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.

Dynamic bandwidth allocation with SLA awareness for QoS in ethernet passive optical networks

Abstract: Quality-of-service (QoS) support in Ethernet passive optical networks is a crucial concern. We propose a new dynamic bandwidth allocation (DBA) algorithm for service differentiation that meets the service-level agreements (SLAs) of the users. The proposed delay-aware (DA) online DBA algorithm provides constant and predictable average packet delay and reduced delay variation for the high- and medium-priority traffic while keeping the packet loss rate under check. We prove the effectiveness of the proposed algorithm by exhaustive simulations.

Constraint-conscious optimal scheduling for cloud infrastructures

Abstract: Systems and methods are disclosed to schedule jobs in a cloud computing infrastructure by receiving in a first queue jobs with deadlines or constraints specified in a hard service level agreement (SLA); receiving in a second queue jobs with a penalty cost metric specified in a soft SLA; and minimizing both constraint violation count and total penalty cost in the cloud computing infrastructure by identifying jobs with deadlines in the first queue and delaying jobs in the first queue within a predetermined slack range in favor of jobs in the second queue to improve the penalty cost metric.

Energy-aware VM placement algorithms for the OpenStack Neat consolidation framework

Abstract: One of the main challenges in cloud computing is an enormous amount of energy consumed in data-centers. Several researches have been conducted on Virtual Machine(VM) consolidation to optimize energy consumption. Among the proposed VM consolidations, OpenStack Neat is notable for its practicality. OpenStack Neat is an open-source consolidation framework that can seamlessly integrate to OpenStack, one of the most common and widely used open-source cloud management tool. The framework has components for deciding when to migrate VMs and for selecting suitable hosts for the VMs (VM placement). The VM placement algorithm of OpenStack Neat is called Modified Best-Fit Decreasing (MBFD). MBFD is based on a heuristic that handles only minimizing the number of servers. The heuristic is not only less energy efficient but also increases Service Level Agreement (SLA) violation and consequently cause more VM migrations. To improve the energy efficiency, we propose VM placement algorithms based on both bin-packing heuristics and servers’ power efficiency. In addition, we introduce a new bin-packing heuristic called a Medium-Fit (MF) to reduce SLA violation. To evaluate performance of the proposed algorithms we have conducted experiments using CloudSim on three cloud data-center scenarios: homogeneous, heterogeneous and default. Workloads that run in the data-centers are generated from traces of PlanetLab and Bitbrains clouds. The results of the experiment show up-to 67% improvement in energy consumption and up-to 78% and 46% reduction in SLA violation and amount of VM migrations, respectively. Moreover, all improvements are statistically significant with significance level of 0.01.

A Survey of Trust in Workflows and Relevant Contexts

Abstract: With the fast-growing Internet technology, several service-based interactions are prevalent and appear in several forms such as e-commerce, content provider, Virtual Organizations, Peer-to-Peer, Web Service, Grids, Cloud Computing, and individual interactions. This demands for an effective mechanism to establish trust among participants in a high-level abstract way, capturing relevant factors ranging on Service Level Agreement, security policies, requirements, regulations, constraints, Quality of Service, reputation, and recommendation. Trust is platform-independent and flexible to be seamlessly integrated into heterogeneous domains and interoperate with different security solutions in distributed environments. Establishing trust in a service workflow leads to the willingness of services to participate. Coordinating service workflows without trust consideration may pose higher risks, possibly results in poor performance, additional vulnerabilities, or failures. Although trust in service workflows and relevant contexts has been studied for a past decade, the standard development is still immature. Nowadays, trust approaches to service workflows comprise a large area of research where one can hardly classify into a comprehensive survey. This survey examines and explores the role of trust in service workflows and their contexts from a wide variety of literatures. Various mechanisms, architecture, techniques, standards, and frameworks are explained along the way with discussions. Working trust definition and classification are newly provided and supported with examples.

Reputation-Based QoS Provisioning in Cloud Computing via Dirichlet Multinomial Model

Abstract: In Cloud computing, users with different service requirements often need to negotiate with service provider via Service Level Agreement (SLA). The unique pay-as-you-go billing way in Cloud computing challenges resource provisioning for service providers. In this paper, based on the Dirichlet multinomial model, we present an efficient reputation-based QoS provisioning scheme, which can minimize the cost of computing resources, while satisfying the desired QoS metrics. Unlike the previous counterparts, we consider the statistical probability of the response time as a practical metric rather than the typical mean response time. Numerical results show the efficiency and effectiveness of the proposed scheme.