Enhancing Web Services Performance Using Adaptive Quality of Service Management
The variation of contexts in which a Web service could be used and the resulting variation in Quality of Service (QoS) requirements motivates further research to extend Web services management platforms with automatic and adaptive management mechanisms in
- PDF / 428,900 Bytes
- 12 Pages / 430 x 660 pts Page_size
- 97 Downloads / 220 Views
School of Computer Sc. and Eng., The University of New South Wales, Sydney, Australia 2 IBM India Research Lab, New Delhi, India [email protected], [email protected]
Abstract. The variation of contexts in which a Web service could be used and the resulting variation in Quality of Service (QoS) requirements motivates further research to extend Web services management platforms with automatic and adaptive management mechanisms in order to achieve differentiated service offerings and to improve quality of service in terms of availability, response time and throughput. However, most Web services platforms are based on a best-effort model, which treats all requests uniformly, without service differentiation. This paper presents WS-DiffServ, a service differentiation middleware based on adaptive scheduling of service requests that prioritizes requests depending on their associated class of service and the current degree of service level conformance. The goal of the proposed approach is to increase conformance to negotiated service levels particularly in case of overloads such that the incurred penalties for violations are minimized. The paper first explores the typical requirements of a differential QoS support for Web services. We then present the design of WS-DiffServ. The effectiveness of the proposed approach is analyzed using supply chain management scenarios. Keywords: Adaptive Quality of Service Management, Differential QoS.
1 Introduction Web services are increasingly used to ease interoperability between heterogeneous and autonomous systems both for internal and external integration. Web services promise business agility and cost savings through re-use and standards-based integration. However, Web services based integration builds a web of interdependencies between participating systems and introduces various challenging interoperability and management issues [1]. One of the major issues with Web services is availability, which refers to the capability of serving requests in timely manner. Typically at the service provider side, if the volume of service requests temporarily exceeds the capacity for serving them the service becomes overloaded. As result this might cause clients to turn to competitor services and lead to loss of revenue. This motivates the need to formally specify and manage QoS coupled with the ability to deliver differentiated services with varying functionality and QoS attributes. For example, a financial Web service could be offered in either premium or basic grades. The service offerings may vary in the depth of the financial analysis, the rate of notification to clients and the guaranteed response time. This calls for B. Benatallah et al. (Eds.): WISE 2007, LNCS 4831, pp. 349–360, 2007. © Springer-Verlag Berlin Heidelberg 2007
350
A. Erradi and P. Maheshwari
development of architectural principles for building such systems, and devising specialized middleware to ease the development and delivery of differentiated services. For example, consider a finance portal offering differe
Data Loading...
