Showing papers on "Service-level agreement published in 2005"

Method and apparatus for dynamically adjusting resources assigned to plurality of customers, for meeting service level agreements (SLAs) with minimal resources, and allowing common pools of resources to be used across plural customers on a demand basis

Abstract: A method (and system) for managing and controlling allocation and de-allocation of resources based on a guaranteed amount of resource and additional resources based on a best effort for a plurality of customers, includes dynamically allocating server resources for a plurality of customers, such that the resources received by a customer are dynamically controlled and the customer receives a guaranteed minimum amount of resources as specified under a service level agreement (SLA).

Service Level Agreement based Allocation of Cluster Resources: Handling Penalty to Enhance Utility

Abstract: Jobs submitted into a cluster have varying requirements depending on user-specific needs and expectations. Therefore, in utility-driven cluster computing, cluster resource management systems (RMSs) need to be aware of these requirements in order to allocate resources effectively. Service level agreements (SLAs) can be used to differentiate different value of jobs as they define service conditions that the cluster RMS agrees to provide for each different job. The SLA acts as a contract between a user and the cluster whereby the user is entitled to compensation whenever the cluster RMS fails to deliver the required service. In this paper, we present a proportional share allocation technique called LibraSLA that takes into account the utility of accepting new jobs into the cluster based on their SLA. We study how LibraSLA performs with respect to several SLA requirements that include: (i) deadline type whether the job can be delayed, (ii) deadline when the job needs to be finished, (iii) budget to be spent for finishing the job, and (iv) penalty rate for compensating the user for failure to meet the deadline

Modeling and Managing State in Distributed Systems: The Role of OGSI and WSRF

Abstract: We often encounter in distributed systems the need to model, access, and manage state. This state may be, for example, data in a purchase order, service level agreements representing resource availability, or the current load on a computer. We introduce two closely related approaches to modeling and manipulating state within a Web services (WS) framework: the Open Grid Services Infrastructure (OGSI) and WS-Resource Framework (WSRF). Both approaches define conventions on the use of the Web service definition language schema that enable the modeling and management of state. OGSI introduces the idea of a stateful Web service and defines approaches for creating, naming, and managing the lifetime of instances of services; for declaring and inspecting service state data; for asynchronous notification of service state change; for representing and managing collections of service instances; and for common handling of service invocation faults. WSRF refactors and evolves OGSI to exploit new Web services standards, specifically WS-addressing, and to respond to early implementation and application experiences. WSRF retains essentially all of the functional capabilities present in OGSI, while changing some syntax (e.g., to exploit WS-addressing) and also adopting a different terminology in its presentation. In addition, WSRF partitions OGSI functionality into five distinct composable specifications. We explain the relationship between OGSI and WSRF and the related WS-notification specifications, explain the common requirements that both address, and compare and contrast the approaches taken to the realization of those requirements.

A multi-agent infrastructure and a service level agreement negotiation protocol for robust scheduling in grid computing

Abstract: In this paper we propose a new infrastructure for efficient job scheduling on the Grid using multi-agent systems and a Service Level Agreement (SLA) negotiation protocol based on the Contract Net Protocol. The agent-based Grid scheduling system involves user agents, local scheduler agents, and super scheduler agents. User agents submit jobs to Grid compute resources. Local scheduler agents schedule jobs on compute resources. Super scheduler agents act as mediators between the local scheduler and the user agents to schedule the jobs at the global level of the Grid. The SLA negotiation protocol is a hierarchical bidding mechanism involving meta-SLA negotiation between the user agents and the super scheduler agents; and sub-SLA negotiation between the super scheduler agents and the local scheduler agents. In this protocol the agents exchange SLA-announcements, SLA-bids, and SLA-awards to negotiate the schedule of jobs on Grid compute resources. In the presence of uncertainties a re-negotiation mechanism is proposed to re-negotiate the SLAs in failure.

Service level agreement design and enforcement for outsourced call center

Abstract: A method for managing support services includes storing one or more support level agreements (SLAs), each having an associated attribute, in a database as one or more corresponding data objects. One or more trouble tickets, each having one or more associated attributes, are entered into the database as one or more corresponding data objects. One or more of the one or more stored SLAs are automatically applied to each of the one or more trouble tickets by matching the attributes of the one or more trouble tickets with the attributes of the one or more SLAs.

GRUBER: a grid resource usage SLA broker

Abstract: Resource sharing within grid collaborations usually implies specific sharing mechanisms at participating sites. Challenging policy issues can arise in such scenarios that integrate participants and resources spanning multiple physical institutions. Resource owners may wish to grant to one or more virtual organizations (VOs) the right to use certain resources subject to local usage policies and service level agreements, and each VO may then wish to use those resources subject to its usage policies. This paper describes GRUBER, an architecture and toolkit for resource usage service level agreement (SLA) specification and enforcement in a grid environment, and a series of experiments on a real grid, Grid3. The proposed mechanism allows resources at individual sites to be shared among multiple user communities.

RBSLA A declarative Rule-based Service Level Agreement Language based on RuleML

Abstract: This paper describes a rule based service level agreement language called RBSLA which is based on RuleML. With this language SLAs can be implemented in a machine readable syntax which can be fed into a rule engine in order to monitor the contract performance at run-time and automatically execute the contractual rules. The declarative logic based approach simplifies interchange, maintenance, management and execution of SLA rules and enables easy combination and revision of contractual rule sets and contract modules

Reputation-Based service level agreements for web services

Abstract: Most web services need to be contracted through service level agreements that typically specify a certain quality of service (QoS) in return for a certain price. We propose a new form of service level agreement where the price is determined by the QoS actually delivered. We show that such agreements make it optimal for the service provider to deliver the service at the promised quality. To allow efficient monitoring of the actual QoS, we introduce a reputation mechanism. A scoring rule makes it optimal for the users of a service to correctly report the QoS they observed. Thus, we obtain a practical scheme for service-level agreements that makes it uninteresting for providers to deviate from their best effort.

System and method for analyzing and coordinating Service-Level-Agreements (SLA) for Application-Service-Providers (ASP)

Abstract: The present invention describes a system for automatically monitoring and managing Service Level Agreements on behalf of Service providers (such as Application Service providers) The system is based on a specialized SLA language that can translate complex or simple Service Level Agreements into measurable and controllable criterion The system enables Application Service providers to set up customized Service Level Agreements with customers, and monitor, modify and control all aspects of these agreements, including billing, sales, Customer Relation Management, customer support and Quality of Service The technology on which the present invention is based is a formula driven language that translates Service Level Agreement details into commands As such these details can be tracked and processed to produce detailed reports and summaries

Reputation-based pricing of P2P services

Abstract: In the future peer-to-peer service oriented computing systems, maintaining a cooperative equilibrium is a non-trivial task. In the absence of Trusted Third Parties (TTP's) or verification authorities, rational service providers minimize their costs by providing ever degrading service quality levels. Anticipating this, rational clients are willing to pay only the minimum amounts (often zero) which leads to the collapse of the market.In this paper, we show how a simple reputation mechanism can be used to overcome this moral hazard problem. The mechanism does not act by social exclusion (i.e. exclude providers that cheat) but rather by allowing flexible service level agreements in which quality can be traded for the price. We show that such a mechanism can drive service providers of different types to exert the social efficient effort levels.

Resource allocation device for providing a differentiated service and a method thereof

Abstract: A resource allocation device includes a database of user and service information, a resource allocation management unit for determining whether a service request agrees with a service level agreement and whether it accepts a resource allocation request, a service level agreement unit for negotiating the service level agreement with the user, sending the received service request to the resource allocation management unit, acquiring the result of the resource allocation request, and transmitting the result of the resource allocation request to the user, a routing information management unit for obtaining a network configuring information, storing the network configuring information in the database, discovering the path to provide the service and storing the discovered path in the database to be reused and a policy control management unit for deciding a policy according to whether the service request and the resource allocation request are accepted.

Intelligent bandwidth allocation for ethernet passive optical networks

Abstract: A method and integrated hardware system for dynamic bandwidth allocation in EPONs which—in sharp contrast to the prior art—provides superior upstream transmission characteristics including QoS considerations consistent with any Service Level Agreement that exists between a customer and a service provider. Advantageously, our inventive method and system for dynamic bandwidth allocation provides fair and efficient upstream bandwidth management in addition to enhanced traffic performance for customer traffic within the EPON. For a service provider, our invention permits the deployment of intelligent traffic management and QoS characteristics capable of supporting existing or novel voice, video, and data services over the EPON.

A process calculus for qos-aware applications

Abstract: The definition of suitable abstractions and models for identifying, understanding and managing Quality of Service (QoS) constraints is a challenging issue of the Service Oriented Computing paradigm. In this paper we introduce a process calculus where QoS attributes are first class objects. We identify a minimal set of primitives that allow capturing in an abstract way the ability to control and coordinate services in presence of QoS constraints.

Method of distributing load amongst two or more computer system resources

Abstract: A method of distributing load amongst two or more computer system resources. The method includes distributing load to the system resources in accordance with their modeled response times and a predetermined Service level Agreement (SLA) associated with each system resource. By modeling the response time of each resource, load can be distributed with a view to maintaining response times within a predetermined Service level Agreement (SLA). The response time may be modeled by analytical modeling, which uses a queuing network model for predicting the response time, typically along with other parameters such as, utilization, throughput and queue length.

Policy refinement for DiffServ quality of service management

Abstract: Policy-based management provides the ability to dynamically re-configure DiffServ networks such that desired quality of service (QoS) goals are achieved. This includes network provisioning decisions, performing admission control, and adapting bandwidth allocation dynamically. QoS management aims to satisfy the service level agreements (SLAs) contracted by the provider and therefore QoS policies are derived from SLA specifications and the provider's business goals. This policy refinement is usually performed manually with no means of verifying that the policies written are supported by the network devices and actually achieve the desired QoS goals. Tool support is lacking and policy refinement has rarely been addressed in the literature. This paper extends our previous approach to policy refinement and shows how to apply it to the domain of DiffServ QoS management. We make use of goal elaboration and abductive reasoning to derive strategies that achieves a given high-level goal. By combining these strategies with events and constraints, we show how policies can be refined, and what tool support can be provided for the refinement process using examples from the QoS management domain. However, the approach presented here can be used in other application domains such as storage area networks or security management.

ContractLog: an approach to rule based monitoring and execution of service level agreements

Abstract: In this paper we evolve a rule based approach to SLA representation and management which allows separating the contractual business logic from the application logic and enables automated execution and monitoring of SLA specifications We make use of a set of knowledge representation (KR) concepts and combine adequate logical formalisms in one expressive formal framework called ContractLog

Managing compliance with service level agreements in a grid environment

Abstract: A computer-implemented method, system, and program for managing compliance with service level agreements in a grid environment are provided. A grid service for managing compliance with service level agreements in a grid environment detects a grid job passing a timing entry point, and flowing towards a grid environment provided by a grid vendor. When the grid job is detected passing the timing entry point, the grid service starts a timer to monitor an amount of time from the grid job passing the timing entry point until a result of the grid job passes a timing exit point while flowing away from the grid environment. When the grid service detects the result of the grid job passing the timing exit point, the grid service determines whether a value of the timer exceeds a timing term agreed to in a service level agreement specifying performance requirements for said grid job agreed to by said grid vendor, such that compliance with the service level agreement is automatically managed within the grid environment.

A model for usage policy-based resource allocation in grids

Abstract: Challenging usage policy issues can arise within virtual organizations (VOs) that integrate participants and resources spanning multiple physical institutions. Participants may wish to delegate to one or more VOs the right to use certain resources subject to local policy and service level agreements; each VO then wishes to use those resources subject to VO policy. How are such local and VO policies to be expressed, discovered, interpreted, and enforced? As a first step to addressing these questions, we develop and evaluate policy management solutions within a specialized context, namely scientific data grids within which the resources to be shared are computers and storage. We propose an architecture and recursive policy model, and define roles and functions, for scheduling resources in grid environments while satisfying resource owner and VO policies.

Method enabling real-time testing of on-demand infrastructure to predict service level agreement compliance

Abstract: Provided is an apparatus and method for demonstrating the efficiency and effectiveness of a customer's information technology (IT) system and applications operating in a shared IT, or electronic business on-demand, environment. A test suite mimics hypothetical settings in an on­demand services environment (129) and then determines how the settings affect the allocation of resources in the on-demand services environment (129). The calculated allocation of resources is then compared to one or more service level agreements (SLAs) in order to determine compliance with a particular SLA.

A theory for setting the "safety margin" on availability guarantees in an SLA

Abstract: A Service Level Agreement (SLA) is a contract between provider and customer that stipulates certain Quality of Service guarantees. One parameter of an SLA can be the maximum downtime guaranteed over the contract time. If the actual outage exceeds the guarantee, the customer is unhappy and the operator may bear financial penalties. It is important therefore that a network operator not only have some way to estimate or calculate the theoretical long-term availability of the services offered, but some basis for also determining a safety factor on the total outage time promised to a customer on any finite-term contract. As the period gets shorter, either nothing will go wrong and the effective availability will be perfect or if a single outage occurs, the unavailability may seem very bad. More generally, the question is how a network operator can build in theoretically justified safety factors on the availability a customer may experience over a finite-term contract. We are told that most service providers give availability guarantees based empirically on experience and historical statistics. A simple theory is thus proposed to help refine these methods for SLA policy setting. A simulation study is implemented to verify the theory within the axioms it assumes to be true.

Template-Based automated service provisioning – supporting the agreement-driven service life-cycle

Abstract: Service Level Agreements (SLAs) are a vital instrument in service-oriented architectures to reserve service capacity at a defined service quality level. Provisioning systems enable service managers to automatically configure resources such as servers, storage, and routers based on a configuration specification. Hence, agreement provisioning is a vital step in managing the life-cycle of agreement-driven services. Deriving detailed resource quantities from arbitrary SLA specifications is a difficult task and requires detailed models of algorithmic behavior of service implementations and capacity of a – potentially heterogeneous – resource environment, which are typically not available today. However, if we look at, e.g., data centers today, system administrators often know the quality-of-service properties of known system configurations and modifications thereof and can write the corresponding provisioning specifications. This paper proposes an approach that leverages the knowledge of existing data center configurations, defines templates of provisioning specifications, and rules on how to fill these templates based on a SLA specification. The approach is agnostic to the specific SLA language and provisioning specification format used, if based on XML.

A framework for automated negotiation of service level agreements in services grids

Abstract: An important aspect of managing service-oriented grid environments is negotiation of service level agreements. In this paper we propose a framework in which we adopt the three-layer architecture of agent-based negotiation to the problem of service level agreement negotiation in services grids. We report on the first experience with an implementation of the framework in the context of the WS-Agreement specification provided by the Global Grid Forum and present lessons learnt when using this framework in a simple practical scenario.

An Investigation into the Application of Different Performance Prediction Methods to Distributed Enterprise Applications

Abstract: Response time predictions for workload on new server architectures can enhance Service Level Agreement--based resource management. This paper evaluates two performance prediction methods using a distributed enterprise application benchmark. The historical method makes predictions by extrapolating from previously gathered performance data, while the layered queuing method makes predictions by solving layered queuing networks. The methods are evaluated in terms of: the systems that can be modelled; the metrics that can be predicted; the ease with which the models can be created and the level of expertise required; the overheads of recalibrating a model; and the delay when evaluating a prediction. The paper also investigates how a prediction-enhanced resource management algorithm can be tuned so as to compensate for predictive inaccuracy and balance the costs of SLA violations and server usage.

SLA Based Profit Optimization in Multi-tier Systems

Abstract: Nowadays, large service centers provide computational capacity to many customers by sharing a pool of IT resources. The service providers and their customers negotiate utility based service level agreement (SLA) to determine the costs and penalties on the base of the achieved performance level. The system is often based on a multi-tier architecture to service requests. The service provider would like to maximize the SLA revenues, while minimizing its operating costs. The system we consider is based on a centralized network dispatcher which controls the allocation of applications to servers, the request volumes at various servers and the scheduling policy at each server. The dispatcher can also decide to turn ON or OFF servers depending on the system load. This paper designs a resource allocation scheduler for such multi-tier environments so as to maximize the profits associated with multiple class SLAs. The overall problem is NP-hard. We develop heuristic solutions by implementing a local-search algorithm. Results are presented to demonstrate the benefits of our approach

Grid-Based SLA management

Abstract: This paper presents an architecture for specifying, monitoring and validating Service Level Agreements (SLA) for use in Grid environments. SLAs are an essential component in building Grid systems where commitments and assurances are specified, implemented and monitored. Targeting compute resources, an SLA manager reserves resources for user applications requiring resources on demand. Methods for automated monitoring and violation capture are discussed showing how Service Level Objectives (SLO) can be validated. A SLA for a compute service is specified and experiments carried out on the White Rose Grid. Results are presented in the form of a SLA document and show the violations that were captured during task execution.

On the flexibility of WS-agreement for job submission

Abstract: This paper considers extensions to the WS-Agreement specification, namely the Guarantee Terms of WS-Agreement [1]. Experiences and conclusions drawn are in the context of Agreement-based job management systems. A key idea of these extensions is the use of functions for the Guarantee Terms of the Agreement rather than constant values or ranges. Functions may contain variables defined in a particular agreement or be drawn from the known set of reference variables, such as wall-clock time, job start time, etc. We show that such an approach can potentially reduce the negotiation overheads associated with job renegotiation and/or reduce the number of failed agreements.

Service Level Agreement Negotiation: A Theory-based Exploratory Study as a Starting Point for Identifying Negotiation Support System Requirements

Abstract: IT outsourcing practices have recently proliferated an interest in service level agreement (SLA) negotiation relevant to engagements with either in-house or external IS service providers. An important research gap exists in establishing Negotiation Support System (NSS) requirements for the processes associated with SLA development. A first step in specifying such requirements is to examine relevant theoretical bases to identify and postulate reasonable propositions. A second step is to examine the efficacy of the theory-based propositions using the constructs adapted in the context of a relevant, practical and exploratory scenario. Accordingly, this paper discusses propositions that rely on theoretical bases from relevant sociological models, it identifies constructs adapted from prior Theory W research in NSS as an exemplar, it discusses an exploratory study related to the research gap identified, and it discusses findings that represent a starting point for identifying SLA NSS requirements.

On the impact of DoS attacks on Internet traffic characteristics and QoS

Abstract: The Internet is on the way of becoming the universal communication network, and then needs to provide various services with guaranteed quality for all kinds of applications. Denial of service (DoS) attacks are then more efficient in a guaranteed multi-services network than in the "old" best effort Internet. Indeed, with best effort services, a DoS attack has to forbid the target of the attack to communicate. With a multi-services network, it is sufficient to make the network not respect the SLA (service level agreement) committed with clients, what is easier and can be performed using simple flooding attacks. Then, the question is: how does a DoS attack impact the quality of service (QoS) of a network given that networks are hugely over-provisioned, and that DoS attacks never succeed to completely overflow these high speed networks? This paper aims at answering this question as we do believe that it can help for defending the network against such attacks. The analysis of DoS attacks has been performed using traffic monitoring tools on the Internet. In particular, the analysis of attacks shows that they are increasing long range dependence (LRD) in the traffic, breaking the invariant power laws of normal Internet traffic. It is also explained in the paper, based on some normal traffic traces characterization and analysis why LRD is such a bad parameter for having good QoS.

Experiences in running workloads over grid3

Abstract: Running workloads in a grid environment is often a challenging problem due the scale of the environment, and to the resource partitioning based on various sharing strategies. A resource may be taken down during a job execution, be improperly setup or just fail job execution. Such elements have to be taken in account whenever targeting a grid environment for execution. In this paper we explore these issues on a real grid, Grid3, by means of a specific workload, the BLAST workload, and a specific scheduling framework, GRUBER – an architecture and toolkit for resource usage service level agreement (SLA) specification and enforcement. The paper provides extensive experimental results. We address in high detail the performance of different site selection strategies of GRUBER and the overall performance in scheduling workloads in Grid3 with workload sizes ranging from 10 to 10,000 jobs.