Device and method for routing secure communication streams between remote sites

Device (D) for interconnecting and routing between a remote local network (E_201 ) and at least one transport network (T_204, T_205, T_206) characterised in that it comprises: * first means (311) capable of selecting, for a communication stream coming from said source local network (E_201), at least one path to the remote network (E_203) for which it is intended and associating this path with a marking value (X), * means (317) of inserting the marking value (X) into a header field of the packets of said stream, * means (331) of encrypting the entirety of said stream except the header fields, * second means (321) capable of switching said encrypted stream towards the transport network (T_204) directly connected to said source local network (E_201) and located on the selected path, according to the marking value (X) read in the header field of said packets, * a gateway (341) for communicating, to said second means (342), the association between the marking value (X) and the switch to apply according to the path selected by said first means (311).