We present an algorithm for performing dynamic per-link admission control. It is designed to be suitable for deployment using existing quality of service and router techniques. The rationale for the algorithm is to find a bitrate limit for reserved capacity, which enables efficient capacity utilization and statistical multiplexing gain. By using simple traffic meters configured with respect to defined service levels, a network resource controller estimates an admission limit. The estimated limit reflects the ratio between reserved capacity and the aggregate behavior of current flows. Simulations indicate that reliable admission limits can be estimated already at low reservation levels.