A new active measurement approach to Internet end-to-end available bandwidth estimation, AB-cap, is proposed, which is based on the concept of self-induced congestion. In this approach, the transmission rates of probing packets are increased step by step and a new decision criteria, NWID (Normalized Weighted Increased Delay), is defined. Another idea is that sliding-window decision is applied to determine the available bandwidth in one measurement. Simulation and test results show that the measurement precision is improved with slightly adding probing overhead compared with pathchirp.