The present application discloses a packet exchange method and a related device. The method includes: obtaining, by a first device, a packet by using a Network Convergence Protocol (NCP) layer of the first device; and sending, by the first device, the packet to an NCP layer of a second device by using the NCP layer of the first device, where the NCP layer is located at a data link layer of a user plane, and the NCP layer of the first device and the NCP layer of the second device form a direct data exchange channel between the first device and the second device; and the first device is a terminal and the second device is a core network device, or the first device is a core network device and the second device is a terminal.