Flexibility to support mesh topologies, dynamic capacity allocation, and automated network control and light path setup are key elements in the design of next-generation optical transport networks. To realize these capabilities, reconfigurable optical add/drop multiplexers with dynamic add/drop structures, embedded control planes, and lightpath characterization are required. This article presents the architectures and various ROADM implementations including colorless, directionless, and contentionless add/drop structures. The effect of scaling bit rates beyond 100 Gb/s on ROADM architectures is reviewed including providing variable channel bandwidth depending on bit rate. Automated provisioning and restoration using the GMPLS control plane and optical measurement approaches for lightpaths are also discussed.

Flexible architectures for optical transport nodes and networks

New applications are likely to ask for a more flexible bandwidth, large bandwidth for limited amount of time. In order to meet these new requirements, flexible optical transport networks in which connections could be set up and released on dynamic short-term basis have to be introduced. We propose a distributed Holding-Time-Aware provisioning framework based on intelligent destination routing to assign and manage the working and the protection paths as well as their wavelength(s) of each connection. In our framework, we propose to utilize knowledge of connection holding time to provide efficient provisioning of shared-path-protected connections in survivable optical mesh networks. We show through a simulation study that the performance of the proposed holding-time-aware compared to a holding-time-unaware is significant.

Distributed Holding-Time-Aware shared-path-protection provisioning framework for optical networks

The invention provides a service awareness route protective method by means of Bayesian classification, and relates to the technical field of optical communications. The service awareness protective method by means of Bayesian classification is proposed to solve the problems that the traditional Bayesian classification algorithm is low in accuracy, a weighting algorithm is not fast and comprehensive in weight judgment, the existing priority level model is unreasonable, the existing priority level model is unidentified in corresponding QoS parameters, and consideration of distinguishing protection is not comprehensive. The importance degree of information defined by the service awareness protective method by means of Bayesian classification can evaluate the importance degree of characteristics effectively, the importance degree of the characteristics is combined with the Bayesian classification algorithm, service priority level can be distinguished accurately, the requirements that services of different priority levels correspond to different QoS parameters are met, and then route is distinguished and protected. Moreover, the wavelength layering topology is adopted, wavelength sources can be used conveniently and fast, and the protective method can be selected from special protection and shared protection. Further, on the condition that the requirements of transmission are met, the number of unoccupied protection paths is minimized, and the utilization rate of network resources is improved.

Service awareness route protective method by means of Bayesian classification

Motivated by the rapid growth of the internet, the increasing demand and the nature of traffic, wavelength division multiplexing (WDM) is now beginning to expand from a network core technology towards the metropolitan and access networks. However, huge amount of data can be lost and large numbers of users can be disrupted during the times of failure in WDM optical networks. Therefore, a reliable optical layer that can quickly and efficiently respond to failures, such as fiber cuts, is a critical issue to users and service providers. The major challenge in survivable mesh networks is the design of distributed management protocols and resource allocation algorithms that allocate network resources efficiently and are able to quickly recover from a failure. This issue is particularly more challenging in optical networks operating under distributed control, where there is no global information available; and under wavelength continuity constraint, where the same wavelength must be assigned on all links in the selected path. This thesis presents a number of new distributed protocols and algorithms to solve these challenges. The second part of this thesis provides new distributed frameworks to support Quality of Service (QoS) differentiation. These frameworks provide differentiated protection services to meet customers' availability requirements effectively. We describe the availability-analysis for connections with different protection schemes. Through this analysis, we show how connection availability is affected by resource sharing. Based on the availability analysis, the proposed framework provisions each connection in which an appropriate level of protection is provided according to its predefined availability requirement. We consider the networks without wavelength conversion capability as well as dynamic traffic environment. In these distributed frameworks we propose several distributed schemes to provision and manage connections cost-effectively while satisfying the existing and new connections availability requirements. To the memory of my father Mahmoud Alsukhni (Abu Ziad) and to my mother Maryam Nawasreh (Um Ziad)

https://www.ruor.uottawa.ca/bitstream/10393/30065/1/NR73892.PDF

Distributed Real Time Algorithms and Design Concepts for Next Generation Survivable Optical Networks

A network engineering framework for upgrading service availability of optical mesh networks

This paper presents a novel distributed protocol for online provisioning in survivable mesh-based wavelength-division multiplexed (WDM) networks. This protocol examines each of the k link disjoint shortest paths as a candidate working path and as a candidate shared protection path at the same time, in parallel which gives the destination node the ability to apply an intelligent adaptive routing and wavelength assignment. Moreover, this protocol is the first distributed protocol can provision the working and the backup paths in parallel. We discuss in details a control and management techniques to set up and tear down connections and determine restoration capacity shareability in a distributed manner. Since only local information is maintained at each node, protocol scalability is guaranteed. The significant contribution of this protocol in terms of connection request blocking probability and connection setup time are discussed. We show through setup time analysis and simulation experiments the effectiveness of the proposed protocol.

Parallel distributed lightpath control and management for survivable optical mesh networks

In transparent optical mesh networks, different protection schemes can be used to satisfy the service availability against network failures. However, in order to satisfy a connection's service availability requirement in distributed controlled optical networks with no global information, we need a framework to provision a working path with the appropriate level of protection for each connection request based on the requested level of availability. Moreover, we need a mechanism to guarantee the availability requirements of the existing connections in the network. In this paper, we propose a novel distributed provisioning framework to provide differentiated protection services in optical mesh networks, where nodes in such networks are Reconfigurable Optical Add/Drop Multiplexers (ROADMs). This framework examines the k most reliable paths as both candidate working paths and candidate shared protection paths at the same time, which gives the destination node the ability to apply an adaptive availability-guaranteed routing and wavelength assignment. Moreover, we propose two new distributed schemes to track the validity of the connections' availability requirements. Finally, we show the effectiveness of the proposed framework using extensive simulation experiments.

Availability-Guaranteed Distributed Provisioning Framework for Differentiated Protection Services in Optical Mesh Networks

In optical WDM mesh networks, different protection schemes can be used to satisfy the service availability against network failures. However, in order to satisfy a connectionpsilas service-availability requirement in a distributed controlled WDM networks with no wavelength converters, we need a mechanism to select a proper protection scheme for each connection request while provisioning the connection. In this paper, we propose to use connection availability as a metric for providing differentiated protection services in WDM mesh networks. In the case of shared-protection, we propose a novel distributed parallel provisioning framework based on fixed alternative routing to select the connectionpsilas working and protection paths as well as the wavelength(s) at the same time by probing the k most reliable paths in parallel. The probing technique used in this framework is the first probing technique that probes each path as both a candidate working path and a candidate shared protection path at the same time. Based on the availability information collected, our provisioning strategy assigns an appropriate level of protection to each connection. The effectiveness of our provisioning approaches is demonstrated through simulation results.

E.M. Al Sukhni

Papers

Parallel distributed lightpath control and management for survivable optical mesh networks

Availability-Guaranteed Distributed Provisioning Framework for Differentiated Protection Services in Optical Mesh Networks

A novel distributed availability-aware provisioning framework for differentiated protection services in optical mesh networks