A YANG Data Model for Optical Impairment-aware Topology

<CODE BEGINS> file "ietf-optical-impairment-topology.yang"


module ietf-optical-impairment-topology {
  yang-version 1.1;

  namespace "urn:ietf:params:xml"
          + ":ns:yang:ietf-optical-impairment-topology";

  prefix "optical-imp-topo";

  import ietf-network {
    prefix "nw";
    reference
      "RFC 8345: A YANG Data Model for Network Topologies";
  }

  import ietf-network-topology {
    prefix "nt";
    reference
      "RFC 8345: A YANG Data Model for Network Topologies";
  }

  import ietf-te-topology {
    prefix "tet";
    reference
      "RFC 8795: YANG Data Model for Traffic Engineering (TE)
      Topologies";
  }

  import ietf-te-types {
    prefix "te-types";
    reference
      "RFC YYYY: Updated Common YANG Data Types for Traffic
      Engineering";
  }

  /* Note: The RFC Editor will replace YYYY with the number assigned
     to the RFC once draft-ietf-teas-rfc8776-update becomes an RFC.*/

  import ietf-layer0-types {
    prefix "l0-types";
    reference
      "RFC ZZZZ: A YANG Data Model for Layer 0 Types";
  }

  /* Note: The RFC Editor will replace ZZZZ with the number assigned
     to the RFC once draft-ietf-ccamp-rfc9093-bis becomes an RFC.*/

  organization
    "IETF CCAMP Working Group";

  contact
    "WG Web: <https://datatracker.ietf.org/wg/ccamp/>
     WG List: <mailto:[email protected]>

     Editor:   Young Lee <[email protected]>
     Editor:   Haomian Zheng <[email protected]>
     Editor:   Nicola Sambo <[email protected]>
     Editor:   Victor Lopez <[email protected]>
     Editor:   Gabriele Galimberti <[email protected]>
     Editor:   Giovanni Martinelli <[email protected]>
     Editor:   Jean-Luc Auge <[email protected]>
     Editor:   Le Rouzic Esther <[email protected]>
     Editor:   Julien Meuric <[email protected]>
     Editor:   Italo Busi <[email protected]>
     Editor:   Dieter Beller <[email protected]>
     Editor:   Sergio Belotti <[email protected]>
     Editor:   Griseri Enrico <[email protected]>
     Editor:   Gert Grammel <[email protected]>";

  description
    "This module contains a collection of YANG definitions for
     impairment-aware optical networks.

     Copyright (c) 2023 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.";

// 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 2023-07-07 {
    description
      "Initial Version";
    reference
      "RFC XXXX: A Yang Data Model for Impairment-aware
       Optical Networks";
  }

  /*
   * Identities
   */

  identity otsi-protection {
    base te-types:lsp-protection-type;
    description
      "Individual OTSi(G) protection LSP protection type.";
    reference
      "ITU-T G.873.1 v5.2 (02/2022): Optical transport network:
      Linear protection";
  }

  // groupings

  grouping sliceable-transponder-attributes {
    description
      "Configuration of a sliceable transponder.";
    list sliceable-transponder-list {
      key "carrier-id";
      config false;
      description "List of carriers";
      leaf carrier-id {
        type uint32;
        description "Identifier of the carrier";
      }
    }
  }

  /*
   * Groupings
   */

  grouping amplifier-params {
    description "describes parameters for an amplifier";
    container amplifier {
      description
        "amplifier type, operatonal parameters are described.";
      leaf type-variety {
        type string;
        mandatory true ;
        description
          "String identifier of amplifier type referencing
          a specification in a separate equipment catalog";
      }
      container operational {
        description "amplifier operational parameters";
        list amplifier-element {
          description
            "The list of parallel amplifier elements within an
            amplifier used to amplify different frequency ranges.";
          leaf name {
            type string;
            description
              "The name of the amplifier element as specified in
              the vendor's specification associated with the
              type-variety.";
          }
          container frequency-range {
            description
              "The frequency range amplified by the amplifier
              element.";
            uses l0-types:frequency-range;
          }
          leaf actual-gain {
            type l0-types:gain-in-db-or-null;
            mandatory true ;
            description
              "The value of the gain provided by the amplification
              stage of the optical amplifier.";
          }
          leaf tilt-target {
            type l0-types:decimal-2-digits-or-null;
            units "dB";
            mandatory true ;
            description
              "The tilt target defined between lower and upper
              frequency of the amplifier frequency range.";
          }
          leaf out-voa {
            type l0-types:loss-in-db-or-null;
            mandatory true;
            description
              "Loss introduced by the Variable Optical Attenuator
              (VOA) at the output of the amplification stage of
              the amplifier, if present.";
          }
          leaf in-voa {
            type l0-types:loss-in-db-or-null;
            mandatory true;
            description
              "Loss introduced by the Variable Optical Attenuator
              (VOA) at the input of the amplification stage of the
              amplifier, if present";
          }
          leaf total-output-power {
            type l0-types:power-in-dbm-or-null;
            mandatory true;
            description
              "It represent total output power measured in the range
              specified by the frequency-range.

              Optical power is especially needed to re-compute/check
              consistency of span (fiber+ concentrated loss) loss
              value, with respect to loss/gain information on
              elements.";
          }
          uses power-param;
          leaf raman-direction {
            type enumeration {
              enum co-propagating {
                description
                  "Co-propagating indicates that optical pump light
                  is injected in the same direction to the optical
                  signal that is amplified (forward pump).";
              }
              enum counter-propagating {
                description
                  "Counter-propagating indicates that optical pump
                  light is injected in opposite direction to the
                  optical signal that is amplified (backward pump).";
              }
            }
            description
              "The direction of injection of the raman pump.";
          }
          list raman-pump {
            description
              "The list of pumps for the Raman amplifier.";
            leaf frequency {
              type l0-types:frequency-thz;
              description
                "The raman pump central frequency.";
            }
            leaf power {
              type l0-types:decimal-2-digits-or-null;
              units "Watts";
              description
                "The total pump power considering a depolarized pump
                at the raman pump central frequency.";
            }
          }
        }  // list amplifier-element
      }  // container operational
    }  // container amplifier
  }  // grouping amplifier-params

  grouping fiber-params {
    description
      "String identifier of fiber type referencing a
       specification in a separate equipment catalog";
    container fiber {
      description "fiber characteristics";
      leaf type-variety {
        type string ;
        mandatory true ;
        description "fiber type";
      }
      leaf length {
        type l0-types:decimal-2-digits-or-null;
        units km;
        mandatory true ;
        description "length of fiber";
      }
      leaf loss-coef {
        type l0-types:decimal-2-digits-or-null;
        units dB/km;
        mandatory true ;
        description "loss coefficient of the fiber";
      }
      leaf total-loss {
        type l0-types:loss-in-db-or-null;
        mandatory true ;
        description
          "includes all losses: fiber loss and conn-in and
           conn-out losses";
      }
      leaf pmd {
        type l0-types:decimal-2-digits-or-null;
        units "ps";
        description "pmd of the fiber";
      }
      leaf conn-in{
        type l0-types:loss-in-db-or-null;
        description "connector-in";
      }
      leaf conn-out{
        type l0-types:loss-in-db-or-null;
        description "connector-out";
      }
    }
  }

  grouping roadm-common-path {
    description
      "The optical impairments of a ROADM which are common to all
      its paths (express path, add path or drop path).";
    leaf roadm-pmd {
      type union {
        type decimal64 {
          fraction-digits 8;
          range "0..max";
        }
        type empty;
      }
      units "ps";
      description
        "Polarization Mode Dispersion (PMD), when known, or an
        empty value when unknown.";
    }
    leaf roadm-cd {
      type l0-types:decimal-5-digits-or-null;
      units "ps/nm";
      description "Chromatic Dispersion (CD)";
    }
    leaf roadm-pdl {
      type l0-types:loss-in-db-or-null;
      description "Polarization Dependent Loss (PDL)";
    }
    leaf roadm-inband-crosstalk {
      type l0-types:decimal-2-digits-or-null;
      units "dB";
      description
        "In-band crosstalk, or coherent crosstalk, can occur in
        components that can have multiple same wavelength inputs
        with the inputs either routed to different output ports,
        or all but one blocked";
    }
    leaf roadm-maxloss {
      type l0-types:loss-in-db-or-null;
      description
        "This is the maximum expected path loss from the
        ROADM ingress to the ROADM egress
        assuming no additional path loss is added";
    }
  } // grouping roadm-common-path

  grouping roadm-express-path {
    description
      "The optical impairments of a ROADM express path.";
    uses roadm-common-path;
  } // grouping roadm-express-path

  grouping roadm-add-path {
    description
      "The optical impairments of a ROADM add path.";
    uses roadm-common-path {
      refine roadm-inband-crosstalk {
        description
          "In-band crosstalk, or coherent crosstalk,
          can occur in components that can have multiple same
          wavelength inputs,with the inputs either
          routed to different output ports,
          or all but one blocked.

          In the case of add path it is the total
          of the add block + egress WSS crosstalk contributions.";
      }
      refine roadm-maxloss {
        description
          "This is the maximum expected add path loss from
          the add/drop port input to the ROADM egress,
          assuming no additional add path loss is added.
          This is used to establish the minimum required
          transponder output power required
          to hit the ROADM egress target power
          levels and preventing
          to hit the WSS attenuation limits.
          If the add path contains an internal amplifier
          this loss value should be based
          on worst case expected amplifier gain due to
          ripple or gain uncertainty";
      }
    }
    leaf roadm-pmax {
      type l0-types:power-in-dbm-or-null;
      description
        "This is the maximum (per carrier) power level
        permitted at the add block input ports,
        that can be handled by the ROADM node.
        This may reflect either add amplifier power
        contraints or WSS adjustment limits.
        Higher power transponders would need to have
        their launch power reduced
        to this value or lower";
    }
    leaf roadm-osnr {
      type l0-types:snr-or-null;
      description
        "Optical Signal-to-Noise Ratio (OSNR).
        If the add path contains the ability to adjust the
        carrier power levels into an add path amplifier
        (if present) to a target value,
        this reflects the OSNR contribution of the
        add amplifier assuming this target value is obtained.
        The worst case OSNR based on the input power and
        NF calculation method, and this value, should be used
        (if both are defined).";
    }
    leaf roadm-noise-figure {
      type l0-types:decimal-5-digits-or-null;
      units "dB";
      description
        "Noise Figure. If the add path contains an amplifier,
        this is the noise figure of that amplifier inferred
        to the add port.
        This permits add path OSNR calculation based
        on the input power levels to the add block
        without knowing the ROADM path losses to
        the add amplifier.";
    }
  } // grouping roadm-add-path

  grouping roadm-drop-path {
    description
      "The optical impairments of a ROADM drop path";
    uses roadm-common-path {
      refine roadm-inband-crosstalk {
        description
          "In-band crosstalk, or coherent crosstalk, can occur in
          components that can have multiple same wavelength
          inputs,with the inputs either routed to different
          output ports,or all but one blocked.

          In the case of drop path it is the total
          of the ingress
          to drop e.g. WSS and drop block crosstalk
          contributions.";
      }
      refine roadm-maxloss {
        description
          "The net loss from the ROADM input,to the output
          of the drop block.
          If ROADM ingress to drop path includes an amplifier,
          the amplifier gain reduces the net loss.
          This is before any additional drop path attenuation
          that may be required
          due to drop amplifier power contraints.
          The max value correspond to worst case expected loss,
          including amplifier gain ripple or uncertainty.
          It is the maximum output power of the drop
          amplifier.";
      }
    }
    leaf roadm-minloss {
      type l0-types:loss-in-db-or-null;
      description
        "The net loss from the ROADM input, to the
        output of the drop block.
        If this ROADM ingress to drop path includes
        an amplifier,the amplifier gain reduces the net loss.
        This is before any additional drop path attenuation
        that may be required due to drop amplifier power
        contraints.
        The min value correspond to best case expected loss,
        including amplifier gain ripple or uncertainty.";
    }
    leaf roadm-typloss {
      type l0-types:loss-in-db-or-null;
      description
        "The net loss from the ROADM input,
        to the output of the drop block.
        If this ROADM ingress to drop path
        includes an amplifier,
        the amplifier gain reduces the net loss.
        This is before any additional drop path
        attenuation
        that may be required due to drop amplifier
        power contraints.
        The typ value correspond to typical case
        expected loss.";
    }
    leaf roadm-pmin {
      type l0-types:power-in-dbm-or-null;
      description
        "If the drop path has additional loss
        that is added, for example,
        to hit target power levels into a
        drop path amplifier, or simply, to reduce the
        power of a strong carrier
        (due to ripple,for example),
        then the use of the ROADM input power levels and
        the above drop losses is not appropriate.
        This parameter corresponds to the min per
        carrier power levels
        expected at the output of the drop block.
        A detail example of the comparison using
        these parameters is
        detailed in section xxx of the document yyy.";
    }
    leaf roadm-pmax {
      type l0-types:power-in-dbm-or-null;
      description
        "If the drop path has additional loss that is added,
        for example, to hit target power levels into a
        drop path amplifier,or simply,to reduce the power
        of a strong carrier(due to ripple,for example),
        then the use of the ROADM input power levels and the
        above drop losses is not appropriate.
        This parameter corresponds to the best case per
        carrier power levels expected at the output of the
        drop block.
        A detail example of the comparison using
        these parameters
        is detailed in section xxx of the document yyy";
    }
    leaf roadm-ptyp {
      type l0-types:power-in-dbm-or-null;
      description
        "If the drop path has additional loss that is added,
        for example, to hit target power levels into a
        drop path amplifier,or simply,to reduce the
        power of a strong carrier(due to ripple,for example),
        then the use of the ROADM input power levels and
        the above drop losses is not appropriate.
        This parameter corresponds to the typical case
        per carrier power levels expected
        at the output of the drop block.";
    }
    leaf roadm-osnr {
      type l0-types:snr-or-null;
      description
        "Optical Signal-to-Noise Ratio (OSNR).
        Expected OSNR contribution of the drop path
        amplifier(if present)
        for the case of additional drop path loss
        (before this amplifier)
        in order to hit a target power level (per carrier).
        If both, the OSNR based on the ROADM
        input power level
        (Pcarrier =
        Pref+10Log(carrier-baudrate/ref-baud) + delta-power)
        and the input inferred NF(NF.drop),
        and this OSNR value, are defined,
        the minimum value between these two should be used";
    }
    leaf roadm-noise-figure {
      type l0-types:decimal-5-digits-or-null;
      units "dB";
      description
        "Drop path Noise Figure.
        If the drop path contains an amplifier,
        this is the noise figure
        of that amplifier, inferred to the
        ROADM ingress port.
        This permits to determine
        amplifier OSNR contribution
        without having to specify the
        ROADM node's losses to that amplifier.
        This applies for the case of no
        additional drop path loss,
        before the amplifier, in order to reduce the power
        of the carriers to a target value";
    }
  } // grouping roadm-drop-path

  grouping concentratedloss-params {
    description "concentrated loss";
    container concentratedloss{
      description "concentrated loss";
      leaf loss {
        type l0-types:loss-in-db-or-null;
        mandatory true;
        description
          "Loss introduced by the concentrated loss element.";
      }
    }
  }

  grouping power-param{
    description
      "optical power or PSD after the ROADM or after the out-voa";
    choice power-param {
      description
        "select the mode: channel power or power spectral density";
      case channel-power {
        when "/nw:networks/nw:network/nt:link/tet:te
            /tet:te-link-attributes/OMS-attributes
            /equalization-mode='carrier-power'";
        leaf nominal-carrier-power{
          type l0-types:power-in-dbm-or-null;
          description
            " Reference channel power. Same grouping is used for the
            OMS power after the ROADM (input of the OMS) or after the
            out-voa of each amplifier. ";
        }
      }
      case power-spectral-density{
        when "/nw:networks/nw:network/nt:link/tet:te
            /tet:te-link-attributes/OMS-attributes
            /equalization-mode='power-spectral-density'";
        leaf nominal-power-spectral-density{
          type l0-types:decimal-16-digits-or-null;
          units W/Hz ;
          description
            " Reference power spectral density after
              the ROADM or after the out-voa.
              Typical value : 3.9 E-14, resolution 0.1nW/MHz";
        }
      }
    }
  }

  grouping oms-general-optical-params {
    description "OMS link optical parameters";
    leaf generalized-snr {
      type l0-types:snr;
      description "generalized snr";
    }
    leaf equalization-mode{
      type identityref {
        base l0-types:type-power-mode;
      }
      description
        "The equalization mode.

        When not present it indicates that the information about
        the equalization mode is not reported.

        Reporting this value is needed to support optical
        impairments applications.";
    }
    uses power-param;
  }

  grouping otsi-group {
    description "OTSiG definition , representing client
     digital information stream supported by one or more OTSi";

    list otsi {
      key "otsi-carrier-id";
      config false;
      description
        "list of OTSi contained in one OTSiG.
        The list could also be of only one element";
      leaf otsi-carrier-id {
        type uint16;
        description "OTSi carrier-id";
      }
      leaf otsi-carrier-frequency {
        type union {
          type l0-types:frequency-thz;
          type empty;
        }
        description
          "OTSi carrier frequency, equivalent to the
          actual configured transmitter frequency, when known, or
          an empty value when unknown.";
      }
      leaf-list e2e-mc-path-id {
        type uint16;
        description
          "The list of the possible end-to-end Media Channel
          (e2e-MC) paths associated with the OTSi which have
          different optical impairments.

          This list is meaningful in case the OTSi can be associated
          with multiple end-to-end Media Channel (e2e-MC) paths
          (e.g., when OPS protection is configured).

          The list can be empty when the OTSi has only one
          e2e-MC path.";
      }
    } // OTSi list
  } // OTSiG grouping

  grouping media-channel-groups {
    description "media channel groups";

    container media-channel-groups {
      presence
        "When present, it indicates that the list media channel
        groups is reported.";
      description
        "The top level container for the list of media channel
        groups.";
      list media-channel-group {
        description
          "The list of media channel groups";
        list media-channels {
          // key "flexi-n";
          description
            "list of media channels represented as (n,m)";

          // this grouping add both n.m values
          uses l0-types:flexi-grid-frequency-slot;

          leaf otsi-group-ref {
            type leafref {
              path "/nw:networks/nw:network/otsis/" +
                  "otsi-group/otsi-group-id";
            }
            description
              "Reference to the OTSiG to which the OTSis carried by
              this media channel belong to.";
          }
          list otsi-ref {
            description
              "The list of references to the OTSis and their
              end-to-end Media Channel (e2e-MC) paths within the
              OTSiG carried by this media channel.";
            leaf otsi-carrier-ref {
              type leafref {
                path  "/nw:networks/nw:network/otsis/" +
                      "otsi-group[otsi-group-id=current()" +
                      "/../../otsi-group-ref]/" +
                      "otsi/otsi-carrier-id" ;
              }
              description
                "Reference to the OTSi within the OTSiG carried
                by this media channel.";
            }
            leaf-list e2e-mc-path-ref {
              type leafref {
                path  "/nw:networks/nw:network/otsis/" +
                      "otsi-group[otsi-group-id=current()" +
                      "/../../otsi-group-ref]/" +
                      "otsi[otsi-carrier-id=current()" +
                      "/../otsi-carrier-ref]/e2e-mc-path-id";
              }
              description
                "References to the end-to-end Media Channel (e2e-MC)
                paths of this OTSi which are routed through this
                media channel.";
            }
          }
          leaf delta-power {
            type l0-types:power-in-dbm-or-null;
            description
              " Deviation from the reference carrier power defined
              for the OMS.";
          }
        } // media channels list
      } // media-channel-groups list
    }
  } // media media-channel-groups grouping

  grouping oms-element {
    description "OMS description";
    container OMS-elements {
      presence
        "When present, it indicates that the list of OMS elements
        is reported.";
      description
        "The top level container for the list of OMS elements.";
      list OMS-element {
        key "elt-index";
        description
          "defines the spans and the amplifier blocks of
          the amplified lines";
        leaf elt-index {
          type uint16;
          description
            "ordered list of Index of OMS element
            (whether it's a Fiber, an EDFA or a
            Concentratedloss)";
        }
        leaf oms-element-uid {
          type union {
            type string;
            type empty;
          }
          description
            "Unique id of the element, if it exists and it is known.

            When unknown, an empty value is reported.

            When it does not exist, the attribute is not present.";
        }
        container reverse-element-ref {
          description
            "It contains references to the elements which are
            associated with this element in the reverse
            direction.";
          leaf link-ref {
            type leafref {
              path "../../../../../../../../nt:link/nt:link-id";
            }
            description
              "The reference to the OMS link which the OMS elements
              belongs to.";
          }
          leaf-list oms-element-ref {
            type leafref {
              path "../../../../../../../../nt:link[nt:link-id="
                  + "current()/../link-ref]/tet:te/"
                  + "tet:te-link-attributes/OMS-attributes/"
                  + "OMS-elements/OMS-element/elt-index";
            }
            description
              "The references to the OMS elements.";
          }
        }
        choice element {
          mandatory true;
          description "OMS element type";
          case amplifier {
            uses tet:geolocation-container;
            uses amplifier-params;
          }
          case fiber {
            uses fiber-params;
          }
          case concentratedloss {
            uses concentratedloss-params ;
          }
        }
      }
    }
  }

  grouping otsi-ref {
    description
      "References to an OTSi.

      This grouping is intended to be reused within the
      transceiver's list only.";
    leaf otsi-group-ref {
      type leafref {
        path  "../../../../../../otsis/otsi-group/" +
              "otsi-group-id";
      }
      description
        "The OTSi generated by the transceiver's transmitter.";
    }
    leaf otsi-ref {
      type leafref {
        path  "../../../../../../otsis/otsi-group" +
              "[otsi-group-id=current()/../otsi-group-ref]/otsi/" +
              "otsi-carrier-id";
      }
      description
        "The OTSi generated by the transceiver's transmitter.";
    }
  }

/*
 * Data nodes
 */

  augment "/nw:networks/nw:network/nw:network-types"
        + "/tet:te-topology" {
    description "optical-impairment topology augmented";
    container optical-impairment-topology {
      presence
        "Indicates an impairment-aware topology of optical networks";
      description
        "Container to identify impairment-aware topology type";
      reference
        "RFC8345: A YANG Data Model for Network Topologies.";
   }
  }

  augment "/nw:networks/nw:network" {
    when "nw:network-types/tet:te-topology" +
         "/optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
        topology.";
    }
    description
      "Network augmentation for optical impairments data.";
    container otsis {
      presence
        "When present, it indicates that OTSi information is
        reported.";
      description
        "The information about the OTSis configured on the WDM-TE
        link.";
      list otsi-group {
        key "otsi-group-id";
        config false;
        description
          "the list of possible OTSiG representing client digital
          stream";
        leaf otsi-group-id {
          type string;
          description
            "A network-wide unique identifier of otsi-group element.
            It could be structured e.g., as an URI or as an UUID.";
        }
        uses otsi-group;
      } // list of OTSiG
    }
  }

  augment "/nw:networks/nw:network/nw:node" {
    when "../nw:network-types/tet:te-topology" +
         "/optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment.";
    }
    description
      "Node augmentation for optical impairments data.";
    container transponders {
      presence
        "If present, it indicates that the list of transponders is
        reported.";
      description
        "The top level container for the list of transponders.";
      list transponder {
        key "transponder-id";
        config false;
        description "The list of transponders.";
        leaf transponder-id {
          type uint32;
          description "transponder identifier";
        }
        leaf termination-type-capabilities {
          type enumeration {
            enum tunnel-only {
              description
                "The transponder can only be used in an Optical
                Tunnel termination configuration.";
            }
            enum 3r-only {
              description
                "The transponder can only be used in a 3R
                configuration.";
            }
            enum 3r-or-tunnel {
              description
                "The transponder can be configure to be used either
                in an Optical Tunnel termination configuration or in
                a 3R configuration.";
            }
          }
          description
            "Describes whether the transponder can be used in an
            Optical Tunnel termination configuration or in a 3R
            configuration (or both).";
        }
        leaf supported-3r-mode {
          when '(../termination-type-capabilities = "3r-only") or
                (../termination-type-capabilities = "3r-or-tunnel")'
                {
            description
              "Applies only when the transponder supports 3R
              configuration.";
          }
          type enumeration {
            enum unidir {
              description
                "Unidirectional 3R configuration.";
            }
            enum bidir {
              description
                "Bidirectional 3R configuration.";
            }
          }
          description
            "Describes the supported 3R configuration type.";
        }
        list transceiver {
          key "transceiver-id";
          config false;
          min-elements 1;
          description "list of transceiver related to a transponder";
          leaf transceiver-id {
            type uint32;
            description "transceiver identifier";
          }
          uses l0-types:transceiver-capabilities;
          leaf configured-mode {
            type union {
              type empty;
              type leafref {
                path "../supported-modes/supported-mode/mode-id";
              }
            }
            description
              "Reference to the configured mode for transceiver
              compatibility approach.

              The empty value is used to report that no mode has
              been configured and there is no default mode.

              When not present, the configured-mode is not reported
              by the server.";
          }
          uses l0-types:common-transceiver-configured-param;
          container outgoing-otsi {
            when "../../../../../otsis" {
              description
                "It applies only when the OTSi information is
                reported.";
            }
            description
              "The OTSi generated by the transceiver's transmitter.";
            uses otsi-ref;
          }
          container incoming-otsi {
            when "../../../../../otsis" {
              description
                "It applies only when the OTSi information is
                reported.";
            }
            description
              "The OTSi received by the transceiver's received.";
            uses otsi-ref;
          }
          leaf configured-termination-type {
            type enumeration {
              enum unused-transceiver {
                description
                  "The transcevier is not used.";
              }
              enum tunnel-termination {
                description
                  "The transceiver is currently used in an Optical
                  Tunnel termination configuration.";
              }
              enum 3r-regeneration {
                description
                  "The transceiver is currently used in a 3R
                  configuration.";
              }
            }
            description
              "Describes whether the current configuration of the
              transceiver is used in an Optical Tunnel termination
              configuration or in a 3R configuration.

              If empty, it means that the information about the
              configured-termination-type is not reported.";
          }
        } // end of list of transceiver
      } // end list of transponder
    }
    container regen-groups {
      presence
        "When present, it indicates that the list of 3R groups
        is reported.";
      description
        "The top level container for the list of 3R groups.";
      list regen-group {
        key "group-id";
        config false;
        description
          "The list of 3R groups.

          Any 3R group represent a group of transponder in which an
          a an electrical connectivity is either in place or could
          be dynamically provided, to associated transponders used
          for 3R regeneration.";
        leaf group-id {
          type uint32;
          description
            "Group identifier used an index to access elements in the
            list of 3R groups.";
        }
        leaf regen-metric {
          type uint32;
          description
            "The cost permits choice among different group of
            transponders during path computation";
        }
        leaf-list transponder-ref {
          type leafref {
            path "../../../transponders/transponder/transponder-id";
          }
          description
            "The list of transponder belonging to this 3R group.";
        }
      } // end 3R-group
    }
  }

  augment "/nw:networks/nw:network/nt:link/tet:te"
        + "/tet:te-link-attributes"   {
    when "../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
        topology.";
    }
    description "Optical Link augmentation for impairment data.";
    container OMS-attributes {
      config false;
      description "OMS attributes";
      uses oms-general-optical-params;
      uses media-channel-groups;
      uses oms-element;
    }
  }

  augment "/nw:networks/nw:network/nw:node/tet:te"
        + "/tet:tunnel-termination-point" {
    when "../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Impairment with
         non-sliceable transponder model";
    }
    description
      "Tunnel termination point augmentation for non-sliceable
       transponder model.";

    list ttp-transceiver {
      when "../../../transponders" {
        description
          "It applies only when the list of transponders is
          reported.";
      }
      key "transponder-ref transceiver-ref";
      config false;
      min-elements 1;
      description
        "The list of the transceivers used by the TTP.";
      leaf transponder-ref {
        type leafref {
          path "../../../../transponders/transponder/transponder-id";
        }
        description
          "The reference to the transponder hosting the transceiver
          of the TTP.";
      }
      leaf transceiver-ref {
        type leafref {
          path "../../../../transponders/transponder" +
               "[transponder-id=current()/../transponder-ref]/" +
               "transceiver/transceiver-id";
        }
        description
          "The reference to the transceiver of the TTP.";
      }
    } // list of transceivers
  } // end of augment

  augment "/nw:networks/nw:network/nw:node/tet:te"
        + "/tet:tunnel-termination-point" {
    when "../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for optical impairment
       with sliceable transponder model";
    }
    description
      "Tunnel termination point augmentation for sliceable
      transponder model.";
    uses sliceable-transponder-attributes;
  }

  // Should this leaf be moved to te-topology?
  augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
    when "../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
        topology";
    }
    description
      "Augment LTP";
    leaf protection-type {
      type identityref {
        base te-types:lsp-protection-type;
      }
      description
        "The protection type that this LTP is capable of.

        When not present it indicates that the information about
        the protection type is not reported.";
    }
  }

  augment "/nw:networks/nw:network/nw:node/tet:te"
        + "/tet:te-node-attributes" {
    when "../../../nw:network-types/tet:te-topology"
       + "/optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
        topology";
    }
    description
      "node attributes augmentantion for optical-impairment ROADM
       node";

    list roadm-path-impairments {
      key "roadm-path-impairments-id";
      config false;
      description
        "The set of optical impairments related to a ROADM path.";

      leaf roadm-path-impairments-id {
        type uint32;
        description "index of the ROADM path-impairment list";
      }
      choice impairment-type {
        description "type path impairment";
        case roadm-express-path {
          list roadm-express-path {
            description
              "The list of optical impairments on a ROADM express
              path for different frequency ranges.

              Two elements in the list must not have the same range
              or overlapping ranges.";
            container frequency-range {
              description
                "The frequency range for which these optical
                impairments apply.";
              uses l0-types:frequency-range;
            }
            uses roadm-express-path;
          }
        }
        case roadm-add-path {
          list roadm-add-path {
            description
              "The list of optical impairments on a ROADM add
              path for different frequency ranges.

              Two elements in the list must not have the same range
              or overlapping ranges.";
            container frequency-range {
              description
                "The frequency range for which these optical
                impairments apply.";
              uses l0-types:frequency-range;
            }
            uses roadm-add-path;
          }
        }
        case roadm-drop-path {
          list roadm-drop-path {
            description
              "The list of optical impairments on a ROADM add
              path for different frequency ranges.

              Two elements in the list must not have the same range
              or overlapping ranges.";
            container frequency-range {
              description
                "The frequency range for which these optical
                impairments apply.";
              uses l0-types:frequency-range;
            }
            uses roadm-drop-path;
          }
        }
      }
    } // list path impairments
  } // augmentation for optical-impairment ROADM

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:information-source-entry/tet:connectivity-matrices"{
    when "../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
        topology ";
    }
    description
      "Augment default TE node connectivity matrix information
      source.";

    leaf roadm-path-impairments {
      type leafref {
        path "../../../tet:te-node-attributes/"
           + "roadm-path-impairments/roadm-path-impairments-id";
      }
      config false;
      description
        "Pointer to the list set of ROADM optical impairments";
    }
  } // augmentation connectivity-matrices information-source

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:information-source-entry/tet:connectivity-matrices/"
        + "tet:connectivity-matrix" {
    when "../../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
         topology ";
    }
    description
      "Augment TE node connectivity matrix entry information
      source.";
    leaf roadm-path-impairments {
      type leafref {
        path "../../../../tet:te-node-attributes/"
           + "roadm-path-impairments/roadm-path-impairments-id";
      }
      config false;
      description
        "Pointer to the list set of ROADM optical impairments";
    }
  } // augmentation connectivity-matrix information-source

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:te-node-attributes/tet:connectivity-matrices" {
    when "../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for Optical Impairment
        topology ";
    }
    description
      "Augment default TE node connectivity matrix.";
    leaf roadm-path-impairments {
      type leafref {
        path "../../roadm-path-impairments/"
        + "roadm-path-impairments-id";
      }
      config false; /*the identifier in the list */
       /*"roadm-path-impairments" of ROADM optical impairment*/
                    /*is read-only as the rest of attributes*/
      description "pointer to the list set of ROADM optical
      impairments";
    }
  } // augmentation connectivity-matrices

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:te-node-attributes/"
        + "tet:connectivity-matrices/tet:connectivity-matrix" {
    when "../../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for
        Optical Impairment topology ";
    }
    description
      "Augment TE node connectivity matrix entry.";
    leaf roadm-path-impairments {
      type leafref {
        path "../../../roadm-path-impairments/"
        + "roadm-path-impairments-id";
      }
      config false;
      description "pointer to the list set of ROADM optical
       impairments";
    }
  } // augmentation connectivity-matrix

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:te-node-attributes/tet:connectivity-matrices/"
        + "tet:connectivity-matrix/tet:from" {
    when "../../../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for
        Optical Impairment topology ";
    }
    description
      "Augment the attributes for the 'from' LTP for the TE node
      connectivity matrix entry.";
    list additional-ltp {
      when "derived-from-or-self(../../../../../../"
         + "nt:termination-point"
         + "[nt:tp-id=current()/../../tet:to/tet:tp-ref]/"
         + "optical-imp-topo:protection-type,"
         + "'optical-imp-topo:otsi-protection')" {
        description
          "This list applies only when the 'to' LTP for this
          connectivity matrix entry supports individual OTSi(G)
          protection.";
      }
      key "ltp-ref";
      config false;
      description
        "The restricted list of the potential secondary LTPs that
        can be selected when the 'from' LTP of this connectivity
        matrix entry is selected as a working LTP.

        If this list is empty, all the other LTPs that can reach
        the 'to' LTP of this connectivity matrix entry can be
        selected as secondary LTPs.";
      leaf ltp-ref {
        type leafref {
          path "../../../../../../../nt:termination-point/nt:tp-id";
        }
        description
          "The reference to the potential secondary LTP that can be
          selected when the 'from' LTP of this connectivity matrix
          entry is selected as a working LTP";
      }
      leaf roadm-path-impairments {
        type leafref {
          path "../../../../../../../tet:te/tet:te-node-attributes/"
             + "roadm-path-impairments/roadm-path-impairments-id";
        }
        description
          "Pointer to ROADM optical impairments of the ROADM path
          between this secondary 'from' LTP and the 'to' LTP of
          this connectivity matrix entry.";
      }
    }
  } // augmentation connectivity-matrix from

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:te-node-attributes/tet:connectivity-matrices/"
        + "tet:connectivity-matrix/tet:to" {
    when "../../../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for
        Optical Impairment topology ";
    }
    description
      "Augment the attributes for the 'to' LTP for the TE node
      connectivity matrix entry.";
    list additional-ltp {
      when "derived-from-or-self(../../../../../../"
         + "nt:termination-point"
         + "[nt:tp-id=current()/../../tet:from/tet:tp-ref]/"
         + "optical-imp-topo:protection-type,"
         + "'optical-imp-topo:otsi-protection')" {
        description
          "This list applies only when the 'from' LTP for this
          connectivity matrix entry supports individual OTSi(G)
          protection.";
      }
      key "ltp-ref";
      config false;
      description
        "The restricted list of the potential secondary LTPs that
        can be selected when the 'to' LTP of this connectivity
        matrix entry is selected as a working LTP.

        If this list is empty, all the other LTPs that can be
        reached from the 'from' LTP of this connectivity matrix
        entry can be selected as secondary LTPs.";
      leaf ltp-ref {
        type leafref {
          path "../../../../../../../nt:termination-point/nt:tp-id";
        }
        description
          "The reference to the potential secondary LTP that can be
          selected when the 'to' LTP of this connectivity matrix
          entry is selected as a working LTP";
      }
      leaf roadm-path-impairments {
        type leafref {
          path "../../../../../../../tet:te/tet:te-node-attributes/"
             + "roadm-path-impairments/roadm-path-impairments-id";
        }
        description
          "Pointer to ROADM optical impairments of the ROADM path
          between the 'from' LTP of this connectivity matrix entry
          and this secondary LTP.";
      }
    }
  } // augmentation connectivity-matrix to

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:tunnel-termination-point/"
        + "tet:local-link-connectivities" {
    when "../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
      "This augment is only valid for Optical Impairment topology ";
    }
    description
      "Augment default TTP LLC.";
    leaf add-path-impairments {
      type leafref {
        path "../../../tet:te-node-attributes/"
        + "roadm-path-impairments/roadm-path-impairments-id" ;
      }
      config false;
      description "pointer to the list set of ROADM optical
       impairments";
    }
    leaf drop-path-impairments {
      type leafref {
        path "../../../tet:te-node-attributes/"
        + "roadm-path-impairments/roadm-path-impairments-id" ;
      }
      config false;
      description "pointer to the list set of ROADM
      optical impairments";
    }
  } // augmentation local-link-connectivities

  augment "/nw:networks/nw:network/nw:node/tet:te/"
        + "tet:tunnel-termination-point/"
        + "tet:local-link-connectivities/"
        + "tet:local-link-connectivity" {
    when "../../../../../nw:network-types/tet:te-topology/"
       + "optical-imp-topo:optical-impairment-topology" {
      description
        "This augment is only valid for
         Optical Impairment topology ";
    }
    description
      "Augment TTP LLC entry.";
    leaf add-path-impairments {
      type leafref {
        path "../../../../tet:te-node-attributes/"
        + "roadm-path-impairments/roadm-path-impairments-id" ;
      }
      config false;
      description "pointer to the list set of ROADM optical
       impairments";
    }
    leaf drop-path-impairments {
      type leafref {
        path "../../../../tet:te-node-attributes/"
        + "roadm-path-impairments/roadm-path-impairments-id" ;
      }
      config false;
      description "pointer to the list set of ROADM optical
      impairments";
    }
    list llc-transceiver {
      key "ttp-transponder-ref ttp-transceiver-ref";
      config false;
      description
        "The list of transceivers having a LLC different from the
        default LLC.";
      leaf ttp-transponder-ref {
        type leafref {
          path "../../../../ttp-transceiver/transponder-ref";
        }
        description
          "The reference to the transponder hosting the transceiver
          of this LLCL entry.";
      }
      leaf ttp-transceiver-ref {
        type leafref {
          path "../../../../ttp-transceiver/transceiver-ref";
        }
        description
          "The reference to the the transceiver of this LLCL entry.";
      }
      leaf is-allowed {
        type boolean;
        description
          "'true' - connectivity from this transceiver is allowed;
          'false' - connectivity from this transceiver is
          disallowed.";
      }
      leaf add-path-impairments {
        type leafref {
          path "../../../../../tet:te-node-attributes/"
          + "roadm-path-impairments/roadm-path-impairments-id" ;
        }
        description "pointer to the list set of ROADM optical
        impairments";
      }
      leaf drop-path-impairments {
        type leafref {
          path "../../../../../tet:te-node-attributes/"
          + "roadm-path-impairments/roadm-path-impairments-id" ;
        }
        description "pointer to the list set of ROADM
        optical impairments";
      }
    }
    list additional-ltp {
      when "derived-from-or-self(../../../tet:protection-type,"
         + "'optical-imp-topo:otsi-protection')" {
        description
          "This list applies only to TTPs that support individual
          OTSi(G) protection.";
      }
      key "ltp-ref";
      config false;
      description
        "The restricted list of the potential secondary LTPs that
        can be selected when the LTP associated with this LLCP
        entry is selected as a working LTP.

        If this list is empty, all the other LTPs that can be
        reached by this TTP can be selected as secondary LTPs.";
      leaf ltp-ref {
        type leafref {
          path "../../../../../../nt:termination-point/nt:tp-id";
        }
        description
          "The reference to potential secondary LTP that can be
          selected when the LTP associated with this LLCP entry is
          selected as a working LTP";
      }
      leaf add-path-impairments {
        type leafref {
          path "../../../../../tet:te-node-attributes/"
          + "roadm-path-impairments/roadm-path-impairments-id" ;
        }
        description "pointer to the list set of ROADM optical
        impairments";
      }
      leaf drop-path-impairments {
        type leafref {
          path "../../../../../tet:te-node-attributes/"
          + "roadm-path-impairments/roadm-path-impairments-id" ;
        }
        description "pointer to the list set of ROADM
        optical impairments";
      }
    }
  } // augmentation local-link-connectivity
}


<CODE ENDS>