Support of Delayed Real-Time Services Over Geo Satellite Networks through a Recovery Service

Delayed real-time (DRT) services are an interesting class of services aimed at supporting real-time transmission through the use of buffering of streams at a receiver or a proxy. This allows to decouple the physical download of realtime streams from the actual playout since streams are delayed before being sent to the playing application. A useful application scenario for these services is represented by employing them in Geo-Satellite networks where different delays and impairments are met downlink when distributing information sent by many content providers to remote users. In this perspective we investigated on the need for optimization of the recovery transport scheme so as to make it responsive to retransmissions priorities reflecting the hurry related to the time available for the recovery of the missing data. The hurry of each retransmission request depends on the length of the different receiver buffers, the amount and the time of lost data and the playout bitrate. Exploiting some previous results, in this paper we propose an Additive Increase Multiplicative Decrease (AIMD) multicast transport protocol aimed at performing bandwidth optimization while avoiding redundant transmissions. To this purpose, we recall the previously introduced DRT Service Architecture and study the multicast transport protocol in the perspective of supporting optimization and fairness in the recovery process.