]> Telefonica

luismiguel.contrerasmurillo@telefonica.com

Nokia

victor.lopez@nokia.com

Huawei

bill.wu@huawei.com

Operations and Management Operations and Management Area Working Group OAM Scheduling Test sequences This document defines a YANG data model for network diagnosis on-demand relying upon Operations, Administration, and Maintenance (OAM) tests. This document defines both 'oam-unitary-test' and 'oam-test-sequence' YANG modules to manage the lifecycle of network diagnosis procedures, primarily intended for use by an SDN controller or network orchestrator, rather than by individual network nodes. About This Document The latest revision of this draft can be found at . Status information for this document may be found at . Discussion of this document takes place on the Operations and Management Area Working Group Working Group mailing list (), which is archived at . Subscribe at . Source for this draft and an issue tracker can be found at .

Introduction Operations, Administration, and Maintenance (OAM) tasks are fundamental functions of the network management (see, e.g., ). Given the emergence of data models and their utilization in Service Provider's network management and the need to automate the overall service management lifecycle , the management of OAM operations becomes also essential. Relevant data models are still missing to cover specific needs. Specifically, OAM functions provide the means to identify and isolate faults, measure and report the network performance (see section 4.2, . For example, defines the three main areas involved in OAM:

• Fault management, which allows network operators quickly identify and isolate faults in the network. Examples of these mechanisms for fault detection and isolation are: continuity check, link trace, and loopback.
• Performance management enables monitoring network performance and diagnosing performance issues (i.e., degradation). Some of the measurements such as frame delay measurement, frame delay variation measurement, and frame loss measurement.
• Security management defines mechanisms to protect OAM communications from unauthorized access and tampering.

presents OAM tools for detecting and isolating failures in networks and for performance monitoring, some examples are:

• Continuity Check: This function verifies that a path exists between two points in a network and that the path is operational.
• Loopback: This function allows a device to loop back a received packet back to the sender for diagnostic purposes. There are multiple technologies for this function, like IP Ping, VCCV Ping, LSP Ping or Ethernet Loopback
• Link Trace: This function allows a network operator to trace a path through a network from one device to another. Some technologies following this approach are Y.1731 Linktrace or IP traceroute.
• Performance Monitoring: This function allows a network operator to monitor the performance of a network and to identify and diagnose performance issues. Protocols like TWAMP, STAMP, Alternative Marking, IOAM (In Situ OAM) , or Y.1731 DMM/SLM can obtain performance measurements.

More recently, Incident Management focuses on the network incident diagnosis, which can be favored by dynamic invocation of OAM tests. , , , and defined YANG models for OAM technologies: o "A YANG Data Model for Connection Oriented OAM": 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 , TRILL OAM, PBB-TE OAM , and T-MPLS OAM. o "A YANG Data Model for Connectionless OAM Protocols": 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). o "A YANG Data Model for Retrieval Methods for the Management of OAM Protocols that Use Connectionless Communications": provides a YANG data model that can be used to retrieve information related to OAM protocols such as BFD (Bidirectional Forwarding Detection), LBM (Loopback Messaging), and VCCV (Virtual Circuit Connectivity Verification). o "A YANG Data Model for Two-Way Active Measurement Protocol (TWAMP)": specifies a YANG data model for client and server implementations of the Two-Way Active Measurement Protocol (TWAMP). These OAM related YANG data models defined parameters required for each of the different tests that are used in network elements today. This work aims to reuse and build upon existing YANG models for OAM technologies, such as those defined in , , and . By leveraging these foundational models, this document specifies a YANG data model for scheduling and coordinating sequences of OAM tests, enabling more advanced and automated network diagnosis procedures. In addition to reusing the device-level OAM YANG models from , , and , this document builds upon the generic scheduling framework defined in . The ietf-schedule module provides reusable groupings and mechanisms for specifying periods of time, recurrence rules, and scheduling status. These constructs are directly imported and used in the OAM unitary test and OAM test sequence models defined in this document, enabling precise scheduling, repetition, and conflict reporting for OAM tasks in a network-wide context. The YANG data model resulting from this document will conform to the Network Management Datastore Architecture (NMDA) .

Terminology and Notations This document assumes that the reader is familiar with the contents of "The YANG 1.1 Data Modeling Language". Following terms are used for the representation of this data model. o OAM unitary test: 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. o OAM test sequence: A set of OAM unitary tests that are run based on a set of time constraints, number of repetitions, order, and reporting outputs. Tree diagrams used in this document follow the notation defined in .

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 , when, and only when, they appear in all capitals, as shown here.

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. Prefixes and Corresponding YANG Modules

Prefix	Yang Module	Reference
oamut	ietf-oam-unitary-tests	RFCXXXX
oamts	ietf-oam-test-sequence	RFCXXXX
yang	ietf-yang-types

• 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.

Network-wide OAM Use Cases This document covers how to use OAM for network-wide use cases. Following, some illustrative examples are presented.

Troubleshooting After the detection of a problem in the network, OAM tests are performed to find the root cause for the detected problem. However, a detected problem can be caused by a variety of factors, such as a misconfiguration, hardware failure, or a software bug. OAM tests can help find the candidate root cause by testing specific components of the network and looking for anomalies or issues. Also, the reliability and efficiency of the tests depend on the nature of the test itself. There are a variety of OAM tests that can be executed as a function of the target scenario. For example, if the issue is related to a Layer 2 capability, specific tests can be designed and run to check the status of the path via Ethernet Linktrace and later run an Ethernet Loopback to a concrete network element. These tests can be coupled with others to test if any filtering is in place by varying, e.g., some Layer 2 fields or checking the configuration of relevant nodes. If these tests are correct, the operator may want to check the availability of the service (or its delivered performance). Even though the troubleshooting process may be different depending on the problem detected, there are certain common procedures or logics that can be executed in order to narrow down the cause of the problem and thus help locate candidate root cause.

Birth Certificate The aim of a birth certificate process is to validate that all relevant parameters are set appropriately in accordance with the target 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 (that is, measured service is matching the expected service) and meets the requirements defined by the operator. The process requires running a set of OAM tasks (e.g., tests) to verify that the service is performing as expected. The set of OAM tests conducted 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, ITU-T Y.1731 Ethernet CFM tests will be executed. Typically, once the birth certificate process has been completed and the OAM tests have been executed, the test results are stored as part of the documentation process performed by the operator. Many of these tasks take place during pre-deployment phases.

Proactive Supervision Some network services require to fulfill strict Service Level Agreements (SLAs). An SLA defines the performance parameters that the service must fulfill in order to meet the requirements of the customer or end user (e.g., IP Connectivity Provisioning Profile (CPP) and Network Slice Service ). As part of service fulfillment and assurance (e.g., Section 2.3.3 of ), proactive verification is undertaken to assess whether SLAs are met and implement appropriate adjustment measures when service distortion is observed. Proactive supervision requires running tests both end-to-end, but also on service components to identify early symptoms and resolve issues before they impact the customer or end user, or to prevent or minimize the impact of the end user. Mitigation action may be enforced to alliviate the impact of networks incidents and nullify the impact on services that are delivered via that network. Proactive testing might 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 (eventually, negotiated and agreed with a customer as part of service assurance).

Performance-based Path Routing Path Computation Elements (PCEs) are used to compute end-to-end paths in a network . PCEs are used for Traffic Engineering (TE) purposes (e.g., 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. In addition to TE Metric Extensions in OSPF or IS-IS , OAM techniques also allow obtaining link metrics like delay and loss which can be used in the PCE algorithms.

Modelling the Scheduling of OAM Tests This document specifies two models: OAM unitary test and OAM test sequence models.

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 . "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. shows the structure of OAM unitary test module:

Tree Structure of OAM Unitary Test

(Note: alignment with will continue with the progress of that document). The 'unitary-test-status' state machine is shown in . 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.

OAM Unitary Test State Machine | planned |----->|configured|----->| ready | | +---------+ +----------+ +---------+ | | | | | V | +-------+ | +----------+ | +-----| error |<--+----------| on-going | | | +-------+ +----------+ | | | | V | | +---------+ +--------+ | +--| finished|<-----| stop |<------------+ +---------+ +--------+ | A | | | +----------------------------------+ ]]>

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 an 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 . "period-of-time" identifies the period values that contain a precise period of time, while "recurrence" identifies theproperties 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. shows the structure of OAM test sequence module:

OAM test sequence

The 'test-sequence-status' state machine is shown in . 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 state when all unitary tests were successful.
• "failure": The state when one or more tests in the sequence got an error.
• "error": The state where an error occurs during the test.

OAM test sequence state machine | planned |----->|configured|----->| ready | | +---------+ +----------+ +---------+ | A A | | | | | | V | | | +-------+ | +----------+ | | ------| error |<--+----------| on-going | | | +-------+ +----------+ | | | | | | | +---------+ +--------+ | | | failure |<-----| stop |<------------+ | +---------+ +--------+ | | | | +---------+ | +-| success |<----------------------------+ +---------+ ]]>

YANG Data Models for Scheduling OAM Tests

YANG Model for Scheduling OAM Unitary Test WG List: Author: Luis Miguel Contreras Murillo Author: Victor Lopez Author: Qin Wu "; 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 "2025-09-15" { 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 } identity basic-test-type { description "Base identity of basic test type."; } identity twamp { base basic-test-type; description "Identity for twamp protocol."; } grouping oam-unitary-test { description "Specifies a grouping for OAM unitary test for network diagnosis procedures."; leaf name { type string; description "Defines the name of the test."; } list ne-config { key ne-id; description "List of node configurations required to enable the unitary tests."; leaf ne-id { type rt-types:router-id; description "A 32-bit number in the dotted-quad format that is used to uniquely identify a node within an autonomous system the ne-id. This identifier is used for both IPv4 and IPv6."; } leaf managed { type boolean; default "true"; description "True if the host can access oam unitary test using the root mount point. This value may not be modifiable in all implementations."; } leaf test-type { type identityref { base basic-test-type; } description "Choose the type of test."; } container root { description "Container for mount point."; yangmnt:mount-point "root" { description "Root for models supported per oam unitary test. This mount point may or may not be inline based on the server implementation. When the associated 'managed' leaf is 'false', any operation that attempts to access information below the root SHALL fail with an error-tag of 'access-denied' and an error-app-tag of 'oamut-not-managed'."; } } } } 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-basic; leaf unitary-test-status { config false; 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."; } } } } ]]>

YANG Model for OAM Test Sequence WG List: Author: Luis Miguel Contreras Murillo Author: Victor Lopez Author: Qin Wu "; description "This module defines the 'oam-test-sequence-test' YANG model for management 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 "2024-11-08" { 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."; } } config false; description "Status of the test sequence execution."; } } } } ]]>

Using Device Mode Within OAM Scheduling Models This section discusses the issues related to 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 desired 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 , which defines a YANG data model for TWAMP, to illustrate how device models could be used.

Operational Considerations

Conflict Resolution and Reporting Among Scheduled OAM Tasks When multiple OAM tasks are scheduled to run concurrently or overlap in time, conflicts may arise due to resource contention or operational constraints. This document leverages the scheduling status groupings defined in the common schedule YANG module (see [RFC XXXX: A Common YANG Data Model for Scheduling]) to detect and report such conflicts. The YANG models defined in this document (both for unitary and sequence tests) uses the unitary-test-status and test-sequence-status grouping to indicate the current scheduling state of each OAM task. If a conflict is detected (e.g., two tests require exclusive access to the same resource at the same time), the unitary-test-status and test-sequence-status leaf will reflect this by reporting a value such as error, reporting the conflict. Operators and management systems SHOULD monitor the scheduling status of OAM tasks and take appropriate action if a conflict is reported. The resolution of conflicts (e.g., rescheduling, prioritization, or cancellation) is implementation-dependent, but MUST be clearly reported via the YANG model status leaves. When a new unitary-test or test-sequence are scheduled, the request MAY be rejected depending on the server's capability to evaluate the scheduling impact and detect conflicts prior to execution.

Coverage of Input Parameters and Output Results The YANG models defined in this document are designed to schedule OAM tests at a network-wide level. The input parameters required to configure and execute specific OAM functions (such as test type, target, and configuration options) are referenced or reused from the existing device-level OAM YANG models (e.g., , , , ). This approach avoids duplication and ensures consistency with established models. Similarly, the output results of OAM tests—such as test status, performance metrics, and diagnostic information—are expected to be reported using the mechanisms and data nodes defined in those foundational YANG modules. The scheduling models in this document provide references to these results and enable their collection and correlation across multiple tests and devices, but do not redefine the detailed input/output parameters of each OAM function. In summary, this document focuses on the scheduling, coordination, and status tracking of OAM tests, while relying on existing YANG models for the detailed specification of test parameters and results.

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 or RESTCONF . The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The NETCONF access control model 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 are also applicable here.

IANA Considerations

Updates to the IETF XML Registry for New YANG Module IANA is requested to register the following URI in the "ns" registry within the "IETF XML Registry" group .

Updates to the YANG Module Names Registry for New YANG Module IANA is requested to register the following YANG module in the "YANG Module Names" registry within the "YANG Parameters" registry group.

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.

References Normative References This document lists architectural and functional requirements for the Operations, Administration, and Maintenance of MPLS Transport Profile. These requirements apply to pseudowires, Label Switched Paths, and Sections. [STANDARDS-TRACK] The One-way Active Measurement Protocol (OWAMP), specified in RFC 4656, provides a common protocol for measuring one-way metrics between network devices. OWAMP can be used bi-directionally to measure one-way metrics in both directions between two network elements. However, it does not accommodate round-trip or two-way measurements. This memo specifies a Two-Way Active Measurement Protocol (TWAMP), based on the OWAMP, that adds two-way or round-trip measurement capabilities. The TWAMP measurement architecture is usually comprised of two hosts with specific roles, and this allows for some protocol simplifications, making it an attractive alternative in some circumstances. [STANDARDS-TRACK] This document presents a base YANG data model for connection-oriented Operations, Administration, and Maintenance (OAM) protocols. It provides a technology-independent abstraction of key OAM constructs for such protocols. The model presented here can be extended to include technology-specific details. This guarantees uniformity in the management of OAM protocols and provides support for nested OAM workflows (i.e., performing OAM functions at different levels through a unified interface). The YANG data model in this document conforms to the Network Management Datastore Architecture. This document presents a base YANG Data model for the management of Operations, Administration, and Maintenance (OAM) protocols that use connectionless communications. The data model is defined using the YANG data modeling language, as specified in RFC 7950. It provides a technology-independent abstraction of key OAM constructs for OAM protocols that use connectionless communication. The base model presented here can be extended to include technology-specific details. There are two key benefits of this approach: First, it leads to uniformity between OAM protocols. Second, it supports both nested OAM workflows (i.e., performing OAM functions at the same level or different levels through a unified interface) as well as interactive OAM workflows (i.e., performing OAM functions at the same level through a unified interface). This document presents a retrieval method YANG data model for connectionless Operations, Administration, and Maintenance (OAM) protocols. It provides technology-independent RPC operations for OAM protocols that use connectionless communication. The retrieval methods model herein presented can be extended to include technology- specific details. There are two key benefits of this approach: First, it leads to uniformity between OAM protocols. Second, it supports both nested OAM workflows (i.e., performing OAM functions at different or the same levels through a unified interface) as well as interactive OAM workflows (i.e., performing OAM functions at the same levels through a unified interface). This document specifies a data model for client and server implementations of the Two-Way Active Measurement Protocol (TWAMP). This document defines the TWAMP data model through Unified Modeling Language (UML) class diagrams and formally specifies it using the YANG data modeling language (RFC 7950). The data model is compliant with the Network Management Datastore Architecture (NMDA). Huawei Huawei Orange Lancaster University This document defines common types and groupings that are meant to be used for scheduling purposes such as event, policy, services, or resources based on date and time. For the sake of better modularity, the YANG module includes a set of recurrence-related groupings with varying levels of representation (i.e., from basic to advanced) to accommodate a variety of requirements. It also defines groupings for validating requested schedules and reporting scheduling status. Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950. YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. In certain networks, such as, but not limited to, financial information networks (e.g., stock market data providers), network performance criteria (e.g., latency) are becoming as critical to data path selection as other metrics and constraints. These metrics are associated with the Service Level Agreement (SLA) between customers and service providers. The link bandwidth utilization (the total bandwidth of a link in actual use for the forwarding) is another important factor to consider during path computation. IGP Traffic Engineering (TE) Metric Extensions describe mechanisms with which network performance information is distributed via OSPF and IS-IS, respectively. The Path Computation Element Communication Protocol (PCEP) provides mechanisms for Path Computation Elements (PCEs) to perform path computations in response to Path Computation Client (PCC) requests. This document describes the extension to PCEP to carry latency, delay variation, packet loss, and link bandwidth utilization as constraints for end-to-end path computation. In certain networks, such as, but not limited to, financial information networks (e.g., stock market data providers), network performance information (e.g., link propagation delay) is becoming critical to data path selection. This document describes common extensions to RFC 3630 "Traffic Engineering (TE) Extensions to OSPF Version 2" and RFC 5329 "Traffic Engineering Extensions to OSPF Version 3" to enable network performance information to be distributed in a scalable fashion. The information distributed using OSPF TE Metric Extensions can then be used to make path selection decisions based on network performance. Note that this document only covers the mechanisms by which network performance information is distributed. The mechanisms for measuring network performance information or using that information, once distributed, are outside the scope of this document. In certain networks, such as, but not limited to, financial information networks (e.g., stock market data providers), network- performance criteria (e.g., latency) are becoming as critical to data-path selection as other metrics. This document describes extensions to IS-IS Traffic Engineering Extensions (RFC 5305) such that network-performance information can be distributed and collected in a scalable fashion. The information distributed using IS-IS TE Metric Extensions can then be used to make path-selection decisions based on network performance. Note that this document only covers the mechanisms with which network-performance information is distributed. The mechanisms for measuring network performance or acting on that information, once distributed, are outside the scope of this document. The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK] This document specifies Version 1.2 of the Transport Layer Security (TLS) protocol. The TLS protocol provides communications security over the Internet. The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery. [STANDARDS-TRACK] The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF protocol access for particular users to a pre-configured subset of all available NETCONF protocol operations and content. This document defines such an access control model. [STANDARDS-TRACK] This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] Informative References Operations, Administration, and Maintenance (OAM) is a general term that refers to a toolset for fault detection and isolation, and for performance measurement. Over the years, various OAM tools have been defined for various layers in the protocol stack. This document summarizes some of the OAM tools defined in the IETF in the context of IP unicast, MPLS, MPLS Transport Profile (MPLS-TP), pseudowires, and Transparent Interconnection of Lots of Links (TRILL). This document focuses on tools for detecting and isolating failures in networks and for performance monitoring. Control and management aspects of OAM are outside the scope of this document. Network repair functions such as Fast Reroute (FRR) and protection switching, which are often triggered by OAM protocols, are also out of the scope of this document. The target audience of this document includes network equipment vendors, network operators, and standards development organizations. This document can be used as an index to some of the main OAM tools defined in the IETF. At the end of the document, a list of the OAM toolsets and a list of the OAM functions are presented as a summary. Data models provide a programmatic approach to represent services and networks. Concretely, they can be used to derive configuration information for network and service components, and state information that will be monitored and tracked. Data models can be used during the service and network management life cycle (e.g., service instantiation, service provisioning, service optimization, service monitoring, service diagnosing, and service assurance). Data models are also instrumental in the automation of network management, and they can provide closed-loop control for adaptive and deterministic service creation, delivery, and maintenance. This document describes a framework for service and network management automation that takes advantage of YANG modeling technologies. This framework is drawn from a network operator perspective irrespective of the origin of a data model; thus, it can accommodate YANG modules that are developed outside the IETF. This document gives an overview of the IETF network management standards and summarizes existing and ongoing development of IETF Standards Track network management protocols and data models. The document refers to other overview documents, where they exist and classifies the standards for easy orientation. The purpose of this document is, on the one hand, to help system developers and users to select appropriate standard management protocols and data models to address relevant management needs. On the other hand, the document can be used as an overview and guideline by other Standard Development Organizations or bodies planning to use IETF management technologies and data models. This document does not cover Operations, Administration, and Maintenance (OAM) technologies on the data-path, e.g., OAM of tunnels, MPLS Transport Profile (MPLS-TP) OAM, and pseudowire as well as the corresponding management models. This document is not an Internet Standards Track specification; it is published for informational purposes. This document describes the format of a set of control messages used in ICMPv6 (Internet Control Message Protocol). ICMPv6 is the Internet Control Message Protocol for Internet Protocol version 6 (IPv6). [STANDARDS-TRACK] This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS-TRACK] This document describes a simple and efficient mechanism that can be used to detect data plane failures in Multi-Protocol Label Switching (MPLS) Label Switched Paths (LSPs). There are two parts to this document: information carried in an MPLS "echo request" and "echo reply" for the purposes of fault detection and isolation, and mechanisms for reliably sending the echo reply. [STANDARDS-TRACK] This document describes the Simple Two-way Active Measurement Protocol (STAMP), which enables the measurement of both one-way and round-trip performance metrics, like delay, delay variation, and packet loss. This document describes the Alternate-Marking technique to perform packet loss, delay, and jitter measurements on live traffic. This technology can be applied in various situations and for different protocols. According to the classification defined in RFC 7799, it could be considered Passive or Hybrid depending on the application. This document obsoletes RFC 8321. In situ Operations, Administration, and Maintenance (IOAM) collects operational and telemetry information in the packet while the packet traverses a path between two points in the network. This document discusses the data fields and associated data types for IOAM. IOAM-Data-Fields can be encapsulated into a variety of protocols, such as Network Service Header (NSH), Segment Routing, Generic Network Virtualization Encapsulation (Geneve), or IPv6. IOAM can be used to complement OAM mechanisms based on, e.g., ICMP or other types of probe packets. CMCC Telefonica Huawei Ciena A network incident refers to an unexpected interruption of a network service, degradation of a network service quality, or sub-health of a network service. Different data sources including alarms, metrics, and other anomaly information can be aggregated into a few of network incidents through data correlation analysis and the service impact analysis. This document defines a YANG Module for the network incident lifecycle management. This YANG module is meant to provide a standard way to report, diagnose, and help resolve network incidents for the sake of network service health and probable cause analysis. The Transport Profile of Multiprotocol Label Switching (MPLS-TP) is a packet-based transport technology based on the MPLS Traffic Engineering (MPLS-TE) and pseudowire (PW) data-plane architectures. This document describes a framework to support a comprehensive set of Operations, Administration, and Maintenance (OAM) procedures that fulfill the MPLS-TP OAM requirements for fault, performance, and protection-switching management and that do not rely on the presence of a control plane. This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunications Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge (PWE3) architectures to support the capabilities and functionalities of a packet transport network as defined by the ITU-T. This document is not an Internet Standards Track specification; it is published for informational purposes. This document specifies a reference framework for Operations, Administration, and Maintenance (OAM) in Transparent Interconnection of Lots of Links (TRILL) networks. The focus of the document is on the fault and performance management aspects of TRILL OAM. This document describes a protocol intended to detect faults in the bidirectional path between two forwarding engines, including interfaces, data link(s), and to the extent possible the forwarding engines themselves, with potentially very low latency. It operates independently of media, data protocols, and routing protocols. [STANDARDS-TRACK] Ciena Old Dog Consulting Swisscom Huawei Huawei Technologies This document sets out some terms that are fundamental to a common understanding of network fault and problem management within the IETF. The purpose of this document is to bring clarity to discussions and other work related to network fault and problem management, in particular to YANG data models and management protocols that report, make visible, or manage network faults and problems. This document describes the Connectivity Provisioning Profile (CPP) and proposes a CPP template to capture IP/MPLS connectivity requirements to be met within a service delivery context (e.g., Voice over IP or IP TV). The CPP defines the set of IP transfer parameters to be supported by the underlying transport network together with a reachability scope and bandwidth/capacity needs. Appropriate performance metrics, such as one-way delay or one-way delay variation, are used to characterize an IP transfer service. Both global and restricted reachability scopes can be captured in the CPP. Such a generic CPP template is meant to (1) facilitate the automation of the service negotiation and activation procedures, thus accelerating service provisioning, (2) set (traffic) objectives of Traffic Engineering functions and service management functions, and (3) improve service and network management systems with 'decision- making' capabilities based upon negotiated/offered CPPs. This document describes network slicing in the context of networks built from IETF technologies. It defines the term "IETF Network Slice" to describe this type of network slice and establishes the general principles of network slicing in the IETF context. The document discusses the general framework for requesting and operating IETF Network Slices, the characteristics of an IETF Network Slice, the necessary system components and interfaces, and the mapping of abstract requests to more specific technologies. The document also discusses related considerations with monitoring and security. This document also provides definitions of related terms to enable consistent usage in other IETF documents that describe or use aspects of IETF Network Slices. This document provides a framework for the operation and management of Layer 3 Virtual Private Networks (L3VPNs). This framework intends to produce a coherent description of the significant technical issues that are important in the design of L3VPN management solutions. The selection of specific approaches, and making choices among information models and protocols are outside the scope of this document. This memo provides information for the Internet community. Constraint-based path computation is a fundamental building block for traffic engineering systems such as Multiprotocol Label Switching (MPLS) and Generalized Multiprotocol Label Switching (GMPLS) networks. Path computation in large, multi-domain, multi-region, or multi-layer networks is complex and may require special computational components and cooperation between the different network domains. This document specifies the architecture for a Path Computation Element (PCE)-based model to address this problem space. This document does not attempt to provide a detailed description of all the architectural components, but rather it describes a set of building blocks for the PCE architecture from which solutions may be constructed. This memo provides information for the Internet community.

Examples This section includes a non-exhaustive list of examples to illustrate the use of the models defined in this document.

Create a TWAMP OAM test defines a YANG model for TWAMP. There is an example for TWAMP. The following example contains the information for the four configurations (Control-Client, Server, Session-Sender and Session-Reflector). An example of a request message body to create a TWAMP OAM test is shown in . Session-Sender and Session-Reflector as expanded for illustrative purposes. The TWAMP Test scheduled in this configuration is a one-hour performance monitoring test that runs daily at 9 AM UTC. This test session is configured to start on October 17, 2023, at 09:00 UTC and recur at the same time every day. The duration of each test run is one hour, as specified by the ISO 8601 format "PT1H", with the test status marked as "scheduled". The test provides insight into network performance by monitoring the selected parameters, allowing for the detection of any potential degradations in service quality over time.

Example of a Message Body to Create a TWAMP OAM test

Acknowledgments TODO acknowledge.