An improved method and apparatus for making forwarding decisions in a switching device. The invention reduces the flooding of frames to particular network segments connected to the switch. To insure a device sees a frame addressed to it, if a switch does not know what segment a device address is connected to for a unicast frame, the switch typically floods the frame to all segments in the broadcast domain. This invention allows segments to be identified as having a predefined maximum number of device addresses that will be associated with it. When that number of addresses is already in the forwarding table the switch will not flood unicast frames to that segment since no more devices should be connected to that segment.