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Service Level Agreement (service + level_agreement)
Selected AbstractsProviding and verifying advanced IP services in hierarchical DiffServ networks-the case of GEANTINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2004Athanassios Liakopoulos Abstract The differentiated services (DiffServ) framework is widely proposed as an efficient method for providing advanced IP services to large-scale networks, with QoS requirements. However, the provisioning of such services in production networks has proved to be more difficult than initially expected, in defining, setting and verifying appropriate Service Level Agreements (SLAs). GEANT, the Gigabit core pan-European research network, on a pilot basis introduced ,Premium IP' service, offering bounded delay and negligible packet loss to the European National Research & Education Networks (NRENs) that it interconnects. However, large scale provisioning of this new service requires the definition of efficient interaction procedures between administrative domains involved and methods for SLA monitoring. This paper focuses on these issues and presents the experience acquired from the early experiments in GEANT, as an example of hierarchical Gigabit multi-domain environment, enabled with QoS provisioning to its constituent NRENs. This model scales more efficiently than the common peering Internet Service provider (ISP) commercial paradigm. Finally, we outline other options that promise QoS, such as Layer 2 VPNs in MPLS backbones, with non-standard (yet) mechanisms. Copyright © 2004 John Wiley & Sons, Ltd. [source] Competition or collaboration , the tensions within the purchaser provider relationship in nurse educationJOURNAL OF NURSING MANAGEMENT, Issue 3 2006LINDA M. BURKE BA Aims, To explore the nature of the relationship between purchasers and providers from the perspectives of the key individuals involved in healthcare education in the late 1990s. To discuss the lessons that can be learned for nursing from their experiences. Background, Although the findings illustrate experiences of individuals at a specific time, the issues that arise have implications for contemporary health care, as contract use is increasing and, with the introduction of foundation trusts, contracts may replace Service Level Agreements. Method, The design was qualitative and the methods used were policy analysis and interviews. Interviews were conducted with a national, purposive sample of 70 participants. Results, The key finding was the amount of variation in effectiveness of relationships. Many purchasers and providers formed strong partnerships but a number had fraught relationships , a situation perceived as detrimental to productive working. A significant issue for current healthcare was the reasons why relationships worked well in some institutions and were ineffective in others. Conclusions, There are a number of key lessons that can be learned about the nature of the relationship between purchasers and providers and applied to contemporary health care. Notably: ,,the value of clear policy aims; ,,the importance of context and history in shaping the relationship; ,,the necessity of ensuring that individuals involved have the ability and commitment to make the relationship work; ,,the need to view the contracting relationship as a dynamic ,project' that must be worked on; ,,the value of sharing good practice. [source] An approach for quality of service adaptation in service-oriented GridsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 5 2004Rashid Al-Ali Abstract Some applications utilizing Grid computing infrastructure require the simultaneous allocation of resources, such as compute servers, networks, memory, disk storage and other specialized resources. Collaborative working and visualization is one example of such applications. In this context, quality of service (QoS) is related to Grid services, and not just to the network connecting these services. With the emerging interest in service-oriented Grids, resources may be advertised and traded as services based on a service level agreement (SLA). Such a SLA must include both general and technical specifications, including pricing policy and properties of the resources required to execute the service, to ensure QoS requirements are satisfied. An approach for QoS adaptation is presented to enable the dynamic adjustment of behavior of an application based on changes in the pre-defined SLA. The approach is particularly useful if workload or network traffic changes in unpredictable ways during an active session. Copyright © 2004 John Wiley & Sons, Ltd. [source] Online end-to-end quality of service monitoring for service level agreement managementINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2008Xiaoyuan Ta Abstract A major challenge in network and service level agreement (SLA) management is to provide Quality of Service (QoS) demanded by heterogeneous network applications. Online QoS monitoring plays an important role in the process by providing objective measurements that can be used for improving network design, troubleshooting and management. Online QoS monitoring becomes increasingly difficult and complex due to the rapid expansion of the Internet and the dramatic increase in the speed of network. Sampling techniques have been explored as a means to reduce the difficulty and complexity of measurement. In this paper, we investigate several major sampling techniques, i.e. systematic sampling, simple random sampling and stratified sampling. Performance analysis is conducted on these techniques. It is shown that stratified sampling with optimum allocation has the best performance. However, stratified sampling with optimum allocation requires additional statistics usually not available for real-time applications. An adaptive stratified sampling algorithm is proposed to solve the problem. Both theoretical analysis and simulation show that the proposed adaptive stratified sampling algorithm outperforms other sampling techniques and achieves a performance comparable to stratified sampling with optimum allocation. A QoS monitoring software using the aforementioned sampling techniques is designed and tested in various real networks. Copyright © 2007 John Wiley & Sons, Ltd. [source] Roaming and service management in public wireless networks using an innovative policy management architectureINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2005Idir Fodil Nowadays, public wireless local area networks (WLANs), commonly called hotspots, are being largely deployed by WISPs (Wireless Internet Service Providers) as a means of offering ubiquitous Internet access to their customers. Although a substantial number of solutions have been proposed to improve security, mobility and quality of service on the wireless area, access network management which is mandatory remains a very significant concern. This paper describes RSM-WISP, a new management architecture designed for WISPs to facilitate the implementation and management of the services they offer at the access side of the WLAN, and to manage roaming contracts between WISPs. Our architecture is based upon the policy-based management principles as introduced by the IETF, combined with more intelligence at the network edge. RSM-WISP adopts an architecture that is composed of two elements: a WISP management center (MC) that deploys policies and monitors all the WLANs, and a programmable access router (CPE) located in each WLAN. The CPE ensures service enforcement, service differentiation (access to different service levels) and guarantee, user access management, and dynamic WLAN adaptation according to the user's SLA (service level agreement). It also permits automatic service updates according to the user's requirements. Concerning roaming management, this is achieved on the CPE through multiple service provider support capabilities. This approach provides WISPs with a simple, flexible and scalable solution that allows easy service deployment and management at the access. This management architecture has been implemented, tested and validated on the 6WINDGate routers.,Copyright © 2005 John Wiley & Sons, Ltd. [source] Monitoring and controlling QoS network domainsINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 1 2005Ahsan Habib Increased performance, fairness, and security remain important goals for service providers. In this work, we design an integrated distributed monitoring, traffic conditioning, and flow control system for higher performance and security of network domains. Edge routers monitor (using tomography techniques) a network domain to detect quality of service (QoS) violations,possibly caused by underprovisioning,as well as bandwidth theft attacks. To bound the monitoring overhead, a router only verifies service level agreement (SLA) parameters such as delay, loss, and throughput when anomalies are detected. The marking component of the edge router uses TCP flow characteristics to protect ,fragile' flows. Edge routers may also regulate unresponsive flows, and may propagate congestion information to upstream domains. Simulation results indicate that this design increases application-level throughput of data applications such as large FTP transfers; achieves low packet delays and response times for Telnet and WWW traffic; and detects bandwidth theft attacks and service violations.,Copyright © 2004 John Wiley & Sons, Ltd. [source] Maximizing revenue in Grid markets using an economically enhanced resource managerCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 14 2010M. Macías Abstract Traditional resource management has had as its main objective the optimization of throughput, based on parameters such as CPU, memory, and network bandwidth. With the appearance of Grid markets, new variables that determine economic expenditure, benefit and opportunity must be taken into account. The Self-organizing ICT Resource Management (SORMA) project aims at allowing resource owners and consumers to exploit market mechanisms to sell and buy resources across the Grid. SORMA's motivation is to achieve efficient resource utilization by maximizing revenue for resource providers and minimizing the cost of resource consumption within a market environment. An overriding factor in Grid markets is the need to ensure that the desired quality of service levels meet the expectations of market participants. This paper explains the proposed use of an economically enhanced resource manager (EERM) for resource provisioning based on economic models. In particular, this paper describes techniques used by the EERM to support revenue maximization across multiple service level agreements and provides an application scenario to demonstrate its usefulness and effectiveness. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simple tariffs based on price multipliers for ATM VBR servicesEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2003Costas Courcoubetis We present an approach for constructing simple time-based tariffs for variable bit-rate (VBR) connections from constant bit-rate (CBR) prices, using price multipliers that depend on the traffic parameters of the VBR connection and reflect the resource usage of VBR connections relative to CBR connections. Our approach employs an effective bandwidth bound as a proxy for the maximum amount of traffic that conforms to the connection's traffic contract, and thus for the maximum resource usage. We compare the price multipliers computed by our approach with the multipliers published by an actual ATM service provider, and with those computed using a proxy for resource usage that is based on ATM Forum's generic CAC algorithm. Although our approach is presented in the context of ATM VBR services, it can be applied for creating tariffs for service level agreements (SLAs) where the maximum amount of conforming traffic is given by leaky (or token) bucket constraints. Copyright © 2003 AEI. [source] | |||||||||||||