A case study for a presence service in the cloud

A presence service enables the end-users to share their availability, willingness and the preferred means of communication to start a session. It is widely used in applications such as instant messaging and it is finding place in innovative solutions such as smart homes. Recent growth in the number of end-users requires the presence service to be scalable in order to handle the increasing load. Overprovisioning of the resources to handle the unanticipated load leads to inefficient usage of resources. Moreover, because of the inherent dynamicity of end-user demands, resources need to be managed in an elastic manner, allowing the efficient usage of available resources. The traditional presence service architecture lacks the ability to cope with the aforementioned challenges. Cloud computing serves as an emerging paradigm in overcoming those challenges. In this paper, we present a case study for a presence service in the cloud, consisting of three components: A stateless front end, a repository and a cache component to support the front end for quick data access. Besides, we build prototype and evaluate its performance. The lessons learned from the evaluation are also discussed.