itu-t rec. g.875 (12/2018) optical transport network

I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n

ITU-T G.875 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU

(12/2018)

SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS

Digital networks – Optical transport networks

Optical transport network: Protocol-neutral management information model for the network element view

Recommendation ITU-T G.875

ITU-T G-SERIES RECOMMENDATIONS

TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS

INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100–G.199

GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS

G.200–G.299

INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES

G.300–G.399

GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES

G.400–G.449

COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450–G.499

TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600–G.699

DIGITAL TERMINAL EQUIPMENTS G.700–G.799

DIGITAL NETWORKS G.800–G.899

General aspects G.800–G.809

Design objectives for digital networks G.810–G.819

Synchronization, quality and availability targets G.820–G.829

Network capabilities and functions G.830–G.839

SDH network characteristics G.840–G.849

Management of transport network G.850–G.859

SDH radio and satellite systems integration G.860–G.869

Optical transport networks G.870–G.879

DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900–G.999

MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE – GENERIC AND USER-RELATED ASPECTS

G.1000–G.1999

TRANSMISSION MEDIA CHARACTERISTICS G.6000–G.6999

DATA OVER TRANSPORT – GENERIC ASPECTS G.7000–G.7999

PACKET OVER TRANSPORT ASPECTS G.8000–G.8999

ACCESS NETWORKS G.9000–G.9999

For further details, please refer to the list of ITU-T Recommendations.

Rec. ITU-T G.875 (12/2018) i


Optical transport network: Protocol-neutral management information model

for the network element view

Summary

Recommendation ITU-T G.875 (ex. G.874.1) provides a protocol-neutral management information

model for managing network elements in the optical transport network (OTN). The model contains

the managed entities and their properties that are useful to describe the information exchanged across

interfaces defined in the ITU-T M.3010 telecommunications management network (TMN)

architecture. The protocol-neutral management information model shall be used as the base for

defining protocol-specific management information models, for example, common management

information service element (CMISE), common object request broker architecture (CORBA) and

simple network management protocol (SNMP) information models. Mapping from the protocol-

neutral entities into protocol-specific objects is a decision of the specific protocol modelling design

and should be described in the protocol-specific information model Recommendations.

The 2012 revision of this Recommendation updated the management information model to support

the management of the new transport functions that were introduced in the 2010 revision of

Recommendation ITU-T G.798 and also to support the management requirements enhancement

introduced in the 2010 revision of Recommendation ITU-T G.874.

Amendment 1 enhanced the model to cover delay measurement (DM), automatic protection switching

(APS) configuration, tributary slot configuration, and optical data channel data (ODU) type and rate

configuration, and to remove the counting of incoming alignment errors (IAEs) and backward

incoming alignment errors (BIAEs).

Amendment 2 added: (1) the use of an organizationally unique identifier (OUI) to the description of

the attributes selectedApplicationIdentifier and supportableApplicationIdentifierList; and (2) sub-

classes the OTN Current Data and History Data object classes from the ITU-T Q.822 Current Data

and History Data object classes.

The 2016 revision of this Recommendation has incorporated Amendment 1 and Amendment 2, and in

addition the following updates: (1) changes the UML modeling tool from RSA to open source Papyrus

tool; (2) updates the ITU-T G.874.1 information model to align with the ITU-T G.7711 v2.0 Core

information model; (3) drops subclassing the TP classes from ITU-T M.3160; and (4) supports the

additional management requirements in Recommendation ITU-T G.874.

The 2018 revision of this Recommendation up-versions the UML model tool to Papyrus v3.2.0 and

the profile to v0.2.13, updates the object class mapping figures to align with ITU-T G.798, updates the

model for ODU, OTU, FlexO, OTSiG-O, OCh-O, OMS-O, and OTS-O, adds Annex A for OTN

specification model, and deprecates the OTU CTP, OChr and OPS (OPSn, OPSMnk, OPS0) layer

object classes to align with ITU-T G.798.

ii Rec. ITU-T G.875 (12/2018)

History

Edition Recommendation Approval Study Group Unique ID*

1.0 ITU-T G.874.1 2002-01-06 15 11.1002/1000/5608

2.0 ITU-T G.874.1 2012-10-29 15 11.1002/1000/11785

2.1 ITU-T G.874.1 (2012) Amd. 1 2013-08-29 15 11.1002/1000/11988

2.2 ITU-T G.874.1 (2012) Amd. 2 2015-08-13 15 11.1002/1000/12558

3.0 ITU-T G.874.1 2016-11-13 15 11.1002/1000/13087

4.0 ITU-T G.875 2018-12-14 15 11.1002/1000/13819

Keywords

Information model, protocol-neutral, optical transport network, OTN, transport resource, unified

modelling language, UML.

____________________

* To access the Recommendation, type the URL http://handle.itu.int/ in the address field of your web

browser, followed by the Recommendation's unique ID. For example, http://handle.itu.int/11.1002/1000/11830-en.

http://handle.itu.int/11.1002/1000/5608






http://handle.itu.int/11.1002/1000/11830-en

http://handle.itu.int/11.1002/1000/11830-en

Rec. ITU-T G.875 (12/2018) iii

FOREWORD

The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication

Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical,

operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.

The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes

the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.

The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.

In some areas of information technology which fall within ITU-T's purview, the necessary standards are

prepared on a collaborative basis with ISO and IEC.

NOTE

In this Recommendation, the expression "Administration" is used for conciseness to indicate both a

telecommunication administration and a recognized operating agency.

Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain

mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other

obligatory language such as "must" and the negative equivalents are used to express requirements. The use of

such words does not suggest that compliance with the Recommendation is required of any party.

INTELLECTUAL PROPERTY RIGHTS

ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve

the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of

the Recommendation development process.

As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are

cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB

patent database at http://www.itu.int/ITU-T/ipr/.

ITU 2019

All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior

written permission of ITU.

http://www.itu.int/ITU-T/ipr/

iv Rec. ITU-T G.875 (12/2018)

Table of Contents

Page

1 Scope ........................................................................................................................ 1

2 References ................................................................................................................ 2

3 Terms and Definitions ............................................................................................... 3

3.1 Definitions from [ITU-T M.3100]................................................................ 3

3.2 Definitions from [ITU-T G.870] .................................................................. 3



3.5 Definitions from [ITU-T G.7710] ................................................................ 4

4 Abbreviations and Acronyms .................................................................................... 4

5 Conventions .............................................................................................................. 5

5.1 Information modeling conventions .............................................................. 5

6 Overview of the model .............................................................................................. 6

7 UML model class diagrams ....................................................................................... 11

7.1 High-level overview .................................................................................... 11

7.2 OxS-O fragment .......................................................................................... 14

7.3 OCh fragment .............................................................................................. 15

7.4 OTU fragment ............................................................................................. 16

7.5 ODU fragment ............................................................................................. 17

7.6 FlexO fragment ........................................................................................... 19

7.7 NIM fragment.............................................................................................. 20

7.8 GCC fragment ............................................................................................. 20

7.9 Protection fragment ..................................................................................... 21

7.10 Performance monitoring (PM) fragment ...................................................... 24

7.11 Fault management fragment ........................................................................ 27

8 UML model file ........................................................................................................ 28

Annex A – OTN specification model ................................................................................... 29

A.1 LTP/LP Spec model .................................................................................... 29

Appendix I – Usage of the model for TCM and GCC ........................................................... 33

I.1 TCM locations ............................................................................................. 35

I.2 GCC access locations .................................................................................. 40

I.3 GCC access and TCM locations together ..................................................... 44

Appendix II – Management termination points ..................................................................... 51

II.1 State management........................................................................................ 51

II.2 Location of TPs inside a ONE ..................................................................... 51

II.3 Definitions of ONE termination points ........................................................ 51

Appendix III – Mapping of ITU-T G.798 atomic functions to ITU-T G.874.1

model artefacts .......................................................................................................... 53

Rec. ITU-T G.875 (12/2018) v

Page

Appendix IV – UML model data dictionary ......................................................................... 54

Appendix V – Overview of object class mapping to OxS-O trail protection sub-layer

functions ................................................................................................................... 55

Bibliography ........................................................................................................................ 56

Rec. ITU-T G.875 (12/2018) 1


Optical transport network: Protocol-neutral management information model

for the network element view

1 Scope

This Recommendation provides a management/control-protocol-neutral information model for

managing/controlling network elements in the optical transport network (OTN) [ITU-T G.872],

[ITU-T G.709] and [ITU-T G.798]. It identifies the managed entities required for the

management/control of OTN network elements. These entities are relevant to information exchanged

across standardized interfaces defined in the ITU-T M.3010 TMN architecture [ITU-T M.3010]. The

management/control-protocol-neutral information model should be used as the base for defining

management-protocol-specific information models, for examples, XML (web service or

Netconf/Yang) information model, CORBA IDL model and SNMP MIB.

The information model defined in this Recommendation is an augmentation to the generic code model

specified in [ITU-T G.7711] for managing OTN transport resources. The core information model

defined in [ITU-T G.7711] can be used as the base for the extension of OTN-specific information

models.

The specific mapping of the management/control-protocol-neutral entities into management/control-

protocol-specific managed object classes is the decision of the management/control-protocol-specific

solution design. For example, an object class defined in this Recommendation may be mapped into

multiple tables in a SNMP MIB. On the other hand, all the monitoring entities may be mapped into a

single class in a protocol-specific model. Protocol-specific solution and their mapping from the

protocol-neutral model is outside the scope of this Recommendation.

This Recommendation applies to OTN network elements and those systems that manage/control OTN

network elements. The management/control system could be a network management system (NMS),

an element management system (EMS) or a software-defined networking (SDN) controller or a

hybrid of them. Recommendation [ITU-T G.7701] defines the management-control-continuum

(MCC) concept whereby management and control functions are considered to be a continuum. Those

systems are thus referred to as a management-control system (MCS) in general in this

Recommendation. Functional capabilities of OTN equipment are defined in [ITU-T G.798], and

requirements of the management of OTN equipment are provided in [ITU-T G.7710] and

[ITU-T G.874]. The information model specified in this Recommendation applies to the

mangement/control interface, as shown in Figure 1-1, specifically for managing/controlling the OTN

functional capabilities of the network element (NE).

2 Rec. ITU-T G.875 (12/2018)

Figure 1-1 – Scope of interface

There are several different perspectives from which information may be defined for management

purposes. The network element viewpoint is concerned with the information that is required to

manage a network element. This refers to information required to manage the network element

function and the physical aspects of the network element. This Recommendation addresses only the

network element view of OTN management.

The management/control-protocol-neutral information model specified in this Recommendation

consists of a set of transport-technology-specific managed object classes, i.e., OTN-specific managed

object classes. These OTN-specific managed object classes are inherited from the generic managed

object classes defined in other ITU-T Recommendation such as [ITU-T G.711] and [ITU-T M.3160],

including Managed Element, Termination Point and its subclasses, Subnetwork, and Subnetwork

Connection1. Because of object class inheritance, the OTN management information model also

inherits the generic object management capabilities, such as object creation/deletion, notification of

object creation/deletion, attribute value retrieval/modification, notification of attribute/state value

change, scoped and filtered retrieval of object instances, and abortion of outstanding operations. The

description of these generic object management capabilities is provided in other ITU-T

Recommendations, such as the M.3700 series, and therefore is outside the scope of this

Recommendation.

The object entities defined in this Recommendation apply to fault management and configuration

management.

2 References

The following ITU-T Recommendations and other references contain provisions which, through

reference in this text, constitute provisions of this Recommendation. At the time of publication, the

editions indicated were valid. All Recommendations and other references are subject to revision;

users of this Recommendation are therefore encouraged to investigate the possibility of applying the

most recent edition of the Recommendations and other references listed below. A list of the currently

____________________

1 The linkage of the OTN-specific object classes to the generic object classes is specified in detail in Appendix

III of this Recommendation.

Rec. ITU-T G.875 (12/2018) 3

valid ITU-T Recommendations is regularly published. The reference to a document within this

Recommendation does not give it, as a stand-alone document, the status of a Recommendation.

[ITU-T G.709] Recommendation ITU-T G.709/Y.1331 (2016), Interfaces for the optical

transport network, plus Amendment 1 (2016), Amendment 2 (2018).

[ITU-T G.798] Recommendation ITU-T G.798 (2017), Characteristics of optical transport

network hierarchy equipment functional blocks, plus Amendment 1 (2018).

[ITU-T G.872] Recommendation ITU-T G.872 (2017), Architecture of optical transport

networks.

[ITU-T G.874] Recommendation ITU-T G.874 (/2017), Management aspects of optical

transport network elements.

[ITU-T G.7044] Recommendation ITU-T G.7044/Y.1347 (2011), Hitless adjustment of

ODUflex (GFP), plus Amendment 1 (02/2012).

[ITU-T G.7701] Recommendation ITU-T G.7701 (11/2016), Common control aspects, plus

Amendment 1 (03/2018).

[ITU-T G.7710] Recommendation ITU-T G.7710/Y.1701 (2012), Common equipment

management function requirements, plus Amendment 1 (11/2016).

[ITU-T G.7711] Recommendation ITU-T G.7711/Y.1702 (2018), Generic protocol-neutral

information model for transport resources.

[ITU-T G.8052] Recommendation ITU-T G.8052/Y.1346 (2016), Protocol-neutral management

information model for the Ethernet Transport capable network element.

[ITU-T M.3010] Recommendation ITU-T M.3010 (2000), Principles for a telecommunications

management network, plus Amendment 1 (12/2003), and Amendment 2

(11/2005).

[ITU-T M.3100] Recommendation ITU-T M.3100 (2005), Generic network information model.

[ITU-T Q.822] Recommendation ITU-T Q.822 (1994), Stage 1, stage 2 and stage 3

description for the Q3 interface – Performance management.

[ITU-T X.739] Recommendation ITU-T X.739 (1993), Information technology – Open

Systems Interconnection – Systems Management: Metric objects and attributes.

3 Terms and Definitions

3.1 Definitions from [ITU-T M.3100]

The following terms are defined in [ITU-T M.3100] and used in this Recommendation:

ASAP Alarm Severity Assignment Profile

CTP Connection Termination Point

TP Termination Point

TTP Trail Termination Point

3.2 Definitions from [ITU-T G.870]

The following terms are defined in [ITU-T G.870] and used in this Recommendation:

OCh Optical Channel

ODUk Optical Channel Data Unit-k

ODUkP Optical Channel Data Unit-k, Path

4 Rec. ITU-T G.875 (12/2018)

ODUkT Optical Channel Data Unit-k, Tandem connection sublayer

OPS Optical Physical Section

OTM Optical Transport Module

OTN Optical Transport Network

OTU Optical Channel Transport Unit

OTUk Optical Transport Unit-k



OMS Optical Multiplex Section

OTS Optical Transmission Section



A Adaptation function

GCC General Communication Channel

MP Management Point

TT Trail Termination function


The following term is defined in [ITU-T G.7710] and used in this Recommendation:

ARC Alarm Reporting Control

4 Abbreviations and Acronyms

This Recommendation uses the following abbreviations and acronyms:

ARC Alarm Reporting Control

ASAP Alarm Severity Assignment Profile

BIAE Backward Incoming Alignment Error

CMISE Common Management Information Service Element

CORBA Common Object Request Broker Architecture

CTP Connection Termination Point

EMS Element Management System

GCC General Communication Channel

IAE Incoming Alignment Error

IDL Interface Definition Language

LP Layer Protocol

LTP Logical Termination Point

MP Management Point

NE Network Element

Rec. ITU-T G.875 (12/2018) 5

NIM Non-Intrusive Monitoring

NMS Network Management System

OCh Optical Channel

ODUk Optical Channel Data Unit-k

ODUkP Optical Channel Data Unit-k, Path

ODUkT Optical Channel Data Unit-k, Tandem connection sublayer

OMS Optical Multiplex Section

OMS-O Optical Multiplex Section – Overhead

OPS Optical Physical Section

OTM Optical Transport Module

OTN Optical Transport Network

OTS Optical Transmission Section

OTSi Optical Tributary Signal

OTSiA Optical Tributary Signal Assembly

OTSiG Optical Tributary Signal Group

OTSiG-O Optical Tributary Signal Group – Overhead

OTU Optical Channel Transport Unit

OUI Organizationally Unique Identifier

SDN Software-Defined Networking

SNMP Simple Network Management Protocol

TCM Tandem Connection Monitoring

TMN Telecommunication Management Network

TP Termination Point

TT Trail Termination function

TTP Trail Termination Point

UML Unified Modelling Language

5 Conventions

5.1 Information modeling conventions

5.1.1 UML modeling conventions

See [ITU-T G.7711] clause 5.1.

5.1.2 Model Artefact Lifecycle Stereotypes conventions


5.1.3 Forwarding entity terminology conventions


6 Rec. ITU-T G.875 (12/2018)

5.1.4 Conditional package conventions


5.1.5 Pictorial diagram conventions


6 Overview of the model

This Recommendation models the optical transport network (OTN) transport functions that are

relevant to OTN network elements management. These functions are defined in the equipment

specification [ITU-T G.798] for the termination, adaptation and connection functions of the OTN

layers, including Optical Transmission Section - Overhead (OTS-O), Optical Multiplex Section –

Overhead (OMS-O), Optical Tributary Signal Group – Overhead (OTSiG-O), Optical Channel –

Overhead (OCh-O), Optical Transmission Unit (OTU), Optical Data Unit (ODU), Tandem

connection sublayer of Optical Data Unit of level k (ODUkT), and the FlexO and OTSi adaptation

functions. In particular, the input and output information exchanged at the management point (MP)

are modelled. The termination, adaptation, and connections functions and input/output information

cover the areas of configuration, fault management, and performance management as described in

[ITU-T G.7710] and [ITU-T G.874]. Details of the management functions that need to be modelled

are provided in [ITU-T G.7710] and [ITU-T G.874].

In this Recommendation, managed resources and management support resources are modelled as

objects in the information model. The management view of a resource is a managed object. This

Recommendation specifies the properties of the resources visible for management. Objects with

similar properties are grouped into object classes. An object instance is an instantiation of an object

class. The properties of an object include the behaviour, attributes and operations that can be applied

to the object. An object instance is characterized by its object class and may possess multiple attribute

types and associated values. In the protocol-neutral model, object classes are represented as unified

modelling language (UML) classes.

Object classes, attribute types and operations are defined for the purpose of communicating network

management messages between systems. They need not be related to the structure of data stored

within those systems.

An object class may be a subclass of another class. A subclass inherits properties of its superclass, in

addition to possessing its own specific attributes and properties. In this Recommendation, the

OTN-specific transport object classes are defined. These object classes are not inherited from any

generic transport superclasses. In the future, when defining protocol-specific OTN object classes,

they could be mapped from the protocol-neutral OTN object classes and also inherited from the

protocol-specific generic transport object classes for additional properties.

In addition to the OTN resource, the model also includes object classes for management support

functions such as alarm reporting control and alarm severity assignment.

Figures 6-1 to 6-5 show the mapping between the OTN managed object classes and the OTN atomic

functions defined in Figures 1-1 to 1-5 of [ITU-T G.798].

Rec. ITU-T G.875 (12/2018) 7

Figure 6-1 – Overview of object class mapping to OTN atomic functions that support single-

OTU (SOTU) and muti-OTU (MOTU) interface

(Based on Figure 1-1 of [ITU-T G.798 (2017)])

Figure 6-2 – Overview of object class mapping to OTN atomic functions that support muti-

OTU (MOTUm) with management interface

(Based on Figure 1-2 of [ITU-T G.798 Corrigendum 1 (2018)])

8 Rec. ITU-T G.875 (12/2018)

Figure 6-3 – Overview of object class mapping to OTN atomic functions specific

for the non-associated overhead information

(Based on Figure 1-3 of [ITU-T G.798 Corrigendum 1 (2018)])

Rec. ITU-T G.875 (12/2018) 9

Figure 6-4 – Overview of object class mapping to OTN atomic functions for FlexO

(Based on Figure 1-4 of [ITU-T G.798 (2017)])

10 Rec. ITU-T G.875 (12/2018)

Rec. ITU-T G.875 (12/2018) 11

Figure 6-5 – Overview of object class mapping to OTN common atomic functions

(Based on Figure 1-5 of [ITU T G.798 Amendment 1 (2018)])

7 UML model class diagrams

The clause contains the UML model class diagrams of the OTN NE management-protocol-neutral

information model.

7.1 High-level overview

The UML diagrams below provide high-level overview of most of the ONT specific managed object

classes without showing the details, such as the attributes and operations of the object classes. More

details class diagrams for the individual fragments of the model are shown in the subsequent

subclauses, in which the attributes and operations are also shown.

12 Rec. ITU-T G.875 (12/2018)

Figure 7-1A – OTN model high-level overview

Rec. ITU-T G.875 (12/2018) 13

NOTE – This figure is also available from the ITU website here.

Figure 7-1B – OTN main entities

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-1B.png

14 Rec. ITU-T G.875 (12/2018)


Figure 7-1C – OTN Inheritance

7.2 OxS-O fragment


Figure 7-2 – OTS-O and OMS-O entities

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-1C.png

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-2.png

Rec. ITU-T G.875 (12/2018) 15

7.3 OCh fragment


Figure 7-3 – OCh entities


16 Rec. ITU-T G.875 (12/2018)

7.4 OTU fragment


Figure 7-4 – OTU entities


Rec. ITU-T G.875 (12/2018) 17

7.5 ODU fragment


Figure 7-5A – ODU entities

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-5A.png

18 Rec. ITU-T G.875 (12/2018)

NOTE – This figure is also available from the ITU website here

Figure 7-5B – ODUCn and ODUk Pacs


Figure 7-5C – ODU TCM entities

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-5B


Rec. ITU-T G.875 (12/2018) 19

7.6 FlexO fragment


Figure 7-6 – FlexO entities


20 Rec. ITU-T G.875 (12/2018)

7.7 NIM fragment


Figure 7-7 – NIM entities

7.8 GCC fragment


Figure 7-8 – GCC entities



Rec. ITU-T G.875 (12/2018) 21

7.9 Protection fragment


Figure 7-9A – OCh protection

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-9A.png

22 Rec. ITU-T G.875 (12/2018)


Figure 7-9B – ODU protection

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-9B.png

Rec. ITU-T G.875 (12/2018) 23


Figure 7-9C – OTS-O and OMS-O trail protection


24 Rec. ITU-T G.875 (12/2018)

7.10 Performance monitoring (PM) fragment


Figure 7-10A – Performance monitoring entities

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-9Cbis.png

Rec. ITU-T G.875 (12/2018) 25

7.10.1 Delay measurement

The following figures provide an overview of the OTN delay measurement function showing

involved atomic functions, management information and managed object classes.

Figure 7-10B – ODU path delay measurement

26 Rec. ITU-T G.875 (12/2018)

Figure 7-10C – ODUk tandem connection delay measurement

Rec. ITU-T G.875 (12/2018) 27


Figure 7-10D – Delay Measurement entities

7.11 Fault management fragment

Figure 7-11 – Fault Management entities

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/F7-10D.png

28 Rec. ITU-T G.875 (12/2018)

8 UML model file

The ITU-T G.875 (ex. G.874.1) UML model is contained in a repository website. The following links

provide the pointers to the ITU-T G.875 UML model files and the supporting materials.

– G.875_v4.00_PAP.zip

This zip contains the ITU-T G.875 model files (i.e., the .project, .di, .notation and .uml files)

and the profiles.

The G.875 4.0 model uses the following modelling tool and profiles

• Eclipse 4.7.2 (i.e., version Oxygen)

• Papyrus 3.2.0,

• OpenModel_Profile 0.2.13,

• OpenInterfaceModel_Profile 0.8,

• ProfileLifecycle_Profile 0.0.4, and

• Gendoc v0.7.0 milestone 2

– G.875_v4.00_DD.zip

This zip file is the data dictionary.

– G.7711_v2.02_PAP.zip

This constains the ITU-T G.7711 model files. In order to use the ITU-T G.875 model, one

also needs to install the ITU-T G.7711 base model.

NOTE – The ITU-T G.875 UML information models and the Open Model Profile are specified using the

Papyrus open-source modelling tool. In order to view and further extend or modify the information model, one

will need to install the open source Eclipse software and the Papyrus tool, which are available at [b-Eclipse-

Papyrus]. The installation guide for Eclipse and Papyrus can be found in [b-ONF TR-515].

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/G.875_v4.00_PAP.zip

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/G.875_v4.00_DD.zip

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/G.7711_v2.00_PAP.zip

Rec. ITU-T G.875 (12/2018) 29

Annex A

OTN specification model

(This annex forms an integral part of this Recommendation.)

This annex describes how the Recommendation ITU-T G.7711 Specification model is used to

augment the Core model with the OTN specific properties.

A.1 LTP/LP Spec model

A.1.1 Overview of the core LTP/LP Spec model

Clause G.3.2 of [ITU-T G.7711] defines a generic logical termination point (LTP) and layer protocol

(LP) Spec model that provides a representation of LP specific parameters for the LTP. Reproduced

below is Figure G.3-18 of [ITU-T G.7711], which shows the LTP/LP spec elements.

Applies to inverse

multiplexing cases

CoreModel Diagram

Spec-LtpCapabilitySpecWithLtp

Applies to virtual

cases

Figure A.1-1 – Relating LTP/LP spec elements

(From Figure G.3-18 of [ITU-T G.7711] – Relating LTP/LP spec elements)

As shown in the figure, the LpSpec class is the touch point to anchor the spec elements for specifying

the various capabilities of a specific type of LP. Among the Spec elements, the following two are

particularly relevant to the layer specific parameters of the termination points defined in the

technology specific recommendations.

ConnectionPointAndAdapterSpec is defined in G.3.2.3.3 of [ITU-T G.7711] as follows:

The specification of the server facing connection point and the adapter that deals with the

transformation of a single signal of the layer protocol to/from the server. Equivalent to an

ITU-T CTP [ITU-T G.8052].

30 Rec. ITU-T G.875 (12/2018)

TerminationSpec is defined in clause G.3.2.3.11 of [ITU-T G.7711] as follows:

The specification of the layer protocol termination (including framing, modulation etc.). For

example, the specification of the function that takes a MAC frame and extracts the content

(removing the MAC address in the process).

Although it is not explicitly stated, the TerminationSpec is obviously equivalent to an ITU-T TTP.

A.1.2 Consideration of OTN specification cases for LTP/LP

Considering:

• The benefit of easy traceability between the attributes of the technology-specific OTN

TTP/CTP of the information models with the corresponding management information (i.e.,

the MI signals) of the ITU-T G.798 OTN technology specific equipment function

specifications,

– This Recommendation continues to keep the current TTP/CTP in the technology-specific

information models

• The equivalency of the TTP/CTP to the spec elements, namely TerminationSpec and

ConnectionPointAndAdapterSpec respectively,

– This Recommendation enhances the technology-specific information models to augment,

for each layer, the core model generic TerminationSpec and

ConnectionPointAndAdapterSpec with the technology-specific TTP and CTP.

A.1.3 OTN specification classes for LTP/LP

For each OTN layer, the core model generic TerminationSpec and ConnectionPointAndAdapterSpec

is augmented with the TTP and CTP object classes as shown in the following UML diagrams.

A.1.3.1 OTU specification classes for LTP/LP

Figure A.1-2 describes the OUT Spec case.

Rec. ITU-T G.875 (12/2018) 31

Figure A.1-2 – OTU Spec case

A.1.3.2 ODU specification classes for LTP/LP

Figure A.1-3 describes the ODU Spec case.

32 Rec. ITU-T G.875 (12/2018)

NOTE – This figure is also available from the ITU website here

Figure A.1-3 – ODU Spec case

https://www.itu.int/ITU-T/formal-language/itu-t/g/g875/2018/FA.1-3.png

Rec. ITU-T G.875 (12/2018) 33

Appendix I

Usage of the model for TCM and GCC

(This appendix does not form an integral part of this Recommendation.)

This appendix provides some examples to illustrate possible positions of TCM and GCC access

functions within ODUk TPs and how they will be represented in the information model. This

representation is defined via the use of containment relationships and the attributes PositionSeq,

Codirectional and Directionality.

The following ODUk layer network configuration will be used as a basis:

34 Rec. ITU-T G.875 (12/2018)

35 Rec. ITU-T G.875 (12/2018)

I.1 TCM locations

I.1.1 TC_Trail between ODUk_CTP source and ODUk_CTP sink (points C and D)

Object Contains PositionSeq Codirectional Directionality

ODUk_CTP at Point C ODUkT_TTP #45 ODUkT_TTP #45 source

ODUkT_TTP #45 true source

ODUk_CTP at Point D ODUkT_TTP #6 ODUkT_TTP #6 sink

ODUkT_TTP #6 true sink

36 Rec. ITU-T G.875 (12/2018)

I.1.2 TC_Trail between ODUk_CTP sink and ODUk_CTP source (points E and F)


ODUk_CTP at Point E ODUkT_TTP #23 ODUkT_TTP #23 sink

ODUkT_TTP #23 false source

ODUk_CTP at Point F ODUkT_TTP #87 ODUkT_TTP #87 source

ODUkT_TTP #87 false sink

37 Rec. ITU-T G.875 (12/2018)

I.1.3 TC_Trail between ODUk_TTP source and ODUk_CTP source (points G and H)


ODUk_TTP at Point G ODUkT_TTP #3 ODUkT_TTP #3 source

ODUkT_TTP #3 meaningless source

ODUk_CTP at Point H ODUkT_TTP #65 ODUkT_TTP #65 source


38 Rec. ITU-T G.875 (12/2018)

I.1.4 Two TC_Trail terminations within one ODUk_CTP

Rec. ITU-T G.875 (12/2018) 39


ODUk_CTP at Point C ODUkT_TTP #19 ODUkT_TTP #19 source




ODUk_CTP at Point F ODUkT_TTP #1

ODUkT_TTP #3

ODUkT_TTP #3

ODUkT_TTP #1

source



40 Rec. ITU-T G.875 (12/2018)

I.2 GCC access locations

I.2.1 COMMS channel between two ODUk_TTPs (points A and B, TT atomic functions are included)


ODUk_TTP at Point A GCC12_TP #100 empty source

GCC12_TP #100 meaningless source

ODUk_TTP at Point B GCC12_TP #2 empty sink

GCC12_TP #2 meaningless sink

41 Rec. ITU-T G.875 (12/2018)

I.2.2 COMMS channel between ODUk_CTP and ODUk_TTP (Points C and B(bis) TT atomic function at B(bis) is not included)


ODUk_CTP at Point C GCC12_TP #22 GCC12_TP #22 source

GCC12_TP #22 true source

ODUk_TTP at Point B GCC12_TP #13 GCC12_TP #13 sink

GCC12_TP #13 meaningless sink

42 Rec. ITU-T G.875 (12/2018)

I.2.3 Several COMMS channels

Rec. ITU-T G.875 (12/2018) 43

Object Contains Position

Seq

Codirec-

tional

Direc-

tionality GCCAccess

ODUk_CTP at Point E GCC12_TP #6

GCC12_TP #9

GCC12_TP #9

GCC12_TP #6

bidirectional

GCC12_TP #6 false bidirectional GCC1

GCC12_TP #9 true bidirectional GCC1

ODUk_CTP at Point F GCC12_TP #4

GCC12_TP #45

GCC12_TP #2

GCC12_TP #8

GCC12_TP #8

GCC12_TP #2

GCC12_TP #45

GCC12_TP #4

bidirectional





ODUk_CTP at Point

B(bis)

GCC12_TP #34

GCC12_TP #5

GCC12_TP #5

GCC12_TP #34

bidirectional



44 Rec. ITU-T G.875 (12/2018)

I.3 GCC access and TCM locations together

I.3.1 TC_Trail and COMMS channel between ODUk_CTP source and ODUk_CTP sink (points C and D)

Rec. ITU-T G.875 (12/2018) 45


ODUk_CTP at Point C GCC12_TP #3

ODUkT_TTP #57

ODUkT_TTP #57

GCC12_TP #3

source



ODUk_CTP at Point D GCC12_TP #23

ODUkT_TTP #44

ODUkT_TTP #44

GCC12_TP #23

sink

GCC12_TP #23 true sink

ODUkT_TTP #44 true sink

46 Rec. ITU-T G.875 (12/2018)

I.3.2 Terminating TC_Trail and inserting GCC within one ODUk_CTP

Rec. ITU-T G.875 (12/2018) 47




ODUk_CTP at Point F ODUkT_TTP #65

GCC12_TP #43

GCC12_TP #43

ODUkT_TTP #65

source



ODUk_CTP

at Point B(bis)

GCC12_TP #8 GCC12_TP #8 sink

GCC12_TP #8 true sink

48 Rec. ITU-T G.875 (12/2018)

I.3.3 Bidirectional example with TCM and GCC access

To ensure readability, only the ODUk_CTP at point F is shown in the table. The other two

ODUk_CTPs at E and B(bis) are as shown in clause I.2.3.

Object Contains PositionSeq Codirec-

tional

Direc-

tionality

GCCAccess/

field

ODUk_CTP

at Point F

ODUkT_TTP #1

GCC12_TP #4

ODUkT_nim #98

GCC12_TP #45

GCC12_TP #2

ODUkT_TTP #49

GCC12_TP #8

GCC12_TP #8

ODUkT_TTP #49

GCC12_TP #2

GCC12_TP #45

ODUkT_nim #98

GCC12_TP #4

ODUkT_TTP #1

bidirectional

ODUkT_TTP #1 false bidirectional 5


ODUkT_nim #98 bidirectional 3



ODUkT_TTP #49 true bidirectional 5


Rec. ITU-T G.875 (12/2018) 49

I.3.4 GCC12TP orientation

Figure I.12 – Bidirectional Gcc12Tp contained by bidirectional TTP

Figure I.13 – Bidirectional Gcc12Tp contained by bidirectional TTP and CTP

50 Rec. ITU-T G.875 (12/2018)

Figure I.14 – Bidirectional Gcc12Tp contained by bidirectional TTP and CTP

Rec. ITU-T G.875 (12/2018) 51

Appendix II

Management termination points


II.1 State management

The ONE shall indicate to the OS when a termination point is no longer able to supervise the signal

(e.g., implementing equipment has a fault or loss of power).

II.2 Location of TPs inside a ONE

Figure II.1 show possible locations of TPs inside a network element (the network elements are

just examples; it is not necessary to define specific NE types):

Figure II.1 – Example of TPs in an optical amplifier

II.3 Definitions of ONE termination points

An otsTTPSource originates a WDM transmission trail between two adjacent optical network

elements. This object class represents the point where the optical line signal outgoes from the NE.

There is always one instance of an otsTTPSource per line output port.

An otsTTPSink terminates a WDM transmission trail between two adjacent optical network. This

object class represents the point where the optical line signal incomes into the NE. There is always

one instance of an otsTTPSink per line input port.

An omsCTPSource originates an optical multiplex section link connection between two adjacent

optical network elements. There is one instance (for the time being; in future there may be more) of

an omsCTPSource per line output port.

An omsCTPSink terminates an optical multiplex section link connection between two adjacent


an omsCTPSink per line input port.

52 Rec. ITU-T G.875 (12/2018)

An omsTTPSource originates an optical multiplex section trail between two (not necessarily

adjacent) optical network elements. There is one instance (for the time being; in future there may be

more) of an omsTTPSource per line output port.

An omsTTPSink terminates an optical multiplex section trail between two (not necessarily adjacent)


an omsTTPSink per line input port.

An ochCTPSource originates an optical channel link connection between two (not necessarily

adjacent) optical network elements. There is one instance of an ochCTPSource per wavelength

channel in a line output port.

An ochCTPSink terminates an optical channel link connection between two (not necessarily

adjacent) optical network elements. There is one instance of an ochCTPSource per wavelength

channel in a line input port.

An ochTTPSource originates an optical channel trail between two (not necessarily adjacent) optical

network elements. There is one instance of an ochTTPSource per OCh adapter.

An ochTTPSink terminates an optical channel trail between two (not necessarily adjacent) optical

network elements. There is one instance of an ochTTPSink per OCh adapter.

Rec. ITU-T G.875 (12/2018) 53

Appendix III

Mapping of ITU-T G.798 atomic functions to ITU-T G.874.1 model artefacts


This appendix provides further detail mapping between the [ITU-T G.798] atomic functions and the

ITU-T G.874.1 UML model artifacts. Note that in some cases a 1:1 mapping is not possible.

Table III.1 – Mapping between [ITU-T G.798] OTN atomic functions and UML model artifacts

For further study

54 Rec. ITU-T G.875 (12/2018)

Appendix IV

UML model data dictionary


The Data Dictionary contains, in MS Word document format, the details of the OTN NE

management-protocol-neutral information model, including the description and properties of the

object classes and their attributes and operations. This detailed information is generated automatically

by a Gendoc tool from the UML model.

The ITU-T G.874.1 data dictionary is provided in the G.875_v4.0_DD.zip file at the repository

mentioned in clause 8.

Rec. ITU-T G.875 (12/2018) 55

Appendix V

Overview of object class mapping to OxS-O trail protection sub-layer functions


Trail protection is modelled as an expansion of the access point for a trail to include a protection

sublayer. The expansion is identical for both the OTS-O and OMS-O layers, so it is described here

with “OxS-O” nomenclature.

Figure V.1 gives an overview of object class mapping to OxS-O trail protection sub-layer functions.

Figure V.1 – Overview of object class mapping to OxS-O trail protection sub-layer functions

(Based on Figure VIII.1 of [ITU-T G.798])

56 Rec. ITU-T G.875 (12/2018)

Bibliography

[b-Eclipse-Papyrus] Papyrus Eclipse UML Modelling Tool <https://www.eclipse.org/papyrus/>

[b-ONF TR-515] ONF TR-515_Papyrus-Guidelines <https://3vf60mmveq1g8vzn48q2o71a-

wpengine.netdna-ssl.com/wp-content/uploads/2018/08/TR-

515_Papyrus_Guidelines_v1.3-1-1.pdf> <https://community.opensourcesdn.org/wg/EAGLE/document/171>

https://www.eclipse.org/papyrus/

https://community.opensourcesdn.org/wg/EAGLE/document/171

Printed in Switzerland Geneva, 2019

SERIES OF ITU-T RECOMMENDATIONS

Series A Organization of the work of ITU-T

Series D Tariff and accounting principles and international telecommunication/ICT economic and policy issues

Series E Overall network operation, telephone service, service operation and human factors

Series F Non-telephone telecommunication services

Series G Transmission systems and media, digital systems and networks

Series H Audiovisual and multimedia systems

Series I Integrated services digital network

Series J Cable networks and transmission of television, sound programme and other multimedia signals

Series K Protection against interference

Series L Environment and ICTs, climate change, e-waste, energy efficiency; construction, installation

and protection of cables and other elements of outside plant

Series M Telecommunication management, including TMN and network maintenance

Series N Maintenance: international sound programme and television transmission circuits

Series O Specifications of measuring equipment

Series P Telephone transmission quality, telephone installations, local line networks

Series Q Switching and signalling, and associated measurements and tests

Series R Telegraph transmission

Series S Telegraph services terminal equipment

Series T Terminals for telematic services

Series U Telegraph switching

Series V Data communication over the telephone network

Series X Data networks, open system communications and security

Series Y Global information infrastructure, Internet protocol aspects, next-generation networks, Internet of Things and smart cities

Series Z Languages and general software aspects for telecommunication systems

itu-t rec. g.875 (12/2018) optical transport network

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