A coding method of vector network address (VNA), which encodes the VNA according to output port names (OPN) of one source device and the forwarding devices along the Data Transmission Path (DTP). Each OPN acts as a component address, and all component addresses compose a sequence in the order along the direction of the DTP. This sequence is the result of the coding method, i.e. the VNA. More specifically, the VNA is a finite sequence as follows: The first component address in the sequence is the OPN of the source device, the second that is the OPN of the first forwarding device in the DTP, the third that is the OPN of the second forwarding device in the DTP, and so on. The final OPN in the sequence is the OPN of the final forwarding device in the DTP.