Method for receiving code block stream, method for sending code block stream, and communications apparatus

An apparatus, comprising:

• a transceiver configured to receive, from a first device that is in a transport network, a first code block stream that comprises a plurality of code blocks and that is in a first Ethernet physical interface rate mode corresponding to a first rate;
• and
• a processor coupled to the transceiver and configured to:
• determine a termination location of an inter-packet gap of the first code block stream based on a second code block of a start type in the first code block stream;
• determine a start location of the inter-packet gap based on a third code block of a first termination type in the first code block stream, wherein the third code block is after a fourth code block of the start type in a transmission sequence;
• determine a first target code block from the inter-packet gap, wherein the first target code block comprises a second target code block of a data type or a third target code block of the first termination type;
• and
• provide a second code block stream by modifying the first target code block to a first code block that is of a first ordered set type and that is in a second Ethernet physical interface rate mode corresponding to a second rate that is lower than the first rate,
• wherein the transceiver is further configured to transmit the second code block stream to a second device using the second Ethernet physical interface rate mode.