Abstract: An optical transport network data frame structure is configured to provide an in-band data channel. The in-band channel data is contained in the data frame space that would otherwise be allocated to forward error correction (“FEC”) bytes. Consequently, the provision of the in-band data channel does not affect the number of client data bytes contained in the data frame structure. In accordance with a practical embodiment, the data frame structure is compliant with Intra Domain Interface (IaDI) specifications set forth in International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation Guide For Recommendation, G.709/Y.1331.

Abstract: A data communication system transports a sequence of digital data frames that convey client input data encoded with secondary data. The system can utilize known, proprietary, or future techniques for digital data encoding, digital watermarking, data encryption, or the like. The secondary data can be frame alignment data, private data intended only for certain destination devices, and/or other data types. In a practical embodiment, the data frames are compliant with optical transport networks.

Abstract: An optical transport network data frame structure is configured to provide an in-band data channel. The in-band channel data is contained in the data frame space that would otherwise be allocated to forward error correction (“FEC”) bytes. Consequently, the provision of the in-band data channel does not affect the number of client data bytes contained in the data frame structure. In accordance with a practical embodiment, the data frame structure is compliant with IaDI specifications set forth in ITU-T Recommendation G.709/Y.1331.

Abstract: A system and method are provided for transporting FTFL messages in a G.709 network-connected simplex device. The method comprises: receiving messages from a first source in a digital wrapper frame format with overhead bytes in every frame; recovering FTFL information from the received message overhead bytes; and, selectively supplying modified FTFL information for transmit message overhead bytes to the first source. Recovering FTFL information from the received message overhead bytes includes recovering a 256 byte FTFL message, including a 128-byte forward message and a 128-byte backward message.