Internet-Draft L0 Common YANG Types July 2024
Belotti, et al. Expires 26 January 2025 [Page]
Workgroup:
CCAMP Working Group
Internet-Draft:
draft-ietf-ccamp-rfc9093-bis-11
Obsoletes:
9093 (if approved)
Published:
Intended Status:
Standards Track
Expires:
Authors:
S. Belotti, Ed.
Nokia
I. Busi, Ed.
Huawei
D. Beller, Ed.
Nokia
E. Le Rouzic
Orange
A. Guo
Futurewei Technologies

Common YANG Data Types for Layer 0 Networks

Abstract

This document defines a collection of common data types, identities, and groupings in the YANG data modeling language. These common types and groupings, derived from the built-in YANG data types, identities, and groupings are intended to be imported by modules that model Layer 0 configuration and state capabilities, such as Wavelength Switched Optical Networks (WSONs) and flexi-grid Dense Wavelength Division Multiplexing (DWDM) networks.

This document obsoletes RFC 9093 by replacing the YANG module it contained with a new revision that includes additional YANG data types, identities and groupings.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 26 January 2025.

Table of Contents

1. Introduction

YANG [RFC7950] is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols such as the Network Configuration Protocol (NETCONF) [RFC6241]. The YANG language supports a small set of built-in data types and provides mechanisms to derive other types from the built-in types.

This document introduces a collection of common data types derived from the built-in YANG data types. The derived types and groupings are designed to be the common types applicable for modeling Traffic Engineering (TE) features as well as non-TE features (e.g., physical network configuration aspects) for Layer 0 optical networks in model(s) defined outside of this document. The applicability of Layer 0 types specified in this document includes Wavelength Switched Optical Networks (WSONs) [RFC6163] [ITU-T_G.694.1] and [ITU-T_G.694.2], and flexi-grid Dense Wavelength Division Multiplexing (DWDM) networks [RFC7698] [ITU-T_G.694.1].

This document adds new type definitions to the YANG modules and obsoletes [RFC9093]. For further details, see the revision statements of the YANG module in Section 4 or the summary in Appendix A.

This document obsoletes [RFC9093] by replacing it in its entirety. It provides a new revision of the YANG module contained in that RFC, and retains the data types previously defined, but also adds new type definitions to the YANG module. For further details, see Appendix A.

The YANG data model in this document conforms to the Network Management Datastore Architecture defined in [RFC8342].

1.1. Terminology and Notations

Refer to [RFC7446] and [RFC7581] for the key terms used in this document, and the terminology for describing YANG data models can be found in [RFC7950].

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

1.2. Prefix in Data Node Names

In this document, names of data nodes and other data model objects are prefixed using the standard prefix associated with the corresponding YANG imported module.

Table 1: Prefixes and corresponding YANG module
Prefix YANG module Reference
l0-types ietf-layer0-types RFC XXXX

RFC Editor Note: Please replace XXXX with the RFC number assigned to this document and remove this note.

2. Layer 0 Types Module Contents

This document defines a YANG module for common Layer 0 types, ietf- layer0-types. This module is used for WSON and flexi-grid DWDM networks. The "ietf-layer0-types" module contains the following YANG reusable YANG data types, identities and groupings:

l0-grid-type:

A base YANG identity for the grid type as defined in [RFC6205] and [RFC7699].

cwdm-ch-spc-type:

A base YANG identity for the Coarse Wavelength Division Multiplexing (CWDM) channel-spacing type as defined in [RFC6205].

dwdm-ch-spc-type:

A base YANG identity for the DWDM channel-spacing type as defined in [RFC6205].

flexi-ncfg-type:

A base YANG identity for the DWDM flexi-grid Nominal Central Frequency Granularity (NCFG) type as defined in [RFC7699].

flexi-slot-width-granularity:

A base YANG identity for the DWDM flexi-grid Slot Width Granularity (SWG) type, as defined in [RFC7699].

Note that the only value for SWG standardized in [ITU-T_G.694.1] is 12.5GHz.

fec-type:

A base YANG identity from which specific FEC (Forward Error Correction) type identities are derived.

line-coding:

A base YANG identity from which specific identities defining the bit rate/line coding of optical tributary signals are derived.

wavelength-assignment:

A base YANG identity from which for Wavelength selection method, as defined in [RFC7689].

otu-type:

This specifies the type of OTU, including the types specified in [ITU-T_G.709].

Since [ITU-T_G.Sup43] does not guarantee interoperability in the data plane, the type of OTUk defined in [ITU-T_G.Sup43] can be defined in vendor-specific YANG modules using the otu-type identity, defined in this document, as the base.

operational-mode:

A YANG data type used to identify an organization (e.g., vendor) specific mode for transceiver capability description, as defined in Section 2.5.2 of [I-D.ietf-ccamp-optical-impairment-topology-yang]

wson-label-start-end:

The WSON label range was defined in [RFC6205], and the generic topology model defines the label-start/label-end in [RFC8795]. This grouping shows the WSON-specific label-start and label-end information. See Section 2.1 for more details.

wson-label-hop:

The WSON label range was defined in [RFC6205], and the generic topology model defines the label-hop in [RFC8795]. This grouping shows the WSON-specific label-hop information. See Section 2.1 for more details.

l0-label-range-info:

A YANG grouping that defines the Layer 0 label range information applicable for WSON as defined in [RFC6205]. The label range info is defined per priority [RFC4203].

This grouping is used in the flexi-grid DWDM by adding more flexi-grid-specific parameters. See Section 2.1 for more details.

wson-label-step:

A YANG grouping that defines label steps for WSON as defined in [I-D.ietf-teas-rfc8776-update]. See Section 2.1 for more details.

flexi-grid-label-start-end:

The flexi-grid label range was defined in [RFC7699], and the generic topology model defines the label-start/label-end in [RFC8795].

This grouping shows the flexi-grid-specific label- start and label-end information which is used to describe the range of available nominal central frequencies. See Section 2.1 for more details.

As described in section 3.1 of [RFC8363], the range of available nominal central frequencies are advertised for m=1, which means that for an available central frequency n, the frequency slot from central frequency n-1 to central frequency n+1 is available.

flexi-grid-label-hop:

The flexi-grid label range was defined in [RFC8363], and the generic topology model defines the label-hop in [RFC8795].

This grouping shows the WSON-specific label-hop information. See Section 2.1 for more details.

flexi-grid-label-range-info:

A YANG grouping that defines flexi-grid label range information as defined in [RFC8363]. See Section 2.1 for more details. See Section 2.1 for more details.

flexi-grid-label-step:

A YANG grouping that defines flexi-grid label steps as defined in [I-D.ietf-teas-rfc8776-update]. See Section 2.1 for more details.

wdm-label-start-end:

A YANG grouping that combines the definition of label-start/label-end information that was defined separately in wson-label-start-end and flexi-grid-label-start-end, to support optical network scenarios that contain both fixed- and flexi-grid links. See Section 2.1 for more details.

wdm-label-hop:

A YANG grouping that combines the definition of label hop information that was defined separately in wson-label-hop and flexi-grid-label-hop, to support optical network scenarios that contain both fixed- and flexi-grid links. See Section 2.1 for more details.

wdm-label-range-info:

A YANG grouping that combines the definition of label range information that was defined separately in wson-label-range-info and flexi-grid-label-range-info, to support optical network scenarios that contain both fixed- and flexi-grid links. See Section 2.1 for more details.

wdm-label-step:

A YANG grouping that combines the definition of label step information defined separately in wson-label-step and flexi-grid-label-step, to support optical network scenarios that contain both fixed- and flexi-grid links. See Section 2.1 for more details.

transceiver-capabilities:

A YANG grouping to define the transceiver capabilities (also called "modes") needed to determine optical signal compatibility.

standard-mode:

A YANG grouping for the standard modes defined in [ITU-T_G.698.2].

organizational-mode:

A YANG grouping to define transponder operational mode supported by organizations or vendors, as defined in [I-D.ietf-ccamp-optical-impairment-topology-yang].

explicit-mode:

A YANG grouping to define the list of attributes related to optical impairments limits in case of transceiver explicit mode, as defined in [I-D.ietf-ccamp-optical-impairment-topology-yang].

Note that the the actual portion of the spectrum occupied by an OTSi is not explicitly reported within the explicit-mode parameters because it can be calculated using the available-baud-rate, the roll-off and the min-carrier-spacing attributes.

transmitter-tuning-range:

A YANG grouping that defines the transmitter tuning range, which includes the minimum and maximum tuning frequency, as well as the frequency tuning steps.

common-organizational-explicit-mode:

A YANG grouping to define the common capabilities attributes limit range in case of operational mode and explicit mode.

modulation:

A base YANG identity to define the different modulation types, as defined in [ITU-T_G.Sup39]

snr:

A YANG data type used to represent an (Optical) Signal to Noise Ratio measured over 0.1 nm resolution bandwidth, as defined in [ITU-T_G.977.1]

psd:

A YANG data type used to represent a Power Spectral Density (PSD), as defined in [ITU-T_G.9700]

penalty-value:

A YANG grouping to define the penalty value for multiple penalty types, such as Chromatic Dispersion (CD), Polarization Mode Dispersion (PMD), as defined in [ITU-T_G.666] or Polarization Dependent Loss(PDL)

2.1. WDM Label and Label Range

As described in [RFC6205] and [RFC7699], the WDM label represents the frequency slot assigned to a WDM Label Switched Path (LSP) on a given WDM Link, which models an Optical Multiplex Section (OMS) Media Channel Group (MCG) as described in [I-D.ietf-ccamp-optical-impairment-topology-yang].

The same WDM label shall be assigned to the same WDM LSP on all the WDM Links on a regen-free LSP path or path segment.

A frequency slot is defined in [ITU-T_G.694.1] as a contiguous frequency range characterized by its nominal central frequency and slot width. The frequency range allocated to a frequency slot is unavailable to other frequency slots.

The definition of the frequency slot depends on the WDM grid type:

  • In case of CWDM fixed-grid, defined in [ITU-T_G.694.2], the frequency slot is defined by a fixed CWDM channel spacing (cwdm-ch-spc-type) and by the nominal central wavelength which is computed as described in [RFC6205]. The formula in [RFC6205] is copied here for reader convenience:

      lambda = 1471 nm + n * channel spacing (measured in nm)
  • where 'n' is defined in [RFC6205] as integer (positive, negative, or 0)

  • In case of DWDM fixed-grid, defined in [ITU-T_G.694.1], the frequency slot is defined by a fixed DWDM channel spacing (dwdm-ch-spc-type) and by the nominal central frequency, which is computed as described in [RFC6205]. The formula in [RFC6205] is copied here for reader convenience:

      f = 193100.000 GHz + n * channel spacing (measured in GHz)
  • where 'n' is defined in [RFC6205] as integer (positive, negative, or 0)

  • In case of DWDM flexible-grid, defined in [ITU-T_G.694.1], the frequency slot is defined by the slot width and by the nominal central frequency, which are computed, based on the slot width granularity (SWG, fixed at 12.5GHz in [ITU-T_G.694.1]), and of the nominal central frequency granularity (NCFG, fixed at 6.25GHz in [ITU-T_G.694.1]) respectively, as described in [RFC7698] and [RFC7699]. The formulas in [RFC7699] can be generalized as follows:

      SW = m * SWG (measured in GHz)
      f = 193100.000 GHz + N * NCFG (measured in GHz)
  • where 'n' is defined in [RFC7699] as integer (positive, negative, or 0) and 'm' is defined in [RFC7698] as an integer greater than or equal to 1.

The definition of the channel spacing, NCFG and SWG in the YANG model have been generalized to support modelling of vendor-specific values (e.g., finer vendor-specific granularity for NCFG and SWG).

The WDM Label Range represents the frequency slots that are available for WDM LSPs to be set up over a given WDM Link.

The WDM Label Range is defined by augmenting the label-restriction list, defined in [I-D.ietf-teas-rfc8776-update], with WDM technology-specific attributes, using the l0-label-range-info grouping (for WSON only models) or the flexi-grid-label-range-info grouping (for DWDM flexible-grid only models) or the wdm-label-range-info grouping (for models that supports both WSON and DWDM flexible-grid).

Each entry in the label-restriction list represents either the range of the available central wavelength values (in case of CWDM fixed-grid) or the range of the available nominal central frequencies values (in case of DWDM fixed or flexible grids): the grid-type attribute defines the type of grid for each entry of the list.

In case of DWDM flexible grid, each entry in the label-restriction list represents also the range of the supported slot width values based on the following attributes, defined based on concepts used in [RFC7699]:

  • slot-width-granularity, which represents the minimum space between slot widths;

  • min-slot-width-factor: a multiplier of the slot width granularity, indicating the minimum slot width supported by each entry in the label-restriction list;

  • max-slot-width-factor: a multiplier of the slot width granularity, indicating the maximum slot width supported by each entry in the label-restriction list.

Each entry of the label-restriction list, as defined in [I-D.ietf-teas-rfc8776-update], defines a label-start, a label-end, a label-step and a range-bitmap.

The label-start and label-end definitions, when used for representing WDM labe range, are augmented with WDM technology-specific attributes, using the wson-label-start-end grouping (for WSON only models) or the flexi-grid-label-start-end grouping (for DWDM flexible-grid only models) or the wdm-label-start-end grouping (for models that supports both WSON and DWDM flexible-grid).

The label-step definition, when used for representing WDM labe range, are augmented with WDM technology-specific attributes, using the wson-label-step grouping (for WSON only models) or the flexi-grid-label-step grouping (for DWDM flexible-grid only models) or the wdm-label-step grouping (for models that supports both WSON and DWDM flexible-grid). The label-step definition for WDM depends on the WDM grid type:

  • For CWDM and DWDM fixed grids, it describes the channel spacing, as defined in [RFC6205];

  • For DWDM flexible grids, it describes the nominal central frequency granularity (e.g., 6,25 GHz) as well as the multiplier for the supported values of n, as defined in [RFC7699].

3. YANG Tree for Layer 0 Types Groupings

module: ietf-layer0-types

  grouping wdm-label-start-end:
    +-- (grid-type)?
       +--:(fixed-dwdm)
       |  +-- dwdm-n?    l0-types:dwdm-n
       +--:(cwdm)
       |  +-- cwdm-n?    l0-types:cwdm-n
       +--:(flexi-grid)
          +-- flexi-n?   l0-types:flexi-n
  grouping wdm-label-step:
    +-- (l0-grid-type)?
       +--:(fixed-dwdm)
       |  +-- wson-dwdm-channel-spacing?    identityref
       +--:(cwdm)
       |  +-- wson-cwdm-channel-spacing?    identityref
       +--:(flexi-grid)
          x-- flexi-grid-channel-spacing?   identityref
          +-- flexi-ncfg?                   identityref
          +-- flexi-n-step?                 uint8
  grouping wdm-label-hop:
    +-- (grid-type)?
       +--:(fixed-dwdm)
       |  +-- (fixed-single-or-super-channel)?
       |     +--:(single)
       |     |  +-- dwdm-n?               l0-types:dwdm-n
       |     +--:(multi)
       |        +-- subcarrier-dwdm-n*    l0-types:dwdm-n
       +--:(cwdm)
       |  +-- cwdm-n?                     l0-types:cwdm-n
       +--:(flexi-grid)
          +-- (single-or-super-channel)?
             +--:(single)
             |  +-- flexi-n?              l0-types:flexi-n
             |  +-- flexi-m?              l0-types:flexi-m
             x--:(super)
             |  x-- subcarrier-flexi-n* [flexi-n]
             |     +-- flexi-n?   l0-types:flexi-n
             |     +-- flexi-m?   l0-types:flexi-m
             +--:(multi)
                +-- frequency-slots
                   +-- frequency-slot* [flexi-n]
                      +-- flexi-n?   l0-types:flexi-n
                      +-- flexi-m?   l0-types:flexi-m
  grouping wdm-label-range-info:
    +-- grid-type?    identityref
    +-- priority?     uint8
    +-- flexi-grid
       +-- slot-width-granularity?   identityref
       +-- min-slot-width-factor?    uint16
       +-- max-slot-width-factor?    uint16
  grouping wson-label-start-end:
    +-- (grid-type)?
       +--:(dwdm)
       |  +-- dwdm-n?   l0-types:dwdm-n
       +--:(cwdm)
          +-- cwdm-n?   l0-types:cwdm-n
  grouping wson-label-hop:
    +-- (grid-type)?
       +--:(dwdm)
       |  +-- (single-or-super-channel)?
       |     +--:(single)
       |     |  +-- dwdm-n?              l0-types:dwdm-n
       |     +--:(super)
       |        +-- subcarrier-dwdm-n*   l0-types:dwdm-n
       +--:(cwdm)
          +-- cwdm-n?                    l0-types:cwdm-n
  grouping l0-label-range-info:
    +-- grid-type?   identityref
    +-- priority?    uint8
  grouping wson-label-step:
    +-- (l0-grid-type)?
       +--:(dwdm)
       |  +-- wson-dwdm-channel-spacing?   identityref
       +--:(cwdm)
          +-- wson-cwdm-channel-spacing?   identityref
  grouping flexi-grid-label-start-end:
    +-- flexi-n?   l0-types:flexi-n
  grouping flexi-grid-frequency-slot:
    +-- flexi-n?   l0-types:flexi-n
    +-- flexi-m?   l0-types:flexi-m
  grouping flexi-grid-label-hop:
    +-- (single-or-super-channel)?
       +--:(single)
       |  +-- flexi-n?              l0-types:flexi-n
       |  +-- flexi-m?              l0-types:flexi-m
       x--:(super)
       |  x-- subcarrier-flexi-n* [flexi-n]
       |     +-- flexi-n?   l0-types:flexi-n
       |     +-- flexi-m?   l0-types:flexi-m
       +--:(multi)
          +-- frequency-slots
             +-- frequency-slot* [flexi-n]
                +-- flexi-n?   l0-types:flexi-n
                +-- flexi-m?   l0-types:flexi-m
  grouping flexi-grid-label-range-info:
    +-- grid-type?    identityref
    +-- priority?     uint8
    +-- flexi-grid
       +-- slot-width-granularity?   identityref
       +-- min-slot-width-factor?    uint16
       +-- max-slot-width-factor?    uint16
  grouping flexi-grid-label-step:
    x-- flexi-grid-channel-spacing?   identityref
    +-- flexi-ncfg?                   identityref
    +-- flexi-n-step?                 uint8
  grouping transceiver-mode:
    +-- (mode)
       +--:(G.698.2)
       |  +--ro standard-mode?            standard-mode
       |  +--ro line-coding-bitrate*      identityref
       |  +-- min-central-frequency?    frequency-thz
       |  +-- max-central-frequency?    frequency-thz
       |  +-- transceiver-tunability?   frequency-ghz
       |  +--ro tx-channel-power-min?     power-dbm
       |  +--ro tx-channel-power-max?     power-dbm
       |  +--ro rx-channel-power-min?     power-dbm
       |  +--ro rx-channel-power-max?     power-dbm
       |  +--ro rx-total-power-max?       power-dbm
       +--:(organizational-mode)
       |  +--ro organizational-mode
       |     +--ro operational-mode?          operational-mode
       |     +--ro organization-identifier?   organization-identifier
       |     +--ro line-coding-bitrate*       identityref
       |     +--ro min-central-frequency?     frequency-thz
       |     +--ro max-central-frequency?     frequency-thz
       |     +--ro transceiver-tunability?    frequency-ghz
       |     +--ro tx-channel-power-min?      power-dbm
       |     +--ro tx-channel-power-max?      power-dbm
       |     +--ro rx-channel-power-min?      power-dbm
       |     +--ro rx-channel-power-max?      power-dbm
       |     +--ro rx-total-power-max?        power-dbm
       +--:(explicit-mode)
          +--ro explicit-mode
             +--ro min-central-frequency?    frequency-thz
             +--ro max-central-frequency?    frequency-thz
             +--ro transceiver-tunability?   frequency-ghz
             +--ro tx-channel-power-min?     power-dbm
             +--ro tx-channel-power-max?     power-dbm
             +--ro rx-channel-power-min?     power-dbm
             +--ro rx-channel-power-max?     power-dbm
             +--ro rx-total-power-max?       power-dbm
             +--ro compatible-modes
  grouping transceiver-capabilities:
    +-- supported-modes!
       +--ro supported-mode* [mode-id]
          +--ro mode-id?                        string
          +--ro (mode)
             +--:(G.698.2)
             |  +--ro standard-mode?            standard-mode
             |  +--ro line-coding-bitrate*      identityref
             |  +--ro min-central-frequency?    frequency-thz
             |  +--ro max-central-frequency?    frequency-thz
             |  +--ro transceiver-tunability?   frequency-ghz
             |  +--ro tx-channel-power-min?     power-dbm
             |  +--ro tx-channel-power-max?     power-dbm
             |  +--ro rx-channel-power-min?     power-dbm
             |  +--ro rx-channel-power-max?     power-dbm
             |  +--ro rx-total-power-max?       power-dbm
             +--:(organizational-mode)
             |  +--ro organizational-mode
             |     +--ro operational-mode?          operational-mode
             |     +--ro organization-identifier?
             |     |       organization-identifier
             |     +--ro line-coding-bitrate*       identityref
             |     +--ro min-central-frequency?     frequency-thz
             |     +--ro max-central-frequency?     frequency-thz
             |     +--ro transceiver-tunability?    frequency-ghz
             |     +--ro tx-channel-power-min?      power-dbm
             |     +--ro tx-channel-power-max?      power-dbm
             |     +--ro rx-channel-power-min?      power-dbm
             |     +--ro rx-channel-power-max?      power-dbm
             |     +--ro rx-total-power-max?        power-dbm
             +--:(explicit-mode)
                +--ro explicit-mode
                   +--ro min-central-frequency?    frequency-thz
                   +--ro max-central-frequency?    frequency-thz
                   +--ro transceiver-tunability?   frequency-ghz
                   +--ro tx-channel-power-min?     power-dbm
                   +--ro tx-channel-power-max?     power-dbm
                   +--ro rx-channel-power-min?     power-dbm
                   +--ro rx-channel-power-max?     power-dbm
                   +--ro rx-total-power-max?       power-dbm
                   +--ro compatible-modes
                      +--ro supported-application-codes*
                      |       -> ../../../../supported-mode/mode-id
                      +--ro supported-organizational-modes*
                              -> ../../../../supported-mode/mode-id
  grouping standard-mode:
    +--ro standard-mode?   standard-mode
  grouping organizational-mode:
    +--ro operational-mode?          operational-mode
    +--ro organization-identifier?   organization-identifier
  grouping penalty-value:
    +--ro penalty-value    union
  grouping explicit-mode:
    +--ro line-coding-bitrate?                identityref
    +--ro bitrate?                            uint16
    +--ro max-diff-group-delay?               decimal-2
    +--ro max-chromatic-dispersion?           decimal-2
    +--ro cd-penalty* [cd-value]
    |  +--ro cd-value         decimal-2
    |  +--ro penalty-value    union
    +--ro max-polarization-mode-dispersion?   decimal-2
    +--ro pmd-penalty* [pmd-value]
    |  +--ro pmd-value        decimal-2
    |  +--ro penalty-value    union
    +--ro max-polarization-dependant-loss     power-loss-or-null
    +--ro pdl-penalty* [pdl-value]
    |  +--ro pdl-value        power-loss
    |  +--ro penalty-value    union
    +--ro available-modulation-type?          identityref
    +--ro min-OSNR?                           snr
    +--ro rx-ref-channel-power?               power-dbm
    +--ro rx-channel-power-penalty* [rx-channel-power-value]
    |  +--ro rx-channel-power-value    power-dbm
    |  +--ro penalty-value             union
    +--ro min-Q-factor?                       decimal-2
    +--ro available-baud-rate?                decimal64
    +--ro roll-off?                           decimal64
    +--ro min-carrier-spacing?                frequency-ghz
    +--ro available-fec-type?                 identityref
    +--ro fec-code-rate?                      decimal64
    +--ro fec-threshold?                      decimal64
    +--ro in-band-osnr?                       snr
    +--ro out-of-band-osnr?                   snr
    +--ro tx-polarization-power-difference?   power-ratio
    +--ro polarization-skew?                  decimal-2
  grouping common-standard-organizational-mode:
    +--ro line-coding-bitrate*   identityref
  grouping transmitter-tuning-range:
    +-- min-central-frequency?    frequency-thz
    +-- max-central-frequency?    frequency-thz
    +-- transceiver-tunability?   frequency-ghz
  grouping common-all-modes:
    +-- min-central-frequency?    frequency-thz
    +-- max-central-frequency?    frequency-thz
    +-- transceiver-tunability?   frequency-ghz
    +--ro tx-channel-power-min?     power-dbm
    +--ro tx-channel-power-max?     power-dbm
    +--ro rx-channel-power-min?     power-dbm
    +--ro rx-channel-power-max?     power-dbm
    +--ro rx-total-power-max?       power-dbm
  grouping common-transceiver-param:
    +-- line-coding-bitrate?   identityref
    +-- tx-channel-power?      power-dbm-or-null
    +--ro rx-channel-power?      power-dbm-or-null
    +--ro rx-total-power?        power-dbm-or-null
  grouping common-transceiver-configured-param:
    +-- line-coding-bitrate?   identityref
    +-- tx-channel-power?      power-dbm-or-null
  grouping common-transceiver-readonly-param:
    +--ro rx-channel-power?   power-dbm-or-null
    +--ro rx-total-power?     power-dbm-or-null
  grouping l0-tunnel-attributes:
    +-- wavelength-assignment?   identityref
  grouping frequency-range:
    +-- lower-frequency    frequency-thz
    +-- upper-frequency    frequency-thz
  grouping l0-path-constraints:
    +-- gsnr-extra-margin?   snr
  grouping l0-path-properties:
    +--ro estimated-gsnr?          snr
    +--ro estimated-eol-gsnr?      snr
    +--ro estimated-lowest-gsnr?   snr
Figure 1

4. YANG Module for Layer 0 Types

This YANG module references [RFC6205], [RFC7689], [RFC7699], [RFC7698], [RFC8363], [RFC8363], [RFC9093], [ITU-T_G.666], [ITU-T_G.694.1], [ITU-T_G.694.2], [ITU-T_G.698.2], [ITU-T_G.709], [ITU-T_G.709.2], [ITU-T_G.709.3], [ITU-T_G.959.1] [ITU-T_G.975], [ITU-T_G.975.1], [ITU-T_G.977.1], [ITU-T_G.9700] and [OIF_400ZR].

<CODE BEGINS> file "ietf-layer0-types@2024-03-04.yang"

module ietf-layer0-types {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-layer0-types";
  prefix l0-types;

  organization
    "IETF CCAMP Working Group";
  contact
    "WG Web:  <https://datatracker.ietf.org/wg/ccamp/>
     WG List: <mailto:ccamp@ietf.org>

     Editor:  Dieter Beller
              <mailto:Dieter.Beller@nokia.com>

     Editor:  Sergio Belotti
              <mailto:Sergio.Belotti@nokia.com>

     Editor:  Italo Busi
              <mailto:Italo.Busi@huawei.com>

     Editor:  Haomian Zheng
              <mailto:zhenghaomian@huawei.com>";
  description
    "This module defines Optical Layer 0 types.  This module
     provides groupings that can be applicable to Layer 0
     Fixed Optical Networks (e.g., CWDM (Coarse Wavelength
     Division Multiplexing) and DWDM (Dense Wavelength Division
     Multiplexing)) and flexi-grid optical networks.

     Copyright (c) 2024 IETF Trust and the persons identified
     as authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with
     or without modification, is permitted pursuant to, and
     subject to the license terms contained in, the Revised
     BSD License set forth in Section 4.c of the IETF Trust's
     Legal Provisions Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX; see
     the RFC itself for full legal notices.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
     'MAY', and 'OPTIONAL' in this document are to be interpreted as
     described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.";

// RFC Ed.: replace XXXX with actual RFC number and remove
// this note

// replace the revision date with the module publication date
// the format is (year-month-day)
  revision 2024-07-23 {
    description
      "To be updated";
    reference
      "RFC XXXX: A YANG Data Model for Layer 0 Types";
  }

  revision 2021-08-13 {
    description
      "Initial version";
    reference
      "RFC 9093: A YANG Data Model for Layer 0 Types";
  }

/*
 * Identities
 */

  identity l0-grid-type {
    description
      "Layer 0 grid type";
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable
      (LSC), Label Switching Routers,

       ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
       CWDM wavelength grid";
  }

    identity wson-grid-cwdm {
      base l0-grid-type;
      description
        "CWDM grid";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
        Label Switching Routers,

        ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
        CWDM wavelength grid";
    }

    identity wson-grid-dwdm {
      base l0-grid-type;
      description
        "DWDM grid";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable
        (LSC), Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

    identity flexi-grid-dwdm {
      base l0-grid-type;
      description
        "Flexi-grid";
      reference
        "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
        Switch Capable (LSC) Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

  identity cwdm-ch-spc-type {
    description
      "CWDM channel-spacing type";
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers,

       ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
       CWDM wavelength grid";
  }

    identity cwdm-20nm {
      base cwdm-ch-spc-type;
      description
        "20nm channel spacing";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
        Label Switching Routers,

        ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
        CWDM wavelength grid";
    }

  identity dwdm-ch-spc-type {
    description
      "DWDM channel-spacing type";
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers,

       ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
       DWDM frequency grid";
  }

    identity dwdm-100ghz {
      base dwdm-ch-spc-type;
      description
        "100 GHz channel spacing";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
        Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

    identity dwdm-50ghz {
      base dwdm-ch-spc-type;
      description
        "50 GHz channel spacing";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
        Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

    identity dwdm-25ghz {
      base dwdm-ch-spc-type;
      description
        "25 GHz channel spacing";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
        Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

    identity dwdm-12p5ghz {
      base dwdm-ch-spc-type;
      description
        "12.5 GHz channel spacing";
      reference
        "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
        Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

  identity flexi-ch-spc-type {
    status deprecated;
    description
      "Flexi-grid channel-spacing type";
  }

    identity flexi-ch-spc-6p25ghz {
      base flexi-ch-spc-type;
      status deprecated;
      description
        "6.25 GHz channel spacing";
    }

  identity flexi-ncfg-type {
    description
      "Flexi-grid Nominal Central Frequency Granularity (NCFG)
      type";
    reference
      "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
      Switch Capable (LSC) Label Switching Routers,

      ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
      DWDM frequency grid";
  }

    identity flexi-ncfg-6p25ghz {
      base flexi-ncfg-type;
      description
        "6.25 GHz Nominal Central Frequency Granularity (NCFG)";
      reference
        "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
        Switch Capable (LSC) Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

  identity flexi-slot-width-granularity {
    description
      "Flexi-grid slot width granularity";
    reference
      "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
      Switch Capable (LSC) Label Switching Routers,

      ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
      DWDM frequency grid";
  }

    identity flexi-swg-12p5ghz {
      base flexi-slot-width-granularity;
      description
        "12.5 GHz slot width granularity";
      reference
        "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
        Switch Capable (LSC) Label Switching Routers,

        ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
        DWDM frequency grid";
    }

  identity modulation {
    description "base identity for modulation type";
  }

    identity DPSK {
      base modulation;
      description
        "DPSK (Differential Phase Shift Keying) modulation";
    }

    identity QPSK {
      base modulation;
      description
        "QPSK (Quadrature Phase Shift Keying) modulation";
    }

    identity DP-QPSK {
      base modulation;
      description
        "DP-QPSK (Dual Polarization Quadrature
        Phase Shift Keying) modulation";
    }

    identity QAM8 {
      base modulation;
      description
        "8QAM (8 symbols Quadrature Amplitude Modulation)";
    }

    identity DP-QAM8 {
      base modulation;
      description
        "DP-QAM8 (8 symbols Dual Polarization Quadrature Amplitude
        Modulation)";
    }

    identity QAM16 {
      base modulation;
      description
        "QAM16 (16 symbols Quadrature Amplitude Modulation)";
    }

    identity DP-QAM16 {
      base modulation;
      description
        "DP-QAM16 (16 symbols Dual Polarization Quadrature Amplitude
        Modulation)";
    }

    identity QAM32 {
      base modulation;
      description
        "QAM32 (32 symbols Quadrature Amplitude Modulation)";
    }

    identity DP-QAM32 {
      base modulation;
      description
        "DP-QAM32 (32 symbols Dual Polarization Quadrature Amplitude
        Modulation)";
    }

    identity QAM64 {
      base modulation;
      description
        "QAM64 (64 symbols Quadrature Amplitude Modulation)";
    }

    identity DP-QAM64 {
      base modulation;
      description
        "DP-QAM64 (64 symbols Dual Polarization Quadrature Amplitude
        Modulation)";
    }

  identity fec-type {
    description
      "Base identity from which specific FEC
      (Forward Error Correction) type identities are derived.";
  }

    identity g-fec {
      base fec-type;
      description
        "Generic Forward Error Correction (G-FEC).";
      reference
        "ITU-T G.975 v2.0 (10/2000): Forward error correction for
        submarine systems.";
    }

    identity super-fec {
      base fec-type;
      description
        "Super Forward Error Correction (S-FEC).";
      reference
        "ITU-T G.975.1 v1.2 (07/2013): Forward error correction for
        high bit-rate DWDM submarine systems.";
    }

    identity no-fec {
      base fec-type;
      description
        "No FEC";
    }

    identity sc-fec {
      base fec-type;
      description
        "Staircase Forward Error Correction (SC-FEC).";
      reference
        "Annex A of ITU-T G.709.2 v1.1 (09/2020):OTU4 long-reach
        interface.";
    }

    identity o-fec {
      base fec-type;
      description
        "Open Forward Error Correction (O-FEC) which reuses the
        Bose, Chaudhuri and Hocquenghem (BCH) FEC.";
      reference
        "Clause 16.4.4 of ITU-T G.709.3 v2.1 (11/2022): Flexible OTN
        long-reach interfaces;

        Annex E of ITU-T G.709.3 v2.1 (11/2022): Flexible OTN
        long-reach interfaces.";
    }

    identity c-fec {
      base fec-type;
      description
        "Concatenated FEC (C-FEC) that combines an outer Staircase
        Forward Error Correction (SC-FEC) code and an inner
        double-extended SD-FEC (128,119) Hamming code.

        More details are provided in clause 15/G.709.3 where it is
        called DSH instead of concatenated FEC.";
      reference
        "Annex A of ITU-T G.709.2 v1.1 (09/2020):OTU4 long-reach
        interface;

        Annex D of ITU-T G.709.3 v2.1 (11/2022): Flexible OTN
        long-reach interfaces;

        Clause 15 of ITU-T G.709.3 v2.1 (11/2022): Flexible OTN
        long-reach interfaces.";
    }

  identity line-coding {
    description
      "Base identity to defined the bit rate/line coding of optical
      tributary signals.";
    reference
      "Section 7.1.2 of ITU-T G.698.2 v3.0 (11/2018).";
  }

    identity line-coding-NRZ-2p5G {
      base line-coding;
      description
        "The non return to zero (NRZ) bit rate/line coding used by
        the optical tributary signal class NRZ 2.5G";
      reference
        "Section 3.2.6 of ITU-T G.959.1 v8.0 (07/2018).";
    }

    identity line-coding-NRZ-OTU1 {
      base line-coding;
      description
        "The non return to zero (NRZ) bit rate/line coding used by
        the Optical channel Transport Unit order 1 (OTU1) optical
        tributary signals";
      reference
        "Section 7.2.1.2 of ITU-T G.959.1 v8.0 (07/2018).";
    }

    identity line-coding-NRZ-10G {
      description
        "The non return to zero (NRZ) bit rate/line coding used by
        the optical tributary signal class NRZ 10G";
      reference
        "Section 3.2.7 of ITU-T G.959.1 v8.0 (07/2018).";
    }

    identity line-coding-NRZ-OTU2 {
      base line-coding;
      description
        "The non return to zero (NRZ) bit rate/line coding used by
        the Optical channel Transport Unit order 2 (OTU2) optical
        tributary signals";
      reference
        "Section 7.2.1.2 of ITU-T G.959.1 v8.0 (07/2018).";
    }

    identity line-coding-OTL4.4-SC {
      base line-coding;
      description
        "The bit rate/line coding used by optical tributary
        signals carrying a 100G Optical Transport Unit order 4
        (OTU4) with Staircase Forward Error Correction (SC FEC)
        from a group of four Optical Transport Lanes (OTL).";
      reference
        "Section 3.2.1 of ITU-T G.698.2 v3.0 (11/2018).";
    }

    identity line-coding-FOIC1.4-SC {
      base line-coding;
      description
        "The bit rate/line coding used by optical tributary signals
        carrying a FlexO Interface of order C1 with 4 lanes
        (FOIC1.1) with Staircase Forward Error Correction
        (SC FEC).";
      reference
        "Section 3.2.1 of ITU-T G.698.2 v3.0 (11/2018).";
    }

  identity wavelength-assignment {
    description
      "Wavelength selection base";
    reference
      "RFC 7689: Signaling Extensions for Wavelength Switched
      Optical Networks";
  }

    identity first-fit-wavelength-assignment {
      base wavelength-assignment;
      description
        "All the available wavelengths are numbered,
        and this WA (Wavelength Assignment) method chooses
        the available wavelength with the lowest index";
      reference
        "RFC 7689: Signaling Extensions for Wavelength Switched
        Optical Networks";
    }

    identity random-wavelength-assignment {
      base wavelength-assignment;
      description
        "This WA method chooses an available
        wavelength randomly";
      reference
        "RFC 7689: Signaling Extensions for Wavelength Switched
        Optical Networks";
    }

    identity least-loaded-wavelength-assignment {
      base wavelength-assignment;
      description
        "This WA method selects the wavelength that
        has the largest residual capacity on the most loaded
        link along the route (in multi-fiber networks)";
      reference
        "RFC 7689: Signaling Extensions for Wavelength Switched
        Optical Networks";
    }

    identity lower-first-wavelength-assignment {
      base wavelength-assignment;
      description
        "Allocate wavelengths in ascending order, beginning from the
        lowest frequency and progressing toward the highest frequency
        within the permissible frequency range.";
    }

    identity upper-first-wavelength-assignment {
      base wavelength-assignment;
      description
        "Allocate wavelengths in decending order, beginning from the
        highest frequency and progressing toward the lowest frequency
        within the permissible frequency range.";
    }

  identity otu-type {
    description
      "Base identity from which specific OTU identities are derived";
    reference
      "ITU-T G.709: Interfaces for the Optical Transport Network";
  }

    identity OTU1 {
      base otu-type;
      description
        "OTU1 (2.66 Gb/s)";
      reference
        "ITU-T G.709 v6.0 (06/2020): Interfaces for the Optical
        Transport Network (OTN)";
    }

    identity OTU2 {
      base otu-type;
      description
        "OTU2 (10.70 Gb/s)";
      reference
        "ITU-T G.709 v6.0 (06/2020): Interfaces for the Optical
        Transport Network (OTN)";
    }

    identity OTU3 {
      base otu-type;
      description
        "OTU3 (43.01 Gb/s)";
      reference
        "ITU-T G.709 v6.0 (06/2020): Interfaces for the Optical
        Transport Network (OTN)";
    }

    identity OTU4 {
      base otu-type;
      description
        "OTU4 (111.80 Gb/s)";
      reference
        "ITU-T G.709 v6.0 (06/2020): Interfaces for the Optical
        Transport Network (OTN)";
    }

    identity OTUCn {
      base otu-type;
      description
        "OTUCn (n x 105.25 Gb/s)";
      reference
        "ITU-T G.709 v6.0 (06/2020): Interfaces for the Optical
        Transport Network (OTN)";
    }

  identity type-power-mode {
    description
      "power equalization mode used within the
       OMS and its elements";
  }

    identity power-spectral-density {
      base type-power-mode;
      description
        "all elements must use power spectral density (W/Hz)";
    }

    identity carrier-power {
      base type-power-mode;
      description
        "all elements must use power (dBm)";
    }

/*
 * Typedefs
 */

  typedef dwdm-n {
    type int16;
    description
      "The given value 'N' is used to determine the nominal central
       frequency.

       The nominal central frequency, 'f', is defined by:
         f = 193100.000 GHz + N x channel spacing (measured in GHz),

       where 193100.000 GHz (193.100000 THz) is the ITU-T 'anchor
       frequency' for transmission over the DWDM grid, and where
       'channel spacing' is defined by the dwdm-ch-spc-type.";
    reference
      "RFC6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers,

       ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
       DWDM frequency grid";
  }

  typedef cwdm-n {
    type int16;
    description
      "The given value 'N' is used to determine the nominal central
       wavelength.

       The nominal central wavelength is defined by:
         Wavelength = 1471 nm + N x channel spacing (measured in nm)

       where 1471 nm is the conventional 'anchor wavelength' for
       transmission over the CWDM grid, and where 'channel spacing'
       is defined by the cwdm-ch-spc-type.";
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers,

       ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
       CWDM wavelength grid";
  }

  typedef flexi-n {
    type int16;
    description
      "The given value 'N' is used to determine the nominal central
       frequency.

       The nominal central frequency, 'f', is defined by:
         f = 193100.000 GHz + N x NCFG (measured in GHz),

       where 193100.000 GHz (193.100000 THz) is the ITU-T 'anchor
       frequency' for transmission over the DWDM grid, and where
       NCFG is defined by the flexi-ncfg-type, or by the deprecated
       flexi-ch-spc-type.";
    reference
      "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
      Switch Capable (LSC) Label Switching Routers,

       ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
       DWDM frequency grid";
  }

  typedef flexi-m {
    type uint16;
    description
      "The given value 'M' is used to determine the slot width.

       A slot width is defined by:
         slot width = M x SWG (measured in GHz),

       where SWG is defined by the flexi-slot-width-granularity.";
    reference
      "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
      Switch Capable (LSC) Label Switching Routers,

       ITU-T G.694.1 (10/2020): Spectral grids for WDM applications:
       DWDM frequency grid";
  }

  typedef standard-mode {
    type string;
    description
      "Identifies an ITU-T G.698.2 standard application code.

      It MUST be a string with a format that follows the
      nomenclature defined in section 5.3 of ITU-T G.698.2.";
    reference
      "ITU-T G.698.2 (11/2018)";
  }

  typedef organization-identifier {
    type string;
    description
      "vendor/organization identifier that uses a private mode
      out of already defined in G.698.2 ITU-T application-code";
    reference
      "Section 2.5.2 of RFC YYYY: A YANG Data Model for Optical
      Impairment-aware Topology.";
  }
// RFC Ed.: replace YYYY with actual RFC number and remove
// this note after draft-ietf-ccamp-optical-impairment-topology-yang
// is published as an RFC

  typedef operational-mode {
    type string;
    description
      "Identifies an organization (e.g., vendor) specific mode.

      The format of the string has to be defined by the
      organization which is responsible for defining the
      corresponding optical interface specification.";
    reference
      "Section 2.5.2 of RFC YYYY: A YANG Data Model for Optical
      Impairment-aware Topology.";
  }
// RFC Ed.: replace YYYY with actual RFC number and remove
// this note after draft-ietf-ccamp-optical-impairment-topology-yang
// is published as an RFC

  typedef frequency-thz {
    type decimal64 {
      fraction-digits 9;
    }
    units "THz";
    description
      "The DWDM frequency in THz, e.g., 193.112500000";
  }

  typedef frequency-ghz {
    type decimal64 {
      fraction-digits 6;
    }
    units "GHz";
    description
      "The DWDM frequency in GHz, e.g., 193112.500000";
  }

  typedef snr {
    type decimal-2;
    units "dB@0.1nm";
    description
      "(Optical) Signal to Noise Ratio measured over 0.1 nm
      resolution bandwidth";
    reference
      "ITU-T G.977.1 (02/2021): Transverse compatible dense
      wavelength division multiplexing applications for repeatered
      optical fibre submarine cable systems";
  }

  typedef snr-or-null {
    type union {
      type snr;
      type empty;
    }
    description
      "(Optical) Signal to Noise Ratio measured over 0.1 nm
      resolution bandwidth, when known, or an empty value when
      unknown.";
  }

  typedef fiber-type {
    type enumeration {
      enum G.652 {
        description
          "G.652 Standard Singlemode Fiber";
      }
      enum G.654 {
        description
          "G.654 Cutoff Shifted Fiber";
      }
      enum G.653 {
        description "G.653 Dispersion Shifted Fiber";
      }
      enum G.655 {
        description "G.655 Non-Zero Dispersion Shifted Fiber";
      }
      enum G.656 {
        description
          "G.656 Non-Zero Dispersion for Wideband Optical Transport";
      }
      enum G.657 {
        description
          "G.657 Bend-Insensitive Fiber";
      }
    }
    description
      "ITU-T based fiber-types";
  }

  typedef decimal-2 {
    type decimal64 {
      fraction-digits 2;
    }
    description
      "A decimal64 value with two digits.";
  }

  typedef decimal-2-or-null {
    type union {
      type decimal-2;
      type empty;
    }
    description
      "A decimal64 value with two digits, when the value is known or
      an empty value when the value is not known.";
  }

  typedef power-gain {
    type decimal-2 {
      range "0..max";
    }
    units "dB";
    description
      "The gain in dB.";
  }

  typedef power-gain-or-null {
    type union {
      type power-gain;
      type empty;
    }
    description
      "The gain in dB, when it is known or an empty
      value when the power gain/loss is not known.";
  }

  typedef power-loss {
    type decimal-2 {
      range "0..max";
    }
    units "dB";
    description
      "The power attenuation in dB.";
  }

  typedef power-loss-or-null {
    type union {
      type power-loss;
      type empty;
    }
    description
      "The power attenuation in dB, when it is known or an empty
      value when the loss is not known.";
  }

  typedef power-ratio {
    type decimal-2;
    units "dB";
    description
      "The power difference in dB.";
  }

  typedef power-ratio-or-null {
    type union {
      type power-ratio;
      type empty;
    }
    description
      "The power difference in dB, when it is known or an empty
      value when the difference is not known.";
  }

  typedef power-dbm {
    type decimal-2;
    units "dBm";
    description
      "The power in dBm.";
  }

  typedef power-dbm-or-null {
    type union {
      type power-dbm;
      type empty;
    }
    description
      "The power in dBm, when it is known or an empty value when the
      power is not known.";
  }

  typedef decimal-5 {
    type decimal64 {
      fraction-digits 5;
    }
    description
      "A decimal64 value with five digits.";
  }

  typedef decimal-5-or-null {
    type union {
      type decimal-5;
      type empty;
    }
    description
      "A decimal64 value with five digits, when the value is known
      or an empty value when the value is not known.";
  }

  typedef psd {
    type decimal64 {
      fraction-digits 16;
    }
    units "W/Hz";
    description
      "The power spectral density (PSD).

      Typical value : 3.9 E-14, resolution 0.1nW/MHz.";
    reference
      "ITU-T G.9700 (07/2019): Fast access to subscriber terminals
      (G.fast) - Power spectral density specification";
  }

  typedef psd-or-null {
    type union {
      type psd;
      type empty;
    }
    description
      "The power spectral density (PSD), when it is known or an
      empty value when the PSD is not known.";
  }

  typedef decimal-18 {
    type decimal64 {
      fraction-digits 18;
    }
    description
      "A decimal64 value with eighteen digits.";
  }

  typedef decimal-18-or-null {
    type union {
      type decimal-18;
      type empty;
    }
    description
      "A decimal64 value with eighteen digits, when the value is
      known or an empty value when the value is not known.";
  }

/*
 * Groupings
 */

  grouping wdm-label-start-end {
    description
      "The WDM label-start or label-end used to specify DWDM and
       CWDM label range.";

    choice grid-type {
      description
        "Label for fixed & flexi-DWDM or CWDM grid";
      case fixed-dwdm {
        leaf dwdm-n {
          when "derived-from-or-self(../../../grid-type,
                \"wson-grid-dwdm\")" {
            description
              "Valid only when grid type is DWDM.";
          }
          type l0-types:dwdm-n;
          description
            "The given value 'N' is used to determine the
             nominal central frequency.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case cwdm {
        leaf cwdm-n {
          when "derived-from-or-self(../../../grid-type,
                \"wson-grid-cwdm\")" {
            description
              "Valid only when grid type is CWDM.";
          }
          type l0-types:cwdm-n;
          description
            "The given value 'N' is used to determine the nominal
             central wavelength.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case flexi-grid {
        uses l0-types:flexi-grid-label-start-end;
      }
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers";
  }

  grouping wdm-label-step {
    description
      "Label step information for fixed & flexi-DWDM or CWDM grid";
    choice l0-grid-type {
      description
        "Grid type: DWDM, CWDM, etc.";
      case fixed-dwdm {
        leaf wson-dwdm-channel-spacing {
          when "derived-from-or-self(../../grid-type,
                \"wson-grid-dwdm\")" {
            description
              "Valid only when grid type is DWDM.";
          }
          type identityref {
            base dwdm-ch-spc-type;
          }
          description
            "Label-step is the channel spacing (GHz), e.g., 100.000,
             50.000, 25.000, or 12.500 GHz for DWDM.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case cwdm {
        leaf wson-cwdm-channel-spacing {
          when "derived-from-or-self(../../grid-type,
                \"wson-grid-cwdm\")" {
            description
              "Valid only when grid type is CWDM.";
          }
          type identityref {
            base cwdm-ch-spc-type;
          }
          description
            "Label-step is the channel spacing (nm), i.e., 20 nm
             for CWDM, which is the only value defined for CWDM.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case flexi-grid {
        uses flexi-grid-label-step;
      }
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers,
       ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
       CWDM wavelength grid,
       RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-Grid
       Dense Wavelength Division Multiplexing (DWDM) Networks";
  }

  grouping wdm-label-hop {
    description
      "Generic label-hop information for fixed & flexi-DWDM or
       CWDM grid";
    choice grid-type {
      description
        "Label for DWDM or CWDM grid";
      case fixed-dwdm {
        choice fixed-single-or-super-channel {
          description
            "single or super channel";
          case single {
            leaf dwdm-n {
              type l0-types:dwdm-n;
              description
                "The given value 'N' is used to determine the
                 nominal central frequency.";
            }
          }
          case multi {
            leaf-list subcarrier-dwdm-n {
              type l0-types:dwdm-n;
              min-elements 2;
              description
                "The given values 'N' are used to determine the
                 nominal central frequency for each subcarrier
                 channel.";
              reference
                "ITU-T G.694.1 (10/2020): Spectral grids for WDM
                applications: DWDM frequency grid";
            }
          }
        }
      }
      case cwdm {
        leaf cwdm-n {
          type l0-types:cwdm-n;
          description
            "The given value 'N' is used to determine the nominal
             central wavelength.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case flexi-grid {
        uses l0-types:flexi-grid-label-hop;
      }
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers";
  }

  grouping wdm-label-range-info {
    description
      "WDM label range related information";
    uses l0-label-range-info;
    container flexi-grid {
      when "derived-from-or-self(../grid-type,
          \"flexi-grid-dwdm\")" {
        description
          "Applicable only when the grid type is flexi-grid-dwdm.";
      }
      description
        "flexi-grid definition";
      leaf slot-width-granularity {
        type identityref {
          base flexi-slot-width-granularity;
        }
        default "flexi-swg-12p5ghz";
        description
          "Minimum space between slot widths. Default is 12.500
           GHz.";
        reference
          "RFC 7698: Framework and Requirements for GMPLS-Based
           Control of Flexi-Grid Dense Wavelength Division
           Multiplexing (DWDM) Networks";
      }
      leaf min-slot-width-factor {
        type uint16 {
          range "1..max";
        }
        default "1";
        description
          "A multiplier of the slot width granularity, indicating
           the minimum slot width supported by an optical port.

           Minimum slot width is calculated by:
             Minimum slot width (GHz) =
               min-slot-width-factor * slot-width-granularity.";
        reference
          "RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-
           Grid Dense Wavelength Division Multiplexing (DWDM)
           Networks";
      }
      leaf max-slot-width-factor {
        type uint16 {
          range "1..max";
        }
        must '. >= ../min-slot-width-factor' {
          error-message
            "Maximum slot width must be greater than or equal to
             minimum slot width.";
        }
        description
          "A multiplier of the slot width granularity, indicating
           the maximum slot width supported by an optical port.

           Maximum slot width is calculated by:
             Maximum slot width (GHz) =
               max-slot-width-factor * slot-width-granularity

           If specified, maximum slot width must be greater than or
           equal to minimum slot width.  If not specified, maximum
           slot width is equal to minimum slot width.";
        reference
          "RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-
           Grid Dense Wavelength Division Multiplexing (DWDM)
           Networks";
      }
    }
  }

  grouping wson-label-start-end {
    description
      "The WSON label-start or label-end used to specify WSON label
       range.";
    choice grid-type {
      description
        "Label for DWDM or CWDM grid";
      case dwdm {
        leaf dwdm-n {
          when "derived-from-or-self(../../../grid-type,
                \"wson-grid-dwdm\")" {
            description
              "Valid only when grid type is DWDM.";
          }
          type l0-types:dwdm-n;
          description
            "The central frequency of DWDM.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case cwdm {
        leaf cwdm-n {
          when "derived-from-or-self(../../../grid-type,
                \"wson-grid-cwdm\")" {
            description
              "Valid only when grid type is CWDM.";
          }
          type l0-types:cwdm-n;
          description
            "Channel wavelength computing input.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers";
  }

  grouping wson-label-hop {
    description
      "Generic label-hop information for WSON";
    choice grid-type {
      description
        "Label for DWDM or CWDM grid";
      case dwdm {
        choice single-or-super-channel {
          description
            "single or super channel";
          case single {
            leaf dwdm-n {
              type l0-types:dwdm-n;
              description
                "The given value 'N' is used to determine the
                 nominal central frequency.";
            }
          }
          case super {
            leaf-list subcarrier-dwdm-n {
              type l0-types:dwdm-n;
              description
                "The given values 'N' are used to determine the
                 nominal central frequency for each subcarrier
                 channel.";
              reference
                "ITU-T G.694.1 (10/2020): Spectral grids for WDM
                applications: DWDM frequency grid";
            }
          }
        }
      }
      case cwdm {
        leaf cwdm-n {
          type l0-types:cwdm-n;
          description
            "The given value 'N' is used to determine the nominal
             central wavelength.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers";
  }

  grouping l0-label-range-info {
    description
      "Information about Layer 0 label range.";
    leaf grid-type {
      type identityref {
        base l0-grid-type;
      }
      description
        "Grid type";
    }
    leaf priority {
      type uint8;
      description
        "Priority in Interface Switching Capability Descriptor
         (ISCD).";
      reference
        "RFC 4203: OSPF Extensions in Support of Generalized
         Multi-Protocol Label Switching (GMPLS)";
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers";
  }

  grouping wson-label-step {
    description
      "Label step information for WSON";
    choice l0-grid-type {
      description
        "Grid type: DWDM, CWDM, etc.";
      case dwdm {
        leaf wson-dwdm-channel-spacing {
          when "derived-from-or-self(../../grid-type,
                \"wson-grid-dwdm\")" {
            description
              "Valid only when grid type is DWDM.";
          }
          type identityref {
            base dwdm-ch-spc-type;
          }
          description
            "Label-step is the channel spacing (GHz), e.g., 100.000,
             50.000, 25.000, or 12.500 GHz for DWDM.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
      case cwdm {
        leaf wson-cwdm-channel-spacing {
          when "derived-from-or-self(../../grid-type,
                \"wson-grid-cwdm\")" {
            description
              "Valid only when grid type is CWDM.";
          }
          type identityref {
            base cwdm-ch-spc-type;
          }
          description
            "Label-step is the channel spacing (nm), i.e., 20 nm
             for CWDM, which is the only value defined for CWDM.";
          reference
            "RFC 6205: Generalized Labels for Lambda-Switch-Capable
             (LSC) Label Switching Routers";
        }
      }
    }
    reference
      "RFC 6205: Generalized Labels for Lambda-Switch-Capable (LSC)
       Label Switching Routers,

       ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
       CWDM wavelength grid";
  }

  grouping flexi-grid-label-start-end {
    description
      "The flexi-grid label-start or label-end used to specify
       flexi-grid label range.";
    leaf flexi-n {
      type l0-types:flexi-n;
      description
        "The given value 'N' is used to determine the nominal
        central frequency.

        As described in section 3.1 of RFC 8363, the range of
        available nominal central frequencies are advertised for
        m=1, which means that for an available central frequency n,
        the frequency slot from central frequency n-1 to central
        frequency n+1 is available.";
    }
    reference
      "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
      Switch Capable (LSC) Label Switching Routers,

      RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-Grid
      Dense Wavelength Division Multiplexing (DWDM) Networks";
  }

  grouping flexi-grid-frequency-slot {
    description
      "Flexi-grid frequency slot grouping.";
    uses flexi-grid-label-start-end;
    leaf flexi-m {
      type l0-types:flexi-m;
      description
        "The given value 'M' is used to determine the slot width.";
    }
    reference
      "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
      Switch Capable (LSC) Label Switching Routers";
  }

  grouping flexi-grid-label-hop {
    description
      "Generic label-hop information for flexi-grid";
    choice single-or-super-channel {
      description
        "single or super channel";
      case single {
        uses flexi-grid-frequency-slot;
      }
      case super {
        status deprecated;
        list subcarrier-flexi-n {
          key "flexi-n";
          status deprecated;
          uses flexi-grid-frequency-slot {
            status deprecated;
          }
          description
            "List of subcarrier channels for flexi-grid super
             channel.";
        }
      }
      case multi {
        container frequency-slots {
          description
            "The top level container for the list of frequency
            slots used for flexi-grid super channel.";
          list frequency-slot {
            key "flexi-n";
            min-elements 2;
            uses flexi-grid-frequency-slot;
            description
              "List of frequency slots used for flexi-grid super
              channel.";
          }
        }
      }
    }
    reference
      "RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-Grid
      Dense Wavelength Division Multiplexing (DWDM) Networks";
  }

  grouping flexi-grid-label-range-info {
    description
      "Flexi-grid-specific label range related information";
    uses l0-label-range-info;
    container flexi-grid {
      description
        "flexi-grid definition";
      leaf slot-width-granularity {
        type identityref {
          base flexi-slot-width-granularity;
        }
        default "flexi-swg-12p5ghz";
        description
          "Minimum space between slot widths. Default is 12.500
           GHz.";
        reference
          "RFC 8363: GMPLS OSPF-TE Extensions in Support of
          Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
          Networks";
      }
      leaf min-slot-width-factor {
        type uint16 {
          range "1..max";
        }
        default "1";
        description
          "A multiplier of the slot width granularity, indicating
           the minimum slot width supported by an optical port.

           Minimum slot width is calculated by:
             Minimum slot width (GHz) =
               min-slot-width-factor * slot-width-granularity.";
        reference
          "RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-
           Grid Dense Wavelength Division Multiplexing (DWDM)
           Networks";
      }
      leaf max-slot-width-factor {
        type uint16 {
          range "1..max";
        }
        must '. >= ../min-slot-width-factor' {
          error-message
            "Maximum slot width must be greater than or equal to
             minimum slot width.";
        }
        description
          "A multiplier of the slot width granularity, indicating
           the maximum slot width supported by an optical port.

           Maximum slot width is calculated by:
             Maximum slot width (GHz) =
               max-slot-width-factor * slot-width-granularity

           If specified, maximum slot width must be greater than or
           equal to minimum slot width.  If not specified, maximum
           slot width is equal to minimum slot width.";
        reference
          "RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-
           Grid Dense Wavelength Division Multiplexing (DWDM)
           Networks";
      }
    }
  }

  grouping flexi-grid-label-step {
    description
      "Label step information for flexi-grid";
    leaf flexi-grid-channel-spacing {
      type identityref {
        base flexi-ch-spc-type;
      }
      default "flexi-ch-spc-6p25ghz";
      status deprecated;
      description
        "Label-step is the nominal central frequency granularity
         (GHz), e.g., 6.25 GHz.";
      reference
        "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
         Switch Capable (LSC) Label Switching Routers";
    }
    leaf flexi-ncfg {
      type identityref {
        base flexi-ncfg-type;
      }
      default "flexi-ncfg-6p25ghz";
      description
        "Label-step is the nominal central frequency granularity
         (GHz), e.g., 6.25 GHz.";
      reference
        "RFC 7699: Generalized Labels for the Flexi-Grid in Lambda
         Switch Capable (LSC) Label Switching Routers";
    }
    leaf flexi-n-step {
      type uint8;
      description
        "This attribute defines the multiplier for the supported
         values of 'N'.

         For example, given a grid with a nominal central frequency
         granularity of 6.25 GHz, the granularity of the supported
         values of the nominal central frequency could be 12.5 GHz.
         In this case, the values of flexi-n should be even and this
         constraint is reported by setting the flexi-n-step to 2.

         This attribute is also known as central frequency
         granularity in RFC 8363.";
      reference
        "RFC 8363: GMPLS OSPF-TE Extensions in Support of Flexi-Grid
         Dense Wavelength Division Multiplexing (DWDM) Networks";
    }
  }

  grouping transceiver-mode {
    description
      "This grouping is intended to be used for reporting the
      information of a transceiver's mode.

      The attributes for the explicit mode shall be augmented when
      used with either:
      - the proper leafrefs, when explicit mode templates are used;
        or,
      - the explicit-mode grouping, when explicit mode templates
        are not used.

      The compatible-modes container shall be augmented with the
      proper leafrefs when used: see for example the
      transceiver-capabilities grouping below.";
    choice mode {
      mandatory true;
      description
        "Indicates whether the transceiver's mode is a standard
          mode, an organizational mode or an explicit mode.";
      case G.698.2 {
        uses standard-mode;
        uses common-standard-organizational-mode;
        uses common-all-modes;
      }
      case organizational-mode {
        container organizational-mode {
          config false;
          description
            "The set of attributes for an organizational mode";
          uses organizational-mode;
          uses common-standard-organizational-mode;
          uses common-all-modes;
        }  // container organizational-mode
      }
      case explicit-mode {
        container explicit-mode {
          config false;
          description
            "The set of attributes for an explicit mode";
          // uses explicit-mode;
          uses common-all-modes;
          container compatible-modes {
            description
              "Container for all the standard and organizational
                modes supported by the transceiver's explicit
                mode.";
          }  // container compatible-modes
        }  // container explicit-mode
      } // end of case explicit-mode
    } // end of choice
  }

  grouping transceiver-capabilities {
    description
      "This grouping is intended to be used for reporting the
      capabilities of a transceiver.

      The attributes for the explicit mode shall be augmented when
      used with either:
      - the proper leafrefs, when explicit mode templates are used;
        or,
      - the explicit-mode grouping, when explicit mode templates
        are not used.";

    container supported-modes {
      presence
        "When present, it indicates that the modes supported by a
        transceiver are reported.";
      description
        "The top level container for the list supported
        transceiver's modes.";
      list supported-mode {
        key "mode-id";
        config false;
        min-elements 1;
        description "The list of supported transceiver's modes.";
        leaf mode-id {
          type string {
            length "1..255";
          }
          description "ID for the supported transceiver's mode.";
        }
        uses transceiver-mode {
          augment "mode/explicit-mode/explicit-mode/"
                + "compatible-modes" {
            description
              "Augments the compatible modes with the proper
              leafrefs.";
            leaf-list supported-application-codes {
              type leafref {
                path "../../../../supported-mode/mode-id";
              }
              must "../../../../"
                  + "supported-mode[mode-id=current()]/"
                  + "standard-mode" {
                description
                  "The pointer is only for application codes
                  supported by transceiver.";
              }
              description
                "List of pointers to the application codes
                supported by the transceiver's explicit mode.";
            }
            leaf-list supported-organizational-modes {
              type leafref {
                path "../../../../supported-mode/mode-id";
              }
              must "../../../../"
                  + "supported-mode[mode-id=current()]/"
                  + "organizational-mode" {
                description
                  "The pointer is only for organizational modes
                  supported by transceiver.";
              }
              description
                "List of pointers to the organizational modes
                  supported by the transceiver's explicit mode.";
            }
          }
        }
      }  // list supported-modes
    }  // container supported-modes
  }  // grouping transceiver-capabilities

  grouping standard-mode {
    description
      "ITU-T G.698.2 standard mode that guarantees interoperability.
       It must be an string with the following format:
       B-DScW-ytz(v) where all these attributes are conformant
       to the ITU-T recomendation";

    leaf standard-mode {
      type standard-mode;
      config false;
      description
        "G.698.2 standard mode";
    }
  }

  grouping organizational-mode {
    description
      "Transponder operational mode supported by organizations or
       vendor";

    leaf operational-mode {
      type operational-mode;
      config false;
      description
        "configured organization- or vendor-specific
         application identifiers (AI) supported by the transponder";
    }
    leaf organization-identifier {
      type organization-identifier;
      config false;
      description
        "organization identifier that uses organizational
         mode";
    }
  }

  grouping penalty-value {
    description
      "A common definition of the penalty value used for describing
      multiple penalty types (.e.g, CD, PMD, PDL).";

    leaf penalty-value {
      type union {
        type decimal-2 {
          range "0..max";
        }
        type empty;
      }
      units "dB";
      config false;
      mandatory true;
      description
        "The OSNR penalty associated with the related optical
        impairment at the receiver, when the value is known or an
        empty value when the value is not known.";
    }
  }

  grouping explicit-mode {
    description
      "Attributes capabilities related to explicit transceiver's
      mode.

      This grouping also contains the list of attributes related to
      optical impairment limits for explicit mode (min OSNR, max PMD,
      max CD, max PDL, Q-factor limit, etc.).

      In case of standard and operational mode the attributes are
      implicit.";
    leaf line-coding-bitrate {
      type identityref {
        base line-coding;
      }
      config false;
      description
        "Bit rate/line coding of the optical tributary signal.";
      reference
        "ITU-T G.698.2 section 7.1.2";
    }
    leaf bitrate {
      type uint16;
      units "Gbit/sec";
      config false;
      description
        "The gross bitrate (e.g., 100, 200) of the optical tributary
        signal.";
    }
    leaf max-diff-group-delay  {
      type decimal-2;
      units "ps";
      config false;
      description
        "Maximum Differential group delay of this mode for this
        lane";
    }
    leaf max-chromatic-dispersion {
      type decimal-2 {
        range "0..max";
      }
      units "ps/nm";
      config false;
      description
        "Maximum acceptable accumulated chromatic dispersion (CD)
        on the receiver";
    }
    list cd-penalty {
      key cd-value;
      config false;
      description
        "Optional penalty associated with a given accumulated
        chromatic dispersion (CD) value.

        This list of pair CD and penalty values can be used to
        sample the function penalty = f(CD).";
      leaf cd-value {
        type decimal-2;
        units "ps/nm";
        config false;
        mandatory true;
        description
          "The Chromatic Dispersion (CD).";
      }
      uses penalty-value;
    }
    leaf max-polarization-mode-dispersion {
      type decimal-2 {
        range "0..max";
      }
      units "ps";
      config false;
      description
        "Maximum acceptable accumulated polarization mode
         dispersion (PMD) on the receiver";
      reference
        "ITU-T G.666 (02/2011): Characteristics of polarization
        mode dispersion compensators and of receivers that
        compensate for polarization mode dispersion";
    }
    list pmd-penalty {
      key pmd-value;
      config false;
      description
        "Optional penalty associated with a given accumulated
        polarization mode dispersion (PMD) value.

        This list of pair PMD and penalty can be used to
        sample the function penalty = f(PMD).";
      leaf pmd-value {
        type decimal-2 {
          range "0..max";
        }
        units "ps";
        config false;
        mandatory true;
        description
          "The Polarization Mode Dispersion (PMD).";
      }
      uses penalty-value;
    }
    leaf max-polarization-dependent-loss {
      type power-loss-or-null;
      config false;
      mandatory true;
      description
        "Maximum acceptable accumulated accumulated polarization
        dependent loss (PDL) on the receiver";
    }
    list pdl-penalty {
      key pdl-value;
      config false;
      description
        "Optional penalty associated with a given accumulated
        polarization dependent loss (PDL) value.

        This list of pair PDL and penalty values can be used to
        sample the function PDL = f(penalty).";
      leaf pdl-value {
        type power-loss;
        config false;
        mandatory true;
        description
          "Maximum acceptable accumulated polarization dependent
          loss (PDL).";
      }
      uses penalty-value;
    }
    leaf available-modulation-type {
      type identityref {
        base modulation;
      }
      config false;
      description
        "Modulation type the specific transceiver in the list
         can support";
    }
    leaf min-OSNR {
      type snr;
      units "dBm";
      config false;
      description
        "min OSNR measured over 0.1 nm resolution bandwidth:
        if received OSNR at Rx-power reference point
        (rx-ref-channel-power) is lower than MIN-OSNR, an increased
        level of bit-errors post-FEC needs to be expected";
    }
    leaf rx-ref-channel-power {
      type power-dbm;
      config false;
      description
        "The channel power used as reference for defining penalties
        and min-OSNR";
    }
    list rx-channel-power-penalty {
      key rx-channel-power-value;
      config false;
      description
        "Optional penalty associated with a received power
        lower than rx-ref-channel-power.

        This list of pair power and penalty can be used to
        sample the function penalty = f(rx-channel-power).";
      leaf rx-channel-power-value {
        type power-dbm;
        units "dBm";
        config false;
        mandatory true;
        description
          "The Received Power.";
      }
      uses penalty-value;
    }
    leaf min-Q-factor {
      type decimal-2;
      units "dB";
      config false;
      description "min Qfactor at FEC threshold";
    }
    leaf available-baud-rate {
      type decimal64 {
        fraction-digits 1;
      }
      units "Bd";
      config false;
      description
        "Baud-rate the specific transceiver in
        the list can support.
         Baud-rate is the unit for
         symbol rate or modulation rate
         in symbols per second or
         pulses per second.
         It is the number of distinct symbol
         changes (signal events) made to the
         transmission medium
         per second in a digitally
         modulated signal or a line code";
    }
    leaf roll-off {
      type decimal64 {
        fraction-digits 4;
        range "0..1";
      }
      config false;
      description
        "the roll-off factor (beta with values from 0 to 1)
        identifies how the real signal shape exceed
        the baud rate. If=0 it is exactly matching
        the baud rate.If=1 the signal exceeds the
        50% of the baud rate at each side.";
    }
    leaf min-carrier-spacing {
      type frequency-ghz;
      config false;
      description
        "This attribute specifies the minimum nominal difference
        between the carrier frequencies of two homogeneous OTSis
        (which have the same optical characteristics but the central
        frequencies) such that if they are placed next to each other
        the interference due to spectrum overlap between them can be
        considered negligible.

        In case of heterogeneous OTSi it is up to path computation
        engine to determine the minimum distance between the carrier
        frequency of the two adjacent OTSi.";
    }
    leaf available-fec-type {
      type identityref {
        base fec-type;
      }
      config false;
      description "Available FEC";
    }
    leaf fec-code-rate {
      type decimal64 {
        fraction-digits 8;
        range "0..max";
      }
      config false;
      description "FEC-code-rate";
    }
    leaf fec-threshold {
      type decimal64 {
        fraction-digits 8;
        range "0..max";
      }
      config false;
      description
        "Threshold on the BER, for which FEC
         is able to correct errors";
    }
    leaf in-band-osnr {
      type snr;
      config false;
      description
        "The OSNR defined within the bandwidth of the transmit
        spectral excursion (i.e.,  between the nominal central
        frequency of the channel and the -3.0dB points of the
        transmitter spectrum furthest from the nominal central
        frequency) measured at reference point Ss.

        The in-band OSNR is referenced to an optical bandwidth of
        0.1nm @ 193.7 THz or 12.5 GHz.";
      reference
        "OIF-400ZR-01.0: Implementation Agreement 400ZR";
    }
    leaf out-of-band-osnr {
      type snr;
      config false;
      description
        "The ratio of the peak transmitter power to the integrated
        power outside the transmitter spectral excursion.

        The spectral resolution of the measurement shall be better
        than the maximum spectral width of the peak.

        The out-of-band OSNR is referenced to an optical bandwidth
        of 0.1nm @ 193.7 THz or 12.5 GHz";
      reference
        "OIF-400ZR-01.0: Implementation Agreement 400ZR";
    }
    leaf tx-polarization-power-difference {
      type power-ratio;
      config false;
      description
        "The transmitter polarization dependent power difference
        defined as the power difference between X and Y
        polarizations";
      reference
        "OIF-400ZR-01.0: Implementation Agreement 400ZR";
    }
    leaf polarization-skew {
      type decimal-2;
      units "ps";
      config false;
      description
        "The X-Y skew, included as a fixed value in the receiver
        polarization mode dispersion (PMD) tolerance limits.";
      reference
        "OIF-400ZR-01.0: Implementation Agreement 400ZR";
    }
  } // grouping explicit-mode

  grouping common-standard-organizational-mode {
    description
      "Common attributes used by standard and organizational
      transceiver's modes.";

    leaf-list line-coding-bitrate {
      type identityref {
        base line-coding;
      }
      config false;
      description
        "The list of the bit rate/line coding of the optical
        tributary signal supported by the transceiver.

        Reporting this list is optional when the standard or
        organization mode supports only one bit rate/line coding.";
      reference
        "ITU-T G.698.2 section 7.1.2";
    }
  } // grouping common-standard-organizational-mode

  grouping transmitter-tuning-range {
    description
      "Transmitter tuning range (f_tx-min, f_tx-max)";

    leaf min-central-frequency {
      type frequency-thz;
      description
        "This parameter indicates the minimum frequency for the
        transmitter tuning range.";
    }
    leaf max-central-frequency {
      type frequency-thz;
      description
        "This parameter indicates the maximum frequency for the
        transmitter tuning range.";
    }

    leaf transceiver-tunability {
      type frequency-ghz;
      description
        "This parameter indicates the transmitter frequency fine
        tuning steps e.g 3.125GHz or 0.001GHz.";
    }
  } // grouping transmitter-tuning-range

  grouping common-all-modes {
    description
      "Common attributes used by all transceiver's modes.";

    uses transmitter-tuning-range;
    leaf tx-channel-power-min {
      type power-dbm;
      config false;
      description "The minimum output power of this interface";
    }
    leaf tx-channel-power-max {
      type power-dbm;
      config false;
      description "The maximum output power of this interface";
    }
    leaf rx-channel-power-min {
      type power-dbm;
      config false;
      description "The minimum input power of this interface";
    }
    leaf rx-channel-power-max {
      type power-dbm;
      config false;
      description "The maximum input power of this interface";
    }
    leaf rx-total-power-max {
      type power-dbm;
      config false;
      description
        "Maximum rx optical power for all the channels.

        It is applicable only to multi-channel modes.";
    }
  } // grouping common-all-modes

  grouping common-transceiver-param {
    description
      "The common parameters of an optical transceiver,
      that supplement the configured mode.";

    uses common-transceiver-configured-param;
    uses common-transceiver-readonly-param;
  }

  grouping common-transceiver-configured-param {
    description
      "The configured parameters of an optical transceiver,
      that supplement the configured mode.";

    leaf line-coding-bitrate {
      type identityref {
        base line-coding;
      }
      description
        "Bit rate/line coding of the optical tributary signal.

        Support of this attribute is optional when the configured
        mode supports only one bit rate/line coding.";
      reference
        "ITU-T G.698.2 section 7.1.2";
    }
    leaf tx-channel-power {
      type power-dbm-or-null;
      description
        "The current channel transmit power, when the value is
        known or an empty value when the value is not known.

        The empty value MUST NOT be used when this attribute is
        configured.";
    }
  } // grouping for configured transceiver attributes out of mode

  grouping common-transceiver-readonly-param {
    description
      "The common read-only parameters of an optical transceiver,
      that supplement the configured mode.";

    leaf rx-channel-power {
      type power-dbm-or-null;
      config false;
      description
        "The current channel received power, when the value is
        known or an empty value when the value is not known.";
    }
    leaf rx-total-power {
      type power-dbm-or-null;
      config false;
      description
        "The current total received power, when the value is known
        or an empty value when the value is not known.";
    }
  } // grouping for read-only transceiver attributes out of mode

  grouping l0-tunnel-attributes {
    description
      "Parameters for Layer0 (WSON or Flexi-Grid) Tunnels.";

    leaf wavelength-assignment {
      type identityref {
        base wavelength-assignment;
      }
      description "Wavelength Allocation Method";
    }
  }

  grouping frequency-range {
    description
      "This grouping defines the lower and upper bounds of a
      frequency range (e.g., a band).

      This grouping SHOULD NOT be used to define a frequency slot,
      which SHOULD be defined using the n and m values instead.";
    leaf lower-frequency {
      type frequency-thz;
      mandatory true;
      description
        "The lower frequency boundary of the
        frequency range.";
    }
    leaf upper-frequency {
      type frequency-thz;
      must '. > ../lower-frequency' {
        error-message
          "The upper frequency must be greater than the lower
          frequency.";
      }
      mandatory true;
      description
        "The upper frequency boundary of the
        frequency range.";
    }
  }

  grouping l0-path-constraints {
    description
      "Common attribute for Layer 0 path constraints to be used by
      Layer 0 computation.";
    leaf gsnr-extra-margin {
      type snr {
        range 0..max;
      }
      default 0;
      description
        "An additional margin to be added to the OSNR-min of the
        transceiver when checking the estimated received Generalized
        SNR (GSNR).";
    }
  }

  grouping l0-path-properties {
    description
      "Common attribute for reporting the Layer 0 computed path
      properties.";
    leaf estimated-gsnr {
      type snr;
      config false;
      description
        "The estimate received GSNR for the computed path.";
    }
    leaf estimated-eol-gsnr {
      type snr;
      config false;
      description
        "The estimate received GSNR for the computed path
         degraded at the end of life.";
    }
    leaf estimated-lowest-gsnr {
      type snr;
      config false;
      description
        "The estimate lowest received GSNR for the computed path
         among all possible wavelength channels along the same
         path.";
    }
  }
}

<CODE ENDS>
Figure 2: Layer 0 Types YANG module

5. Security Considerations

The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].

The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. The NETCONF protocol over Secure Shell (SSH) specification [RFC6242] describes a method for invoking and running NETCONF within a Secure Shell (SSH) session as an SSH subsystem.

The objects in this YANG module are common data types and groupings. No object in this module can be read or written to. These definitions can be imported and used by other Layer 0 specific modules. It is critical to consider how imported definitions will be utilized and accessible via RPC operations, as the resultant schema will have data nodes that can be writable, or readable, and will have a significant effect on the network operations if used incorrectly or maliciously. All of these considerations belong in the document that defines the modules that import from this YANG module. Therefore, it is important to manage access to resultant data nodes that are considered sensitive or vulnerable in some network environments.

The security considerations spelled out in the YANG 1.1 specification [RFC7950] apply for this document as well.

6. IANA Considerations

For the following URI in the "IETF XML Registry" [RFC3688], IANA has updated the reference field to refer to this document:

   URI:  urn:ietf:params:xml:ns:yang:ietf-layer0-types
   Registrant Contact:  The IESG
   XML:  N/A; the requested URI is an XML namespace.

This document also adds an updated YANG module to the "YANG Module Names" registry [RFC7950]:

   Name:  ietf-layer0-types
   Namespace:  urn:ietf:params:xml:ns:yang:ietf-layer0-types
   Prefix:  l0-types
   Reference:  RFC XXXX

RFC Editor Note: Please replace XXXX with the RFC number assigned to this document.

7. References

7.1. Normative References

[I-D.ietf-ccamp-optical-impairment-topology-yang]
Beller, D., Le Rouzic, E., Belotti, S., Galimberti, G., and I. Busi, "A YANG Data Model for Optical Impairment-aware Topology", Work in Progress, Internet-Draft, draft-ietf-ccamp-optical-impairment-topology-yang-16, , <https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-optical-impairment-topology-yang-16>.
[I-D.ietf-teas-rfc8776-update]
Busi, I., Guo, A., Liu, X., Saad, T., and I. Bryskin, "Common YANG Data Types for Traffic Engineering", Work in Progress, Internet-Draft, draft-ietf-teas-rfc8776-update-12, , <https://datatracker.ietf.org/doc/html/draft-ietf-teas-rfc8776-update-12>.
[ITU-T_G.666]
International Telecommunication Union, "Characteristics of polarization mode dispersion compensators and of receivers that compensate for polarization mode dispersion"", ITU-T Recommendation G.666 , , <https://www.itu.int/rec/T-REC-G.666>.
[ITU-T_G.694.1]
International Telecommunication Union, "Spectral grids for WDM applications: DWDM frequency grid", ITU-T Recommendation G.694.1 , , <https://www.itu.int/rec/T-REC-G.694.1>.
[ITU-T_G.694.2]
International Telecommunication Union, "Spectral grids for WDM applications: CWDM wavelength grid", ITU-T Recommendation G.694.2 , , <https://www.itu.int/rec/T-REC-G.694.2>.
[ITU-T_G.698.2]
International Telecommunication Union, "Amplified multichannel dense wavelength division multiplexing applications with single channel optical interfaces", ITU-T Recommendation G.698.2 , , <https://www.itu.int/rec/T-REC-G.698.2>.
[ITU-T_G.709]
International Telecommunication Union, "Interfaces for the optical transport network", ITU-T Recommendation G.709 , , <https://www.itu.int/rec/T-REC-G.709>.
[ITU-T_G.709.2]
International Telecommunication Union, "OTU4 long-reach interface", ITU-T Recommendation G.709.2, Corrigendum 1 , , <https://www.itu.int/rec/T-REC-G.709.2>.
[ITU-T_G.709.3]
International Telecommunication Union, "Flexible OTN B100G long-reach interfaces", ITU-T Recommendation G.709.3, Amendment 1 , , <https://www.itu.int/rec/T-REC-G.709.3>.
[ITU-T_G.959.1]
International Telecommunication Union, "Optical transport network physical layer interfaces", ITU-T Recommendation G.959.1 , , <https://www.itu.int/rec/T-REC-G.959.1>.
[ITU-T_G.9700]
International Telecommunication Union, "Fast access to subscriber terminals (G.fast) - Power spectral density specification", ITU-T Recommendation G.9700 , , <https://www.itu.int/rec/T-REC-G.9700>.
[ITU-T_G.975]
International Telecommunication Union, "Forward error correction for submarine systems", ITU-T Recommendation G.975 , , <https://www.itu.int/rec/T-REC-G.975>.
[ITU-T_G.975.1]
International Telecommunication Union, "Forward error correction for high bit-rate DWDM submarine systems", ITU-T Recommendation G.975.1, Corrigendum 2 , , <https://www.itu.int/rec/T-REC-G.975.1>.
[ITU-T_G.977.1]
International Telecommunication Union, "Transverse compatible dense wavelength division multiplexing applications for repeatered optical fibre submarine cable systems", ITU-T Recommendation G.977.1 , , <https://www.itu.int/rec/T-REC-G.977.1>.
[OIF_400ZR]
Optical Internetworking Forum, "Implementation Agreement 400ZR", OIF-400ZR-01.0 Implementation Agreement , , <https://www.oiforum.com/wp-content/uploads/OIF-400ZR-01.0_reduced2.pdf>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC4203]
Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, , <https://www.rfc-editor.org/info/rfc4203>.
[RFC6205]
Otani, T., Ed. and D. Li, Ed., "Generalized Labels for Lambda-Switch-Capable (LSC) Label Switching Routers", RFC 6205, DOI 10.17487/RFC6205, , <https://www.rfc-editor.org/info/rfc6205>.
[RFC6241]
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC7689]
Bernstein, G., Ed., Xu, S., Lee, Y., Ed., Martinelli, G., and H. Harai, "Signaling Extensions for Wavelength Switched Optical Networks", RFC 7689, DOI 10.17487/RFC7689, , <https://www.rfc-editor.org/info/rfc7689>.
[RFC7698]
Gonzalez de Dios, O., Ed., Casellas, R., Ed., Zhang, F., Fu, X., Ceccarelli, D., and I. Hussain, "Framework and Requirements for GMPLS-Based Control of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM) Networks", RFC 7698, DOI 10.17487/RFC7698, , <https://www.rfc-editor.org/info/rfc7698>.
[RFC7699]
Farrel, A., King, D., Li, Y., and F. Zhang, "Generalized Labels for the Flexi-Grid in Lambda Switch Capable (LSC) Label Switching Routers", RFC 7699, DOI 10.17487/RFC7699, , <https://www.rfc-editor.org/info/rfc7699>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/info/rfc8341>.
[RFC8342]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/info/rfc8342>.
[RFC8363]
Zhang, X., Zheng, H., Casellas, R., Gonzalez de Dios, O., and D. Ceccarelli, "GMPLS OSPF-TE Extensions in Support of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM) Networks", RFC 8363, DOI 10.17487/RFC8363, , <https://www.rfc-editor.org/info/rfc8363>.
[RFC8446]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <https://www.rfc-editor.org/info/rfc8446>.
[RFC8795]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, , <https://www.rfc-editor.org/info/rfc8795>.
[RFC9093]
Zheng, H., Lee, Y., Guo, A., Lopez, V., and D. King, "A YANG Data Model for Layer 0 Types", RFC 9093, DOI 10.17487/RFC9093, , <https://www.rfc-editor.org/info/rfc9093>.

7.2. Informative References

[ITU-T_G.Sup39]
International Telecommunication Union, "Optical system design and engineering considerations", ITU-T Supplement G.Sup39 , .
[ITU-T_G.Sup43]
International Telecommunication Union, "Transport of IEEE 10GBASE-R in optical transport networks (OTN)", ITU-T Supplement G.Sup43 , .
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
[RFC6163]
Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, DOI 10.17487/RFC6163, , <https://www.rfc-editor.org/info/rfc6163>.
[RFC7446]
Lee, Y., Ed., Bernstein, G., Ed., Li, D., and W. Imajuku, "Routing and Wavelength Assignment Information Model for Wavelength Switched Optical Networks", RFC 7446, DOI 10.17487/RFC7446, , <https://www.rfc-editor.org/info/rfc7446>.
[RFC7581]
Bernstein, G., Ed., Lee, Y., Ed., Li, D., Imajuku, W., and J. Han, "Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical Networks", RFC 7581, DOI 10.17487/RFC7581, , <https://www.rfc-editor.org/info/rfc7581>.

Appendix A. Changes from RFC 9093

This version adds new data types, identities, and groupings to the YANG modules.

The following new YANG data types have been added to the 'ietf-layer0-types' module:

The following new YANG identities have been added to the 'ietf-layer0-types' module:

The following new YANG groupings have been added to the 'ietf-layer0-types' module:

Acknowledgments

The authors and the working group give their sincere thanks to Robert Wilton for the YANG doctor review and to Adrian Farrel and Tom Petch for their comments during the model and document development.

This document was prepared using kramdown.

Contributors

Haomian Zheng
Huawei
Daniel King
University of Lancaster
Gabriele Galimberti
Cisco
Enrico Griseri
Nokia
Dhruv Dhody
Huawei
Bin Yeong Yoon
ETRI
Ricard Vilalta
CTTC
Young Lee
Samsung
Victor Lopez
Nokia

Authors' Addresses

Sergio Belotti (editor)
Nokia
Italo Busi (editor)
Huawei
Dieter Beller (editor)
Nokia
Esther Le Rouzic
Orange
Aihua Guo
Futurewei Technologies