Optical Network Resources Research Articles

Energy aware planning of multiple virtual infrastructures over converged optical network and IT physical resources

This paper studies energy efficient planning of multiple concurrent virtual infrastructures over a converged physical infrastructure incorporating integrated optical network and IT resources. An MILP model for virtualization of the underlying physical resources is proposed and validated achieving significant energy savings.

Elastic and adaptive optical networks: possible adoption scenarios and future standardization aspects

There is growing recognition that we are rapidly approaching the physical capacity limit of standard optical fiber. It is important to make better use of optical network resources to accommodate the ever-increasing traffic demand. One promising way is to introduce elasticity and adaptation into the optical domain through more flexible spectrum allocation, where the required minimum spectral resources are allocated adaptively based on traffic demand and network conditions. In this article, we discuss elastic and adaptive optical networks from the perspective of future standardization. We first overview the architecture, enabling technologies, and benefits of elastic and adaptive optical networks with the new concept of an optical corridor. We then present possible adoption scenarios from current rigid optical networks to elastic and adaptive optical networks. We discuss some possible study items that are relevant to the future standardization activities. These items include optical transport network architecture, structure and mapping of the optical transport unit, automatically switched optical network/generalized multiprotocol label switching control plane issues, and some physical aspects with possible extension of the current frequency grid.

100Gb/s Ethernet Inverse Multiplexing Based on Aggregation at the Physical Layer

We propose a packet-based inverse multiplexing method to allow scalable network access with a bigger-pipe physical interface. The method is based on aggregation at the physical layer (APL) that fragments an original packet-flow and distributes the fragments among an adequate numbers of physical links or networks. It allows us to share wavelengths and/or bandwidth resources in optical networks. Its technical feasibility at the speed of newly standardized 100Gb/s Ethernet (100GbE) is successfully evaluated by implementing the inverse multiplexing logic functions on a prototype board. We demonstrate super-high-definition video streaming and huge file transfer by transmitting 100GbE MAC frames over multiple 10GbE physical links via inverse multiplexing.

Deployment and Validation of GMPLS-Controlled Multi-layer Integrated Routing over the ASON/GMPLS CARISMA Test-bed

The efficient accommodation of subwavelength client flows on optical channels is a current challenge for the optimization of resources in GMPLS-controlled optical networks. While the capacity of the optical channels usually exceeds 10 Gbps, connection requests show finer granularity. This paper concentrates on the design and implementation of the ASON/GMPLS CARISMA test-bed a GMPLS-controlled grooming-capable transport network. Through the paper, the operation of a GMPLS-controlled multi-layer network architecture is introduced, reviewing those implementation issues that come into light. Then, an experimental evaluation is conducted on two alternative network scenarios with different number of nodes and nodal degree. From the results, GMPLScontrolled grooming makes a good trade-off between network blocking probability and E/O port usage when compared to all-optical and opaque solutions, leading to enhanced network performance while reducing network capital expenditures (CAPEX) .

Design and Development of a Semantic Information Modelling Framework for a Service Oriented Optical Internet

The evolution of IT and network technologies has generated far-reaching opportunities for complex service innovation in future Internet. This has resulted in an increase in the heterogeneity and complexity in service provisioning. Such complex services demand efficient coordination of distributed IT resources (storage and computing) interconnected by high capacity optical networks. This paper proposes a service plane architecture as an architectural enhancement promising to handle these complexities. It implements a unified service provisioning concept that can adapt to the heterogeneous, dynamic and complex nature of emerging service requirements as well as optical network and IT resource capabilities. The main elements of the proposed architecture consist of information discovery and service discovery that require a semantic modelling framework to address heterogeneity and automation. This paper focuses on a novel semantic modelling framework which is central to the proposed service plance architecture. It is used for information description in a service-oriented environment based on Web Services Modelling Ontology (WSMO). The framework describes the information model and entities needed to communicate requirements for autonomous, homogeneous service discovery, selection and composition.

一种适用于OCDMA网络的新型二维三码重非对称光正交码

A new generation algorithm of two-dimensional triple-codeweight asymmetric optical orthogonal codes for optical code division multiple access (OCDMA) networks is proposed. The code cardinality is obtained and the error-probability performance for corresponding OCDMA system is analyzed. The codes with two constraints (i.e., auto- and cross-correlation properties) being unequal are taken into account. On the premise of fixed system resources, the code cardinality can be significantly improved. By analysis of the error-probability performance, it is shown that the codes with different parameters have different performances. Therefore, this type of codes can be applied to support diverse quality of service (QoS) and satisfy the quality requirement of different multimedia or distinct users, and simultaneously make the better use of bandwidth resources in optical networks.

Between grids and networks: grid‐enabled network control planes

PurposeThis article seeks to introduce the concept of the Grid‐GMPLS control plane architecture with focus on new services, models, and interoperability issues of Grid‐GMPLS (G2MPLS) and GMPLS control planes. The purpose of this activity is to design, implement and test extensions of the GMPLS Control Plane that can enable the paradigm of a G2MPLS network.Design/methodology/approachThe approach deploys extended GMPLS implementations aiming to facilitate bandwidth provisioning to Grid users.FindingsG2MPLS is a Network Control Plane architecture that implements the concept of Grid Network Services. GNS is a service that allows the provisioning of network and Grid resources in a single‐step through a set of integrated procedures. By providing a unified network/Grid infrastructure the control plane can adapt to the demands of applications having intensive requirements on both computational and network resources.Research limitations/implicationsThe project delivers the prototype implementation of G2MPLS. Consideration should be given to involving the vendors of the optical equipment in the development process to incorporate the project findings into their operating systems.Practical implicationsThe G2MPLS protocol stack has been designed to be compatible with the ASON/GMPLS architecture. This could lead to possible integration of Grids in the existing operational networks, by overcoming the current limitations of Grids running over dedicated networks with their own administrative procedures.Originality/valueThe paper provides the description of Grid Network Infrastructures with a common and transversal Control Plane approach based on G2MPLS, in which Grid resources and optical network resources are both controlled by the same Control Plane, seamlessly spanning the different Control and Management domains of the network.

Construction and performance analysis of 2-D variable-length variable-weight optical orthogonal codes

In this paper, a new generation algorithm of a two-dimensional variable-length and variable-weight optical orthogonal codes (2-D VLVWOOCs) is proposed. By analysis of the BER performance for the corresponding optical code division multiple access (OCDMA) system, it is shown that the users with different codewords have significant differences in performance. Users with heavier-weight address matrices always outperform those with lighter-weight address matrices, and shorter-length and longer-length matrices support high bit-rate and low bit-rate in OCDMA applications, respectively. Therefore, heavier-weight shorter-length matrices can accommodate high bit-rate and high-quality of services (QoS) (e.g., real-time video), and lighter-weight longer-length matrices can achieve low bit-rate and low-QoS (e.g., voice). The system performance becomes worse as the users concentrate on one type of service. Especially, a surge of the number of users with shorter-length matrices has particularly impact on system performance. Thus, the 2-D VLVWOOCs can be used to provide many different types of services with different rate-levels and different levels of QoS, and simultaneously make better use of bandwidth resources in optical networks.

Co-scheduling in Lambda Grid Systems by means of Ant Colony Optimization

The use of a dynamic reconfigurable optical network is an important requirement for the new advanced resource-intensive, highly distributed Grid applications that begin to emerge on the e-Science field. In this paper, we propose an ACO-based algorithm that is capable of the co-scheduling of both computational and optical network resources. We assess the performance of the proposed algorithm by comparison with traditional publish-and-subscribe grid systems that make use of topological routing of the lightpaths. The proposed algorithm can be used as a viable alternative for grid scheduling in Lambda Grids.

Task scheduling accuracy analysis in optical grid environments

Currently optical networks have been employed to meet the ever-increasing data transfer demands of grid applications and thus give rise to the concept of an “optical grid”. Task scheduling is an important issue for an optical grid, for it optimally allocates both grid and optical network resources to accelerate application execution and increase the resource utilization ratio. However, most task scheduling algorithms based on theoretical models may generate accuracy deviations between the scheduled results and the actual finish time of the applications. Accuracy deviations may lead to inefficient resources utilization and unsatisfied Quality of Service (QoS). This paper aims to improve the accuracy of task scheduling algorithms in optical grid environments. We first propose the theoretical task scheduling algorithm and demonstrate that the scheduling result is deviated with actual finish time in the real optical grid environment. Then, we reveal several factors which are likely to influence scheduling accuracy and develop a realistic task scheduling algorithm. We evaluate the theoretical and realistic task scheduling algorithms in our optical grid testbed. The experimental result shows the scheduling accuracy can be improved significantly by the realistic task scheduling algorithm.

Multi-domain lightpath authorization, using tokens

This paper highlights the concepts and results of our research, leading to demonstrations during the period 2005–2007 to develop a flexible and simple access control model, and corresponding support tools to provision multi-domain optical network resources on demand. We introduce the general network resources provisioning model that extends the Generic AAA Authorisation sequences for multi-domain scenarios, and explain how token based access control and policy enforcement can be used during the provisioned resource access. To build a solid conceptual foundation for the proposed token, based access control, the paper revisits existing token definition and proposes a new definition in the context of our research. We subsequently show the use of tokens during different stages of the lightpath provisioning process. The paper identifies and describes two major scenarios in multidomain lightpath provisioning: the chain and tree approaches. The proposed token concept allows a simple combination of access control enforcement at different networking layers: the packet layer, the path layer, and the service layer. We end with a brief description of a few demonstrations that proves the proposed concepts and illustrates its acceptance by a wider networking community.

A new family of 2D variable-weight optical orthogonal codes for OCDMA systems supporting multiple QoS and analysis of its performance

A new family of two-dimensional variable-weight and constant-length optical orthogonal codes (2D VWOOCs) is proposed, and the code cardinality and BER performance for the corresponding OCDMA system are analyzed in this article. It is shown that the cardinality of 2D VWOOC is larger than that of constant-weight 2D OOC and close to the upper bound in theory. In an OCDMA network, the users employing 2D VWOOC codewords with larger Hamming weight outperform the users using 2D VWOOC codewords with smaller Hamming weight in bit-error-rate performance. Therefore, the OCDMA network employing 2D VWOOC can support diverse quality-of-services (QoS) classes and multimedia services, and make the better use of bandwidth resources in optical networks.

Policy-Based Grooming in Optical Networks

This work presents a discussion about policies and architecture to aggregate Internet Protocol/Multiprotocol Label Switching (IP/MPLS) traffics within lightpaths. The scenario is that of IP/MPLS client networks over an optical network. It is well known that aggregating lower traffic flows (e.g., packet-based LSPs--Label Switched Path) within higher traffic flows (e.g., lambda-based LSPs) is considered an effective way to maximize the use of the optical network resources. In this work, the policies are divided into two groups. The first one, which solely considers the class of the flow (High Priority--HP or Low Priority--LP), consists of simple policies meant to aggregate packet-based LSPs within lightpaths. In this group, the policies we have defined intend to reduce the optical network overhead to remove and reroute LP LSPs. The second group presents more sophisticated policies taking into account the possibility of having to deal with further transport faults. In this case, the grooming is better planned and the defined policies tend to reduce the negative impact when a failure is detected in the optical transport network. Our approach has been implemented to validate the policies and the results for each group are showed and discussed.

Flexible Allocation of Optical Access Network Resources Using Constraint Satisfaction Problem

A method for flexibly allocating and reallocating optical access network (OAN) resources, including fibers and equipment, using the constraint satisfaction problem (CSP) is described. OAN resource allocation during service delivery provisioning involves various input conditions and allocation sequences, so an OAN resource allocation method has to support various workflow patterns. Furthermore, exception processing, such as reallocating OAN resources once they are allocated, is inevitable, especially during the spread of service using optical fiber and during the deployment of an optical access network. However, it is almost impossible to describe all workflow patterns including exception processes. Improving the efficiency of these exception processes, as well as that of the typical processes, is important for reducing the service delivery time. Describing all these patterns and process flows increases development cost. The CSP can be used to search for solutions without having to fix the process sequence and input conditions beforehand. We have formulated the conditions for OAN resource allocation and reallocation as a CSP. Use of this method makes it possible to handle various allocation workflow patterns including exception processes. Evaluation of the solution search time demonstrated its feasibility.

Efficient use of protection bandwidth and switching resources in optical WDM networks

Feature Issue on Photonics in SwitchingWe propose a method for simultaneously achieving high resource usage efficiency in terms of both bandwidth and switching resources in protected optical WDM networks. Branch points in protection bandwidth have previously been shown to lead to slower recovery times. We show that branch avoidance may also lead to more efficient use of resources within optical switches. Through our experimental simulations of our online algorithm with an incremental traffic model, we have found that considering bandwidth alone leads to inefficient use of switching resources. Similarly, total elimination of branching leads to inefficient bandwidth usage. However, taking a balanced approach leads to high efficiency with both resources.

Cost optimal configuration of optical networks

In order to address the challenges of tackling the ever-increasing demand for data and voice services while facing diminishing financial returns from deployed networks, efficient utilization of available resources in optical networks is required. In this paper, an efficient set of algorithms is developed for selecting a cost-optimal subset of commercially available fixed or parameterized modules such as dispersion compensation modules and optical amplifiers subject to a wide range of engineering and financial constraints. A comprehensive analysis is performed on these algorithms, and their applicability is confirmed by carrying out simulation experiments to allocate resources for typical optical links

Global E-Science Collaboration

Today's e-science, with its extreme-scale scientific applications, marks a turning point for high-end requirements on the compute infrastructure and, in particular, on optical networking resources. Although ongoing research efforts are aimed at exploiting the vast bandwidth of fiber-optic networks to both interconnect resources and enable high-performance applications, challenges continue to arise in the area of the optical control plane. The ultimate goal in this area is to extend the concept of application-driven networking into the optical space, providing unique features that couldn't be achieved otherwise. Many researchers in the e-science community are adopting grid computing to meet their ever-increasing computational and bandwidth needs as well as help them with their globally distributed collaborative efforts. This recent awareness of the network as a prime resource has led to a sharper focus on interactions with the optical control plane, grid middleware, and other applications. This article attempts to explain the rationale for why high-end e-science applications consider optical network resources to be as essential and dynamic as CPU and storage resources in a grid infrastructure and why rethinking the role of the optical control plane is essential for next-generation optical networks.

Backup resource reoptimization for survivable optical network

A backup resource reoptimization scheme is presented. The presented scheme dynamically adjusts backup lightpaths and reoptimizes the optical network resources. Link load and link reliability that vary with time are considered in this reoptimization scheme. Reserved backup lightpaths are dynamically adjusted to avoid traversing both the heavily loaded links and the unreliable links during the network operation. A heuristic algorithm is presented to achieve fast online backup resource reoptimization. Simulation results show that the presented backup resource reoptimization scheme reduces the network blocking probability while improving the robustness of optical networks against multiple link failures, and thus improves the network performance.

Explicit routing with QoS constraints in IP over WDM

Generalised multiprotocol label switching (GMPLS) is being developed as a unified control architecture for the optical transport network and the layers above it. GMPLS supports traffic engineering (TE) by allowing explicit routing (ER) of data-bearing paths across networks, which will help to guarantee quality of service (QoS) for types of services in IP over WDM networks. Although there have been many approaches to allocate resources in optical data networks using constrained linear programs, these do not consider the delays at layer 3, which impacts QoS. In networks where it is not possible to create a virtual topology at layer 3 that is a full mesh, more than one lightpath will be required to route traffic between certain pairs of source and destination IP routers. The authors present a technique for traffic engineering in optical networks that support QoS considering the traffic flows with delay QoS requirements across optical networks. This technique provides real-time services with a specific optical label switched path and optimises an objective function including the queueing delay at layer 3.

Quadro: A solution to packet switching in optical transmission networks

To provide very high end-to-end bandwidth, all-optical networks need to maintain the transmitted information in the optical domain throughout the network. Through packet switching, this bandwidth can then be flexibly shared among a large number of users according to the demands of their applications. In this process users need to share the various optical communication-handling network resources, such as wavelengths, switches, receivers and transmitters. Extant packet switching solutions, based on electronic buffering and processing, are not appropriate for the optical environment, as, due to the relatively slower electronic rates, their use leads to the “electronic performance bottleneck”. In this paper we overview a recent approach termed Quadro (Queueing Arrivals for Delayed Reception/Routing Operation), that supports the sharing of resources in an optical system without the need for O/E and E/O conversions, or electronic buffering and processing of the data packets. We then show how the Quadro resource sharing solution can be generalized to provide optical packet switching. The proposed solution opens a new direction for optical networking, allowing optical network realization without the need to wait for the technological realization of optical processing devices to replace the relatively slow nodal electronic processing in existing networks. The design and operation of Quadro is presented and demonstrated for different types of LAN and MAN systems.