Methods to Ensure Quality of Service in Cloud Computing Environment

Cloud computing systems promise to offer subscription-based, enterprise-quality computing services to users worldwide. As the demand for delivering services to a large number of users has increased, they need to offer differentiated services to users and meet their expected quality requirements. Service-Oriented Computing (SOC) enables the alignment of loosely coupled services with different levels of Quality of Service (QoS). Choosing an optimal set of services for a composition in terms of QoS is critical when many functionally alike services are available. With the arrival of Cloud Computing, the number of such services and their distribution across the network are rising rapidly. So, this paper describes EXACT and Fully Polynomial Time Approximation Scheme (FAPTS) algorithms for QoS aware service composition to optimize user’s experiences for Cloud service access, introduces the concept of cloud computing, explains the QoS Aware Services Mashup (QASM) Model. One of the challenging issues of cloud services mashup is how to find the optimal paths for services, to route the service instances through the provider while meeting the applications’ resource requirements so that the QoS compulsions are satisfied. However, the service routing problem aware of QoS is typically NP-hard. The purpose of this paper is to explain a QASM model to solve this problem more effectively. Keywords—Cloud Computing, QoS, QASM, EXACT, FAPTS.