A method and system for transporting ancillary network data is provided. A sub-carrier modulation signal containing ancillary network data is superimposed on a high bit-rate data signal prior to transport over an optical link. The monitoring subcarrier signal is significantly lower in both frequency and amplitude than the main data signal so as to not impact reliable reception of the main data signal. A low-pass filter filters the sub-carrier modulation signal from the data signal. By demodulating the sub-carrier signal, the ancillary network data is recovered. The ancillary network data includes any combination of data type information related to different network elements. The recovered ancillary network data is useful for any network management purpose. Especially important applications include restoration, wavelength re-use and routing, and any other general network management operation.