Internet-Draft Scheduling OAM YANG July 2024
Contreras & Lopez Expires 9 January 2025 [Page]
Workgroup:
Operations and Management Area Working Group
Internet-Draft:
draft-contreras-opsawg-scheduling-oam-tests-02
Published:
Intended Status:
Informational
Expires:
Authors:
L. M. Contreras
Telefonica
V. Lopez
Nokia

A YANG Data Model for Network Diagnosis by Scheduling Sequences of OAM Tests

Abstract

This document defines a YANG data model for network diagnosis on-demand using Operations, Administration, and Maintenance (OAM) tests. This document defines both 'oam-unitary-test' and 'oam-test-sequence' data models to enable activation of network diagnosis procedures.

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://vlopezalvarez.github.io/draft-contreras-opsawg-scheduling-oam-tests/draft-contreras-opsawg-scheduling-oam-tests.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-contreras-opsawg-scheduling-oam-tests/.

Discussion of this document takes place on the Operations and Management Area Working Group Working Group mailing list (mailto:opsawg@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/opsawg/. Subscribe at https://www.ietf.org/mailman/listinfo/opsawg/.

Source for this draft and an issue tracker can be found at https://github.com/vlopezalvarez/draft-contreras-opsawg-scheduling-oam-tests.

Status of This Memo

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

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

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

This Internet-Draft will expire on 9 January 2025.

Table of Contents

1. Introduction

Operations, Administration, and Maintenance (OAM) tasks are fundamental functionalities of the network management. Given the emerging of data models and their utilization in Service Provider's management, the management of OAM tests represent also an area of interest for operators, which requires to be defined as a data model. OAM functionalities provide the means to identify and isolate faults, measure and report of performance. [RFC5860] defines the three main areas involved in OAM:

[RFC6428] defines several use cases for OAM tools, including:

More recently, Incident Management [I-D.ietf-nmop-network-incident-yang] also considers the possibility of incident diagnosis, which can be favoured by dynamic invocation of OAM tests.

[RFC8531], [RFC8532] and, [RFC8533] defined YANG models for OAM technologies. On the other hand, [RFC8531] defines a YANG data model for connection-oriented OAM protocols. The main aim of this document is to define a generic YANG data model that can be used to configure, control and monitor connection-oriented OAM protocols such as MPLS-TP OAM, PBB-TE OAM, and G.7713.1 OAM. [RFC8532] provides a generic YANG data model that can be used to configure, control and monitor connectionless OAM protocols such as BFD (Bidirectional Forwarding Detection), LBM (Loopback Messaging) and VCCV (Virtual Circuit Connectivity Verification). [RFC8533] provides a YANG data model that can be used to retrieve information related to OAM protocols such as Bidirectional Forwarding Detection (BFD), Loopback Messaging (LBM) and Virtual Circuit Connectivity Verification (VCCV).

[RFC8913] specifies a YANG data model for client and server implementations of the Two-Way Active Measurement Protocol (TWAMP).

Previous RFCs defined the parameters required for each of the different tests that are used in network elements today. This document covers how to use OAM for network-wide use cases. Following, some illustrative examples are presented.

The YANG data model resulting from this document will conform to the Network Management Datastore Architecture (NMDA) [RFC8342].

1.1. Terminology and Notations

This document assumes that the reader is familiar with the contents of [RFC7950], [RFC8345], [RFC8346] and [RFC8795].

Following terms are used for the representation of this data model.

  • OAM unitary test: it is a set of parameters that define a type of OAM test to be invoked. As an example, it includes the type test, configuration parameters, and target results.

  • OAM test sequence: it is a set of OAM unitary tests that are run based on a set of time constraints, number of repetitions, order, and reporting outputs.

1.2. Requirements Language

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

1.3. Prefix in Data Node Names

In this document, names of data nodes and other data model objects will be prefixed using the standard prefix associated with the corresponding YANG imported modules, as shown in the following table.

Table 1: Prefixes and corresponding YANG modules
Prefix Yang Module Reference
oamut ietf-oam-unitary-tests RFCXXX
oamts ietf-oam-test-sequence RFCXXX
yang ietf-yang-types [RFC6991]

RFC Editor Note: Please replace XXXX with the RFC number assigned to this document if the document becomes a RFC. Please remove this note in that case.

2. Network-wide OAM Use Cases

2.1. Troubleshooting

After the detection of a problem in the network, OAM tests are performed to find the root cause for the detected issue. However, a problem detected can be caused by a variety of factors, such as a misconfiguration, hardware failure, or a software bug. OAM tests can help to find the root cause by testing specific components of the network and looking for anomalies or issues.

There are a variety of different OAM tests that can be executed depending on the nature of the scenario. For example, if the issue is related to a L2 capability, tests can be run to check the status of the path via Ethernet Linktrace and later run an Ethernet Loopback to a concrete network element. If these tests are correct, the operator may want to check the availability of the service or its performance.

Even though the troubleshooting process may be different depending on the problem detected, there are certain common procedures or logic that can be executed in order to narrow down the cause of the problem.

2.2. Birth Certificate

The aim of a birth certificate process is to validate that all relevant parameters are correct for a specific network service. The birth certificate process is done once the configuration of the network elements is completed and they are ready for service.

If the birth certificate is successful, it means that the network service is functioning correctly and meets the requirements defined by the operator. The process requires running a set of OAM tests to verify that the service is performing as expected.

The set of OAM tests done as part of a birth certificate process depends on the network service that is tested. For example, if the service is a virtual private network (VPN) Two-Way Active Measurement Protocol (TWAMP) Light will be used, while if the service is an E-LINE, Ethernet CFM tests will be executed.

Once the birth certificate process has been completed and the OAM tests have been run, the test results are stored as part of the documentation process performed by the operator.

2.3. Proactive Supervision

There are communication services that require to fulfill Service Level Agreements (SLAs). SLAs define performance parameters that the service must fulfill in order to meet the requirements of the customer or end user.

Proactive testing ensures the SLAs are met. Proactive supervision requires running tests on service components to identify and resolve issues before they impact the customer or end user, or to minimize the impact of the end user.

Proactive testing can be done via OAM tests. These tests can be run periodically at regular intervals depending on the specific SLA requirements and the network operator procedures. These procedures may require documenting the test results for future auditing processes with the customers.

2.4. Performance-based Path Routing

Path Computation Elements (PCEs) allow computing end-to-end paths in a network. PCEs are used to facilitate traffic engineering and can be used to optimize network performance, reduce congestion, and improve the overall user experience.

There are different algorithms to calculate a path in the network for some of them the PCE requires traffic engineering information. TE information includes data such as link metrics, bandwidth availability, and routing constraints. By using this information, the PCE can compute the optimal path for a particular service, taking into account its constraints and requirements. OAM techniques allow obtaining link metrics like delay and loss which can be used in the PCE algorithms.

3. Modelling the Scheduling of OAM Tests

This document proposes two models: OAM unitary test and OAM test sequence models.

3.1. OAM Unitary Test

The OAM unitary test model encompasses parameters that define a specific type of OAM test to be performed. The YANG model includes a container named "oam-unitary-tests" that serves as a container for activating OAM unitary tests for network diagnosis procedures. Inside the container, there is a list called "oam-unitary-test" representing a list of specific OAM unitary tests. The list key is defined as "name", which provides a unique name for each test. Each OAM test in the list references a test type with its concrete parameters. The test types are out of the scope of this document. Moreover, each OAM unitary test has two temporal parameters: "period-of-time" and "recurrence". Both are imported from the "ietf-schedule" module from [I-D.ietf-netmod-schedule-yang]. "period-of-time" identifies the period values that contain a precise period of time, while "recurrence" identifies the properties that contain a recurrence rule specification. "unitary-test-status" enumerates the state of the OAM unitary test.

Figure 1 contains the tree of the proposed model. Tree diagrams used in this document follow the notation defined in [RFC8340].

module: ietf-oam-unitary-test
  +--rw oam-unitary-tests
     +--rw oam-unitary-test* [name]
        +--rw name                      string
        +--rw (test-type)
        +--rw period-description?       string
        +--rw period-start              yang:date-and-time
        +--rw time-zone-identifier?     sys:timezone-name
        +--rw (period-type)?
        |  +--:(explicit)
        |  |  +--rw period-end?         yang:date-and-time
        |  +--:(duration)
        |     +--rw duration?           duration
        +--rw recurrence-description?   string
        +--rw frequency                 identityref
        +--rw interval?                 uint32
        +--rw unitary-test-status?      enumeration
Figure 1: OAM unitary test

The 'unitary-test-status' state machine is shown in Figure 2. The state machine includes the following states:

  • "planned": The initial state where the test is planned.

  • "configured": The state where the test is being configured.

  • "ready": The state where the test is ready to be executed.

  • "on-going": The state where the test is currently running.

  • "stop": The state where the test is manually stopped.

  • "error": The state where an error occurs during the test.

  • "finished": The final state where the test is completed.

   +---------+      +----------+      +---------+
+->| planned |----->|configured|----->|  ready  |
|  +---------+      +----------+      +---------+
|      A                 |                |
|      |                 |                V
|      |     +-------+   |          +----------+
|      ------| error |<--+----------| on-going |
|      |     +-------+              +----------+
|      |                                  |
|      V                                  |
|  +---------+      +--------+            |
+--| finished|<-----|  stop  |<------------+
   +---------+      +--------+            |
       A                                  |
       |                                  |
       +----------------------------------+

Figure 2: OAM unitary test state machine

3.2. OAM Test Sequence

The OAM test sequence model consists of a collection of OAM unitary tests that are executed based on specified time constraints, repetitions, ordering, and reporting outputs. These sequences provide a structured approach to running multiple OAM tests in a coordinated manner. Each OAM test sequence references a OAM unitary test type with its concrete parameters. Each OAM test sequence has two temporal parameters: "period-of-time" and "recurrence". Both are imported from the "ietf-schedule" module from [I-D.ietf-netmod-schedule-yang]. "period-of-time" identifies the period values that contain a precise period of time, while "recurrence" identifies the properties that contain a recurrence rule specification. "unitary-test-status" enumerates the state of the OAM test. Finally, "test-sequence-status" shows the state of the OAM test sequence.

An example of the proposed structure Figure 3.

module: ietf-oam-test-sequence
  +--rw oam-test-sequence
     +--rw test-sequence* [name]
        +--rw name                      string
        +--rw test-ref* [name]
        |  +--rw name             string
        |  +--rw (test-type)
        |  +--rw numexecutions?   uint32
        +--rw period-description?       string
        +--rw period-start              yang:date-and-time
        +--rw time-zone-identifier?     sys:timezone-name
        +--rw (period-type)?
        |  +--:(explicit)
        |  |  +--rw period-end?         yang:date-and-time
        |  +--:(duration)
        |     +--rw duration?           duration
        +--rw recurrence-first
        |  +--rw utc-start-time?   yang:date-and-time
        |  +--rw duration?         uint32
        +--rw (recurrence-bound)?
        |  +--:(until)
        |  |  +--rw utc-until?          yang:date-and-time
        |  +--:(count)
        |     +--rw count?              uint32
        +--rw recurrence-description?   string
        +--rw frequency                 identityref
        +--rw interval?                 uint32
        +--rw test-sequence-status?     enumeration

Figure 3: OAM test sequence

The 'test-sequence-status' state machine is shown in Figure 4. The state machine includes the following states:

  • "planned": The initial state where the test is planned.

  • "configured": The state where the test is being configured.

  • "ready": The state where the test is ready to be executed.

  • "on-going": The state where the test is currently running.

  • "stop": The state where the test is manually stopped.

  • "success": The success state when all unitary tests were successful.

  • "failure": The success state when One or more tests in the sequence got an error.

  • "error": The state where an error occurs during the test.

    +---------+      +----------+      +---------+
 +->| planned |----->|configured|----->|  ready  |
 |  +---------+      +----------+      +---------+
 |    A   A                 |              |
 |    |   |                 |              V
 |    |   |     +-------+   |          +----------+
 |    |   ------| error |<--+----------| on-going |
 |    |         +-------+              +----------+
 |    |                                    |
 |    |                                    |
 | +---------+      +--------+             |
 | | failure |<-----|  stop  |<------------+
 | +---------+      +--------+             |
 |                                         |
 | +---------+                             |
 +-| success |<----------------------------+
   +---------+

Figure 4: OAM unitary test state machine

4. YANG Data Models for Scheduling OAM Tests

4.1. YANG Models Overview

This document proposes two models: OAM unitary test and OAM test sequence. OAM unitary test is a set of parameters that define a type of OAM test to be invoked. As an example, it includes the type test, configuration parameters, and target results. The OAM test sequences are a set of OAM unitary tests that are run based on a set of time constraints, number of repetitions, order, and reporting outputs.

4.2. YANG Model for Scheduling OAM Unitary Test

<CODE BEGINS> file ietf-oam-unitary-test@2024-07-05.yang
module ietf-oam-unitary-test {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-oam-unitary-test";
  prefix "oamut";

  // Import OAM models from RFCs RFC8531, RFC8532 and RFC8533

  // reference ietf-netmod-schedule-yang
  import ietf-schedule { prefix "schedule"; }

  organization
    "IETF OPSAWG (Operations and Management Area Working Group)";

  contact
    "WG Web:   <https://datatracker.ietf.org/wg/opsawg/>
     WG List:  <mailto:opsawg@ietf.org>
     Author: Luis Miguel Contreras Murillo
          <luismiguel.contrerasmurillo@telefonica.com>
     Author: Victor Lopez
          <victor.lopez@nokia.com>";
  description
    "This module defines the 'ietf-oam-unitary-test' YANG model for
     activation of network diagnosis procedures.

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

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

     This version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
     for full legal notices.";

  // RFC Ed.: update the date below with the date of RFC
  // publication and remove this note.
  // RFC Ed.: replace XXXX with actual RFC number and remove
  // this note.

  revision "2024-07-05" {
    description
      "Initial version";
    reference
      "RFCXXXX: A YANG Data Model for Network Diagnosis by Scheduling
       Sequences of OAM Tests";
       // Update with the correct RFC number when assigned
  }

  grouping oam-unitary-test {
    description
        "This grouping is defined for OAM unitary test for network
        diagnosis procedures.";

    leaf name {
      type string;
      description
        "Name for the test.";
    }

    choice test-type {
      mandatory true;
      description
        "Choose the type of test.";
        // Import OAM models from RFCs RFC8531, RFC8532 and RFC8533
    }
  }

  container oam-unitary-tests {
    description
      "Container for OAM unitary tests activation for network
      diagnosis procedures.";

    list oam-unitary-test {
      key name;
      description
        "List of OAM unitary tests activation for network diagnosis
        procedures.";

      uses oam-unitary-test;

      uses schedule:period-of-time;

      uses schedule:recurrence;

      leaf unitary-test-status {
        type enumeration {
          enum "planned" {
            description
              "The test is planned.";
          }
          enum "configure" {
            description
              "The test is configured.";
          }
          enum "ready" {
            description
              "The test status is ready.";
          }
          enum "ongoing" {
            description
              "The test is ongoing.";
          }
          enum "stop" {
            description
              "The test is stopped.";
          }
          enum "finish" {
            description
              "The test is finished.";
          }
          enum "error" {
            description
              "The test has an error.";
          }
        }
        description
          "Status of the test.";
      }
    }
  }
}


<CODE ENDS>

4.3. YANG Model for OAM Test Sequence

<CODE BEGINS> file ietf-oam-test-sequence@2024-07-05.yang

module ietf-oam-test-sequence {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-oam-test-sequence";
  prefix "oamts";

  import ietf-oam-unitary-test {
    prefix "oamut";
    // Update the reference with the correct RFC number or other
    // reference when assigned
    // reference "RFCXXXX";
  }

  // reference ietf-netmod-schedule-yang
  import ietf-schedule { prefix "schedule"; }

  organization
    "IETF OPSAWG (Operations and Management Area Working Group)";

  contact
    "WG Web:   <https://datatracker.ietf.org/wg/opsawg/>
     WG List:  <mailto:opsawg@ietf.org>
     Author: Luis Miguel Contreras Murillo
          <luismiguel.contrerasmurillo@telefonica.com>
     Author: Victor Lopez
          <victor.lopez@nokia.com>";
  description
    "This module defines the 'oam-unitary-test' YANG model for
    activation of network diagnosis procedures.

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

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

     This version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
     for full legal notices.";

  // RFC Ed.: update the date below with the date of RFC
  // publication and remove this note.
  // RFC Ed.: replace XXXX with actual RFC number and remove
  // this note.

  revision "2024-07-05" {
    description "Initial version";
    reference "RFCXXXX";
    // Update with the correct RFC number when assigned
  }

  // Data model definition

  container oam-test-sequence {
    description
      "Container for executing a sequence of ietf-oam-unitary-tests
      N times.";

    list test-sequence {
      key "name";
      description "List of test sequences.";

      leaf name {
        type string;
        description "Unique name for the test sequence.";
      }

      list test-ref {
        key "name";
        description "References to the ietf-oam-unitary-tests.";

        uses "oamut:oam-unitary-test";

        leaf numexecutions {
          type uint32;
          default 1;
          description
            "Number of times the test sequence should be
            executed.";
        }
      }

      uses schedule:period-of-time;

      uses schedule:recurrence-utc;

      leaf test-sequence-status {
        type enumeration {
          enum "planned" {
            description
              "The test sequence is planned.";
          }
          enum "configured" {
            description
              "The test sequence is configured.";
          }
          enum "ready" {
            description
              "The test sequence is ready.";
          }
          enum "ongoing" {
            description
              "The test sequence status is ongoing.";
          }
          enum "stop" {
            description
              "The test sequenceis stopped.";
          }
          enum "success" {
            description
              "All tests in the sequence were successful.";
          }
          enum "failure" {
            description
              "One or more tests in the sequence got an error.";
          }
          enum "error" {
            description
              "The test sequence status has an error.";
          }
        }

        description
          "Status of the test sequence execution.";
      }
    }
  }
}


<CODE ENDS>

5. Using Device Mode Within OAM Scheduling Models

This section discusses the problematic of reusing device models already defined in IETF within the context of scheduling OAM tests. There are two main approaches to enable OAM scheduling models: * Importing YANG model into the OAM scheduling models. This approach will copy the device model into the OAM unitary test model to enable the configuration and utilization of the desire OAM test. This approach requires to recreate new YANG models for each new test type or variation of the device models. * Schema-mount allows mounting a data model at a specified location of another (parent) schema. The main difference with importing the YANG modules is that they don't have to be prepared for mounting; any existing modules such as "ietf-twamp" can be mounted without any modifications.

As an exmaple, we will use [RFC8913], which defines a YANG data model for TWAMP, to illustrate how device models could be used.

6. Security Considerations

The YANG module targeted in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC5246].

The NETCONF access control model [RFC6536] 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 a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations.

In which refers to the scheduling of the tests, security considerations in [I-D.ietf-netmod-schedule-yang] are also applicable here.

7. IANA Considerations

TBC

8. Implementation Status

This section will be used to track the status of the implementations of the model. It is aimed at being removed if the document becomes RFC.

9. Normative References

[I-D.ietf-netmod-schedule-yang]
Ma, Q., Wu, Q., Boucadair, M., and D. King, "A Common YANG Data Model for Scheduling", Work in Progress, Internet-Draft, draft-ietf-netmod-schedule-yang-02, , <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-schedule-yang-02>.
[I-D.ietf-nmop-network-incident-yang]
Hu, T., Contreras, L. M., Wu, Q., Davis, N., and C. Feng, "A YANG Data Model for Network Incident Management", Work in Progress, Internet-Draft, draft-ietf-nmop-network-incident-yang-01, , <https://datatracker.ietf.org/doc/html/draft-ietf-nmop-network-incident-yang-01>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC5246]
Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, , <https://www.rfc-editor.org/rfc/rfc5246>.
[RFC5860]
Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed., "Requirements for Operations, Administration, and Maintenance (OAM) in MPLS Transport Networks", RFC 5860, DOI 10.17487/RFC5860, , <https://www.rfc-editor.org/rfc/rfc5860>.
[RFC6241]
Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/rfc/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/rfc/rfc6242>.
[RFC6428]
Allan, D., Ed., Swallow, G., Ed., and J. Drake, Ed., "Proactive Connectivity Verification, Continuity Check, and Remote Defect Indication for the MPLS Transport Profile", RFC 6428, DOI 10.17487/RFC6428, , <https://www.rfc-editor.org/rfc/rfc6428>.
[RFC6536]
Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, , <https://www.rfc-editor.org/rfc/rfc6536>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/rfc/rfc6991>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/rfc/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/rfc/rfc8040>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/rfc/rfc8340>.
[RFC8342]
Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/rfc/rfc8342>.
[RFC8345]
Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, , <https://www.rfc-editor.org/rfc/rfc8345>.
[RFC8346]
Clemm, A., Medved, J., Varga, R., Liu, X., Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model for Layer 3 Topologies", RFC 8346, DOI 10.17487/RFC8346, , <https://www.rfc-editor.org/rfc/rfc8346>.
[RFC8531]
Kumar, D., Wu, Q., and Z. Wang, "Generic YANG Data Model for Connection-Oriented Operations, Administration, and Maintenance (OAM) Protocols", RFC 8531, DOI 10.17487/RFC8531, , <https://www.rfc-editor.org/rfc/rfc8531>.
[RFC8532]
Kumar, D., Wang, Z., Wu, Q., Ed., Rahman, R., and S. Raghavan, "Generic YANG Data Model for the Management of Operations, Administration, and Maintenance (OAM) Protocols That Use Connectionless Communications", RFC 8532, DOI 10.17487/RFC8532, , <https://www.rfc-editor.org/rfc/rfc8532>.
[RFC8533]
Kumar, D., Wang, M., Wu, Q., Ed., Rahman, R., and S. Raghavan, "A YANG Data Model for Retrieval Methods for the Management of Operations, Administration, and Maintenance (OAM) Protocols That Use Connectionless Communications", RFC 8533, DOI 10.17487/RFC8533, , <https://www.rfc-editor.org/rfc/rfc8533>.
[RFC8795]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, , <https://www.rfc-editor.org/rfc/rfc8795>.
[RFC8913]
Civil, R., Morton, A., Rahman, R., Jethanandani, M., and K. Pentikousis, Ed., "Two-Way Active Measurement Protocol (TWAMP) YANG Data Model", RFC 8913, DOI 10.17487/RFC8913, , <https://www.rfc-editor.org/rfc/rfc8913>.

Acknowledgments

TODO acknowledge.

Authors' Addresses

Luis M. Contreras
Telefonica
Victor Lopez
Nokia