



CCAMP Working Group                                              I. Busi
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                                  A. Guo
Expires: 28 November 2026                         Futurewei Technologies
                                                              S. Belotti
                                                                   Nokia
                                                             27 May 2026


    A YANG Data Model for requesting Path Computation in an Optical
                        Transport Network (OTN)
             draft-ietf-ccamp-otn-path-computation-yang-08

Abstract

   This document provides a mechanism to request path computation in an
   Optical Transport Network (OTN) by augmenting the Remote Procedure
   Calls (RPCs) defined in RFC YYYY.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at https://ietf-ccamp-
   wg.github.io/ietf-ccamp-otn-path-computation/draft-ietf-ccamp-otn-
   path-computation-yang.html.  Status information for this document may
   be found at https://datatracker.ietf.org/doc/draft-ietf-ccamp-otn-
   path-computation-yang/.

   Discussion of this document takes place on the Common Control and
   Measurement Plane Working Group mailing list (mailto:ccamp@ietf.org),
   which is archived at https://mailarchive.ietf.org/arch/browse/ccamp/.
   Subscribe at https://www.ietf.org/mailman/listinfo/ccamp/.

   Source for this draft and an issue tracker can be found at
   https://github.com/ietf-ccamp-wg/ietf-ccamp-otn-path-computation.

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/.





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   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 28 November 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Editorial Note (To be removed by RFC Editor)  . . . . . .   3
     1.2.  Terminology and Notations . . . . . . . . . . . . . . . .   3
     1.3.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   4
     1.4.  Prefix in Data Node Names . . . . . . . . . . . . . . . .   4
   2.  YANG Data Model for OTN Path Computation  . . . . . . . . . .   4
     2.1.  YANG Model Overview . . . . . . . . . . . . . . . . . . .   5
     2.2.  Bandwidth Augmentation  . . . . . . . . . . . . . . . . .   5
     2.3.  Label Augmentations . . . . . . . . . . . . . . . . . . .   5
   3.  YANG Model for OTN Path Computation . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Appendix A.  OTN Path Computation Tree Diagram  . . . . . . . . .  15
   Appendix B.  Change Log . . . . . . . . . . . . . . . . . . . . .  19
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  19
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20








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1.  Introduction

   [I-D.ietf-teas-yang-path-computation] describes key use cases, where
   a client needs to request underlying SDN controllers for path
   computation.  In some of these use cases, the underlying SDN
   controller can control an Optical Transport Network (OTN).

   This document defines a YANG data model, which augment the generic
   Path Computation RPC defined in
   [I-D.ietf-teas-yang-path-computation], with OTN technology-specific
   augmentations required to request path computation to an underlying
   OTN SDN controller.  These models allow a client to delegate path
   computation tasks to the underlying SDN controller without having to
   obtain OTN detailed information from the controller and performing
   feasible path computation itself.

1.1.  Editorial Note (To be removed by RFC Editor)

      Note to the RFC Editor: This section is to be removed prior to
      publication.

   This document contains placeholder values that need to be replaced
   with finalized values at the time of publication.  This note
   summarizes all of the substitutions that are needed.

   Please apply the following replacements:

   *  XXXX --> the assigned RFC number for this I-D

   *  YYYY --> the assigned RFC number for
      [I-D.ietf-teas-yang-path-computation]

   *  ZZZZ --> the assigned RFC number for [I-D.ietf-ccamp-layer1-types]

   *  KKKK --> the assigned RFC number for [I-D.ietf-teas-yang-te]

   *  2026-05-19 --> the actual date of the publication of this document

1.2.  Terminology and Notations

   Refer to [I-D.ietf-ccamp-otn-topo-yang] and
   [I-D.ietf-ccamp-layer1-types] for the OTN specific terms used in this
   document.

   The following terms are defined in [RFC7950] and are not redefined
   here:

   *  client



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   *  server

   *  augment

   *  data model

   *  data node

   The following terms are defined in [RFC6241] and are not redefined
   here:

   *  configuration data

   *  state data

   The terminology for describing YANG data models is found in
   [RFC7950].

1.3.  Tree Diagram

   A simplified graphical representation of the data model is used in
   Appendix A of this document.  The meaning of the symbols in these
   diagrams is defined in [RFC8340].

1.4.  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, as shown in Table 1.

           +==========+===========================+===========+
           | Prefix   | YANG module               | Reference |
           +==========+===========================+===========+
           | l1-types | ietf-layer1-types         | [RFCZZZZ] |
           +----------+---------------------------+-----------+
           | te       | ietf-te                   | [RFCKKKK] |
           +----------+---------------------------+-----------+
           | te-pc    | ietf-te-path-computation  | [RFCYYYY] |
           +----------+---------------------------+-----------+
           | otn-pc   | ietf-otn-path-computation | RFCXXXX   |
           +----------+---------------------------+-----------+

             Table 1: Prefixes and corresponding YANG modules

2.  YANG Data Model for OTN Path Computation






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2.1.  YANG Model Overview

   The YANG data model for requesting OTN path computation is defined as
   an augmentation of the generic Path Computation RPC defined in
   [I-D.ietf-teas-yang-path-computation], as shown in Figure 1.

                       +--------------------------+
          TE generic   | ietf-te-path-computation |
                       +--------------------------+
                                    ^
                                    |
                                    | Augments
                                    |
                      +-------------+-------------+
          OTN         | ietf-otn-path-computation |
                      +---------------------------+

     Figure 1: Relationship between OTN and TE path computation models

   The entities and Traffic Engineering (TE) attributes, such as
   requested path and tunnel attributes, defined in
   [I-D.ietf-teas-yang-path-computation], are still applicable when
   requesting OTN path computation and the models defined in this
   document only specifies the additional OTN technology-specific
   attributes/information, using the attributes defined in
   [I-D.ietf-ccamp-layer1-types].

2.2.  Bandwidth Augmentation

   The OTN path computation model augments all the occurrences of the
   te-bandwidth container with the OTN technology-specific attributes
   using the otn-link-bandwidth and otn-path-bandwidth groupings defined
   in [I-D.ietf-ccamp-layer1-types].

2.3.  Label Augmentations

   The OTN path computation model augments all the occurrences of the
   label-restriction list with OTN technology-specific attributes using
   the otn-label-range-info grouping defined in
   [I-D.ietf-ccamp-layer1-types].

   Moreover, the model augments all the occurrences of the te-label
   container with the OTN technology-specific attributes using the otn-
   label-start-end, otn-label-hop and otn-label-step groupings defined
   in [I-D.ietf-ccamp-layer1-types].

3.  YANG Model for OTN Path Computation




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   <CODE BEGINS> file "ietf-otn-path-computation@2026-05-19.yang"
   module ietf-otn-path-computation {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-otn-path-computation";
     prefix otn-pc;

     import ietf-te-path-computation {
       prefix te-pc;
       reference
         "RFC YYYY: A YANG Data Model for requesting path computation";
     }
     import ietf-te {
       prefix te;
       reference
         "RFC KKKK: A YANG Data Model for Traffic Engineering Tunnels,
                    Label Switched Paths, and Interfaces";
     }
     import ietf-layer1-types {
       prefix l1-types;
       reference
         "RFC ZZZZ: Common YANG Data Types for Layer 1 Networks";
     }

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

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

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

        Editor:   Sergio Belotti
                  <mailto:sergio.belotti@nokia.com>";
     description
       "This module defines a model for requesting
        OTN Path Computation.

        Copyright (c) 2026 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



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        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        All revisions of IETF and IANA published modules can be found
        at the YANG Parameters registry group
        (https://www.iana.org/assignments/yang-parameters).

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

     revision 2026-05-19 {
       description
         "Initial version.";
       reference
         "RFC XXXX: A YANG Data Model for requesting Path Computation
                    in an Optical Transport Network (OTN)";
     }

     /*
      * Data nodes
      */
     /*
      * Augment TE bandwidth
      */

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:te-bandwidth/te-pc:technology" {
       description
         "Augment TE bandwidth of the requested path.";
       case otn {
         uses l1-types:otn-path-bandwidth;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:tunnel-attributes/te-pc:te-bandwidth/"
           + "te-pc:technology" {
       description
         "Augment TE bandwidth of the requested tunnel attributes.";
       case otn {
         uses l1-types:otn-path-bandwidth;
       }
     }

     augment "/te:tunnels-path-compute/te:output/"
           + "te:path-compute-result/te-pc:response/"
           + "te-pc:computed-paths-properties/"
           + "te-pc:computed-path-properties/te-pc:path-properties/"



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           + "te-pc:te-bandwidth/te-pc:technology" {
       description
         "Augment TE bandwidth of the computed path properties.";
       case otn {
         uses l1-types:otn-path-bandwidth;
       }
     }

     /*
      * Augment TE label range information
      */

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-in-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction" {
       description
         "Augment TE label range information for the ingress segment
          of the requested path.";
       uses l1-types:otn-label-range-info;
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-out-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction" {
       description
         "Augment TE label range information for the egress segment
          of the requested path.";
       uses l1-types:otn-label-range-info;
     }

     /*
      * Augment TE label.
      */

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:optimizations/te-pc:algorithm/"
           + "te-pc:metric/te-pc:optimization-metric/"
           + "te-pc:explicit-route-exclude-objects/"
           + "te-pc:route-object-exclude-object/te-pc:type/"
           + "te-pc:label/te-pc:label-hop/te-pc:te-label/"
           + "te-pc:technology" {
       description
         "Augment TE label hop for the optimization of the explicit
          route objects excluded by the path computation of the
          requested path.";
       case otn {
         uses l1-types:otn-label-hop;
       }



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     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:optimizations/te-pc:algorithm/"
           + "te-pc:metric/te-pc:optimization-metric/"
           + "te-pc:explicit-route-include-objects/"
           + "te-pc:route-object-include-object/te-pc:type/"
           + "te-pc:label/te-pc:label-hop/te-pc:te-label/"
           + "te-pc:technology" {
       description
         "Augment TE label hop for the optimization of the explicit
          route objects included by the path computation of the
          requested path.";
       case otn {
         uses l1-types:otn-label-hop;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:explicit-route-objects/"
           + "te-pc:route-object-exclude-always/"
           + "te-pc:type/te-pc:label/te-pc:label-hop/te-pc:te-label/"
           + "te-pc:technology" {
       description
         "Augment TE label hop for the explicit route objects always
          excluded by the path computation of the requested path.";
       case otn {
         uses l1-types:otn-label-hop;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:explicit-route-objects/"
           + "te-pc:route-object-include-exclude/te-pc:type/"
           + "te-pc:label/te-pc:label-hop/te-pc:te-label/"
           + "te-pc:technology" {
       description
         "Augment TE label hop for the explicit route objects included
          or excluded by the path computation of the requested path.";
       case otn {
         uses l1-types:otn-label-hop;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-in-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction/"
           + "te-pc:label-start/te-pc:te-label/te-pc:technology" {



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       description
         "Augment TE label range start for the ingress segment
          of the requested path.";
       case otn {
         uses l1-types:otn-label-start-end;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-in-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction/"
           + "te-pc:label-end/te-pc:te-label/te-pc:technology" {
       description
         "Augment TE label range end for the ingress segment
          of the requested path.";
       case otn {
         uses l1-types:otn-label-start-end;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-in-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction/"
           + "te-pc:label-step/te-pc:technology" {
       description
         "Augment TE label range step for the ingress segment
          of the requested path.";
       case otn {
         uses l1-types:otn-label-step;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-out-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction/"
           + "te-pc:label-start/te-pc:te-label/te-pc:technology" {
       description
         "Augment TE label range start for the egress segment
          of the requested path.";
       case otn {
         uses l1-types:otn-label-start-end;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-out-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction/"
           + "te-pc:label-end/te-pc:te-label/te-pc:technology" {



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       description
         "Augment TE label range end for the egress segment
          of the requested path.";
       case otn {
         uses l1-types:otn-label-start-end;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:path-request/te-pc:path-out-segment/"
           + "te-pc:label-restrictions/te-pc:label-restriction/"
           + "te-pc:label-step/te-pc:technology" {
       description
         "Augment TE label range end for the egress segment
          of the requested path.";
       case otn {
         uses l1-types:otn-label-step;
       }
     }

     augment "/te:tunnels-path-compute/te:input/te:path-compute-info/"
           + "te-pc:synchronization/te-pc:exclude-objects/"
           + "te-pc:excludes/te-pc:type/te-pc:label/te-pc:label-hop/"
           + "te-pc:te-label/te-pc:technology" {
       description
         "Augment TE label hop for the explicit route objects to always
          exclude from synchronized path computation.";
       case otn {
         uses l1-types:otn-label-hop;
       }
     }

     augment "/te:tunnels-path-compute/te:output/"
           + "te:path-compute-result/te-pc:response/"
           + "te-pc:computed-paths-properties/"
           + "te-pc:computed-path-properties/te-pc:path-properties/"
           + "te-pc:path-route-objects/te-pc:path-route-object/"
           + "te-pc:type/te-pc:label/"
           + "te-pc:label-hop/te-pc:te-label/te-pc:technology" {
       description
         "Augment TE label hop for the route object of the computed
          path.";
       case otn {
         uses l1-types:otn-label-hop;
       }
     }
   }
   <CODE ENDS>



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                 Figure 2: OTN path computation YANG module

4.  Security Considerations

   This section is modeled after the template described in Section 3.7
   of [RFC9907].

   The "ietf-otn-path-computation" YANG module defines a data model that
   is designed to be accessed via YANG-based management protocols, such
   as NETCONF [RFC6241] and RESTCONF [RFC8040].  These YANG-based
   management protocols (1) have to use a secure transport layer (e.g.,
   SSH [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and (2) have to use
   mutual authentication.

   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.

   There are no particularly sensitive RPC or action operations.

   This YANG module uses groupings from other YANG modules that define
   nodes that may be considered sensitive or vulnerable in network
   environments.  Refer to the Security Considerations of
   [I-D.ietf-ccamp-layer1-types] for information as to which nodes may
   be considered sensitive or vulnerable in network environments.

   The YANG module defined in this document augments the "tunnels-path-
   compute" and the "tunnel-actions" RPCs, defined in
   [I-D.ietf-teas-yang-te] and in [I-D.ietf-teas-yang-path-computation],
   with OTN technology-specific attributes.  The security considerations
   provided in [I-D.ietf-teas-yang-te] and in
   [I-D.ietf-teas-yang-path-computation] are also applicable to the YANG
   module defined in this document.

5.  IANA Considerations

   IANA is requested to register the following URI in the "ns" registry
   within the "IETF XML Registry" group [RFC3688]:

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

   IANA is requested to register the following YANG module in the "YANG
   Module Names" registry [RFC6020] within the "YANG Parameters"
   registry group.




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     Name:         ietf-otn-path-computation
     Maintained by IANA?  N
     Namespace:    urn:ietf:params:xml:ns:yang:ietf-otn-path-computation
     Prefix:       otn-pc
     Reference:    RFC XXXX

6.  References

6.1.  Normative References

   [I-D.ietf-ccamp-layer1-types]
              Zheng, H. and I. Busi, "Common YANG Data Types for Layer 1
              Networks", Work in Progress, Internet-Draft, draft-ietf-
              ccamp-layer1-types-18, 23 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
              layer1-types-18>.

   [I-D.ietf-teas-yang-path-computation]
              Busi, I., Belotti, S., de Dios, O. G., Sharma, A., and Y.
              Shi, "A YANG Data Model for requesting path computation",
              Work in Progress, Internet-Draft, draft-ietf-teas-yang-
              path-computation-28, 12 May 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              yang-path-computation-28>.

   [I-D.ietf-teas-yang-te]
              Saad, T., Gandhi, R., Liu, X., Beeram, V. P., and I.
              Bryskin, "A YANG Data Model for Traffic Engineering
              Tunnels, Label Switched Paths, and Interfaces", Work in
              Progress, Internet-Draft, draft-ietf-teas-yang-te-44, 26
              March 2026, <https://datatracker.ietf.org/doc/html/draft-
              ietf-teas-yang-te-44>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/rfc/rfc6020>.

   [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/rfc/rfc6241>.

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





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   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/rfc/rfc8340>.

   [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/rfc/rfc8341>.

6.2.  Informative References

   [I-D.draft-gbb-ccamp-optical-path-computation-yang]
              Busi, I., Guo, A., and S. Belotti, "YANG Data Models for
              requesting Path Computation in Optical Networks", Work in
              Progress, Internet-Draft, draft-gbb-ccamp-optical-path-
              computation-yang-02, 12 September 2022,
              <https://datatracker.ietf.org/doc/html/draft-gbb-ccamp-
              optical-path-computation-yang-02>.

   [I-D.ietf-ccamp-otn-topo-yang]
              Zheng, H., Busi, I., Liu, X., Belotti, S., and O. G. de
              Dios, "A YANG Data Model for Optical Transport Network
              Topology", Work in Progress, Internet-Draft, draft-ietf-
              ccamp-otn-topo-yang-20, 7 November 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
              otn-topo-yang-20>.

   [I-D.ietf-teas-actn-poi-applicability]
              Peruzzini, F., Bouquier, J., Busi, I., King, D., and D.
              Ceccarelli, "Applicability of Abstraction and Control of
              Traffic Engineered Networks (ACTN) to Packet Optical
              Integration (POI)", Work in Progress, Internet-Draft,
              draft-ietf-teas-actn-poi-applicability-18, 14 March 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              actn-poi-applicability-18>.

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

   [RFC4252]  Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
              January 2006, <https://www.rfc-editor.org/rfc/rfc4252>.

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




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   [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/rfc/rfc8446>.

   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/rfc/rfc9000>.

   [RFC9907]  Bierman, A., Boucadair, M., Ed., and Q. Wu, "Guidelines
              for Authors and Reviewers of Documents Containing YANG
              Data Models", BCP 216, RFC 9907, DOI 10.17487/RFC9907,
              March 2026, <https://www.rfc-editor.org/rfc/rfc9907>.

Appendix A.  OTN Path Computation Tree Diagram

   Figure 3 below shows the tree diagram of the YANG data model defined
   in module ietf-otn-path-computation.yang.  See [RFC8340] for an
   explanation of the symbols used.  The data type of every leaf node is
   shown near the right end of the corresponding line.

   module: ietf-otn-path-computation

     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:te-bandwidth/te-pc:technology:
       +--:(otn)
          +-- otn-bandwidth
             +-- odu-type?                     identityref
             +-- (oduflex-type)?
                +--:(generic)
                |  +-- nominal-bit-rate        union
                +--:(cbr)
                |  +-- client-type             identityref
                +--:(gfp-n-k)
                |  +-- gfp-n                   uint8
                |  +-- gfp-k?                  gfp-k
                +--:(flexe-client)
                |  +-- flexe-client            flexe-client-rate
                +--:(flexe-aware)
                |  +-- flexe-aware-n           uint16
                +--:(packet)
                   +-- opuflex-payload-rate    union
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:tunnel-attributes/te-pc:te-bandwidth
               /te-pc:technology:
       +--:(otn)
          +-- otn-bandwidth
             +-- odu-type?                     identityref



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             +-- (oduflex-type)?
                +--:(generic)
                |  +-- nominal-bit-rate        union
                +--:(cbr)
                |  +-- client-type             identityref
                +--:(gfp-n-k)
                |  +-- gfp-n                   uint8
                |  +-- gfp-k?                  gfp-k
                +--:(flexe-client)
                |  +-- flexe-client            flexe-client-rate
                +--:(flexe-aware)
                |  +-- flexe-aware-n           uint16
                +--:(packet)
                   +-- opuflex-payload-rate    union
     augment /te:tunnels-path-compute/te:output/te:path-compute-result
               /te-pc:response/te-pc:computed-paths-properties
               /te-pc:computed-path-properties/te-pc:path-properties
               /te-pc:te-bandwidth/te-pc:technology:
       +--:(otn)
          +--ro otn-bandwidth
             +--ro odu-type?                     identityref
             +--ro (oduflex-type)?
                +--:(generic)
                |  +--ro nominal-bit-rate        union
                +--:(cbr)
                |  +--ro client-type             identityref
                +--:(gfp-n-k)
                |  +--ro gfp-n                   uint8
                |  +--ro gfp-k?                  gfp-k
                +--:(flexe-client)
                |  +--ro flexe-client            flexe-client-rate
                +--:(flexe-aware)
                |  +--ro flexe-aware-n           uint16
                +--:(packet)
                   +--ro opuflex-payload-rate    union
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-in-segment
               /te-pc:label-restrictions/te-pc:label-restriction:
       +-- otn-label-range
          +-- range-type?      otn-label-range-type
          +-- tsg?             identityref
          +-- odu-type-list*   identityref
          +-- priority?        uint8
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-out-segment
               /te-pc:label-restrictions/te-pc:label-restriction:
       +-- otn-label-range
          +-- range-type?      otn-label-range-type



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          +-- tsg?             identityref
          +-- odu-type-list*   identityref
          +-- priority?        uint8
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:optimizations/te-pc:algorithm
               /te-pc:metric/te-pc:optimization-metric
               /te-pc:explicit-route-exclude-objects
               /te-pc:route-object-exclude-object/te-pc:type/te-pc:label
               /te-pc:label-hop/te-pc:te-label/te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?       otn-tpn
             +-- tsg?       identityref
             +-- ts-list?   string
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:optimizations/te-pc:algorithm
               /te-pc:metric/te-pc:optimization-metric
               /te-pc:explicit-route-include-objects
               /te-pc:route-object-include-object/te-pc:type/te-pc:label
               /te-pc:label-hop/te-pc:te-label/te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?       otn-tpn
             +-- tsg?       identityref
             +-- ts-list?   string
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:explicit-route-objects
               /te-pc:route-object-exclude-always/te-pc:type/te-pc:label
               /te-pc:label-hop/te-pc:te-label/te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?       otn-tpn
             +-- tsg?       identityref
             +-- ts-list?   string
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:explicit-route-objects
               /te-pc:route-object-include-exclude/te-pc:type
               /te-pc:label/te-pc:label-hop/te-pc:te-label
               /te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?       otn-tpn
             +-- tsg?       identityref
             +-- ts-list?   string
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-in-segment
               /te-pc:label-restrictions/te-pc:label-restriction
               /te-pc:label-start/te-pc:te-label/te-pc:technology:



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       +--:(otn)
          +-- otn-label
             +-- tpn?   otn-tpn
             +-- ts?    otn-ts
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-in-segment
               /te-pc:label-restrictions/te-pc:label-restriction
               /te-pc:label-end/te-pc:te-label/te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?   otn-tpn
             +-- ts?    otn-ts
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-in-segment
               /te-pc:label-restrictions/te-pc:label-restriction
               /te-pc:label-step/te-pc:technology:
       +--:(otn)
          +-- otn-label-step
             +-- tpn?   otn-tpn
             +-- ts?    otn-ts
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-out-segment
               /te-pc:label-restrictions/te-pc:label-restriction
               /te-pc:label-start/te-pc:te-label/te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?   otn-tpn
             +-- ts?    otn-ts
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-out-segment
               /te-pc:label-restrictions/te-pc:label-restriction
               /te-pc:label-end/te-pc:te-label/te-pc:technology:
       +--:(otn)
          +-- otn-label
             +-- tpn?   otn-tpn
             +-- ts?    otn-ts
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:path-request/te-pc:path-out-segment
               /te-pc:label-restrictions/te-pc:label-restriction
               /te-pc:label-step/te-pc:technology:
       +--:(otn)
          +-- otn-label-step
             +-- tpn?   otn-tpn
             +-- ts?    otn-ts
     augment /te:tunnels-path-compute/te:input/te:path-compute-info
               /te-pc:synchronization/te-pc:exclude-objects
               /te-pc:excludes/te-pc:type/te-pc:label/te-pc:label-hop
               /te-pc:te-label/te-pc:technology:



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       +--:(otn)
          +-- otn-label
             +-- tpn?       otn-tpn
             +-- tsg?       identityref
             +-- ts-list?   string
     augment /te:tunnels-path-compute/te:output/te:path-compute-result
               /te-pc:response/te-pc:computed-paths-properties
               /te-pc:computed-path-properties/te-pc:path-properties
               /te-pc:path-route-objects/te-pc:path-route-object
               /te-pc:type/te-pc:label/te-pc:label-hop/te-pc:te-label
               /te-pc:technology:
       +--:(otn)
          +--ro otn-label
             +--ro tpn?       otn-tpn
             +--ro tsg?       identityref
             +--ro ts-list?   string

                Figure 3: OTN path computation tree diagram

Appendix B.  Change Log

   The initial YANG data model requesting path computation in optical
   networks was draft-gbb-ccamp-optical-path-computation-yang-00.  This
   document included path computation request capabilities for WSON,
   Flexi-Grid and OTN technologies.  However, it was proposed at IETF
   113 (March 25, 2022) to split the initial document into separate
   documents for WDM (WSON and Flexi-Grid) and OTN technologies, as each
   technology may be developed and implemented separately.

   The WDM technology capabilities were kept in
   [I-D.draft-gbb-ccamp-optical-path-computation-yang], and the OTN
   capabilities were moved into this document.

   Editors note, please remove this appendix before publication.

Acknowledgments

   The authors of this document would like to thank the authors of
   [I-D.ietf-teas-actn-poi-applicability] for having identified the gap
   and requirements to trigger this work.

   This document was prepared using kramdown.

Contributors

   Daniel King
   Old Dog Consulting
   Email: daniel@olddog.co.uk



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Authors' Addresses

   Italo Busi
   Huawei Technologies
   Email: italo.busi@huawei.com


   Aihua Guo
   Futurewei Technologies
   Email: aihuaguo.ietf@gmail.com


   Sergio Belotti
   Nokia
   Email: sergio.belotti@nokia.com




































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