A network node encapsulates an IPv6 packet into a data frame including a layer-2 forwarding header and a MAC header, where the data frame includes a 6LoWPAN compressed IPv6 packet, and the layer-2 forwarding header and the MAC header are located in an outer layer of the 6LoWPAN compressed IPv6 packet. The network node obtains a MAC address of a next-hop node based on a final MAC address in the layer-2 forwarding header, and sends the data frame to the next-hop node, so that the next-hop node forwards the data frame directly based on the layer-2 forwarding header.