Traffic Contracts Based Optimizations for QoS Support in DVB-RCS Satellite Systems

The Return Channel for Satellite (DVB-RCS) standard has become a mature technology for Internet communications via satellite access networks. Because of the propagation delay, as well as the expensive and scarce resources, the QoS support has to be optimized and harmonized. Indeed, it is provided at different independent layers (mainly layer 2,3 and application level) which are potentially either redundant or inconsistent. This paper suggests optimizations (between layer 2 and 3) for the resource sharing based on traffic contracts and using cross layer mechanisms. The traffic contracts are mainly used to perform a prediction of the incoming traffic evolution in order to reduce the effects of the transmission delay. In addition, a way to coordinate layer 2 and 3 schedulers is introduced. A first performance assessment of the proposed mechanisms in a DVB-RCS context shows that the layer 3 delays (introduced by queuing) are significantly reduced.