Service-level agreement

About: Service-level agreement is a research topic. Over the lifetime, 4358 publications have been published within this topic receiving 75333 citations. The topic is also known as: SLA.

Virtual Machine Consolidation in Cloud Computing Systems: Challenges and Future Trends

Abstract: Cloud Computing Systems (CCSs) provides a computing capability through the Internet. It enables organizations or individuals to have a computing power without deploying and maintaining their own Information Technology infrastructure. As a cloud is realized on a vast scale cloud, it consumes an enormous amount of energy. Migration pattern, where several Virtual Machines (VMs) can be placed on a minimum number of active Physical Machines is called VMs Consolidation (VMC). Thus, this technique can be a practical approach for balancing electricity consumption and other QoS requirement in CCSs. Especially, VMC must meet the service quality requirements, minimization of both energy consumption and Service Level Agreement violation in CCSs. This paper presents a systematic survey of VMC in CCSs with particular attention to the VMC phases, metrics, objectives, migration patterns, optimization methods, and evaluation approaches of VMC. Our review study is presented based on the past literature with a focus on the type of hardware metrics, software metrics, objectives, algorithms, and architectures of VMC in CCSs.

The First Step of Introducing Risk Management for Prepossessing SLAs

Abstract: Using Service Level Agreements (SLAs) is a central concept for the Grid commercialization since customers require guarantees for a successful job execution. However, agreeing on SLAs is a business risk for resource providers: system failures can lead to paying tremendous penalties. Accordingly, resource providers require an estimation about the risk of agreeing on an SLA. Furthermore, risks can be published and integrated into the negotiations as an additional SLA parameter. Each offer is linked with a possible execution on a specific resource since the risk of failure depends especially on the resource?s stability. Therewith making reservations is the initial step for integrating risk management into the Grid. This paper describes the necessary workflow and measurements for selecting a resource according to assessed risks. A global perspective is presented in order to afford user-specific configurations. Concrete examples for several measurements present one possibility for rating and the important input factors.

Leveraging Service Incident Analytics to Determine Cost-Optimal Service Offers

Abstract: In this work we address the challenge for an IT service customer to select the cost-optimal service among different offers by external providers. We describe the customer’s optimization problem by considering the negative monetary impact of potential service incidents on its business. First, we demonstrate that the information currently used in service level agreements may lead to suboptimal customer decisions. Second, we discuss how providers’ private information about the behavior of service delivery environments could be leveraged by the customer when selecting service offers. Third, we propose a procurement auction as a mechanism to optimize total cost for the customer – choosing from different service offers by risk-neutral providers. In introducing this approach, we suggest that customers and providers collaborate to define service performance measures, which allow providers to better tailor service offers to customers’ business requirements.

SLA-Aware Fine-Grained QoS Provisioning for Multi-Tenant Software-Defined Networks

Abstract: Multi-tenant software-defined networks have emerged as a promising service platform to manage and share virtual network services between tenants and end-users. However, when using a service level agreement (SLA) in a multi-tenant circumstance, the resource competition among tenants incurred in many challenges on the quality of services (QoS) provisioning. First, as the existing QoS provisioning was to translate the high-level SLA contact into a group of corresponding low-level QoS rules, this traditional top-down translation mechanism was too ossified to support the dynamic SLA negotiation. Second, since an end-user usually requested multiple services and different services had different QoS requirements, the QoS provisioning required tenants to monitor and control the network status though OpenFlow protocol in a fine-grained way. To address these issues, we propose an SLA-aware fine-grained QoS provisioning (SFQP) scheme for MTSDN. The SFQP scheme extracts the eigen characteristics of each packet by application-aware technology automatically. Considering tenants are more willing to serve for users which have popular SLA contact to earn more revenues, we predict the SLA popularity by K-nearest neighbor. Moreover, we present an SLA-aware dynamic bandwidth allocation algorithm to implement the proposed SFQP scheme. The feasibility of the proposed scheme is verified by simulations of the SLA taxonomy, bandwidth utilization, and bandwidth fluctuation.

A Bandwidth Aggregation-Aware QoS Negotiation Mechanism for Next-Generation Wireless Networks

Abstract: The transmission of high quality video requires high bandwidth. Ensuring constantly high bandwidth in wireless environments is a challenging task given constraints in the current wireless network resources. Current mobile computers are equipped with multiples wireless interfaces that can be used to improve the video quality by aggregating the bandwidth of these interfaces. Such Bandwidth Aggregation (BAG) approach involves multiple paths in communication and gives rise to a number of issues related to the management of the Service Level Agreement (SLA) and packet reordering. To guarantee an efficient and fair management of SLA, this paper presents a bandwidth aggregation-aware QoS negotiation mechanism that enables users to dynamically negotiate their desired service levels and to reach them through the use of bandwidth aggregation. This operation is performed while ensuring a fair use of the network resources among all competing users. To cope with packet reordering, a new scheduling strategy is presented. The performance evaluation of the proposed bandwidth aggregation-aware QoS negotiation scheme and the proposed scheduling algorithm are conducted via simulations and the results are discussed.