Prioritization of application layer FEC information for IP television services QoS

In the digital television world, an important transformation is represented by the television over IP service. One of the key factors enabling the spreading of television over IP is represented by the quality. Furthermore, packet loss is probably the main service degradation source for that services. The proposed approach combines the use of AL-FEC with the set-up of a transport quality mechanism based on FEC packets prioritization. To AL-FEC packets is assigned a transfer priority higher than that of the media packets transferred under the best effort paradigm, thus reducing in congested routers the amount of FEC packet losses. In this way the error correction capability is improved. Furthermore, as the FEC stream is usually a percentage of the media one, the choice of applying the prioritization to the FEC stream and not to the whole media allows reducing the impact of prioritization of television service traffic on other types of traffic, concurrent on the same link. The tests have been performed on a simulated network and on a real IP test-bed. The results show the effectiveness of the proposed approach with respect the un-prioritized one, allowing to obtain higher video quality at the same packet loss rate.