PURPOSE: To confirm whether or not a sender of a signal and the signal are correct by setting a node number to a section overhead (SOH) at a node inserting the SOH and allowing a node separating the SOH to check the node number.
CONSTITUTION: Each of wavelengths λ1, λ2 is allocated to signal paths 6-1, 6-2 respectively, a node B being a wavelength cross connector checks the wavelength and shares an input signal whose wavelength is λ1 to a node C and an input signal whose wavelength is λ2 to a node D. In this case, the node B does not implement the processing of an electric level, that is, the processing of a section overhead (SOH) and then the SOH added in the node A reaches the nodes C, D. One byte of the SOH is used in the node A for the insertion of the number of the node A to which a different number is allocated and it is detected by the nodes B, C. Thus, whether or not the sender of the signal and the signal itself are set correctly are confirmed.
NAKANO YUKIO
ASHI MASAHIRO
