Abstract: A method and system for actively controlling transport and delivery of content across best-effort networks (FIG. 3A) includes computing expected content bit rate values (315) associated with a distributed application, and expected quality of service (QoS) metrics (325) for the application. Along with the actual measurements that are indicative of the content bit rate and metrics, the expected bit rates (315) and metrics (325) are used to control the bit rate being generated by the application. The expected bit rates (315) and metrics (325) may be based on measured values of previous bit rates, and metrics, or their various transformations, as well as previously forecasted bit rates and metrics (360), or their various transformations. The forecasting of bit rates and metrics may be facilitated by the use of an appropriate predictive algorithm. In this manner, active control of content being distributed over best-effort networks is achieved without substantially modifying the core network infrastructure.