An Optical Transport Network (OTN) is a transmission network based on wavelength division multiplexing (WDM) technology. Key elements of OTN include: Standardized framing (the “digital wrapper”): OTN adds overhead. OTN, or Optical Transport Network, is a telecommunications standard for transporting data over optical networks. It is designed to provide a high-speed, scalable, and reliable infrastructure for the transmission of data between different network nodes. OTN is built on a series of protocols, including G.