The design of a storage architecture for mobile heterogeneous devices.

Mobile computing devices such as smart PDAs and ultra-light laptops with several networking interfaces are becoming commonplace. The provision of networked data storage facilities will greatly extend their use. This paper looks at the design of a storage architecture for such devices. A two-level structure is proposed in which one component, the mobile memory cache (MMC), moves when the node is mobile. A prototype MMC was designed and evaluated. Preliminary results are presented which show that the system should be able to provide a high performance service

Dynamic edge-caching for mobile users: minimising inter-AS traffic by moving cloud services and VMs

In recent years, Cloud technology has revolutionized the way services are delivered to end-users. The advent of truly mobile computing in the form of smart phones and tablets has also driven the demand for Cloud resources in order to compensate for the inherent lack of local resources on these devices. Furthermore, modern mobile devices are equipped with multiple network interfaces and in combination with the rapid deployment of wireless networks, it is expected that they will always have Internet connectivity and access to Cloud resources. In this paper we will focus on traffic management for interactive multimedia services accessed by a mobile user by means of dynamic migration of a Virtual Machine. Network performance measurements are taken from a network of virtualization-enabled hosts that perform live migrations of a Virtual Machine which hosts multimedia content. The data is used as input to an equation that determines whether a migration would be beneficial in terms of traffic localization based on a user's mobility characteristics and network usage patterns. The contribution of this paper lies in the proposed mechanism of managing traffic for interactive services in the context of mobile cloud computing. This helps alleviate the increased network costs introduced by dynamic migrations driven by Quality of Service parameters and may result in increased network traffic for the benefit of improved QoS

Exploring gate-limited analytical models for high-performance network storage servers

Gate-limited service is a type of service discipline found in queueing theory and can be used to describe a number of operational environments, for example, large transport systems such as buses, trains or taxis, etc. Recently, there has been the observation that such systems can also be used to describe interactive Internet Services which use a Client/Server interaction. In addition, new services of this genre are being developed for the local area. One such service is a Network Memory Server (NMS) being developed here at Middlesex University. Though there are several examples of real systems that can be modelled using gate-limited service, it is fair to say that the analytical models which have been developed for gate-limited systems have been difficult to use, requiring many iterations before practical results can be generated. In this paper, a detailed gate-limited bulk service queueing model based on Markov chains is explored and a numerical solution is demonstrated for simple scenarios. Quantitative results are presented and compared with a mathematical simulation. The analysis is used to develop an algorithm based on the concept of optimum operational points. The algorithm is then employed to build a high-performance server which is capable of balancing the need to prefetch for streaming applications while promptly satisfying demand misses. The algorithm is further tested using a systems simulation and then incorporated into an Experimental File System (EFS) which showed that the algorithm can be used in a real networking environment