Abstract: Reconfigurable ring transmission network with multiplexing in wavelength for semi-permanent links, the network including at least one ring (10) comprising nodes (12) and at least one optical fiber (18, 20) passing through the nodes, and each site (13) in the network comprises transmission-reception means (EN, ES, RN, RS) for one or more wavelengths and each node comprises optical add-drop means (IN, IS, XN, XS) for this wavelength and optical switching means (CN, CS) to connect these means to the transmission-reception means, the network used for optical telecommunications.

Abstract: This network, intended for the transmission of information in optical form, wavelength multiplexed, comprises nodes (N1, N2) linked to each other by at least one optical fiber (F1), at least one wavelength being treated in each node. The system comprises unit (OF1, OF2, OS1, OS2) for superimposing on the information, for at least one wavelength per node, a surveillance signal whose frequency is outside the transmission band and, in each node, a surveillance circuit (CS1, CS2) for sampling at least one part of the surveillance signals, elaborating surveillance information in function of this part and sending this information to the processing units of the network. Application in optical telecommunications.