A method implemented by an optical line terminal (OLT) comprising a memory storage comprising instructions, a processor in communication with the memory, wherein the processor executes the instructions to generate a multi-rate downstream frame having a pre-defined length, the multi-rate downstream frame comprising a plurality of subframes that are each associated with a respective data rate, and a transmitter coupled to the processor and configured to transmit each subframe of the plurality of subframes of the multi-rate downstream frame at the respective data rate.