Towards horizontally scalable apps: Resource sharing in the mobile cloud with CoAP

Mobile cloud-computing (MCC) is a term introduced by Mark Beccue in 2009 (Beccue and Shey 2009) that popularized the idea of using cloud-hosted components as a means to overcome the resource constraints of mobile devices. But as the smartphones and tablets overcame their resource-constraints, the meaning of the term MCC changed. Nowadays MCC is mainly associated with using mobile devices to engage cloud-hosted services and to a lesser extend with combining multiple mobile devices (e.g. cloud of devices). However, as the number of users with multiple mobile devices increases there is a growing demand for enabling apps on mobile devices to share hardware and software resources. This in turn leads to questions regarding decentralized interaction, coordination and resource sharing among multiple mobile devices. This paper focuses on the horizontal scalability of apps e.g. the ability to combine multiple mobile devices (executing the same mobile app) into a single compute environment that utilizes all available hardware and software resources in a decentralized manner. One possible approach to achieve this is by designing mobile apps as sets of RESTful micro-services and to allow these services to communicate via low-bandwidth IoT communication protocols. Security becomes critical when exploring scaling out of an app. Designing such apps should seriously be taken into account in order to limit additional data confidentiality and privacy risks. This paper presents the results of our performance evaluations using RESTful micro-services on mobile devices that communicate via the IoT protocol CoAP in different WIFI environments and different encryption methods. © 2016, Springer-Verlag Berlin Heidelberg.