An Overview on Application of Machine Learning Techniques in Optical Networks

Today's telecommunication networks have become sources of enormous amounts of widely heterogeneous data. This information can be retrieved from network traffic traces, network alarms, signal quality indicators, users' behavioral data, etc. Advanced mathematical tools are required to extract meaningful information from these data and take decisions pertaining to the proper functioning of the networks from the network-generated data. Among these mathematical tools, Machine Learning (ML) is regarded as one of the most promising methodological approaches to perform network-data analysis and enable automated network self-configuration and fault management. The adoption of ML techniques in the field of optical communication networks is motivated by the unprecedented growth of network complexity faced by optical networks in the last few years. Such complexity increase is due to the introduction of a huge number of adjustable and interdependent system parameters (e.g., routing configurations, modulation format, symbol rate, coding schemes, etc.) that are enabled by the usage of coherent transmission/reception technologies, advanced digital signal processing and compensation of nonlinear effects in optical fiber propagation. In this paper we provide an overview of the application of ML to optical communications and networking. We classify and survey relevant literature dealing with the topic, and we also provide an introductory tutorial on ML for researchers and practitioners interested in this field. Although a good number of research papers have recently appeared, the application of ML to optical networks is still in its infancy: to stimulate further work in this area, we conclude the paper proposing new possible research directions

Software defined networking: meeting carrier grade requirements

Software Defined Networking is a networking paradigm which allows network operators to manage networking elements using software running on an external server. This is accomplished by a split in the architecture between the forwarding element and the control element. Two technologies which allow this split for packet networks are ForCES and Openflow. We present energy efficiency and resilience aspects of carrier grade networks which can be met by Openflow. We implement flow restoration and run extensive experiments in an emulated carrier grade network. We show that Openflow can restore traffic quite fast, but its dependency on a centralized controller means that it will be hard to achieve 50 ms restoration in large networks serving many flows. In order to achieve 50 ms recovery, protection will be required in carrier grade networks

Survivable multicasting in WDM optical networks

Opportunities abound in the global content delivery service market and it is here that multicasting is proving to be a powerful feature. In WDM networks, optical splitting is widely used to achieve multicasting. It removes the complications of optical-electronic-optical conversions [1]. Several multicasting algorithms have been proposed in the literature for building light trees. As the amount of fiber deployment increases in networks, the risk of losing large volumes of data traffic due to a fiber span cut or due to node failure also increases. In this thesis we propose heuristic schemes to make the primary multicast trees resilient to network impairments. We consider single link failures only, as they are the most common cause of service disruptions. Thus our heuristics make the primary multicast session survivable against single link failures by offering alternate multicast trees. We propose three algorithms for recovering from the failures with proactive methodologies and two algorithms for recovering from failures by reactive methodologies. We introduce the new and novel concept of critical subtree. Through our new approach the proactive and reactive approaches can be amalgamated together using a criticality threshold to provide recovery to the primary multicast tree. By varying the criticality threshold we can control the amount of protection and reaction that will be used for recovery. The performance of these five algorithms is studied in combinations and in standalone modes. The input multicast trees to all of these recovery heuristics come from a previous work on designing power efficient multicast algorithms for WDM optical networks [1]. Measurement of the power levels at receiving nodes is indeed indicative of the power efficiency of these recovery algorithms. Other parameters that are considered for the evaluation of the algorithms are network usage efficiency, (number of links used by the backup paths) and the computation time for calculating these backup paths. This work is the first to propose metrics for evaluating recovery algorithms for multicasting in WDM optical networks. It is also the first to introduce the concept of hybrid proactive and reactive approach and to propose a simple technique for achieving the proper mix

Lightpath routing with survivability requirements in WDM optical mesh networks

Ph.DDOCTOR OF PHILOSOPH

Regenerator placement and fault management in multi-wavelength optical networks.

Shen, Dong.Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.Includes bibliographical references (p. 98-106).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 --- Translucent Optical Networks --- p.1Chapter 1.1.1 --- The Way Towards Translucent --- p.1Chapter 1.1.2 --- Translucent Optical Network Architecture Design and Planning --- p.3Chapter 1.1.3 --- Other Research Topics in Translucent Optical Networks --- p.6Chapter 1.2 --- Fault Monitoring in All-Optical Networks --- p.12Chapter 1.2.1 --- Fault Monitoring in Network Layer's Perspective --- p.12Chapter 1.2.2 --- Passive Optical Monitoring --- p.14Chapter 1.2.3 --- Proactive Optical Monitoring --- p.16Chapter 1.3 --- Contributions --- p.17Chapter 1.3.1 --- Translucent Optical Network Planning with Heterogeneous Modulation Formats --- p.17Chapter 1.3.2 --- Multiplexing Optimization in Translucent Optical Networks --- p.19Chapter 1.3.3 --- An Efficient Regenerator Placement and Wavelength Assignment Scheme in Translucent Optical Networks --- p.20Chapter 1.3.4 --- Adaptive Fault Monitoring in All-Optical Networks Utilizing Real-Time Data Traffic --- p.20Chapter 1.4 --- Organization of Thesis --- p.22Chapter Chapter 2 --- Regenerator Placement and Resource Allocation Optimization in Translucent Optical Networks --- p.23Chapter 2.1 --- Introduction --- p.23Chapter 2.2 --- Translucent Optical Network Planning with Heterogeneous Modulation Formats --- p.25Chapter 2.2.1 --- Motivation and Problem Statements --- p.25Chapter 2.2.2 --- A Two-Step Planning Algorithm Using Two Modulation Formats to Realize Any-to-Any Topology Connectivity --- p.28Chapter 2.2.3 --- Illustrative Examples --- p.30Chapter 2.2.3 --- ILP Formulation of Minimizing Translucent Optical Network Cost with Two Modulation Formats under Static Traffic Demands --- p.34Chapter 2.2.4 --- Illustrative Numeric Examples --- p.42Chapter 2.3 --- Resource Allocation Optimization in Translucent Optical Networks --- p.45Chapter 2.3.1 --- Multiplexing Optimization with Auxiliary Graph --- p.45Chapter 2.3.2 --- Simulation Study of Proposed Algorithm --- p.51Chapter 2.3.3 --- An Efficient Regenerator Placement and Wavelength Assignment Solution --- p.55Chapter 2.3.4 --- Simulation Study of Proposed Algorithm --- p.60Chapter 2.4 --- Summary --- p.64Chapter Chapter 3 --- Adaptive Fault Monitoring in All-Optical Networks Utilizing Real-Time Data Traffic --- p.65Chapter 3.1 --- Introduction --- p.65Chapter 3.2 --- Adaptive Fault Monitoring --- p.68Chapter 3.2.1 --- System Framework --- p.68Chapter 3.2.2 --- Phase 1: Passive Monitoring --- p.70Chapter 3.2.3 --- Phase 2: Proactive Probing --- p.71Chapter 3.2.4 --- Control Plane Design and Analysis --- p.80Chapter 3.2.5 --- Physical Layer Implementation and Suggestions --- p.83Chapter 3.3 --- Placement of Label Monitors --- p.83Chapter 3.3.1 --- ILP Formulation --- p.84Chapter 3.3.2 --- Simulation Studies --- p.86Chapter 3.3.3 --- Discussion of Topology Evolution Adaptiveness --- p.93Chapter 3.4 --- Summary --- p.95Chapter Chapter 4 --- Conclusions and Future Work --- p.95Chapter 4.1 --- Conclusions --- p.96Chapter 4.2 --- Future Work --- p.97Bibliography --- p.98Publications during M.Phil Study --- p.10

Optimization of BGP Convergence and Prefix Security in IP/MPLS Networks

Multi-Protocol Label Switching-based networks are the backbone of the operation of the Internet, that communicates through the use of the Border Gateway Protocol which connects distinct networks, referred to as Autonomous Systems, together. As the technology matures, so does the challenges caused by the extreme growth rate of the Internet. The amount of BGP prefixes required to facilitate such an increase in connectivity introduces multiple new critical issues, such as with the scalability and the security of the aforementioned Border Gateway Protocol. Illustration of an implementation of an IP/MPLS core transmission network is formed through the introduction of the four main pillars of an Autonomous System: Multi-Protocol Label Switching, Border Gateway Protocol, Open Shortest Path First and the Resource Reservation Protocol. The symbiosis of these technologies is used to introduce the practicalities of operating an IP/MPLS-based ISP network with traffic engineering and fault-resilience at heart. The first research objective of this thesis is to determine whether the deployment of a new BGP feature, which is referred to as BGP Prefix Independent Convergence (PIC), within AS16086 would be a worthwhile endeavour. This BGP extension aims to reduce the convergence delay of BGP Prefixes inside of an IP/MPLS Core Transmission Network, thus improving the networks resilience against faults. Simultaneously, the second research objective was to research the available mechanisms considering the protection of BGP Prefixes, such as with the implementation of the Resource Public Key Infrastructure and the Artemis BGP Monitor for proactive and reactive security of BGP prefixes within AS16086. The future prospective deployment of BGPsec is discussed to form an outlook to the future of IP/MPLS network design. As the trust-based nature of BGP as a protocol has become a distinct vulnerability, thus necessitating the use of various technologies to secure the communications between the Autonomous Systems that form the network to end all networks, the Internet

Cross-Layer Platform for Dynamic, Energy-Efficient Optical Networks

The design of the next-generation Internet infrastructure is driven by the need to sustain the massive growth in bandwidth demands. Novel, energy-efficient, optical networking technologies and architectures are required to effectively meet the stringent performance requirements with low cost and ultrahigh energy efficiencies. In this thesis, a cross-layer communications platform is proposed to enable greater intelligence and functionality on the physical layer. Providing the optical layer with advanced networking capabilities will facilitate the dynamic management and optimization of optical switching based on performance monitoring measurements and higher-layer attributes. The cross-layer platform aims to create a new framework for networks to incorporate packet-scale measurement subsystems and techniques for monitoring the health of the optical channel. This will allow for quality-of-service- and energy-aware routing schemes, as well as an enhanced awareness of the optical data signals. This thesis first presents the design and development of an optical packet switching fabric. Leveraging a networking test-bed environment to validate networking hypotheses, advanced switching functionalities are demonstrated, including the support for quality-of-service based routing and packet multicasting. The investigated cross-layering is based on emerging optical technologies, enabling packet protection techniques and packet-rate switching fabric reconfiguration. Coupled with fast performance monitoring, the platform will achieve significant performance gains within the endeavor of all-optical switching. Allowing for a more intelligent, programmable optical layer aims to support greater flexibility with respect to bandwidth allocation and potentially a significant reduction in the network's energy consumption. The ultimate deliverable of this work is a high-performance, cross-layer enabled optical network node. The experimental demonstration of an initial prototype creates a dynamic network element with distributed control plane management, featuring fast packet-rate optical switching capabilities and embedded physical-layer performance monitoring modules. The cross-layer box enables an intelligent traffic delivery system that can dynamically manipulate optical switching on a packet-granular scale. With the goal of achieving advanced multi-layer routing and control algorithms, the network node requires an intelligent co-optimization across all the layers. The proposed cross-layer design should drive optical technologies and architectures in an innovative way, in order to fulfill the void between the design of basic photonic devices and the networking protocols that use them. The performance of the entire network -- from the optical components, to the routing algorithms and user applications -- should be optimized in concert. This contribution to the area of cross-layer network design creates an adaptable optical pipe that is extremely flexible and intelligent aware of both the physical optical signals and higher-layer requirements. The impact of this work will be seen in the realization of dynamic, energy-efficient optical communication links in future networking infrastructures