Pluggable SaaS Integration: Quality Characteristics for Cloud Based Application Services

Cloud services have recently gained popularity and play an increasing role in enterprise architectures. Organizations adopting cloud services expect not only improvements in flexibility and scalability, but also a means of outsourcing IT tasks. In contrast to custom or packaged applications, software as a service offerings help to reduce the technical expertise required to provide the necessary IT resources. Software quality models help organizations to assess the state of their application systems and have been subject to research for a couple of decades. However, the stakeholder of the existing quality models is mainly concerned with the internal structure of software components. With the shift towards cloud based service offerings, a different conception of quality arises. Current quality models consider resource owner and provider as a single entity. Thus, most of the quality characteristics covered in the models reflect the internal view of a software service. To address the deficiency, this paper puts forward a new quality characteristic that reflects the priorities of the service user as a distinct party, implying six different phases of service consumption. We introduce the notion of pluggability to illustrate the aspired user experience of a service and propose a preliminary measurement instrument.