A data processing method, a packet sending method, and an apparatus. The data processing method includes: a first device obtains a first periodicity parameter and a second periodicity parameter, where the first periodicity parameter is determined based on duration of transmitting a packet from a first network device to a second network device along a first path, and the second periodicity parameter is determined based on duration of transmitting a packet from the first network device to the second network device along a second path; and the first device determines a third periodicity parameter based on the first periodicity parameter and the second periodicity parameter, where the third periodicity parameter reflects a quantity of periodicities between a periodicity in which the first network device sends a data packet and a periodicity in which the second network device forwards the data packet.