Data transmission method and apparatus, network device, system, and storage medium

A data transmission method applicable to an ONU, comprising:

• receiving downlink data frames of different rates continuously sent by an OLT at a first designated wavelength in a time-division multiplexing manner, with the downlink data frames carrying clock recovery information and time slot identification information of the downlink data frames of the different rates;
• performing, according to the clock recovery information, clock recovery on a downlink data frame of a corresponding rate of the ONU;
• obtaining, according to the time slot identification information, time slot information of the downlink data frame of the corresponding rate of the ONU at the first designated wavelength;
• and
• acquiring the downlink data frame of the corresponding rate of the ONU using a recovered clock and the time slot information of the downlink data frame of the corresponding rate of the ONU at the first designated wavelength,
• wherein performing, according to the clock recovery information, clock recovery on the downlink data frame of the corresponding rate of the ONU comprises:
• performing, by an ONU of each rate, clock recovery on a downlink data frame of a corresponding rate of the ONU according to the clock recovery information before the downlink data frame of the corresponding rate,
• in response to an integral multiple relationship existing between the different rates, the corresponding clock recovery information is not carried before a downlink data frame of the highest rate of the different rates, and the method further comprises:
• holding, by an ONU with the highest rate, a clock of a downlink data frame of a corresponding rate,
• in response to an integral multiple relationship existing between the different rates and a receiving bandwidth of an ONU with a non-highest rate of the different rates being greater than a preset receiving bandwidth threshold, the method further comprises:
• recovering, by the ONU with the non-highest rate, a clock of a downlink data frame of a corresponding rate of the ONU from a downlink data frame of a second rate, wherein the second rate is an integral multiple of the non-highest rate, and
• in response to an ONU with any rate failing to recover a clock in a process of receiving the downlink data frames of the different rates, the method further comprises:
• enabling the ONU failing to recover the clock to use a held clock or start a local clock.