An access network device sends first information and second information to a terminal, where the first information includes a value set of a communication time interval, and the second information indicates a value of the communication time interval in the value set, and the value is used to determine timing duration of a hybrid automatic repeat request (HARQ) round trip time (RTT) timer. The communication time interval includes at least one of a time interval from the terminal receiving downlink scheduling grant information to the terminal receiving downlink data scheduled by using the downlink scheduling grant information, a time interval from the terminal receiving downlink data to the terminal sending HARQ feedback information of the downlink data, and a time interval from the terminal receiving uplink scheduling grant information to the terminal sending uplink data scheduled by using the uplink scheduling grant information.