A YANG Data Model for Layer 0 Types
draft-ietf-ccamp-layer0-types-09

Document Type Active Internet-Draft (ccamp WG)
Authors Haomian Zheng  , Young Lee  , Aihua Guo  , Victor Lopez  , Daniel King 
Last updated 2021-05-06 (latest revision 2020-12-29)
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Details
CCAMP Working Group                                             H. Zheng
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                                  Y. Lee
Expires: July 2, 2021                                            Samsung
                                                                  A. Guo
                                                               Futurewei
                                                                V. Lopez
                                                              Telefonica
                                                                 D. King
                                                 University of Lancaster
                                                       December 29, 2020

                  A YANG Data Model for Layer 0 Types
                    draft-ietf-ccamp-layer0-types-09

Abstract

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

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 July 2, 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology and Notations . . . . . . . . . . . . . . . .   3
     1.2.  Prefix in Data Node Names . . . . . . . . . . . . . . . .   3
   2.  Layer 0 Types Module Contents . . . . . . . . . . . . . . . .   3
   3.  YANG Code for Layer 0 Types . . . . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  18
   7.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  18
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  20
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

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 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 aspect) for Layer 0 optical networks in
   model(s) defined outside of this document.  The applicability of
   Layer 0 types specified in this document include Wavelength Switched
   Optical Networks (WSONs) [RFC6163] and [ITU-Tg6982], and Flexi-grid
   Dense Wavelength Division Multiplexing (DWDM) Networks [RFC7698] and
   [ITU-Tg6941] .

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

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 modules.

      +-------------+---------------------------+----------------------+
      | Prefix      | YANG module               | Reference            |
      +-------------+---------------------------+----------------------+
      | l0-types    | ietf-layer0-types         | [RFCXXXX]            |
      +-------------+---------------------------+----------------------+

   Note: The RFC Editor will replace XXXX with the number assigned to
   the RFC once this document becomes an RFC.

   YANG module ietf-layer0-types (defined in Section 3) references
   [RFC6163], [RFC6205], and [RFC7698].

2.  Layer 0 Types Module Contents

   This document defines 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 types and groupings:

   l0-grid-type:

   A base YANG identity for the grid type as defined in [RFC6163] and
   [RFC7698].

   dwdm-ch-spc-type:

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

   cwdm-ch-spc-type:

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

   wson-label-start-end:

   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.

   wson-label-hop:

   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.

   l0-label-range-info:

   A YANG grouping that defines the layer 0 label range information
   applicable for both WSON per priority level as defined in [RFC6205].
   This grouping is used in the flexi-grid DWDM by adding more flexi-
   grid-specific parameters.

   wson-label-step:

   A YANG grouping that defines label steps for WSON as defined in
   [RFC8776].

   flexi-grid-label-start-end:

   Flexi-grid label range was defined in [RFC7698], 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.

   flexi-grid-label-hop:

   Flexi-grid label range was defined in [RFC7698], and the generic
   topology model defines the label-hop in [RFC8795].  This grouping
   shows the WSON-specific label-hop information.

   flexi-grid-label-range-info:

   A YANG grouping that defines flexi-grid label range information and
   per priority level as defined in [RFC7698] and [RFC8363].

   flexi-grid-label-step:

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   A YANG grouping that defines flexi-grid label steps as defined in
   [RFC8776].

3.  YANG Code for Layer 0 Types

   <CODE BEGINS>file "ietf-layer0-types@2020-12-29.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: <http://tools.ietf.org/wg/ccamp/>
        WG List: <mailto:ccamp@ietf.org>

        Editor: Haomian Zheng
          <mailto:zhenghaomian@huawei.com>

        Editor: Young Lee
          <mailto:younglee.tx@gmail.com>

        Editor: Aihua Guo
          <mailto:aihuaguo.ietf@gmail.com>

        Editor: Victor Lopez
          <mailto:victor.lopezalvarez@telefonica.com>

        Editor: Daniel King
          <mailto:d.king@lancaster.ac.uk>";

     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) 2020 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 Simplified
        BSD License set forth in Section 4.c of the IETF Trust's

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        Legal Provisions Relating to IETF Documents
        (http://trustee.ietf.org/license-info).

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

     revision "2020-12-29" {
       description
         "Initial Version";
       reference
         "RFC XXXX: A YANG Data Model for Layer 0 Types";
     }

     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 C band; 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 (02/2012): 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 ITU-T 'anchor wavelength' for
          transmission over the C band; and where 'channel-spacing' is
          defined by the cwdm-ch-spc-type.";
       reference
         "RFC6205: Generalized Labels for Lambda-Switch-Capable (LSC)
          Label Switching Routers,
          ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:

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          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 channel-spacing (measured in GHz),

          where 193100.000 GHz (193.100000 THz) is the ITU-T 'anchor
          frequency' for transmission over the C band; and where
          'channel-spacing' is defined by the flexi-ch-spc-type.

          Note that the term 'channel-spacing' can be alternated by the
          term 'nominal central frequency granularity' defined in
          clause 7 of ITU-T G.694.1.";
       reference
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
          Networks.
          ITU-T G.694.1 (02/2012): 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
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
          Networks.
          ITU-T G.694.1 (02/2012): Spectral grids for WDM applications:
          DWDM frequency grid";
     }

     identity l0-grid-type {
       description
         "Layer 0 grid type";
       reference

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         "RFC6163:Framework for GMPLS and Path Computation Element
          (PCE) Control of Wavelength Switched Optical Networks (WSONs),
          ITU-T G.694.1 (02/2012): Spectral grids for WDM applications:
          DWDM frequency grid,
          ITU-T G.694.2 (12/2003): Spectral grids for WDM applications:
          CWDM wavelength grid";
     }

     identity flexi-grid-dwdm {
       base l0-grid-type;
       description
         "Flexi-grid";
       reference
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
          Networks,
          ITU-T G.694.1 (02/2012): Spectral grids for WDM applications:
          DWDM frequency grid";
     }

     identity wson-grid-dwdm {
       base l0-grid-type;
       description
         "DWDM grid";
       reference
         "RFC6163:Framework for GMPLS and Path Computation Element
          (PCE) Control of Wavelength Switched Optical Networks (WSONs),
          ITU-T G.694.1 (02/2012): Spectral grids for WDM applications:
          DWDM frequency grid";
     }

     identity wson-grid-cwdm {
       base l0-grid-type;
       description
         "CWDM grid";
       reference
         "RFC6205: 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
         "RFC6205: Generalized Labels for Lambda-Switch-Capable (LSC)
          Label Switching Routers,

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          ITU-T G.694.1 (02/2012): Spectral grids for WDM applications:
          DWDM frequency grid";
     }

     identity dwdm-100ghz {
       base dwdm-ch-spc-type;
       description
         "100GHz channel spacing";
     }

     identity dwdm-50ghz {
       base dwdm-ch-spc-type;
       description
         "50GHz channel spacing";
     }

     identity dwdm-25ghz {
       base dwdm-ch-spc-type;
       description
         "25GHz channel spacing";
     }

     identity dwdm-12p5ghz {
       base dwdm-ch-spc-type;
       description
         "12.5GHz channel spacing";
     }

     identity flexi-ch-spc-type {
       description
         "Flexi-grid channel spacing type";
       reference
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
          Networks
          ITU-T G.694.1 (02/2012): Spectral grids for WDM applications:
          DWDM frequency grid";
     }

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

     identity flexi-slot-width-granularity {
       description
         "Flexi-grid slot width granularity";

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     }

     identity flexi-swg-12p5ghz {
       base flexi-slot-width-granularity;
       description
         "12.5GHz slot width granularity";
     }

     identity cwdm-ch-spc-type {
       description
         "CWDM channel spacing type";
       reference
         "RFC6205: 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";
     }

     /* Groupings. */

     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
               "RFC6205: Generalized Labels for Lambda-Switch-Capable
                (LSC) Label Switching Routers";
           }

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         }
         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
               "RFC6205: Generalized Labels for Lambda-Switch-Capable
                (LSC) Label Switching Routers";
           }
         }
       }
       reference
         "RFC6205: 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
                    channels.";
                 reference

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                   "ITU-T Recommendation G.694.1: 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
               "RFC6205: Generalized Labels for Lambda-Switch-Capable
                (LSC) Label Switching Routers";
           }
         }
       }
       reference
         "RFC6205: 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
           "RFC4203: OSPF Extensions in Support of Generalized
            Multi-Protocol Label Switching (GMPLS).";
       }
       reference
         "RFC6205: Generalized Labels for Lambda-Switch-Capable (LSC)
          Label Switching Routers";
     }

     grouping wson-label-step {
       description "Label step information for WSON";

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       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
               "RFC6205: 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
               "RFC6205: Generalized Labels for Lambda-Switch-Capable
                (LSC) Label Switching Routers";
           }
         }
       }
       reference
         "RFC6205: 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";
     }

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     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.";
       }
       reference
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          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
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM)
          Networks";
     }

     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 {
           list subcarrier-flexi-n {
             key flexi-n;
             uses flexi-grid-frequency-slot;
             description
               "List of subcarrier channels for flexi-grid super
                channel.";
           }
         }

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       }
       reference
         "RFC7698: Framework and Requirements for GMPLS-Based Control
          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
             "RFC7698: 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
             "RFC8363: 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";
           }

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           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
             "RFC8363: 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;
         description
           "Label-step is the nominal central frequency granularity
            (GHz), e.g., 6.25 GHz";
         reference
            "RFC7699: 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

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            constraint is reported by setting the flexi-n-step to 2.

            This attribute is also known as central frequency
            granularity in RFC8363.";
         reference
           "RFC8363: GMPLS OSPF-TE Extensions in Support of Flexi-Grid
            Dense Wavelength Division Multiplexing (DWDM) Networks";
       }
     }
   }

   <CODE ENDS>

4.  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 NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF users to a preconfigured
   subset of all available NETCONF protocol operations and content.  The
   NETCONF Protocol over Secure Shell (SSH) [RFC6242] describes a method
   for invoking and running NETCONF within a Secure Shell (SSH) session
   as an SSH subsystem.  The NETCONF access control model [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 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 this consideration belongs 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.

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

5.  IANA Considerations

   It is proposed to IANA to assign new URIs from the "IETF XML
   Registry" [RFC3688] as follows:

         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 registers following YANG modules in 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(TBD)

6.  Acknowledgements

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

7.  Contributors

   Dhruv Dhody
   Huawei
   Email: dhruv.ietf@gmail.com

   Bin Yeong Yoon
   ETRI
   Email: byyun@etri.re.kr

   Ricard Vilalta
   CTTC
   Email: ricard.vilalta@cttc.es

   Italo Busi
   Huawei
   Email: Italo.Busi@huawei.com

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8.  References

8.1.  Normative References

   [ITU-Tg6982]
              International Telecommunication Union, "Amplified
              multichannel dense wavelength division multiplexing
              applications with single channel optical interfaces",
              ITU-T G.698.2, November 2018.

   [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, October 2005,
              <https://www.rfc-editor.org/info/rfc4203>.

   [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, April 2011,
              <https://www.rfc-editor.org/info/rfc6163>.

   [RFC6205]  Otani, T., Ed. and D. Li, Ed., "Generalized Labels for
              Lambda-Switch-Capable (LSC) Label Switching Routers",
              RFC 6205, DOI 10.17487/RFC6205, March 2011,
              <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, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [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, November 2015,
              <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,
              November 2015, <https://www.rfc-editor.org/info/rfc7699>.

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   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <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, March 2018,
              <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, May 2018,
              <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, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8776]  Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
              "Common YANG Data Types for Traffic Engineering",
              RFC 8776, DOI 10.17487/RFC8776, June 2020,
              <https://www.rfc-editor.org/info/rfc8776>.

   [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, August 2020,
              <https://www.rfc-editor.org/info/rfc8795>.

8.2.  Informative References

   [ITU-Tg6941]
              International Telecommunication Union, "Spectral grids for
              WDM applications: DWDM frequency grid", ITU-T G.694.1,
              February 2012.

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   [ITU-Tg6942]
              International Telecommunication Union, "Spectral grids for
              WDM applications: CWDM wavelength grid", ITU-T G.694.2,
              December 2003.

   [ITU-Tg709]
              International Telecommunication Union, "Interfaces for the
              optical transport network", ITU-T G.709, June 2016.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [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, February 2015,
              <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, June 2015,
              <https://www.rfc-editor.org/info/rfc7581>.

Authors' Addresses

   Haomian Zheng
   Huawei Technologies
   H1, Huawei Xiliu Beipo Village, Songshan Lake
   Dongguan, Guangdong  523808
   China

   Email: zhenghaomian@huawei.com

   Young Lee
   Samsung
   South Korea

   Email: younglee.tx@gmail.com

   Aihua Guo
   Futurewei

   Email: aihuaguo.ietf@gmail.com

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   Victor Lopez
   Telefonica

   Email: victor.lopezalvarez@telefonica.com

   Daniel King
   University of Lancaster

   Email: d.king@lancaster.ac.uk

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