Dimensionerings- en werkverdelingsalgoritmen voor lambda grids

Grids bestaan uit een verzameling reken- en opslagelementen die geografisch verspreid kunnen zijn, maar waarvan men de gezamenlijke capaciteit wenst te benutten. Daartoe dienen deze elementen verbonden te worden met een netwerk. Vermits veel wetenschappelijke applicaties gebruik maken van een Grid, en deze applicaties doorgaans grote hoeveelheden data verwerken, is het noodzakelijk om een netwerk te voorzien dat dergelijke grote datastromen op betrouwbare wijze kan transporteren. Optische transportnetwerken lenen zich hier uitstekend toe. Grids die gebruik maken van dergelijk netwerk noemt men lambda Grids. Deze thesis beschrijft een kader waarin het ontwerp en dimensionering van optische netwerken voor lambda Grids kunnen beschreven worden. Ook wordt besproken hoe werklast kan verdeeld worden op een Grid eens die gedimensioneerd is. Een groot deel van de resultaten werd bekomen door simulatie, waarbij gebruik gemaakt wordt van een eigen Grid simulatiepakket dat precies focust op netwerk- en Gridelementen. Het ontwerp van deze simulator, en de daarbijhorende implementatiekeuzes worden dan ook uitvoerig toegelicht in dit werk

Accepted for Photonic Network Communications

Abstract-When deploying Grid infrastructure, the problem of dimensioning arises: how many servers to provide, where to place them, and which network to install for interconnecting server sites and users generating Grid jobs? In contrast to classical optical network design problems, it is typical of optical Grids that the destination of traffic (jobs) is not known beforehand. This leads to so-called anycast routing of jobs. For network dimensioning, this implies the absence of a clearly defined (source,destination)-based traffic matrix, since only the origin of Grid jobs (and their data) is known, but not their destination. The latter depends not only on the state of Grid resources, including network, storage, and computational resources, but also the Grid scheduling algorithm used. We present a phased solution approach to dimension all these resources, and use it to evaluate various scheduling algorithms in two European network case studies. Results show that the Grid scheduling algorithm has a substantial impact on the required network capacity. This capacity can be minimized by appropriately choosing a (reasonably small) number of server site locations: an optimal balance can be found, in between the single server site case requiring a lot of network traffic to this single location, and an overly fragmented distribution of server capacity over too many sites without much statistical multiplexing opportunities, and hence a relatively large probability of not finding free servers at nearby sites

Signaling strategies for consumer oriented Grid over Optical Burst Switching networks

Dissertação mest., Engenharia Eléctrica e Telecomunicações, Universidade do Algarve, 2009The concept of Grid networks has recently emerged as an infrastructure able to support, both scientific and commercial applications. The Grid is a dynamic, distributed collection of heterogeneous computational, storage and network resources geographically distributed and shared between organizations. Optical Burst Switching (OBS) networks have been identified as a technology with potential to support the requirements of the Grids. This approach, known as Grid over Optical Burst Switching (GOBS) is currently the object of intensive research. This dissertation focus is on GOBS architectures employing Active OBS Routers with centralized control. This approach enables the balance of the overall network traffic potentially minimizing congestion and consequently reducing job blocking. Two different strategies are explored. The first strategy is a novel signaling scheme applied to a GOBS network employing Active Routers. The Active Router reduces the job blocking probability, because the path used by the Data Burst to reach the Grid Job Resource is selected based on the network actual status. Since the Active Router maintains the network status always updated, the bursts are only dropped when is not possible to connect the source to the end node. Another study associated with this signaling scheme is the reservation time. It is demonstrated that this approach decreases the network blocking probability at the same time that decreases the time delay that a job suffers until it reaches the Grid service provider. In the second strategy, the Active Router only select the Grid Resource used to resolve the job, the path used to reach it is selected by the Grid client based on the probabilistic model for the link demands. The probabilistic model is used to predict a possible network usage based on the demands from all nodes to all nodes. The results obtained show overall performance improvement

Joint path and resource selection for OBS grids with adaptive offset based QOS mechanism

Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2007.Thesis (Master's) -- Bilkent University, 2007.Includes bibliographical references leaves 71-76It is predicted that grid computing will be available for consumers performing their daily computational needs with the deployment of high bandwidth optical networks. Optical burst switching is a suitable switching technology for this kind of consumer grid networks because of its bandwidth granularity. However, high loss rates inherent in OBS has to be addressed to establish a reliable transmission infrastructure. In this thesis, we propose mechanisms to reduce loss rates in an OBS grid scenario by using network-aware resource selection and adaptive offset determination. We first propose a congestion-based joint resource and path selection algorithm. We show that path switching and network-aware resource selection can reduce burst loss probability and average completion time of grid jobs compared to the algorithms that are separately selecting paths and grid resources. In addition to joint resource and path selection, we present an adaptive offset algorithm for grid bursts which minimizes the average completion time. We show that the adaptive offset based QoS mechanism significantly reduces the job completion times by exploiting the trade-off between decreasing loss probability and increasing delay as a result of the extra offset time.Köseoğlu, MehmetM.S

Scalable Impairment-Aware Anycast Routing in Multi-Domain Optical Grid Networks

ABSTRACT In optical Grid networks, the main challenge is to account for not only network parameters, but also for resource availability. Anycast routing has previously been proposed as an effective solution to provide job scheduling services in optical Grids, offering a generic interface to access Grid resources and services. The main weakness of this approach is its limited scalability, especially in a multi-domain scenario. This paper proposes a novel anycast proxy architecture, which extends the anycast principle to a multi-domain scenario. The main purpose of the architecture is to perform aggregation of resource and network states, and as such improve computational scalability and reduce control plane traffic. Furthermore, the architecture has the desirable properties of allowing Grid domains to maintain their autonomy and hide internal configuration details from other domains. Finally, we propose an impairment-aware anycast routing algorithm that incorporates the main physical layer characteristics of large-scale optical networks into its path computation process. By integrating the proposed routing scheme into the introduced architecture we demonstrate significant network performance improvements. Keywords: Grid computing, routing algorithms, optical networks, physical impairments, anycast routing. INTRODUCTION Today, the need for network systems to support storage and computing services for science and business, is often satisfied by relatively isolated computing infrastructure (clusters). Migration to truly distributed and integrated applications requires optimization and (re)design of the underlying network technology to create a Grid platform for the cost and resource efficient delivery of network services with substantial data transfer, processing power and/or data storage requirements. Optical networks offer an undeniable potential for the Grid, given their proven track-record in the context of high-speed, long-haul, networking. Not only eScience applications dealing with large experimental data sets (e.g. particle physics) but also business/consumer oriented applications can benefit from optical Grid infrastructure [1]: both the high data rates typical of eScience applications and the low latency requirements of consumer/business applications (cf. interactivity) can effectively be addressed. When using transparent WDM as such network technology, signals are transported end-to-end optically without being converted to the electrical domain in between. Connection provisioning of all-optical connections (lightpaths) between source and destination nodes is based on specific routing and wavelength assignment algorithms (RWA). Traditional RWA schemes only account for network conditions such as connectivity and available capacity, without considering physical layer details. However, in transparent optical networks covering large geographical areas, the optical signal experiences the accumulation of physical impairments through transmission and switching, possibly resulting in unacceptable signal quality Another emerging and challenging task in distributed and heterogeneous computing environments, is job scheduling: when and where to execute a given Grid job, based on the requirements of the job (for instance a deadline and minimal computational power) and the current state of the network and resources. Traditionally, a local scheduler optimizes utilization and performance of a single Grid site, while a meta-scheduler is distributes workload across different sites. Current implementations of these (meta-)schedulers only account for Grid resource availability In this paper we propose a novel architecture to support impairment-aware anycast routing for large-scale optical Grid networks. Section 2 discusses general approaches to support multi-domain networks. We then proceed to introduce a novel architecture, which can provide anycast Grid services in a multi-domain scenario (Section 3). Simulation analysis is used to demonstrate the improved scalability without incurring significant performance loss. Furthermore, Section 4 shows how to incorporate physical layer impairments, to further improve the performance of optical Grid networks. Conclusions are presented in Section 5

Architecture de simulation multiressource pour un réseau grille basé sur OBS

Le concept de la grille de calcul a émergé récemment comme infrastructure apte à répondre aux exigences des applications scientifiques et économiques en termes de stockage et calcul. Le principe de la grille est de regrouper toute la puissance inexploitée des ordinateurs d'un réseau pour la mettre à la disposition des applications nécessitant de grands calculs. Il s'agit également d'utiliser l'espace de stockage inutilisé des serveurs pour y entreposer des données. Une grille de calcul représente donc une collection de ressources informatiques réparties en plusieurs emplacements et agissent en tant que ressources de traitement unifiées ou comme une collection d'ordinateurs virtuels. L'avantage de la grille consiste en un traitement plus rapide et plus efficace. Elle permet aussi d'éliminer l'inconvénient de lier étroitement des machines spécifiques à des travaux spécifiques. Puisqu'elle permet à des utilisateurs et à des applications d'accéder et de contrôler efficacement diverses ressources de différentes locations distribuées. Toutefois, sans un moyen de transport de données assez rapide, il y aurait aucun avantage dans le traitement distribué des données. La commutation optique par rafales (OBS) a été identifiée comme la technologie idéale pour répondre aux exigences de la grille. Cette approche est connue sous le nom de grille basée sur OBS « GOBS ». Dans ce mémoire nous étudions et évaluons la performance d'un réseau GOBS. Nous présentons aussi le problème de multi-ressource dans le cas où plusieurs ressources informatiques seront dédiées pour le traitement des tâches de la grille. Les résultats obtenus nous ont permis de démontrer que l'approche multi-ressource est efficace pour le traitement distribuée au sein de la grille et particulièrement dans le cas de grandes tâches. Elle permet de réduire le taux de perte et aussi d'assurer un traitement plus rapide. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Grille de calcul, GOBS, OBS, Tâche, Burst, Rafale, Paquet de contrôle, Ressource

The emerging energy web

There is a general need of elaborating energy-effective solutions for managing our increasingly dense interconnected world. The problem should be tackled in multiple dimensions -technology, society, economics, law, regulations, and politics- at different temporal and spatial scales. Holistic approaches will enable technological solutions to be supported by socio-economic motivations, adequate incentive regulation to foster investment in green infrastructures coherently integrated with adequate energy provisioning schemes. In this article, an attempt is made to describe such multidisciplinary challenges with a coherent set of solutions to be identified to significantly impact the way our interconnected energy world is designed and operated. Graphical abstrac