Analysis of Content Size Based Routing Schemes in Hybrid Satellite / Terrestrial Networks

Satellite networks are easy-to-deploy solutions to connect rural un-served and underserved areas. But satellite latency has a significant negative impact on performance. Hybrid networks, combining high-throughput long-delay links (e.g. GEO satellites) and short-delay low-throughput links (e.g. poor ADSL), can improve user experience by the use of intelligent routing. Emerging solutions, such as MultiPath TCP (MPTCP), already optimize the throughput in these hybrid networks. However, this kind of solutions does not take into account QoE requirements by the lack of relevant flows information, leading to sub-optimal path selection. This paper proposes an architecture able to retrieve the content size through interconnection with Content Delivery Networks (CDNs). Then, we conduct an analytical study of a probabilistic and a size threshold based routing schemes with the Mean Value Analysis (MVA) method. This shows the great benefit brought by size information in terms of QoE. To solve the limitations due to the threshold configuration, we propose a third algorithm that takes into account the path delay and capacity. Finally, we develop a testbed in order to validate our model and to compare this third scheme to the previous ones. We obtain results equivalent to the size threshold scheme, without its disadvantages.