A method is provided for transmitting a sequence of N virtual network identifier fields from a client entity to a server entity, the server entity belonging to a packet switching transport network. The method includes, at the level of the client entity, choosing a coder from among a plurality of coders, coding the sequence of N identifier fields with the aid of the chosen coder, and writing the coded sequence and the associated coding parameters in a packet. At the level of the server entity, on receipt of a packet, the method includes reading the coding parameters in the packet received, so as to identify at least the coder used and in decoding the coded sequence received with the aid of a decoder corresponding to the identified coder.