A Lightweight Distributed Solution to Content Replication in Mobile Networks

Performance and reliability of content access in mobile networks is conditioned by the number and location of content replicas deployed at the network nodes. Facility location theory has been the traditional, centralized approach to study content replication: computing the number and placement of replicas in a network can be cast as an uncapacitated facility location problem. The endeavour of this work is to design a distributed, lightweight solution to the above joint optimization problem, while taking into account the network dynamics. In particular, we devise a mechanism that lets nodes share the burden of storing and providing content, so as to achieve load balancing, and decide whether to replicate or drop the information so as to adapt to a dynamic content demand and time-varying topology. We evaluate our mechanism through simulation, by exploring a wide range of settings and studying realistic content access mechanisms that go beyond the traditional assumptionmatching demand points to their closest content replica. Results show that our mechanism, which uses local measurements only, is: (i) extremely precise in approximating an optimal solution to content placement and replication; (ii) robust against network mobility; (iii) flexible in accommodating various content access patterns, including variation in time and space of the content demand.Comment: 12 page

AS-cast: Lock Down the Traffic of Decentralized Content Indexing at the Edge

International audienceAlthough the holy grail to store and manipulate data in Edge infrastructures is yet to be found, state-of-the-art approaches demonstrated the relevance of replication strategies that bring content closer to consumers: The latter enjoy better response time while the volume of data passing through the network decreases overall. Unfortunately, locating the closest replica of a specific content requires indexing every live replica along with its location. Relying on remote services for such a aim enters in contradiction with the properties of Edge infrastructures as locating replicas may effectively take more time than actually downloading content. At the opposite, maintaining such an index at every node would prove overly costly in terms of memory and traffic. In this paper, we propose a decentralized implementation of content indexing called AS-cast. Using AS-cast, every node only indexes its closest replica; and all connected nodes with a similar index compose a partition. AS-cast is (i) efficient, for it uses partitions to lock down the traffic generated by its operations to relevant nodes, yet it (ii) guarantees that every node eventually acknowledges its closest replica despite concurrent operations. Our prototype, implemented on PeerSim, shows that AS-cast scales well in terms of generated messages and termination time. As such, AS-cast can constitute a novel building block for geo-distributed services in need of efficient resource sharing in the vicinity of regions

Vehicle-based Disconnected Data Distribution

The world today is highly connected and there is an immense dependency on this connectivity to accomplish basic everyday tasks. However much of the world lacks connectivity. Even in well-connected locations, natural disasters can cause infrastructure disruption. To combat these situations, Delay Tolerant Networks (DTNs) employ to store and forward techniques along with intermittently connected transports to provide data connectivity. DTNs focus on intermittently connected networks however what if the regions are never connected? For example, Region A - is never connected to the internet, and Region B – has internet connectivity. Using a vehicle that travels between the two regions it is possible to transport the data from A to B and vice versa. Current vehicular-based DTN approaches make use of dedicated hardware infrastructures mounted on vehicles. Our research focuses to shift all this computing to personal smartphone devices. The users in disconnected areas will install the Disconnect Data Distribution(DDD Android application on their phones. This application will receive data from various applications on their phone via inter-process communication(IPC) and package the data into bundles using a DDD library. Vendors, transportation operators, delivery people, and others that regularly travel between connected and dis-connected areas can download the Bundle Transport Application on their Android phones. These devices will then communicate with each other using short-range wireless technology like WiFi-Direct in the disconnected region. The device on the transport can communicate with the Servers over the internet. For this project, we should assume that the Client and Server can provide data as desired and our focus is on the Transport