Rec. ITU-T G.872 Amendment 1 (01/2021) Architecture of the optical transport network
Table of Contents
1 Scope
2 References
3 Definitions
     3.1 Terms defined elsewhere
     3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
     5.1 Notational
     5.2 Diagrammatic
6 Functional architecture of OTN
7 OTN digital layers
     7.1 Optical data unit (ODU) layer network
          7.1.1 ODUk multiplexing
          7.1.2 ODU clients and servers
          7.1.3 ODU trail termination
          7.1.4 ODU transport entities
      ODU tandem connections
          7.1.5 ODU topological components
     7.2 Optical transport unit (OTU) layer network
          7.2.1 OTU trail termination
          7.2.2 OTU transport entities
          7.2.3 OTU topological components
     7.3 Client/server associations
          7.3.1 ODU/client adaptation
          7.3.2 ODU/ODU adaptation
          7.3.3 OTU/ODU adaptation
8 Architecture of the media network supporting the OTN digital layers
     8.1 Media constructs
     8.2 Media element
     8.3 Optical tributary signals (OTSi)
          8.3.1 Flexible OTN interfaces
          8.4 Management of optical signals
          8.4.1 OMS and OTS media channel group
          8.4.2 OSC
          8.4.3 Optical signal maintenance entities (OSMEs)
          8.4.4 Media channels and OSMEs
     8.5 Management of media and signals
          8.5.1 Management of media channels
          8.5.2 Assignment of signals to media channels
          8.5.3 Management of OTSiA connections
     8.6 Modulator/demodulator and termination functions
     8.7 Client/server associations
          8.7.1 Digital-laneM-AI/OTU adaptation function
          8.7.2 OMS-O/OTSiG-O adaptation function
          8.7.3 OTS-O/OMS-O adaptation function
          8.7.4 Digital-laneM-AI/OTS-O adaptation
9 Media network topology
10 Management
     10.1 Capabilities
          10.1.1 Fault, configuration and performance management
          10.1.2 Client/server interaction
          10.1.3 Adaptation management
          10.1.4 Connection and MCG supervision
      Continuity supervision
      Connectivity supervision
      Maintenance information
      Subnetwork/tandem/unused connection supervision
          10.1.5 Connection quality supervision
          10.1.6 Management communications
          10.1.7 Frequency and time synchronization
     10.2 Connection supervision techniques
     10.3 Connection supervision applications
          10.3.1 Unused connections
          10.3.2 Connection monitoring
11 OTN survivability techniques
Appendix I  Relationship between OCh and OTSi terminology
Appendix II  Use of the OTN to carry Flex Ethernet
     II.1 Overview of Flex Ethernet
     II.2 FlexE unaware
     II.3 FlexE aware
     II.4 FlexE terminating
Appendix III  Examples of views of an ODU layer network
Appendix IV  Examples of multi-domain OTN applications