Active congestion control (ACC) applies active networking to feedback congestion control in a high bandwidth-delay product network, shortening the feedback loop by filtering traffic in the network near congestion. This paper describes recent simulation results showing the function of the system in TCP networks across a range of bandwidth-delay products. It also discusses the implementation of another version of the system in the ASP EE, an active networking execution environment implemented at USC/ISI. An assessment of ACC overhead in that implementation is made.