Optimal on-demand VoIP quality in an H.323 network

The perceived quality of a VoIP call depends both on terminal and network performance. A proper selection of the terminal working parameters, such as codec or packetization, may reduce the QoS requirements imposed on the network to grant the expected end-to-end quality. This paper introduces an application-level QoS management model to provide user-selected end-to-end call quality with optimal transport resource usage. The model adapts the QoS entities and interfaces defined by the ETSI TIPHON QoS Management Reference Architecture to H.323 networks, integrating call and QoS signalling. It is further enhanced by defining a resource optimization policy and a signalling procedure. As a result, the IP Telephony Service Provider can fullfill the user's expectations at the best cost/performance tradeoff.