In combination with the abovementioned possible implementation mode, in a second possible implementation mode of the first aspect, the layer-2 identifier of the remote terminal equipment may be configured in one of a MAC layer, a PDCP layer and an RLC layer; or layer 2 of each of the remote terminal equipment and the network equipment may include an Adaptation (ADP) layer, the ADP layer may be located between the MAC layer and the PDCP layer, and the layer-2 identifier of the remote terminal equipment may be set in the ADP layer.
In such case, optionally, if the identification information (for example, the layer-2 identifier) of the remote terminal equipment is configured in the ADP layer, that is, encapsulation and identification are performed in the ADP layer, layer 2 of the relay terminal equipment may include the ADP layer, and the remote terminal equipment corresponding to the first layer-2 PDU is determined in the ADP layer.