Haiqin Wang

Service level management using QoS monitoring, diagnostics, and adaptation for networked enterprise systems

As enterprise services increasingly interconnect as networked services in a service-oriented architecture (SOA), service level management (SLM) is becoming a complex problem and can no longer be handled by traditional monitoring tools like Microsoft SMS. SLM is a process managing the quality of services demanded by clients and offered by providers. This paper presents two contributions to the research of SLM. First, instead of considering monitoring as an isolated service, it incorporates monitoring as an integral part of a comprehensive QoS management framework. This framework consists of QoS management concepts and services including service level contract management, admission control, resource management, monitoring, diagnostics, and adaptation. Using this framework, clients are able to negotiate quality of service contracts with providers and providers are able to optimize system resources to meet contract requirements. The second contribution is the incorporation of diagnostic service in the QoS management framework. Based on data feed from monitoring service, diagnostic service is able to detect any condition changes and to reason about the causes of any degradation conditions in the networked enterprise system. With condition detection and situation understanding, QoS management can then proactively activate adaptation mechanisms to maximize the systems ability to meet QoS contract requirements of concurrent clients. Our monitoring service uses both reporting approach and probing approach to acquire the information of the health status of elements of a networked system. The monitored data is then fed to our diagnostic service to reason about root causes of anomalies, using graphical models. Depending on the system health status and root causes, appropriate adaptations are triggered proactively to improve the system performance under the constraints of concurrent QoS contracts. We validate our SLM approach using QoS management services integrated in a publish/subscribe style of SOA. We then demonstrate via experiments some benefits of QoS monitoring, diagnostics, and adaptation services for responsiveness SLM.

A policy-based approach for QoS specification and enforcement in distributed service-oriented architecture

A significant challenge of successful application of the service-oriented architecture (SOA) in large-scale distributed systems is the quality of service (QoS) management, which provides various QoS guarantee levels for concurrent clients through effective resource allocations and adaptations. In this paper, we propose a policy-based approach for specifying QoS management strategies and enforcing QoS guarantees. This approach enables easy adaptation of new business rules and adaptation to system resource changes. This approach is also effective for supporting QoS management, as demonstrated in our experiments in a publish/subscribe system.

Quality of Service Contract Specification, Establishment, and Monitoring for Service Level Management.

This paper describes an approach and the architecture of Quality of Service (QoS) contract specification, establishment, and monitoring for Service Level Management (SLM). Contract is an essential concept in SLM. The service consumer side and the service provider side must share common understanding of QoS characteristics and agree on the common language for specifying desired QoS parameters in the form of QoS contracts. A service consumer must also negotiate with a service provider to establish mutually agreed QoS contracts for an interactive session. The service provider must consider QoS contracts already agreed upon with existing consumers and system resource conditions in establishing a new QoS contract. Similarly, a service consumer must be prepared in revising its contract with the service provider as conditions change over time. Once a QoS contract is established, SLM must provide monitoring to make sure that the service is provided at agreed QoS parameter range. If necessary, SLM must activate adaptation mechanisms to bring the service quality to the desired level. A case study is presented to validate the QoS contract management design approach and architecture for SLM.

Service Level Management in Global Enterprise Services: from QoS Monitoring and Diagnostics to Adaptation, a Case Study

We developed a quality of service (QoS) management system to support service level management (SLM) for global enterprise services. The QoS management system is integrated with one of our enterprise services in a preproduction system, an identical system as the production system but in a test environment. Lab experiments showed that our integrated solution helps global enterprise services to better maintain the service level agreements. Test results have validated our architecture design and integration approach. This paper describes our QoS management architecture and its integration within the enterprise service system with a focus on QoS monitoring, diagnostics and adaptation. We will also present the validation test results as a case study in this paper.