n a traditional WDM system, to change a fixed signal transmission path, maintenance personnel have to visit the site to install related hardware and connect optical fibers, which are time- and labor-consuming. The OTN network uses electrical-layer grooming and optical-layer grooming to address these issues. With the help of the two grooming technologies, maintenance personnel can remotely adjust the transmission paths of signals from the control center.

How do electrical-layer grooming and optical-layer groomingwork respectively?

Electrical-Layer Grooming

Grooms electrical signals at a granularity of ODUk(k =1, 2(e), 3, 4, or flex)

  • Services are transmitted to tributary boards and groomed to line boards through the cross-connect board, encapsulated and mapped to OTU signals on the line boards, and then transmitted to the WDM side.
  • Through electrical-layer grooming, services of different granularities are groomed and encapsulated into one wavelength and output to the WDM side. This enables multiple services to share the bandwidth, greatly improving bandwidth utilization.
  • Optical-Layer Grooming

    Grooms optical signals at a granularity of wavelength (λ) by flexibly selecting transmission paths.

    The core unit for optical-layer grooming is the ROADM board.
  • After receiving OTU optical signals, the ROADM board creates optical cross-connection paths internally and outputs the signals to specified egresses. Each egress corresponds to a specific path
  • Operation personnel can remotely control the transmission paths of optical signals by creating and adjusting cross-connection paths on the NMS
  • Optical-layer grooming used together with the ASON technology can implement automatic fault detection and line adjustment to ensure normal transmission of services.
  • Electrical-layer grooming and optical-layer grooming form the grooming center of an OTN, so that the transmission paths of signals can be controlled remotely, realizing flexible grooming of signals.