Optical Grid Research Articles

Load Balancing in Optical Grids

This collaboration of geographically distributed domains in multi-domain optical grid environment should be done in a way that maintains the privacy of each participant domain. This calls for a new load balancing hierarchical approach to deal with such environments. In this paper, we propose two load balancing techniques within this hierarchical approach: Network Aware Divisible Load Algorithm (NADLA) and Genetic Algorithm based Load Distribution (GA-LD). Both algorithms are considered as Network Aware. Simulation results show the scalability and feasibility of the proposed approach and the advantages of the two proposed techniques compared to the classical Divisible Load Algorithm (DLA). In the last years, the growing of the scientific and enterprise applications pushes grid systems to more scalable and collaborative direction. Single domain resources are becoming insufficient to deal with application requirements. Grid applications require massive amounts of data to be transferred and processed in geographically distributed sites across the grid. The grid is an inter- connected multi-domain environment where each domain consists of computational, storage and communication resources grouped together for business or administrative reasons. Each domain is independently administrated and is free to deploy different technologies. Achieving better resource utilization calls for running load balancing techniques across different grid domains. This calls for novel load balancing techniques running in multi-domain scalable architecture to achieve better resource utilization without sacrificing domain security or privacy. The proposed multi-domain optical grid architecture assumes a dynamic on-demand reconfigurable optical network instead of pre-planned statically provisioned optical network. Dynamic reconfigurable optical grids presented in different projects such as Phosphorus (1) and G-lambda Projects (2). These projects present the structure and different components of optical network deployment in grids, and how these components interact to provide the grid applications with the services and capabilities making it able to manage its grid and optical network resource. In this paper, we present load balancing techniques in multi-domain hierarchical optical grid architecture that maintains the privacy, integration and scalability requirements. The privacy of a grid domain must be maintained in for confidentiality and commercial competition. For example, internal topology information of a domain should not be revealed to other domains (3). The domain privacy could be maintained by keeping the full resource information internally, while

Revised Slide Window First Algorithm for Advanced Reservation in Optical Grid

Revised Slide Window First Algorithm for Advanced Reservation in Optical Grid

Upgrading and extending PON by using in-band WDM overlay

This paper presents a new approach to upgrade and extend the reach of the current passive optical network (PON) by using wavelength division multiplexing (WDM) in the standardized optical grid of gigabit PON (In-band WDM PON overlay). The aim is to increase the number of optical distribution networks (ODNs) fed by a single fiber while preserving the users bandwidth. In this approach four downstream (DS) wavelength signals are transmitted from an optical line terminal (OLT) to four different ODNs using the standard DS PON spectrum ranging from 1480 to 1500 nm. The upstream (US) signals from the four different ODNs are also wavelength multiplexed within the standardized US PON spectrum ranging from 1270 to 1330 nm. Experimental proofs of concept are presented in a 20 km PON serving 32 ONTs and in a 58 km extended PON in order to demonstrate the feasibility of this proposal.

Techniques for Designing Survivable Optical Grid Networks

Grid computing involves high performance computing with resource sharing to support data-intensive applications, and requires high speed communications. Wavelength division multiplexing (WDM) optical networks become a natural choice for interconnecting the distributed computational and/or storage resources due to their high throughput, high reliability and low cost. This has led to increased research attention on techniques for developing fault tolerant optical grids. Different solutions have been proposed in the literature to provide protection and fault-tolerance in both grid computing and optical networks. However, the design of a resilient optical grid network should consider the inter-relation between computing and networking resource usage and how they are affected by potential faults. Hence, it is necessary to develop integrated, sophisticated algorithms that jointly allocate both computing and networking resources to improve the resource utilization while guaranteeing service availability. In this paper, we investigate the survivability of optical grids and review the state-of-the-art techniques and approaches in this area. We also identify some open problems and point out a number of promising approaches for future research direction to achieve fault tolerance in optical grid networks.

New Technology for Grids and Scales Manufacturing in Optical Devices

Using the laser controlled thermocracking method, research results for the new technology of optical grids and scales manufacturing are given in this paper. The opportunity of grids and scales manufacturing is shown for a wide range of the sizes, scale’s pitches and its width: from 10 nanometers up to 10 microns with a backlight in various optical ranges.

Anycast Routing for Survivable Optical Grids: Scalable Solution Methods and the Impact of Relocation

In this paper, we address the issue of resiliency against single link network failures in optical grids and show how the anycast routing principle, which is typical of grids, can be exploited in providing efficient shared path protection. We investigate two different integer linear program models for the full anycast routing problem, deciding on the primary and backup server locations as well as on the lightpaths toward them. The first model is a classical integer linear programming (ILP) model, which lacks scalability. The second model is a large-scale optimization model which can be efficiently solved using column generation techniques. We also design two new heuristics: the first one is an improvement of a previously proposed one which, although providing near optimal solutions, lacks scalability, while the second one is highly scalable, at the expense of reduced accuracy. Numerical results are presented for three mesh networks with varying node degrees. They allow an illustration of the scalability of the newly proposed approaches. Apart from highlighting the difference in performance (i.e., scalability and optimality) among the algorithms, our case studies demonstrate the bandwidth savings that can be achieved by exploiting relocation rather than using a backup path to the original (failure-free) destination site. Numerical results for varying network topologies, as well as different numbers of server sites show that relocation allows bandwidth savings in the range of 7–21%.

Parallel and multi-wavelength downloading in optical grid networks

In optical grid networks, data files for job execution are replicated at multiple sites in order to distribute loads and achieve high performance computing. Those replicas are downloaded in parallel in order to reduce downloading time. Furthermore, each replica is downloaded with multiple wavelengths. Although parallel and multi-wavelength downloading reduce downloading time, they raise blocking probability of file downloading. This is because they use a lot of wavelength resources and thus often generate bottleneck links. To resolve this problem, this paper proposes a parallel and multi-wavelength downloading scheme for optical grid networks. The proposed scheme provides replica selection, route selection, and wavelength selection for parallel and multi-wavelength downloading. In the proposed scheme, clients dynamically select combinations of a replica, a route, and a wavelength in such a way that they suppress the generation of bottleneck links. Through simulation experiments, we show that the proposed scheme efficiently improves blocking probability of parallel and multi-wavelength downloading.

Providing resiliency for optical grids by exploiting relocation: A dimensioning study based on ILP

Grids use a form of distributed computing to tackle complex computational and data processing problems scientists are presented with today. When designing an (optical) network supporting grids, it is essential that it can overcome single network failures, for which several protection schemes have been devised in the past. In this work, we extend the existing Shared Path protection scheme by incorporating the anycast principle typical of grids: a user typically does not care on what specific server this job gets executed and is merely interested in its timely delivery of results. Therefore, in contrast with Classical Shared Path protection (CSP), we will not necessarily provide a backup path between the source and the original destination. Instead, we allow to relocate the job to another server location if we can thus provide a backup path which comprises less wavelengths than the one CSP would suggest. We assess the bandwidth savings enabled by relocation in a quantitative dimensioning case study on an European and an American network topology, exhibiting substantial savings of the number of required wavelengths (in the order of 11–50%, depending on network topology and server locations). We also investigate how relocation affects the computational load on the execution servers. The case study is based on solving a grid network dimensioning problem: we present Integer Linear Programming (ILP) formulations for both the traditional CSP and the new resilience scheme exploiting relocation (SPR). We also outline a strategy to deal with the anycast principle: assuming we are given just the origins and intensity of job arrivals, we derive a static (source, destination)-based demand matrix. The latter is then used as input to solve the network dimensioning ILP for an optical circuit-switched WDM network.

The Measurement of Liquid Free Surface in Buoyant-Thermocapillary Convection by the Optical Grid Line Method

The Measurement of Liquid Free Surface in Buoyant-Thermocapillary Convection by the Optical Grid Line Method

Automated Sensor Network to Advance Ocean Science

Oceanography is evolving from a shipbased expeditionary science to a distributed, observatory‐based approach in which scientists continuously interact with instruments in the field. These new capabilities will facilitate the collection of long‐term time series while also providing an interactive capability to conduct experiments using data streaming in real time.The U.S. National Science Foundation has funded the Ocean Observatories Initiative (OOI), which over the next 5 years will deploy infrastructure to expand scientists' ability to remotely study the ocean. The OOI is deploying infrastructure that spans global, regional, and coastal scales. A global component will address planetary‐scale problems using a new network of moored buoys linked to shore via satellite telecommunications. A regional cabled observatory will “wire” a single region in the northeastern Pacific Ocean with a high‐speed optical and power grid. The coastal component will expand existing coastal observing assets to study the importance of high‐frequency forcing on the coastal environment.

Markovian Approximations for a Grid Computing Network with a Ring Structure

Optical grid networks allow many computing sites to share their resources by connecting them through high-speed links, providing a more efficient use of the resources and a timely response for incoming jobs. These jobs originate from users connected to each of the sites and, in contrast to traditional queueing networks, a particular job does not have to be processed in a predefined site. Furthermore, a job is always processed locally if there is an available local server. In this paper we propose two different methods to approximate the performance of an optical grid network with a ring topology. The first method is based on approximating the inter-overflow time process, while the second separately characterizes the periods where jobs are overflowed and the periods where they are served locally. Both approaches rely on a marked Markovian representation of the overflow process at each station and on reducing this representation by moment-matching methods. The results show that the methods accurately approximate the rate of locally processed jobs, one of the main performance measures.

Availability-Driven Scheduling for Real-Time Directed Acyclic Graph Applications in Optical Grids

Optical grid systems have been viewed as a promising virtual computing environment to support distributed real-time directed acyclic graph (DAG) applications. For such a system involving many heterogeneous computing and network resources, faults seem to be inevitable. Therefore, a fault-tolerant DAG scheduling scheme is necessary to improve the performance of the optical grid system. However, existing joint task scheduling schemes for real-time DAG applications generally do not consider the availability issues when making scheduling decisions. We develop an availability-driven scheduling scheme that improves the DAG availability iteratively by allocating two copies of one communication task to two disjoint lightpaths for data transfer while satisfying application deadline requirements. Extensive simulation results demonstrate the effectiveness and the feasibility of the proposed scheduling scheme.

Mean Field Calculation for Optical Grid Dimensioning

For traditional optical network dimensioning, a plethora of algorithms exists to design the amount of network resources required to accommodate a given amount of traffic, expressed as a (source, destination)-based traffic matrix. In optical Grid dimensioning, however, the anycast principle applies: Grid users do not really care where exactly their tasks (Grid jobs) end up being executed. Thus, the destination of traffic is not known beforehand and traditional dimensioning algorithms are not applicable. In this paper we propose a mean field calculation method to analytically derive the traffic matrix for given job arrival intensities at the originating Grid sites (the sources). We also indicate how it can be integrated in a stepwise dimensioning approach to compute not only the amount of network resources, but also Grid resources (computational and/or storage). Hence it forms part of a solution for Grid dimensioning: determining how many servers to provide, where to place them, and which network to install for interconnecting server sites and users generating Grid jobs.

Research on aspect-oriented open grid services architecture

This paper proposed an Aspect-Oriented Open Grid Services Architecture (AO-OGSA) to tackle the multi-binding of Open Grid Services Architecture (OGSA). Through forming the grid public demand into aspect module,AO-OGSA realized the separation between crosscutting concerns and core concerns in the grid application software. Therefore,it reduced the coupling between modules. Finally,taking the service packaging and resource scheduling in the optical grid as an example,the simulation modules based on OGSA and AO-OGSA were respectively constructed,and the simulation results were contrastively analyzed according to software system performance.

Fiber Optical Spatial Filter Anemometry – Intravital Measurement of Red Blood Flow Velocity (RBCV) in the Microcirculation

The fiberoptical spatial filter anemometry (SFA) is a common technique based on an optical grid to measure the velocity of corpuscular components in a multiphase flow, e.g. in the microvessels. The technical innovation is the analysis of flow velocities using an optical grid sensor and frequency analysis by Fast Fourier Transformation (FFT). This study describes a non-invasive, on-line technique to measure RBCV in the microcirculation. The sensor's validity was proven by in vitro measurements using a rotation disk of an exactly defined velocity with a correlation coefficient of 0.99967. For validation of RBCV measurements in the microcirculation in vivo, the setup was adapted to an intravital microscope. RBCV was measured in arterioles, capillaries, and postcapillary venules ranging from 8-140 microm diameter. As reference method for velocity measurements a computer assisted imaging system was used to measure the RBC-velocity in the identical vessels by frame to frame analysis. Both methods revealed a high significant correlation using transillumination technique for capillaries (r=0.986, p<0.001) and venules (r=0.952, p<0.001) as well as epiillumination technique (capillaries r=0.939, venules r=0.975, p<0.001).

Energy Efficiency in Telecom Optical Networks

Since the energy crisis and environmental protection are gaining increasing concerns in recent years, new research topics to devise technological solutions for energy conservation are being investigated in many scientific disciplines. Specifically, due to the rapid growth of energy consumption in ICT (Information and Communication Technologies), lot of attention is being devoted towards green ICT solutions. In this paper, we provide a comprehensive survey of the most relevant research activities for minimizing energy consumption in telecom networks, with a specific emphasis on those employing optical technologies. We investigate the energy-minimization opportunities enabled by optical technologies and classify the existing approaches over different network domains, namely core, metro, and access networks. A section is also devoted to describe energy-efficient solutions for some of today's important applications using optical network technology, e.g., grid computing and data centers. We provide an overview of the ongoing standardization efforts in this area. This work presents a comprehensive and timely survey on a growing field of research, as it covers most aspects of energy consumption in optical telecom networks. We aim at providing a comprehensive reference for the growing base of researchers who will work on energy efficiency of telecom networks in the upcoming years.

On-Demand End-to-End Optical Network Construction for Grid Applications with Adaptive and Distributed Control over Multi-Domain WSONs

In this paper, we address the on-demand end-to-end optical network construction problem for grid applications in new generation large-scale multi-domain wavelength switched optical networks (WSON). According to users' requests for high-performance distributed computing, groups of dedicated end-to-end lightpaths among geographically distributed grid resources can be established dynamically forming multiple-lightpath optical networks for grid applications, namely, optical grid network (OGN). To facilitate the automated OGN construction, we introduce an optical grid network infrastructure providing an integrated and self-contained OGN service to grid users with totally distributed control. In this infrastructure, for easy construction, especially in a large-scale multi-domain WSON environment, we propose an overlay approach to construct OGNs in a peer-to-peer fashion, which conceals the communication architecture of the underlying heterogeneous optical networks. In particular, we propose an adaptive construction mechanism that can develop the OGN flexibly by adapting to the dynamically changed optical network circumstance. To enable users to take the advantage of the end-to-end lightpaths of WSON directly, a wavelength-oriented end-host configuration scheme is proposed. Experimental results on a developed prototype and an optical-fibre test-bed network successfully validate the proposal.

Optical grid networking exploiting path computation element (PCE) architecture

A dynamic and joint optimisation of computational and network resources may significantly improve the performance of grid-enabled applications. In this paper, the path computation element protocol (PCEP) is first proposed as standard grid network service interface between grid resource manager (GRM) and network resource manager (NRM). Then, two different schemes exploiting the PCEP protocol and the PCE capability to provide synchronised and optimal path computations are proposed. The schemes allow the GRM to exploit performance metrics representative of the expected network resource utilisation and to perform a jointly optimal choice of both computational and network resources. Simulation results show that the proposed schemes significantly improve the overall amount of successfully established grid services. Experimental implementations on the 'JGN2plus' testbed are presented to show that the proposed schemes avoid control plane extensions or interfaces specifically designed for grid purposes and do not substantially affect the overall grid service delivery time.

Joint resource and network scheduling with adaptive offset determination for optical burst switched grids

Optical burst switching (OBS) is a promising technology for optical grids with short-lived and interactive data communication requirements. On the other hand, burst losses are in the nature of the OBS protocol and these losses severely affect the grid job completion times. This paper first proposes a joint grid resource and network provisioning method to avoid congestion in the network in order to minimize grid job completion times. Simulations show that joint provisioning significantly reduces completion times in comparison to other methods that perform network provisioning after grid scheduling. An adaptive extra offset based quality of service (QoS) mechanism is also proposed in order to reduce grid burst losses in case of network congestion. Results show that this adaptive mechanism significantly reduces grid completion times by exploiting the trade-off between decreasing loss probability and increasing delay introduced by the extra offset time.

Converged Optical Network Infrastructures in Support of Future Internet and Grid Services Using IaaS to Reduce GHG Emissions

With the rapid and growing volume of green house gas (GHG) we may soon cross a tipping point where there may be dramatic climatic catastrophes such that governments will be forced to order the shutdown of coal powered electrical production or mandate carbon neutrality across all sectors of society. On the other hand, in the event of such a development, the future Internet and Grid infrastructure may become absolutely essential for communications and a replacement for travel and for the delivery of critical services such as health, education, research, etc. Information and Communication Technologies (ICT) produce 2%-3% of the world's GHG emissions through the consumption of electricity largely produced by coal plants. This rate of GHG is expected to double in the next few years and is clearly unsustainable. Therefore it is critical that any future Internet and Grid infrastructure be designed not only to survive, but also be sustained, through an age where no additional GHG emissions will be allowed. Converged optical networks, Grid and cloud services hosted at zero carbon renewable energy sites using Infrastructure as a Service (IaaS) where each network and computer element is represented to a user as a configurable virtual service will allow for the deployment of what are often referred to as ldquofollow the sun or follow the windrdquo optical network and Grid architectures where the network and Grid topology and Grid resources availability and location are constantly changing depending on local availability states of the wind or sun.