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Über dieses Buch

This book presents an in-depth treatment of routing and wavelength assignment for optical networks, and focuses specifically on quality-of-service and fault resiliency issues. It reports on novel approaches for the development of routing and wavelength assignment schemes for fault-resilient optical networks, which improve their performance in terms of signal quality, call blocking, congestion level and reliability, without a substantial increase in network setup cost.

The book first presents a solution for reducing the effect of the wavelength continuity constraint during the routing and wavelength assignment phase. Further, it reports on an approach allowing the incorporation of a traffic grooming mechanism with routing and wavelength assignment to enhance the effective channel utilization of a given capacity optical network using fewer electrical-optical-electrical conversions. As a third step, it addresses a quality of service provision scheme for wavelength-division multiplexing (WDM)-based optical networks. Lastly, the book describes the inclusion of a tree-based fault resilience scheme in priority-based dispersion-reduced wavelength assignment schemes for the purpose of improving network reliability, while maintaining a better utilization of network resources.

Mainly intended for graduate students and researchers, the book provides them with extensive information on both fundamental and advanced technologies for routing and wavelength assignment in optical networks. The topics covered will also be of interest to network planners and designers.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction to Optical Network

The rapid growth in world-wide communications and proliferating use of Internet has significantly modified the ways of life. This revolution has led to vast growth of communication bandwidth in every year. At the same time, the quick evolution of optical communication technologies has allowed the transmission of vast quantities of information on a single optical fiber. However, the communication protocols adopted by telecommunication service providers have proved to be quite inefficient to exploit the enormous information carrying capacity of the emerging next-generation optical networks, which need further research initiatives. This chapter briefly introduces the wavelength division multiplexing based optical networks and describes the problems addressed in current research.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 2. Literature Survey

This chapter presents a comprehensive survey on various works done in the field of wavelength division multiplexing based optical networks. We start with a brief introduction of lightpath establishment in optical networks, and then move to different routing algorithms that are used for finding a end-to-end route between a source-destination pair. Thereafter, this chapter presents different wavelength assignment policies for lightpath establishment and compares them. Furthermore, the traffic grooming mechanisms are presented for better utilization of network resources. Finally, this chapter explores the fault management techniques that are used for recovery purpose.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 3. Performance Analysis of Major Conventional Routing and Wavelength Assignment Approaches

This chapter evaluates the performance analysis of the major conventional routing and wavelength assignment approaches in terms of blocking probability and average setup time. Simulation results indicate that the blocking performance of the first-fit wavelength assignment policy is the lowest among all the wavelength assignment policies. Adaptive routing provides lowest blocking performance among routing algorithms, but its average setup time is higher compared to others.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 4. End-to-End Traffic Grooming

To enhance the channel utilization in optical networks, this chapter introduces an end-to-end traffic grooming mechanism. The end-to-end traffic grooming mechanism multiplexes the connection/bandwidth requests that having the same source-destination pair into a lightpath within the channel capacity. Simulation results indicate that the incorporation of end-to-end traffic grooming with routing and wavelength assignment approach outperforms the non-traffic grooming scenario in terms of admissible traffic volume.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 5. Priority-Based Routing and Wavelength Assignment Scheme

One of the challenging issues in optical networks is call blocking and it increases with the number of lightpath requests due to the limited number of wavelength channels in each fiber link. This chapter introduces a priority based routing and wavelength assignment (PRWA) scheme in order to reduce call blocking in the network. The introduced PRWA scheme serves the lightpath requests for routing and wavelength assignment according to their priority order. The priority order of each lightpath request is estimated based on type of path (direct link physical path or indirect link physical path) first and then the traffic volume. If the priority order of lightpath requests is estimated using these criteria, blocking of lightpath requests due to wavelength continuity constraints can be reduced to a great extent, which leads to better performance of the network in terms of lower call blocking. The simulation results indicate that the introduced PRWA scheme outperforms the conventional non-priority based routing and wavelength assignment scheme (NPRWA) in terns of blocking probability.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 6. Priority-Based Dispersion-Reduced Wavelength Assignment Scheme

Dispersion in optical fiber degrades the quality of signal in optical networks. Although the use of dispersion compensating fiber (DCF) reduces the effects of dispersion, it requires additional cost, and has more propagation loss compared to step-index fiber (SIF). This chapter introduces a priority based dispersion-reduced wavelength assignment (PDRWA) scheme to reduce overall dispersion in optical networks. The introduced PDRWA scheme assigns longer lightpath requests to the wavelengths having lesser dispersion and the wavelengths having higher dispersion are assigned to the lightpaths with shorter distance. If the lightpath requests are assigned to the wavelengths using such constraint on dispersion, the overall dispersion in the network is reduced to a great extent, which leads to better performance of the network in terms of overall signal quality (Q-factor) without increasing network setup cost. The performance analysis of the introduced PDRWA scheme using SIF is conducted with different channel speeds, such as 10, 40 and 100 Gbps, in terms of total dispersion and compared the same with the use of DCF. Simulation results indicates that the Q-factor, considering PMD effect, using the introduced PDRWA scheme with SIF is higher than that of using the introduced PDRWA scheme with DCF due to the higher PMD coefficient.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 7. A Reliable Fault Resilience Scheme

The reliability has become an important and challenging issue in practical use of optical networks. This chapter introduces a reliable fault resilience scheme to improve the network reliability. In the introduced scheme, established lightpaths are protected using the reliable shared protection tree to provide higher reliability. This protection tree is constructed by restricted sharing of a wavelength in the sub branch of the tree. In the reliable shared protection tree, any two different end-to-end routes from the root node to leaf nodes sharing at least one link are allocated with different wavelengths. The backup paths on the same end-to-end route share the same wavelength among themselves in order to save the resource usages. Simulation results show that the introduced scheme tradeoffs between network reliability and blocking probability.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki

Chapter 8. Limitations of Conventional WDM Optical Networks and Elastic Optical Networks for Possible Solutions

This chapter introduces the limitations of convention wavelength division multiplexing (WDM)-based optical networks, and then presents elastic optical networks for future high-speed communications. The chapter describes the architecture of the elastic optical network and its operation principle. To complete the discussion of network architecture, this chapter focuses on the different node architectures, and finally compares their performance in terms of scalability and flexibility.
Bijoy Chand Chatterjee, Nityananda Sarma, Partha Pratim Sahu, Eiji Oki
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