This Recommendation provides physical layer specifications for intra-domain (IaD) DWDM optical networking applications. These specifications are provided for point-to-point, multichannel line systems with or without line amplifiers. The goal is to enable longitudinally compatible applications inside an administrative domain. The primary purpose is to enable multiple vendors to provide transmission equipment for fibre links that are compliant with this Recommendation.

In order to provide a framework for IaD application specifications, this Recommendation includes a generic reference model for the physical layer applications. The specifications are organized according to application codes, which take into account parameters such as operating wavelength ranges of the optical amplifiers, combinations of channel counts, client classes, span distances, fibre types and system configurations.

This initial Recommendation focuses on IaD applications without intervening optical switching elements. It is expected that future versions and/or other new Recommendations may address more complex physical layer configurations and/or support a higher level of compatibility. For these applications, different parameters beyond those specified for a point-to-point configuration may be required.

This Recommendation presumes that the optical tributary signals transported within optical channels are digital rather than analogue. Specifications for systems enabling transport of analogue optical tributary signals are for further study.