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 TitleDate AddedCompany
whitepaper Transparent Optical Network Design With Sparse Wavelength Conversion2007-06-13 Zuse-Institut Berlin
  This paper considers the design of transparent optical networks from a practical perspective. Network operators aim at satisfying the communication demands at minimum cost. Such an optimization involves three interdependent planning issues: the dimensioning of the physical topology, the routing of lightpaths, and the wavelength assignment. Further topics include the reliability of the configuration and sparse wavelength conversion for efficient use of the capacities. This paper investigates this extensive optical network design task. Using a flexible device-based model, the paper presents an integer programming formulation that supports greenfield planning as well as expansion planning on top of an existing network.

Tags: Network Design, Green IT		   
whitepaper Analysis of Randomized Scheduling Algorithm for a Practical Bufferless Optical Network2007-06-01 Institute of Electrical and Electronics Engineers
  This paper evaluates a plausible bufferless star-based packet-switched optical network. A randomized scheduling algorithm is used to resolve contention, alleviating the need for a centralized controller to coordinate the edge nodes. A bipartite graph matching algorithm is proposed to be used at the core node to minimize the packet drop rate. The paper examines the performance of the system via simulation, to establish the potential of this architecture for practical packet-switched optical networks.

Tags: Switching		   
whitepaper Routing in Optical and Non-Optical Networks Using Boolean Satisfiability2007-06-01 Institute of Electrical and Electronics Engineers
  Off late, most routing problems are solved using Dijkstra's shortest path algorithm. Many efficient implementations of Dijkstra's algorithm exist and can handle large networks in short runtimes. Despite these advances, it is difficult to incorporate user-specific conditions on the solution when using Dijkstra's algorithm. Such conditions can include forcing the path to go through a specific node, forcing the path to avoid a specific node, using any combination of inclusion/exclusion of nodes in the path, etc. This paper proposes a new approach to solving the shortest path problem using advanced Boolean SATisfiability (SAT) techniques. SAT has been heavily researched in the last few years.

Tags: Switching, Software Engineering		   
whitepaper Optical Burst Switching Network: A Multi-Layered Approach2007-05-09 IOS Press
  This paper defines a new multi-layered architecture for supporting Optical Burst Switching (OBS) in an optical core network. The architecture takes into account both the control plane as well as the data plane. The paper describes the functionality and the primary protocols that are required at each layer and it explains how the layers interact with each other in the proposed architecture. This paper also identifies some of the challenges and issues surrounding the development of OBS networks, such as data burst scheduling, contention resolution mechanism, supporting QoS, and handling TCP/IP, and provides a brief survey of proposed OBS protocols.

Tags: Switching, TCP - IP		   
whitepaper Federated Grid Clusters Using Service Address Routed Optical Networks2007-05-05 Reed Elsevier
  Clusters of computers have emerged as cost-effective parallel and/or distributed computing systems for computationally intensive tasks. Normally, clusters are composed of high performance computational nodes linked together by low-latency/high-bandwidth interconnection networks. With the advent of modern optical networking technologies, geographically distant clusters can be federated to yield systems considered tightly-coupled. By using Service Address Routed (SAR) optical networks, cluster federations are shown to be effective in dealing with complex scientific computations in a manner that is transparent to the user. The analysis of such federated clusters is carried out using a discrete event simulator.

Tags: High Availability		   
whitepaper A Performance Study on Optical Burst Switched Networks: Ring Topology2007-05-02 MCNC Research and Development Institute
  Existing performance studies on Optical Burst Switched (OBS) networks have been focusing on channel blocking, i.e., when the required wavelength is not available on a link along a burst's route. However, the paper identifies another type of blocking as the receiver blocking, i.e., when the receiver at a burst's destination node is occupied by another burst. Receiver blocking may account for the much larger part of total burst blocking. Receiver blocking has been largely ignored in existing research. This paper proposes using multiple receivers or Fiber Delay Lines (FDL) in front of the receivers in order to reduce the receiver blocking probability. Extensive simulation results on bi-directional OBS rings are presented to illustrate the problem and the performance of the proposed approaches.

Tags: Switching		   
whitepaper Alternatives for In-Service BER Estimation in All-Optical Networks: Towards Minimum Intrusion2007-05-01 Academy Publisher
  Combining the existing approaches for optical intelligence and the speed and capacity of light is undoubtedly the only viable strategy for building future-proof, high-speed networks. Future optical networks are also expected to provide added value through service quality. However, the performance parameters included in current Service Level Agreements (SLA) require the termination of a channel (wavelength) at an Optical-Electrical (O/E) conversion point to measure them. In all-optical networks, this is associated with higher cost. Therefore, the optimal monitoring solution for all-optical networks will be one that implements the minimum amount of O/E conversions required to measure or estimate the SLA parameters. This is very challenging due to the complex relations of electrical and optical parameters.

Tags: Monitoring Systems, SLA		   
whitepaper Raman Crosstalk Suppression in CATV Overlay Passive Optical Network2007-05-01 Institute of Electrical and Electronics Engineers
  In CAble TeleVision (CATV) overlay Passive Optical Networks (PONs), where a CATV signal copropagates with a downstream baseband signal, the crosstalk components mediated by Stimulated Raman Scattering (SRS) limit the performance of low-number CATV channels. This paper proposes and demonstrates a way of reducing the SRS-induced crosstalk in CATV overlay PONs. The proposed scheme utilizes a high-speed polarization scrambler in the transmitter to make the SRS-induced crosstalk independent of polarization evolution along the fiber and a subtractor module to compensate for the crosstalk. The demonstration shows that crosstalk can be reduced by 9 dB.

Tags: Web TV - Set Top Boxes		   
whitepaper Finding Elephant Flows for Optical Networks2007-04-30 Institute of Electrical and Electronics Engineers
  Optical networks are fast and reliable networks that enable, amongst others, dedicated light paths to be established for elephant IP flows. Elephant IP flows are characterized by being small in number, but long in time and high in traffic volume. Moving these flows from the general IP network to dedicated light paths can be beneficial for both the elephant flows as well as the general IP network. Elephant flows over light paths would benefit from receiving better Quality of Service (at the optical level there is no jitter and far more bandwidth) and, at the same time, IP networks would be off-loaded and therefore offer better Quality of Service to the remaining, smaller IP flows.

Tags: Diagnostics and Analysis, TCP - IP		   
whitepaper Self-Management of Lambda-Connections in Optical Networks2007-04-20 Springer Science+Business Media
  This paper presents a new idea for the management of lambda-connections in optical networks. The idea consists of making multi-service optical switches responsible for automatically detecting IP flows at the packet-level, creating lambda-connections for them, and moving them to the optical-level. In addition to that, they are also in charge of tearing down the connections when no longer needed.

Tags: Switching, IP Technologies