Abstract. Software-as-a-service (SaaS) is a very successful model for providing cloud-based services over the internet. However, due to the dynamic nature of SaaS services, it becomes very challenging to ensure provision of scalability, applying frequent maintenance and functionality updates to SaaS Services. SOAP and REST are the two mostly used software architectural styles for accessing and consuming SaaS services in cloud environment and each have its distinct advantages. Therefore, to address above mentioned challenges, it is critical to choose the suitable architectural style because the success of a SaaS is strongly coupled with its architecture style. Choosing the right software architecture for a system is a multi-criteria decision making problem and it takes into consideration the architectural style characteristics, non-functional requirements and working domain requirements. In this paper, we propose a rule-based multi-criteria decision support system (DSS) for a SaaS application architecture selection. Our proposed DSS uses weighted sum model (WSM) that take into account the architectural style characteristics, non-functional and domain specific requirements.
IntroductionCloud computing provides ubiquitous access to shared pool of configurable computing resources, software and data services hosted over the internet. The five important characteristics of cloud computing model are on-demand self-service, broad network access, resource pooling, rapid elasticity and measured service [2]. The cloud computing service models are software-as-a-service (SaaS), infrastructure-as-a-service (IaaS), and platform-as-a-service (PaaS). Cloud computing is built on top of virtualization that consists of compute, storage and network components in servers. Virtualization provides a solid foundation for cloud computing to expand. However, cloud computing service models are not mature enough. These service models require proven software design and architecture in order to provide scalable cloud computing platforms [4]. Therefore, selecting a suitable architecture for SaaS service provisioning is a critical decision and it contributes