VAQoS: Architecture for End-to-End QoS Management of Value Added Web Services

During the last few years, Value Added Web Services (VAWS) are increasingly becoming a hot issue in both research and industry. With the abundance of VAWS providers, Quality of Service (QoS) is a key factor to allow potential clients to differentiate between providers. In this paper, we propose a new architecture, called VAQoS, for managing and assuring QoS provision for VAWS. This architecture performs management of QoS by: (1) allowing providers to extend the service description with QoS-centered annotations, (2) including a validation process that enables providers to test their service interfaces as well as the level of QoS they can provide prior to publishing the service, (3) allowing clients to express their required functionalities with QoS requirements; (4) providing support for QoS negotiation between clients and providers, (5) allowing monitoring of the agreed QoS between clients and providers, and therefore, detecting any QoS violation; (6) providing an application programming interface that shields the application of the provider and client from the complexity of managing QoS specification, QoS publication, and QoS discovery. A first prototype of VAQoS is developed.