A network includes an access point using a first protocol and a station using both the first protocol and a second protocol. The station uses the first protocol before a first threshold and a second protocol after the first threshold. A first duration between the second threshold and the first threshold is at least of sufficient length for the station to receive one data packet from the access point and send an acknowledgment. The station transmits to the access point a current clear-to-send packet at a current time during a current exchange based on success or failure of a previous exchange during which a previous clear-to-send packet was transmitted to the access point at a previous time.