- p.11Chapter 2.2.1 --- Phased-Array-Based WDM Device --- p.11Chapter 2.2.2 --- Wavelength-tunable lasers --- p.11Chapter 2.2.3 --- Tunable optical Filter --- p.12Chapter 2.2.4 --- Wavelength Converter --- p.13Chapter 2.3 --- OCDM/WDM --- p.16Chapter 2.3.1 --- Optical En/Decoder --- p.17Chapter 2.3.2 --- Optical Switch --- p.18Chapter 2.3.3 --- Optical Code Conversion --- p.18Chapter 2.4 --- OTDM/WDM --- p.21Chapter 2.4.1 --- Fast Optical Switch --- p.22Chapter 2.4.2 --- Optical Time Slot Interchanger (OTSI) --- p.22Chapter 2.5 --- Conclusion --- p.23Chapter 3 --- Performance of Code/Wavelength Routing Networks --- p.24Chapter 3.1 --- Background --- p.24Chapter 3.2 --- Reconfiguration Capability --- p.25Chapter 3.3 --- Analytic Models --- p.27Chapter 3.3.1 --- Trunk Switched Model --- p.27Chapter 3.3.2 --- Assumptions --- p.28Chapter 3.3.3 --- Blocking of the Paths with Various Configurations --- p.29Chapter 3.4 --- Numerical Results --- p.34Chapter 3.5 --- Conclusion --- p.35Chapter 4 --- Decomposition Schemes --- p.40Chapter 4.1 --- Introduction --- p.40Chapter 4.2 --- Inclusive Converted Networks --- p.41Chapter 4.3 --- Decompositions --- p.43Chapter 4.3.1 --- Spatial Decomposition (S.D.) --- p.43Chapter 4.3.2 --- Dimensional Decomposition (D.D.) --- p.44Chapter 4.3.3 --- Iterative Decompositions --- p.45Chapter 4.4 --- Conclusion --- p.46Chapter 5 --- Performance of Multi-Dimensional Optical Routing Networks --- p.48Chapter 5.1 --- Homogeneous Trunk Switched Networks --- p.48Chapter 5.2 --- Analytical Model --- p.49Chapter 5.3 --- Utilization Gain --- p.53Chapter 5.4 --- Conversion Gain --- p.54Chapter 5.5 --- Comparison on the Utilization Gain by Multiplexing and by Conversion --- p.56Chapter 5.6 --- Conclusion --- p.57Chapter 6 --- Conclusion --- p.65Chapter 6.1 --- Summary of the Thesis --- p.65Chapter 6.2 --- Future Work --- p.6