Traffic pending delivery to sleeping Mobile Units is buffered in an Access Controller. When a particular sleeping Mobile Unit wakes up, the Access Point with which the Mobile Unit is associated signals to the Mobile Unit indicating that traffic is buffered for that Mobile Unit. In response to signaling from the Mobile Unit via the Access Point, the Access Controller forwards the traffic buffered for that Mobile Unit. In particular, the traffic is transmitted from the Access Controller to the Access Point, and then from the Access Point to the Mobile Unit. A limit may be placed on the amount of time during which the Access Controller buffers traffic for a particular Mobile Unit.