Online Load Balancing for Network Functions Virtualization

Network Functions Virtualization (NFV) aims to support service providers to deploy various services in a more agile and cost-effective way. However, the softwarization and cloudification of network functions can result in severe congestion and low network performance. In this paper, we propose a solution to address this issue. We analyze and solve the online load balancing problem using multipath routing in NFV to optimize network performance in response to the dynamic changes of user demands. In particular, we first formulate the optimization problem of load balancing as a mixed integer linear program for achieving the optimal solution. We then develop the ORBIT algorithm that solves the online load balancing problem. The performance guarantee of ORBIT is analytically proved in comparison with the optimal offline solution. The experiment results on real-world datasets show that ORBIT performs very well for distributing traffic of each service demand across multipaths without knowledge of future demands, especially under high-load conditions

DTN Support for News Dissemination in an Urban Area

Part 3: DTN and Sensor NetworksInternational audienceWe are studying the practicality of news dissemination over a Delay Tolerant Network (DTN) in an urban area. The target application is the distribution of the electronic version of a newspaper in a large city. Therefore, although strict time constraints do not apply, spreading the information should be achieved within a reasonable delay. We consider that mobile users subscribe to their content of interest and expect to receive it within their journey from their home to their office. We provide two contributions. Firstly, we consider a simple DTN environment when content is distributed solely through inter-contact of mobile nodes. We derive analytical expressions for the packet delay in such environments and suggest how to improve effectively the expected message delay in the case of an area with low or high density of mobile nodes. Secondly, if the delay is found to be excessive, we suggest the deployment of some data kiosks in the environment to better support the dissemination of content. Data kiosks are simple devices that receive content directly from the source, usually using wired or cellular networks. We investigate both an upper bound and a lower bound of the number of data kiosks to distribute the content over a geographical area within an expected delay objective. We also show the important property that those bounds scale linearly with the contact rates between a mobile node and a data kiosk. The analytical results are validated through simulation using a number of mobility models