G-QoSM: Grid Service Discovery Using QoS Properties

We extend the service abstraction in the Open Grid Services Architecture citeogsa for Quality of Service (QoS) properties. The realization of QoS often requires mechanisms such as advance or on-demand reservation of resources, varying in type and implementation, and independently controlled and monitored. Foster et al. propose the GARA citeFostKessl99 architecture. The GARA library provides a restricted representation scheme for encoding resource properties and the associated monitoring of Service Level Agreements (SLAs). Our focus is on the application layer, whereby a given service may indicate the QoS properties it can offer, or where a service may search for other services based on particular QoS properties

Capacity planning and stochastic scheduling in grid computing environments

Imperial Users onl

Economic-based Distributed Resource Management and Scheduling for Grid Computing

Computational Grids, emerging as an infrastructure for next generation computing, enable the sharing, selection, and aggregation of geographically distributed resources for solving large-scale problems in science, engineering, and commerce. As the resources in the Grid are heterogeneous and geographically distributed with varying availability and a variety of usage and cost policies for diverse users at different times and, priorities as well as goals that vary with time. The management of resources and application scheduling in such a large and distributed environment is a complex task. This thesis proposes a distributed computational economy as an effective metaphor for the management of resources and application scheduling. It proposes an architectural framework that supports resource trading and quality of services based scheduling. It enables the regulation of supply and demand for resources and provides an incentive for resource owners for participating in the Grid and motives the users to trade-off between the deadline, budget, and the required level of quality of service. The thesis demonstrates the capability of economic-based systems for peer-to-peer distributed computing by developing users' quality-of-service requirements driven scheduling strategies and algorithms. It demonstrates their effectiveness by performing scheduling experiments on the World-Wide Grid for solving parameter sweep applications

Planning and Optimization During the Life-Cycle of Service Level Agreements for Cloud Computing

Ein Service Level Agreement (SLA) ist ein elektronischer Vertrag zwischen dem Kunden und dem Anbieter eines Services. Die beteiligten Partner kl aren ihre Erwartungen und Verp ichtungen in Bezug auf den Dienst und dessen Qualit at. SLAs werden bereits f ur die Beschreibung von Cloud-Computing-Diensten eingesetzt. Der Diensteanbieter stellt sicher, dass die Dienstqualit at erf ullt wird und mit den Anforderungen des Kunden bis zum Ende der vereinbarten Laufzeit ubereinstimmt. Die Durchf uhrung der SLAs erfordert einen erheblichen Aufwand, um Autonomie, Wirtschaftlichkeit und E zienz zu erreichen. Der gegenw artige Stand der Technik im SLA-Management begegnet Herausforderungen wie SLA-Darstellung f ur Cloud- Dienste, gesch aftsbezogene SLA-Optimierungen, Dienste-Outsourcing und Ressourcenmanagement. Diese Gebiete scha en zentrale und aktuelle Forschungsthemen. Das Management von SLAs in unterschiedlichen Phasen w ahrend ihrer Laufzeit erfordert eine daf ur entwickelte Methodik. Dadurch wird die Realisierung von Cloud SLAManagement vereinfacht. Ich pr asentiere ein breit gef achertes Modell im SLA-Laufzeitmanagement, das die genannten Herausforderungen adressiert. Diese Herangehensweise erm oglicht eine automatische Dienstemodellierung, sowie Aushandlung, Bereitstellung und Monitoring von SLAs. W ahrend der Erstellungsphase skizziere ich, wie die Modellierungsstrukturen verbessert und vereinfacht werden k onnen. Ein weiteres Ziel von meinem Ansatz ist die Minimierung von Implementierungs- und Outsourcingkosten zugunsten von Wettbewerbsf ahigkeit. In der SLA-Monitoringphase entwickle ich Strategien f ur die Auswahl und Zuweisung von virtuellen Cloud Ressourcen in Migrationsphasen. Anschlie end pr ufe ich mittels Monitoring eine gr o ere Zusammenstellung von SLAs, ob die vereinbarten Fehlertoleranzen eingehalten werden. Die vorliegende Arbeit leistet einen Beitrag zu einem Entwurf der GWDG und deren wissenschaftlichen Communities. Die Forschung, die zu dieser Doktorarbeit gef uhrt hat, wurde als Teil von dem SLA@SOI EU/FP7 integriertem Projekt durchgef uhrt (contract No. 216556)

Advance Reservations of Bandwidth in Computer Networks

In dieser Arbeit wurden die unterschiedlichen Aspekte untersucht, die die Leistungsfähigkeit eines Systems zur Vorausreservierung in Computer-Netzwerken bestimmen. Basierend auf einer Architektur, welche den Basisdienst für Vorausreservierungen mittels Multiprotocol Label Switching (MPLS) zur Verfügung stellt, wurden innerhalb eines Netzwerkmanagementsystems unterschiedliche Dienste implementiert und simulativ auf ihre Auswirkungen auf die Leistungsfähigkeit des Netzwerks in Bezug auf Anzahl zugelassener Datenströme sowie transportierte Datenmenge untersucht. Diese Dienste erweitern in entscheidendem Maße auch die Breite des Dienstangebots in Netzwerken im Vergleich zu bisherigen Implementierungen. So ist es möglich bei Angabe einer festen Datenmenge vom Netzwerkmanagement geeignete Übertragungszeiten und raten bestimmen zu lassen. Diese Parameter werden dann, zum Beispiel in Form von Service Level Agreements (SLA), vom Netzwerkmanagement garantiert und sind insbesondere in Umgebungen wichtig, in denen die Übertragung sehr großer Datenmengen notwendig ist, beispielsweise in Grid-Computing- Systemen. Die erweiterten Dienste dienen jedoch nicht nur den Nutzern, sondern sind auch für Betreiber interessant, da sie es ermöglichen die Leistungsfähigkeit des Netzwerkes zu erhöhen. Dies ist insbesondere zusammen mit weiteren Verfahren möglich, die die zusätzlich zur Verfügung stehenden Informationen über zeitliche Aspekte, wie die Dauer von Übertragungen, nutzen. Im Vergleich zu den heute hauptsächlich betrachteten Systemen zur sog. unmittelbaren Reservierung, kann bei geschicktem Einsatz der hier implementierten Dienste und Verfahren eine deutliche Verbesserung der Leistung erzielt werden. Hinzu kommen bei Vorausreservierungen die erheblichen Vorteile für die Nutzer eines Netzwerkes, wie z.B. der oben beschriebene Datentransfer. Die Leistung eines Netzwerkes bemisst sich jedoch nicht nur an der transportierten Datenmenge, sondern auch am Verhalten im Fehlerfall und der Geschwindigkeit des Managementsystems. Dazu wurden im Rahmen dieser Arbeit mögliche Strategien zur Reaktion von Vorausreservierungssystemen im Fall von Link-Ausfällen entwickelt und untersucht. Auch hier kommt dem zeitlichen Aspekt eine wichtige Bedeutung zu. Es erwies sich als erfolgreich, nicht nur unmittelbar betroffene Datenströme sondern auch solche, die zwar bereits bekannt, jedoch noch nicht aktiv waren, in die Fehlerbehandlungsstrategie mit einzubeziehen. Datenstrukturen, die von der Zugangskontrolle des Managementsystems benötigt werden und dort die Geschwindigkeit maßgeblich bestimmen, wurden unter den Aspekten der Zugriffsgeschwindigkeit und des Speicherverbrauchs untersucht. Hierbei wurde gezeigt, dass Arrays erhebliche Vorteile im Hinblick auf beide Aspekte haben und in den meisten Fällen einer Baumstruktur, die speziell für die Aufgabe innerhalb der Zugangskontrolle entwickelt wurde, überlegen sind. Die Nutzung von Vorausreservierungen in Computer-Netzwerken ist damit eine nützliche und wichtige Erweiterung der Funktionalität eines Netzwerkes sowohl in Bezug auf das zur Verfügung stehende Angebot an Diensten, als auch im Hinblick auf die Leistungsfähigkeit des Netzwerkes.In this thesis, the impact of using advance reservations of bandwidth in a computer network on the performance for both clients and operators of the network is examined. Based on an architecture that uses multi-protocol label switching (MPLS) controlled by bandwidth brokers, a number of services that - compared to todays best-effort or immediate reservation networks - provide an enhanced functionality for clients were developed. These services allow clients to specify requests in a less stringent way than currently necessary, for example, it is possible to define only the amount of data to be transmitted between two network endpoints and the management system then determines suitable transmission parameters such as start and stop time and transmission rate. This functionality provides reliable feedback to clients and can serve as a foundation for providing service-level agreements, e.g., guaranteeing deadlines for the transmission of a certain amount of data. The additional services can also be used by network operators to improve the overall utilization of the network. In addition, the various opportunities of using the additional temporal dimension of the advance reservation service are suitable to improve the network performance. It can be shown that the amount of blocked requests and bandwidth can be considerably decreased making use of both services and the additional information available in the given environment. Besides the achievable throughout and amount of admitted requests, the term performance in the context of advance reservation systems also covers other aspects such as failure recovery strategies and the processing time required by the network management system. In the thesis, several strategies to be applied in case of link failures are outlined and examined with respect to their applicability and achievable performance. For example, it can be shown that it is worthwhile to consider not only flows which are active at the time a failure occurs but also to take inactive but already admitted flows into account in order to achieve the best possible performance. In addition to failure recovery, also the processing speed of the management system is of importance. For that purpose, in particular the data structures used to store the current and future network status need to be examined since they dominate the processing time of the management system. Two data structures, arrays and a tree which was especially designed for this purpose were examined, showing that arrays are superior with respect to processing speed and memory consumption in almost any environment

QoS Abstraction Layer in 4G Access Networks

Tese de Mestrado. Redes e Serviços de Comunicação. Faculdade de Engenharia. Universidade do Porto. 200

Decentralising resource management in operating systems

This dissertation explores operating system mechanisms to allow resource-aware applications to be involved in the process of managing resources under the premise that these applications (1) potentially have some (implicit) notion of their future resource demands and (2) can adapt their resource demands. The general idea is to provide feedback to resource-aware applications so that they can proactively participate in the management of resources. This approach has the benefit that resource management policies can be removed from central entities and the operating system has only to provide mechanism. Furthermore, in contrast to centralised approaches, application specific features can be more easily exploited. To achieve this aim, I propose to deploy a microeconomic theory, namely congestion or shadow pricing, which has recently received attention for managing congestion in communication networks. Applications are charged based on the potential "damage" they cause to other consumers by using resources. Consumers interpret these congestion charges as feedback signals which they use to adjust their resource consumption. It can be shown theoretically that such a system with consumers merely acting in their own self-interest will converge to a social optimum. This dissertation focuses on the operating system mechanisms required to decentralise resource management this way. In particular it identifies four mechanisms: pricing & charging, credit accounting, resource usage accounting, and multiplexing. While the latter two are mechanisms generally required for the accurate management of resources, pricing & charging and credit accounting present novel mechanisms. It is argued that congestion prices are the correct economic model in this context and provide appropriate feedback to applications. The credit accounting mechanism is necessary to ensure the overall stability of the system by assigning value to credits

Negotiated resource brokering for quality of service provision of grid applications

Grid Computing is a distributed computing paradigm where many computers often formed from different organisations work together so that their computing power may be aggregated. Grids are often heterogeneous and resources vary significantly in CPU power, available RAM, disk space, OS, architecture and installed software etc. Added to this lack of uniformity is that best effort services are usually offered, as opposed to services that offer guarantees upon completion time via the use of Service Level Agreements (SLAs). The lack of guarantees means the uptake of Grids is stifled. The challenge tackled here is to add such guarantees, thus ensuring users are more willing to use the Grid given an obvious reluctance to pay or contribute, if the quality of the services returned lacks any guarantees. Grids resources are also finite in nature, hence priorities need establishing in order to best meet any guarantees placed upon the limited resources available. An economic approach is hence adopted to ensure end users reveal their true priorities for jobs, whilst also adding incentive for provisioning services, via a service charge. An economically oriented model is therefore proposed that provides SLAs with bicriteria constraints upon time and cost. This model is tested via discrete event simulation and a simulator is presented that is capable of testing the model. An architecture is then established that was developed to utilise the economic model for negotiating SLAs. Finally experimentation is reported upon from the use of the software developed when it was deployed upon a testbed, including admission control and steering of jobs within the Grid. Results are presented that show the interactions and relationship between the time and cost constraints within the model, including transitions between the dominance of one constraint over the other and other things such as the effects of rescheduling upon the market

Service management for multi-domain Active Networks

The Internet is an example of a multi-agent system. In our context, an agent is synonymous with network operators, Internet service providers (ISPs) and content providers. ISPs mutually interact for connectivity's sake, but the fact remains that two peering agents are inevitably self-interested. Egoistic behaviour manifests itself in two ways. Firstly, the ISPs are able to act in an environment where different ISPs would have different spheres of influence, in the sense that they will have control and management responsibilities over different parts of the environment. On the other hand, contention occurs when an ISP intends to sell resources to another, which gives rise to at least two of its customers sharing (hence contending for) a common transport medium. The multi-agent interaction was analysed by simulating a game theoretic approach and the alignment of dominant strategies adopted by agents with evolving traits were abstracted. In particular, the contention for network resources is arbitrated such that a self-policing environment may emerge from a congested bottleneck. Over the past 5 years, larger ISPs have simply peddled as fast as they could to meet the growing demand for bandwidth by throwing bandwidth at congestion problems. Today, the dire financial positions of Worldcom and Global Crossing illustrate, to a certain degree, the fallacies of over-provisioning network resources. The proposed framework in this thesis enables subscribers of an ISP to monitor and police each other's traffic in order to establish a well-behaved norm in utilising limited resources. This framework can be expanded to other inter-domain bottlenecks within the Internet. One of the main objectives of this thesis is also to investigate the impact on multi-domain service management in the future Internet, where active nodes could potentially be located amongst traditional passive routers. The advent of Active Networking technology necessitates node-level computational resource allocations, in addition to prevailing resource reservation approaches for communication bandwidth. Our motivation is to ensure that a service negotiation protocol takes account of these resources so that the response to a specific service deployment request from the end-user is consistent and predictable. To promote the acceleration of service deployment by means of Active Networking technology, a pricing model is also evaluated for computational resources (e.g., CPU time and memory). Previous work in these areas of research only concentrate on bandwidth (i.e., communication) - related resources. Our pricing approach takes account of both guaranteed and best-effort service by adapting the arbitrage theorem from financial theory. The central tenet for our approach is to synthesise insights from different disciplines to address problems in data networks. The greater parts of research experience have been obtained during direct and indirect participation in the 1ST-10561 project known as FAIN (Future Active IP Networks) and ACTS-AC338 project called MIAMI (Mobile Intelligent Agent for Managing the Information Infrastructure). The Inter-domain Manager (IDM) component was integrated as an integral part of the FAIN policy-based network management systems (PBNM). Its monitoring component (developed during the MIAMI project) learns about routing changes that occur within a domain so that the management system and the managed nodes have the same topological view of the network. This enabled our reservation mechanism to reserve resources along the existing route set up by whichever underlying routing protocol is in place