A method for monitoring a wireless channel or wireless network. Preferably, the method and system monitors a web-based network. Active data probing is used to estimate bandwidth availability when no a-priori knowledge of the current channel or network condition is available, and passive monitoring is used to track ongoing web traffic in estimating the current bandwidth available. Data probes are selected that are dynamically customized based on application requirements and the network variability observed in view of a balancing between accuracy of the bandwidth estimation and the potential overhead in terms of time consumed and additional traffic used. In this way, under specified limits of overhead, the active probing attempts to achieve best-effort network bandwidth estimation, and the passive monitoring tracks ongoing web traffic in estimating the current bandwidth available.