Real-time Interaction over the Internet (RTI2) is an Internet service that is required typically by remote experimentation applications. From a quality of service (QoS) point of view, RTI2 has constraints that differ from usual real-time multimedia services such as video streaming or video conferencing. The RTI2 QoS can be expressed by three values that represent the level of interaction, the dynamics rendering and the semantic content. The RTI2 metrics, derived from these values, are essential to successfully implement an end-to-end (E2E) control scheme that adapts the transmission parameters to the equivalent E2E infrastructure that encompass not only to the network state, but also to the server and client applications processing capabilities. A model of the end-to-end system is exploited to ensure a minimal transmission time for a given E2E system.