Emulation-based study of dynamic service placement in mobile micro-clouds

Tactical networks are highly constrained in communication and computation resources, particularly at the edge. This limitation can be effectively addressed by the emerging technology of mobile micro-clouds (MMCs) that is aimed at providing seamless computing/data access at the edge of such networks. Deployment of MMCs can enable the delivery of critical, timely, and mission relevant situational awareness to end users in highly dynamic environments. Different from traditional clouds, an MMC is smaller and deployed closer to users, typically attached to a fixed or mobile basestation that is deployed in the field. Due to the relatively small coverage area of each basestation, a mobile user may frequently switch across areas covered by different basestations. An important issue therefore is where to place the service so that acceptable service performance can be maintained, while coping with the user and network dynamics. Existing work has considered this problem mainly from a theoretical angle. In this paper, with the aim of pushing the theoretical results one step closer to practice, we study the performance of dynamic service placement using an emulation framework, namely the Common Open Research Emulator (CORE) which embeds the Extendable Mobile Ad-hoc Network Emulator (EMANE). We first present the system architecture used in the emulation. Then, we present the message exchange and control process between different network entities, as well as methods of deciding where to place the services. Finally, we perform emulation using real-world user mobility traces of San Francisco taxis and present the results. The results show several insightful observations in a realistic network setting, such as the impact of randomness and delay on the service placement performance.