Tariff Dependent Error Control for Heterogeneous Real-Time Multicast Services

Multicast transport of audio and video is becoming an important application for IP-based networks. A desired application-level QoS can be achieved by network-layer QoS provision, by transport-layer error control, or by a combination of both. The most suitable approach depends on the tariffs set by the provider for network services with different QoS, the overhead introduced by error control, and the requirements of the user. In this paper we introduce an architecture that provides QoS support for audio and video in heterogeneous multicast scenarios by combining network-layer QoS with transport-layer QoS enhancement by Forward Error Correction (FEC). We present a utility-price optimisation tool for automatic service selection that takes user preferences and charging information as input. User preferences are expressed by utility functions. For the representation of tariff information a Tariff Formula Language (TFL) is defined. To achieve an accurate quality prediction, the optimisation tool is supported by RTP/RTCP loss measurements.