A method includes: A first transmission unit packs, at a protocol layer of the first transmission unit, to-be-transmitted data of an application layer of the first transmission unit, to generate a data packet. The data packet includes data type information, the data type information indicates an application scenario of the data packet, and the application scenario includes any one of a camera scenario, a display scenario, and a storage scenario. The first transmission unit sends the data packet to a physical layer of the first transmission unit through the protocol layer of the first transmission unit. The first transmission unit sends the data packet to a second transmission unit through the physical layer of the first transmission unit.