Network Working Group                                           D. Kumar
Internet-Draft                                                     Cisco
Intended status: Standards Track                                 M. Wang
Expires: May 17, 2018                                         Q. Wu, Ed.
                                                                  Huawei
                                                               R. Rahman
                                                             S. Raghavan
                                                                   Cisco
                                                       November 13, 2017


       Generic YANG Data Model for the Management of Operations,
Administration, and Maintenance (OAM) Protocols that use Connectionless
                             Communications
               draft-ietf-lime-yang-connectionless-oam-18

Abstract

   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, as specified in RFC7950 data modeling language.  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.  And second, it support both nested
   OAM workflows (i.e., performing OAM functions at different or same
   levels through a unified interface) as well as interactive OAM
   workflows (i.e., performing OAM functions at same levels through a
   unified interface).

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."



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   This Internet-Draft will expire on May 17, 2018.

Copyright Notice

   Copyright (c) 2017 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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Overview of the Connectionless OAM Model  . . . . . . . . . .   5
     3.1.  TP Address  . . . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Tools . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.3.  OAM neighboring test points . . . . . . . . . . . . . . .   7
     3.4.  Test Point Locations Information  . . . . . . . . . . . .   8
     3.5.  Test Point Locations  . . . . . . . . . . . . . . . . . .   8
     3.6.  Path Discovery Data . . . . . . . . . . . . . . . . . . .   9
     3.7.  Continuity Check Data . . . . . . . . . . . . . . . . . .   9
     3.8.  OAM data hierarchy  . . . . . . . . . . . . . . . . . . .   9
   4.  LIME Time Types YANG Module . . . . . . . . . . . . . . . . .  12
   5.  Connectionless OAM YANG Module  . . . . . . . . . . . . . . .  14
   6.  Connectionless model applicability  . . . . . . . . . . . . .  43
     6.1.  BFD Extension . . . . . . . . . . . . . . . . . . . . . .  43
       6.1.1.  Augment Method  . . . . . . . . . . . . . . . . . . .  43
       6.1.2.  Schema Mount  . . . . . . . . . . . . . . . . . . . .  46
     6.2.  LSP Ping extension  . . . . . . . . . . . . . . . . . . .  48
       6.2.1.  Augment Method  . . . . . . . . . . . . . . . . . . .  48
       6.2.2.  Schema Mount  . . . . . . . . . . . . . . . . . . . .  49
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  51
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  53
   9.  Acknowlegements . . . . . . . . . . . . . . . . . . . . . . .  53
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  53
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  53
     10.2.  Informative References . . . . . . . . . . . . . . . . .  55
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  57



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1.  Introduction

   Operations, Administration, and Maintenance (OAM) are important
   networking functions that allow operators to:

   1.  Monitor network communications (i.e., Reachability Verification,
       Continuity Check)

   2.  Troubleshoot failures (i.e., Fault verification and Localization)

   3.  Monitor service-level agreements and performance (i.e.,
       Performance Management)

   An overview of OAM tools is presented at [RFC7276].

   Ping and Traceroute (see [RFC792] and [RFC4443]) are respectively
   well-known fault verification and isolation tools for IP network.
   Over the years, different technologies have developed similar
   toolsets for equivalent purposes.

   The different sets of OAM tools may support both connection-oriented
   technologies or connectionless technologies.  In connection-oriented
   technologies, a connection is established prior to the transmission
   of data.  After the connection is established, no additional control
   information such as signaling or operations and maintenance
   information is required to transmit the actual user data.  In
   connectionless technologies, data is typically sent between
   communicating end points without prior arrangement, but control
   information is required to identify the destination (e.g., [G.800]
   and [RFC7276]).  The YANG Data model for OAM protocols using
   connection-oriented communications is specified in
   [I-D.ietf-lime-yang-connection-oriented-oam-model].

   This document defines a base YANG Data model for OAM protocols that
   use connectionless communications.  The data model is defined using
   the YANG [RFC7950] data modeling language.  This generic YANG model
   for connectionless OAM includes only configuration and state data.
   It can be used in conjunction with data retrieval method model
   described in [I-D.ietf-lime-yang-connectionless-oam-methods], which
   focuses on the data retrieval procedures such as RPC, or it can be
   used independently of this data retrieval method model.

2.  Conventions used in this document

   The following terms are defined in [RFC6241] and are used in this
   specification:

   o  client



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   o  configuration data

   o  server

   o  state data

   The following terms are defined in [RFC7950] and are used in this
   specification:

   o  augment

   o  data model

   o  data node

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

2.1.  Abbreviations

   BFD - Bidirectional Forwarding Detection [RFC5880].

   RPC - Remote Procedure Call [RFC1831].

   DSCP - Differentiated Services Code Point.

   VRF - Virtual Routing and Forwarding [RFC 4382].

   OWAMP - One-Way Active Measurement Protocol [RFC 4656].

   TWAMP - Two-Way Active Measurement Protocol [RFC 5357].

   AS - Autonomous System.

   LSP - Label Switched Path.

   TE - Traffic Engineering.

   MPLS - Multiprotocol Label Switching.

   NI - Network Instance.

   PTP - Precision Time Protocol [IEEE.1588].

   NTP - Network Time Protocol [RFC5905].






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2.2.  Terminology

   MAC - Media Access Control.

   MAC address - Address for the data-link layer interface.

   TP - Test Point.  The TP is a functional entity that is defined at a
   node in the network and can initiate and/or react to OAM diagnostic
   tests.  This document focuses on the data-plane functionality of TPs.

   RPC Operation - A specific Remote Procedure Call.

   CC - Continuity Checks [RFC7276] are used to verify that a
   destination is reachable and therefore also referred to as
   reachability verification.

3.  Overview of the Connectionless OAM Model

   The YANG data model for OAM protocols that use Connectionless
   Communications has been split into two modules:

   o  The ietf-lime-common-types.yang module provides common definitions
      such as Time-related data types and Timestamp-related data types.

   o  The ietf-connectionless-oam.yang module defines technology-
      independent abstraction of key OAM constructs for OAM protocols
      that use connectionless communication.

   The ietf-connectionless-oam module augments the "/networks/network/
   node" path defined in the ietf-network module
   [I-D.ietf-i2rs-yang-network-topo] with 'test-point-locations'
   grouping defined in Section 3.5.  The network node in
   "/networks/network/node" path are used to describe the network
   hierarchies and the inventory of nodes contained in a network.

   Under the 'test-point-locations' grouping, each test point location
   is chosen based on 'tp-location-type' leaf which when chosen, leads
   to a container that includes a list of 'test-poit-locations'.

   Each 'test-point-locations' list includes a 'test-point-location-
   info' grouping.  The 'test-point-location-info' grouping includes:

   o  'tp-technology' grouping,

   o  'tp-tools' grouping, and

   o  'connectionless-oam-tps' grouping.




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   The groupings of 'tp-address' and 'tp-address-ni' are kept out of
   'test-point-location-info' grouping to make it addressing agnostic
   and allow varied composition.  Depending upon the choice of the 'tp-
   location-type' (determined by the 'tp-address-ni'), the containers
   differ in its composition of 'test-point-locations' while the 'test-
   point-location-info', is a common aspect of every 'test-point-
   locations'.

   The 'tp-address-ni' grouping is used to describe the corresponding
   network instance.  The 'tp-technology' grouping indicate OAM
   technology details.  The 'connectionless-oam-tps' grouping is used to
   describe the relationship of one test point with other test points.
   The 'tp-tools' grouping describe the OAM tools supported.

   In addition, at the top of the model, there is an 'cc-oper-data'
   container for session statistics.  A grouping is also defined for
   common session statistics and these are only applicable for proactive
   (see Section 3.2) OAM sessions.

3.1.  TP Address

   With connectionless OAM protocols, the TP address can be one of the
   following types:

   o  MAC address [RFC6136] at the data-link layer for TPs

   o  IPv4 or IPv6 address at IP layer for TPs

   o  TP-attribute identifying a TP associated with an application layer
      function

   o  Router-id to represent the device or node, which is commonly used
      to identify nodes in routing and other control plane protocols
      [I-D.ietf-rtgwg-routing-types].

   To define a forwarding treatment of a test packet, the 'tp-address'
   grouping needs to be associated with additional parameters, e.g.,
   DSCP for IP or Traffic Classic [RFC5462] for MPLS.  In the generic
   connectionless OAM YANG model, these parameters are not explicitly
   configured.  The model user can add corresponding parameters
   according to their requirements.

3.2.  Tools

   The different OAM tools may be used in one of two basic types of
   activation: proactive and on-demand.  Proactive OAM refers to OAM
   actions which are carried out continuously to permit proactive
   reporting of faults.  The proactive OAM method requires persistent



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   configuration.  On-demand OAM refers to OAM actions which are
   initiated via manual intervention for a limited time to carry out
   specific diagnostics.  The on-demand OAM method requires only
   transient configuration (e.g., [RFC7276] and [G.8013]).  In
   connectionless OAM, tbe 'session-type' grouping is defined to
   indicate which kind of activation will be used by the current
   session.

   In connectionless OAM, the tools attribute is used to describe a
   toolset for fault detection and isolation.  And it can serve as a
   constraint condition when the base model be extended to a specific
   OAM technology.  For example, to fulfill the ICMP PING configuration,
   the "../coam:continuity-check" leaf should be set to "true", and then
   the lime base model should be augmented with ICMP PING specific
   details.

3.3.  OAM neighboring test points

   Given tbat typical network communication stacks have a multi-layer
   architecture, the set of associated OAM protocols has also a multi-
   layer structure; each communication layer in the stack may have its
   own OAM protocol [RFC7276] that may also be linked to a specific
   administrative domain.  Management of these OAM protocols will
   necessitate associated test points in the nodes accessible by
   appropriate management domains.  Accordingly, a given network
   interface may actually present several test points.

   Each OAM test point may have an associated list of neighboring test
   points in other layers up and down the protocol stack for the same
   interface and are therefore related to the current test point.  This
   allows users to easily navigate between related neighboring layers to
   efficiently troubleshoot a defect.  In this model, the 'position'
   leaf defines the relative position of the neighboring test point
   corresponding to the current test point, and is provided to allow
   correlation of faults at different locations.  If there is one
   neighboring test point placed before the current test point, the
   'position' leaf is set to -1.  If there is one neighboring test point
   placed after the current test point, the 'position' leaf is set to 1.
   If there is no neighboring test point placed before or after the
   current test point, the 'position' leaf is set to 0.











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                list oam-neighboring-tps {
                  key "index";
                  leaf index {
                     type uint16 {
                        range "0..65535";
                     }
                    description
                     "Index of a list of neighboring test points
                      in layers up and down the stack for
                      the same interface that are related to the
                      current test point.";
                  }
                  leaf position {
                      type int8 {
                           range "-1..1";
                      }
                      description
                        "The relative position
                        of neighboring test point
                        corresponding to the current
                        test point";
                  }

                  description
                     "List of related neighboring test points in adjacent
                     layers up and down the stack for the same interface
                     that are related to the current test point.";

              }

3.4.  Test Point Locations Information

   This is a generic grouping for Test Point Locations Information
   (i.e., test-point-location-info grouping).  It Provide details of
   Test Point Location using 'tp-technology','tp-tools' grouping, 'oam-
   neighboring-tps' grouping, all of which are defined above.

3.5.  Test Point Locations

   This is a generic grouping for Test Point Locations.  'tp-location-
   type 'leaf is used to define locations types, for example 'ipv4-
   location-type', 'ipv6-location-type', etc.  Container is defined
   under each location type containing list keyed to test point address,
   Test Point Location Information defined in section above, and network
   instance name (e.g., VRF instance name) if required.






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3.6.  Path Discovery Data

   This is a generic grouping for the path discovery data model that can
   be retrieved by any data retrieval methods including RPC operations.
   Path discovery data output from methods, includes 'src-test-point'
   container, 'dst-test-point' container, 'sequence-number'leaf, 'hop-
   cnt' leaf, session statistics of various kinds, path verification and
   path trace related information.  Path discovery includes data to be
   retrieved on a 'per-hop' basis via a list of 'path-trace-info- list'
   items which includes information such as 'timestamp' grouping,
   'ingress-intf-name', 'egress-intf-name' and 'app-meta-data'.  The
   path discovery data model is made generic enough to allow different
   methods of data retrieval.  None of the fields are made mandatory for
   that reason.  Note that a set of retrieval methods are defined in
   [I-D.ietf-lime-yang-connectionless-oam-methods].

3.7.  Continuity Check Data

   This is a generic grouping for the continuity check data model that
   can be retrieved by any data retrieval methods including RPC
   operations.  Continuity check data output from methods, includes
   'src-test- point' container, 'dst-test-point' container, 'sequence-
   number'leaf, 'hop-cnt' leaf and session statistics of various kinds.
   The continuity check data model is made generic enough to allow
   different methods of data retrieval.  None of the fields are made
   mandatory for that reason.  Noted that a set of retrieval methods are
   defined in [I-D.ietf-lime-yang-connectionless-oam-methods].

3.8.  OAM data hierarchy

   The complete data hierarchy related to the OAM YANG model is
   presented below.

  module: ietf-connectionless-oam
      +--ro cc-session-statistics-data {continuity-check}?
         +--ro cc-session-statistics* [type]
            +--ro type                           identityref
            +--ro cc-ipv4-sessions-statistics
            |  +--ro cc-session-statistics
            |     +--ro session-count?              uint32
            |     +--ro session-up-count?           uint32
            |     +--ro session-down-count?         uint32
            |     +--ro session-admin-down-count?   uint32
            +--ro cc-ipv6-sessions-statistics
               +--ro cc-session-statistics
                  +--ro session-count?              uint32
                  +--ro session-up-count?           uint32
                  +--ro session-down-count?         uint32



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                  +--ro session-admin-down-count?   uint32
    augment /nd:networks/nd:network/nd:node:
      +--rw tp-location-type?                identityref
      +--rw ipv4-location-type
      |  +--rw test-point-ipv4-location-list
      |     +--rw test-point-locations* [ipv4-location ni]
      |        +--rw ipv4-location          inet:ipv4-address
      |        +--rw ni                     routing-instance-ref
      |        +--rw (technology)?
      |        |  +--:(technology-null)
      |        |     +--rw tech-null?             empty
      |        +--rw tp-tools
      |        |  +--rw continuity-check    boolean
      |        |  +--rw path-discovery      boolean
      |        +--rw root?                  <anydata>
      |        +--rw oam-neighboring-tps* [index]
      |           +--rw index                    uint16
      |           +--rw position?                int8
      |           +--rw (tp-location)?
      |              +--:(mac-address)
      |              |  +--rw mac-address-location?    yang:mac-address
      |              +--:(ipv4-address)
      |              |  +--rw ipv4-address-location?   inet:ipv4-address
      |              +--:(ipv6-address)
      |              |  +--rw ipv6-address-location?   inet:ipv6-address
      |              +--:(as-number)
      |              |  +--rw as-number-location?      inet:as-number
      |              +--:(router-id)
      |                 +--rw router-id-location?      rt:router-id
      +--rw ipv6-location-type
      |  +--rw test-point-ipv6-location-list
      |     +--rw test-point-locations* [ipv6-location ni]
      |        +--rw ipv6-location          inet:ipv6-address
      |        +--rw ni                     routing-instance-ref
      |        +--rw (technology)?
      |        |  +--:(technology-null)
      |        |     +--rw tech-null?             empty
      |        +--rw tp-tools
      |        |  +--rw continuity-check    boolean
      |        |  +--rw path-discovery      boolean
      |        +--rw root?                  <anydata>
      |        +--rw oam-neighboring-tps* [index]
      |           +--rw index                    uint16
      |           +--rw position?                int8
      |           +--rw (tp-location)?
      |              +--:(mac-address)
      |              |  +--rw mac-address-location?    yang:mac-address
      |              +--:(ipv4-address)



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      |              |  +--rw ipv4-address-location?   inet:ipv4-address
      |              +--:(ipv6-address)
      |              |  +--rw ipv6-address-location?   inet:ipv6-address
      |              +--:(as-number)
      |              |  +--rw as-number-location?      inet:as-number
      |              +--:(router-id)
      |                 +--rw router-id-location?      rt:router-id
      +--rw mac-location-type
      |  +--rw test-point-mac-address-location-list
      |     +--rw test-point-locations* [mac-address-location]
      |        +--rw mac-address-location    yang:mac-address
      |        +--rw (technology)?
      |        |  +--:(technology-null)
      |        |     +--rw tech-null?              empty
      |        +--rw tp-tools
      |        |  +--rw continuity-check    boolean
      |        |  +--rw path-discovery      boolean
      |        +--rw root?                   <anydata>
      |        +--rw oam-neighboring-tps* [index]
      |           +--rw index                    uint16
      |           +--rw position?                int8
      |           +--rw (tp-location)?
      |              +--:(mac-address)
      |              |  +--rw mac-address-location?    yang:mac-address
      |              +--:(ipv4-address)
      |              |  +--rw ipv4-address-location?   inet:ipv4-address
      |              +--:(ipv6-address)
      |              |  +--rw ipv6-address-location?   inet:ipv6-address
      |              +--:(as-number)
      |              |  +--rw as-number-location?      inet:as-number
      |              +--:(router-id)
      |                 +--rw router-id-location?      rt:router-id
      +--rw group-as-number-location-type
      |  +--rw test-point-as-number-location-list
      |     +--rw test-point-locations* [as-number-location]
      |        +--rw as-number-location     inet:as-number
      |        +--rw ni?                    routing-instance-ref
      |        +--rw (technology)?
      |        |  +--:(technology-null)
      |        |     +--rw tech-null?             empty
      |        +--rw tp-tools
      |        |  +--rw continuity-check    boolean
      |        |  +--rw path-discovery      boolean
      |        +--rw root?                  <anydata>
      |        +--rw oam-neighboring-tps* [index]
      |           +--rw index                    uint16
      |           +--rw position?                int8
      |           +--rw (tp-location)?



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      |              +--:(mac-address)
      |              |  +--rw mac-address-location?    yang:mac-address
      |              +--:(ipv4-address)
      |              |  +--rw ipv4-address-location?   inet:ipv4-address
      |              +--:(ipv6-address)
      |              |  +--rw ipv6-address-location?   inet:ipv6-address
      |              +--:(as-number)
      |              |  +--rw as-number-location?      inet:as-number
      |              +--:(router-id)
      |                 +--rw router-id-location?      rt:router-id
      +--rw group-router-id-location-type
         +--rw test-point-system-info-location-list
            +--rw test-point-locations* [router-id-location]
               +--rw router-id-location     rt:router-id
               +--rw ni?                    routing-instance-ref
               +--rw (technology)?
               |  +--:(technology-null)
               |     +--rw tech-null?             empty
               +--rw tp-tools
               |  +--rw continuity-check    boolean
               |  +--rw path-discovery      boolean
               +--rw root?                  <anydata>
               +--rw oam-neighboring-tps* [index]
                  +--rw index                    uint16
                  +--rw position?                int8
                  +--rw (tp-location)?
                     +--:(mac-address)
                     |  +--rw mac-address-location?    yang:mac-address
                     +--:(ipv4-address)
                     |  +--rw ipv4-address-location?   inet:ipv4-address
                     +--:(ipv6-address)
                     |  +--rw ipv6-address-location?   inet:ipv6-address
                     +--:(as-number)
                     |  +--rw as-number-location?      inet:as-number
                     +--:(router-id)
                        +--rw router-id-location?      rt:router-id

4.  LIME Time Types YANG Module

   <CODE BEGINS> file "ietf-lime-time-types@2017-09-06.yang"

 module ietf-lime-time-types {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-lime-time-types";
     prefix "lime";

     organization
       "IETF Layer Independent OAM Management (LIME)



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        Working Group";

     contact
       "WG Web:   <https://datatracker.ietf.org/wg/lime>
        WG List:  <mailto:lmap@ietf.org>

        Editor:   Qin Wu
                  <bill.wu@huawei.com>";

     description
       "This module provides time related definitions used by the data
        models written for Layer Independent OAM Management (LIME).
        This module defines identities but no schema tree elements.";

     revision "2017-09-06" {
       description
         "Initial version";
       reference
         "RFC xxxx: A YANG Data Model for OAM Protocols that use Connectionless
           Communications";
     }

  /*** Collection of common types related to time ***/
    /*** Time unit identity ***/
  identity time-unit-type {
    description
      "Time unit type";
  }
  identity hours {
    base time-unit-type;
    description
      "Time unit in Hours";
  }
  identity minutes {
    base time-unit-type;
    description
      "Time unit in Minutes";
  }
  identity seconds {
    base time-unit-type;
    description
      "Time unit in Seconds";
  }
  identity milliseconds {
    base time-unit-type;
    description
      "Time unit in Milliseconds";
  }



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  identity microseconds {
    base time-unit-type;
    description
      "Time unit in Microseconds";
  }
  identity nanoseconds {
    base time-unit-type;
    description
      "Time unit in Nanoseconds";
  }
   /*** Timestamp format Identity ***/
 identity timestamp-type {
  description
   "Base identity for Timestamp Type.";
 }
 identity truncated-ptp {
  base timestamp-type;
  description
   "Identity for 64bit short format PTP timestamp.";
 }
 identity truncated-ntp {
  base timestamp-type;
  description
   "Identity for 32bit short format NTP timestamp.";
 }
 identity ntp64 {
  base timestamp-type;
  description
   "Identity for 64bit NTP timestamp.";
 }
 identity icmp {
  base timestamp-type;
  description
   "Identity for 32bit ICMP timestamp.";
 }
}

   <CODE ENDS>

5.  Connectionless OAM YANG Module

   This module imports Core YANG Derived Types definition (i.e.,ietf-
   yang-types.yang module) and Internet-Specific Derived Types
   definitions (ietf-inet-types.yang module) from [RFC6991], ietf-
   routing-types.yang module from [I-D.ietf-rtgwg-routing-types], ietf-
   interfaces.yang module from [RFC7223],ietf-network.yang module from
   [I-D.ietf-i2rs-yang-network-topo],ietf-network-instance.yang module




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   from [I-D.ietf-rtgwg-ni-model] and the ietf-lime-common-types.yang
   module in Section 4.

   <CODE BEGINS> file "ietf-connectionless-oam@2017-09-06.yang"

module ietf-connectionless-oam {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-connectionless-oam";
  prefix cl-oam;
  import ietf-yang-schema-mount {
   prefix yangmnt;
  }
  import ietf-network {
    prefix nd;
  }
  import ietf-yang-types {
    prefix yang;
  }
  import ietf-interfaces {
    prefix if;
  }
  import ietf-inet-types {
    prefix inet;
  }
  import ietf-network-instance {
    prefix ni;
  }
  import ietf-routing-types {
   prefix rt;
  }
  import ietf-lime-time-types {
   prefix lime;
  }
  organization
    "IETF LIME Working Group";
  contact
    "Deepak Kumar dekumar@cisco.com
     Qin Wu bill.wu@huawei.com
     S Raghavan srihari@cisco.com
     Zitao Wang wangzitao@huawei.com
     R Rahman rrahman@cisco.com";
  description
    "This YANG module defines the generic configuration,
     data model, and statistics for OAM protocols using
     connectionless communications, described in a
     protocol independent manner. It is assumed that each
     protocol maps corresponding abstracts to its native
     format. Each protocol mayextend the YANG model defined



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     here to include protocol specific extensions.";
  revision 2017-09-06 {
    description
      "Base model for Connectionless
       Operations, Administration,
       and Maintenance (OAM)";
    reference
      "RFC XXXX: Connectionless
       Operations, Administration, and
       Maintenance (OAM) YANG Data Model";
  }
  feature connectionless {
    description
      "This feature indicates that OAM solution is connectionless.";
  }
  feature continuity-check {
    description
      "This feature indicates that the server supports
       executing continuity check OAM command and
       returning a response. Servers that do not advertise
       this feature will not support executing
       continuity check command or RPC operation model for
       continuity check command.";
  }
  feature path-discovery {
    description
      "This feature indicates that the server supports
       executing path discovery OAM command and
       returning a response. Servers that do not advertise
       this feature will not support executing
       path discovery command or RPC operation model for
       path discovery command.";
  }
  feature ptp-long-format {
    description
      "This feature indicates that timestamp is PTP long format.";
  }
  feature ntp-short-format {
    description
      "This feature indicates that timestamp is NTP short format.";
  }
  feature icmp-timestamp {
    description
      "This feature indicates that timestamp is ICMP timestamp.";
  }
  identity traffic-type {
   description
   "This is base identity of traffic type



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   which include IPv4 and IPv6, etc.";
  }
  identity ipv4 {
  base traffic-type;
  description
   "identity for IPv4 traffic type.";
 }
  identity ipv6 {
  base traffic-type;
   description
   "identity for IPv4 traffic type.";
 }
  identity address-attribute-types {
    description
      "This is base identity of address
       attribute types which are Generic
       IPv4/IPv6 Prefix, BGP Labeled
       IPv4/IPv6 Prefix, Tunnel ID,
       PW ID, VPLS VE ID, etc. (see RFC8029
       for details.)";
  }
  typedef address-attribute-type {
    type identityref {
      base address-attribute-types;
    }
    description
      "Target address attribute type.";
  }
  typedef percentage {
      type decimal64 {
         fraction-digits 5;
         range "0..100";
     }
   description "Percentage.";
   }
  typedef routing-instance-ref {
    type leafref {
      path "/ni:network-instances/ni:network-instance/ni:name";
    }
    description
      "This type is used for leafs that reference a routing instance
       configuration.";
  }
  grouping cc-session-statistics {
    description
      "Grouping for session statistics.";
    container cc-session-statistics {
      description



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        "cc session counters";
      leaf session-count {
        type uint32;
        default "0";
        description
          "Number of Continuity Check sessions.
          A value of zero indicates that no session
          count is sent.";
      }
      leaf session-up-count {
        type uint32;
        default "0";
        description
          "Number of sessions which are up.
          A value of zero indicates that no up
          session count is sent.";
      }
      leaf session-down-count {
        type uint32;
        default "0";
        description
          "Number of sessions which are down.
         A value of zero indicates that no down
         session count is sent.";
      }
      leaf session-admin-down-count {
        type uint32;
       default "0";
        description
          "Number of sessions which are admin-down.
          A value of zero indicates that no admin
          down session count is sent.";
      }
    }
  }
  grouping session-packet-statistics {
    description
      "Grouping for per session packet statistics";
    container session-packet-statistics {
      description
        "Per session packet statistics.";

      leaf rx-packet-count {
        type uint32{
            range "0..4294967295";
        }
        default "0";
        description



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          "Total number of received OAM packet count.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
      leaf tx-packet-count {
        type uint32{
        range "0..4294967295";
        }
       default "0";
        description
          "Total number of transmitted OAM packet count.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
      leaf rx-bad-packet {
        type uint32 {
        range "0..4294967295";
        }
        default "0";
        description
          "Total number of received bad OAM packet.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
      leaf tx-packet-failed {
        type uint32 {
        range "0..4294967295";
        }
        default "0";
        description
          "Total number of failed sending OAM packet.
          The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
    }
  }



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  grouping cc-per-session-statistics {
    description
      "Grouping for per session statistics";
    container cc-per-session-statistics {
      description
        "per session statistics.";

      leaf create-time {
        type yang:date-and-time;
        description
          "Time and date when session is created.";
      }
      leaf last-down-time {
        type yang:date-and-time;
        description
          "Time and date last time session is down.";
      }
      leaf last-up-time {
        type yang:date-and-time;
        description
          "Time and date last time session is up.";
      }
      leaf down-count {
        type uint32 {
        range "0..4294967295";
        }
        default "0";
        description
          "Total Continuity Check sessions down count.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
      leaf admin-down-count {
        type uint32 {
        range "0..4294967295";
        }
        default "0";
        description
          "Total Continuity Check sessions admin down count.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }



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      uses session-packet-statistics;
    }
  }
  grouping session-error-statistics {
    description
      "Grouping for per session error statistics";
    container session-error-statistics {
      description
        "Per session error statistics.";
      leaf packet-loss-count {
        type uint32 {
        range "0..4294967295";
        }
       default "0";
        description
          "Total received packet drops count.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
          leaf loss-ratio{
           type percentage;
                description
                 "Loss ratio of the packets. Express as percentage
                 of packets lost with respect to packets sent.";
                }
      leaf packet-reorder-count {
        type uint32 {
        range "0..4294967295";
        }
        default "0";
        description
          "Total received packet reordered count.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
      leaf packets-out-of-seq-count {
        type uint32 {
        range "0..4294967295";
        }
        description
          "Total received out of sequence count.
           The value of count will be set to zero (0)



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           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero..";
      }
      leaf packets-dup-count {
        type uint32 {
        range "0..4294967295";
        }
        description
          "Total received packet duplicates count.
          The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
    }
  }
  grouping session-delay-statistics {
    description
      "Grouping for per session delay statistics";
    container session-delay-statistics {
      description
        "Session delay summarised information. By default,
         one way measurement protocol (e.g., OWAMP) is used
         to measure delay. When two way measurement protocol
         (e.g., TWAMP) is used instead, it can be indicated
         using and protocol-id defined in RPC operation of
         draft-ietf-lime-yang-connectionless-oam-methods, i.e.,
         set protocol-id as OWAMP. Note that only one measurement
         protocol for delay is specified for interoperability reason.";
      leaf time-unit-value {
        type identityref {
          base lime:time-unit-type;
        }
        default lime:milliseconds;
        description
          "Time units among choice of s, ms, ns, etc.";
      }
      leaf min-delay-value {
        type uint32;
        description
          "Minimum delay value observed.";
      }
      leaf max-delay-value {
        type uint32;
        description



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          "Maximum delay value observed.";
      }
      leaf average-delay-value {
        type uint32;
        description
          "Average delay value observed.";
      }
    }
  }
  grouping session-jitter-statistics {
    description
      "Grouping for per session jitter statistics";
    container session-jitter-statistics {
      description
        "Session jitter summarised information. By default,
         jitter is measured using IP Packet Delay Variation
         (IPDV) as defined in RFC3393. When the other measurement
         method is used instead (e.g., Packet Delay Variation used
         in Y.1540, it can be indicated using protocol-id-meta-data
         defined in RPC operation of
         draft-ietf-lime-yang-connectionless-oam-methods. Note that
         only one measurement method for jitter is specified
         for interoperability reason.";
      leaf unit-value {
        type identityref {
          base lime:time-unit-type;
        }
       default lime:milliseconds;
        description
          "Time units among choice of s, ms, ns, etc.";
      }
      leaf min-jitter-value {
        type uint32;
        description
          "Minimum jitter value observed.";
      }
      leaf max-jitter-value {
        type uint32;
        description
          "Maximum jitter value observed.";
      }
      leaf average-jitter-value {
        type uint32;
        description
          "Average jitter value observed.";
      }
    }
  }



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  grouping session-path-verification-statistics {
    description
      "Grouping for per session path verification statistics";
    container session-path-verification-statistics {
      description
        "OAM per session path verification statistics.";
      leaf verified-count {
        type uint32 {
        range "0..4294967295";
        }
        description
          "Total number of OAM packets that
           went through a path as intended.
           The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
      leaf failed-count {
        type uint32 {
        range "0..4294967295";
        }
        description
          "Total number of OAM packets that
           went through an unintended path.
          The value of count will be set to zero (0)
           on creation and will thereafter increase
           monotonically until it reaches a maximum value
           of 2^32-1 (4294967295 decimal), when it wraps
           around and starts increasing again from zero.";
      }
    }
  }
  grouping session-type {
    description
      "This object indicates which kind
      of activation will be used by the current
      session.";
    leaf session-type {
      type enumeration {
        enum "proactive" {
          description
            "The current session is proactive session.";
        }
        enum "on-demand" {
          description
            "The current session is on-demand session.";



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        }
      }
      default "on-demand";
      description
        "Indicate which kind of activation will be used
         by the current session";
    }
  }
  identity tp-address-technology-type {
    description
      "Test point address type";
  }
  identity mac-address-type {
    base tp-address-technology-type;
    description
      "MAC address type";
  }
  identity ipv4-address-type {
    base tp-address-technology-type;
    description
      "IPv4 address type";
  }
  identity ipv6-address-type {
    base tp-address-technology-type;
    description
      "IPv6 address type";
  }
  identity tp-attribute-type {
    base tp-address-technology-type;
    description

      "Test point attribute type";
  }
  identity router-id-address-type {
    base tp-address-technology-type;
    description
      "System id address type";
  }
  identity as-number-address-type {
    base tp-address-technology-type;
    description
      "AS number address type";
  }
  identity route-distinguisher-address-type {
    base tp-address-technology-type;
    description
      "Route Distinguisher address type";
  }



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  grouping tp-address {
    leaf tp-location-type {
      type identityref {
        base tp-address-technology-type;
      }
      mandatory true;
      description
        "Test point address type.";
    }
      container mac-address {
        when "derived-from-or-self(../tp-location-type,"+
       "'cl-oam:mac-address-type')" {
          description
            "MAC address type";
        }
        leaf mac-address {
          type yang:mac-address;
          mandatory true;
          description
            "MAC Address";
        }
        description
          "MAC Address based TP Addressing.";
      }
      container ipv4-address {
        when "derived-from-or-self(../tp-location-type,"+
        "'cl-oam:ipv4-address-type')" {
          description
            "IPv4 address type";
        }
        leaf ipv4-address {
          type inet:ipv4-address;
          mandatory true;

          description
            "IPv4 Address";
        }
        description
          "IP Address based TP Addressing.";
      }
      container ipv6-address {
        when "derived-from-or-self(../tp-location-type,"+
        "'cl-oam:ipv6-address-type')" {
          description
            "IPv6 address type";
        }
        leaf ipv6-address {




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          type inet:ipv6-address;
          mandatory true;
          description
            "IPv6 Address";
        }
        description
          "ipv6 Address based TP Addressing.";
      }
      container tp-attribute {
        when "derived-from-or-self(../tp-location-type,"+
        "'cl-oam:tp-attribute-type')" {
          description
            "Test point attribute type";
        }
        leaf tp-attribute-type {
          type address-attribute-type;
          description
            "Test point type.";
        }
        choice tp-attribute-value {
          description
            "Test point value.";
          case ip-prefix {
            leaf ip-prefix {
              type inet:ip-prefix;
              description
                "Generic IPv4/IPv6 prefix. See Section 3.2.13 and
                Section 3.2.14 of RFC8029.";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
          }
          case bgp {
            leaf bgp {
              type inet:ip-prefix;
              description
               "BGP Labeled IPv4/IPv6 Prefix. See section
               3.2.11 and section 3.2.12 of RFC8029 for details. ";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
          }
          case tunnel {
            leaf tunnel-interface {
              type uint32;
              description



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               "Basic IPv4/IPv6 Tunnel ID. See section 3.2.3
                and Section 3.2.4 of RFC8029 for details.";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures.";
            }
          }
          case pw {
            leaf remote-pe-address {
              type inet:ip-address;
              description
                "Remote PE address. See section 3.2.8
                of RFC8029 for details.";
                reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
            leaf pw-id {
              type uint32;
              description
                "Pseudowire ID is a non-zero 32-bit ID. See section
                 3.2.8 and Section 3.2.9 for details.";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
          }
          case vpls {
            leaf route-distinguisher {
              type rt:route-distinguisher;
              description
                "Route Distinguisher is an 8 octets identifier
                used to distinguish information about various
                L2VPN advertised by a node.";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
            leaf sender-ve-id {
              type uint16;
              description
                "Sender's VE ID. The VE ID (VPLS Edge Identifier)
                 is a 2-octet identifier.";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
            leaf receiver-ve-id {



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              type uint16;
              description
                "Receiver's VE ID. The VE ID (VPLS Edge Identifier)
                 is a 2-octet identifier.";
              reference
                "RFC 8029 :Detecting Multi-Protocol Label
                Switched (MPLS) Data Plane Failures";
            }
          }
          case mpls-mldp {
            choice root-address {
              description
                "Root address choice.";
              case ip-address {
                leaf source-address {
                  type inet:ip-address;
                  description
                    "IP address.";
                }
                leaf group-ip-address {
                  type inet:ip-address;
                  description
                    "Group ip address.";
                }
              }
              case vpn {
                leaf as-number {
                  type inet:as-number;
                  description
                  "The AS number represents autonomous system
                  numbers which identify an Autonomous System.";
                }
              }
              case global-id {
                leaf lsp-id {
                  type string;
                  description
                    "LSP ID is an identifier of a LSP
                     within a MPLS network.";
                  reference
                  "RFC 8029 :Detecting Multi-Protocol Label
                   Switched (MPLS) Data Plane Failures";
                }
              }
            }
          }
        }
        description



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         "Test Point Attribute Container";
      }
      container system-info {
        when "derived-from-or-self(../tp-location-type,"+
       "'cl-oam:router-id-address-type')" {
          description
            "System id address type";
        }
        leaf router-id {
          type rt:router-id;
          description
            "Router ID assigned to this node.";
        }
        description
           "Router ID container.";
      }
    description
      "TP Address";
  }
  grouping tp-address-ni {
    description
      "Test point address with VRF.";
    leaf ni {
      type routing-instance-ref;
      description
        "The ni is used to describe virtual resource partitioning
        that may be present on a network device. Example of common
        industry terms for virtual resource partitioning is VRF
        instance.";
    }
    uses tp-address;
  }
  grouping connectionless-oam-tps {
    list oam-neighboring-tps {
      key "index";
      leaf index {
        type uint16{
        range "0..65535";
       }
        description
          "Index of a list of neighboring test points
           in layers up and down the stack for
           the same interface that are related to the
           current test point.";
      }
      leaf position {
        type int8 {
          range "-1..1";



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        }
        default "0";
        description
          " The relative position of neighboring test point corresponding
            to the current test point. Level 0 indicates test point corresponding
            to a specific index is in the same layer as the current test point.-1
            means there is test point corresponding to a specific index is the test
            point down the stack and +1 means there is a test point corresponding to
           a specific index is the test point up the stack.";
      }
      choice tp-location {
        case mac-address {
          leaf mac-address-location {
            type yang:mac-address;
            description
              "MAC Address";
          }
          description
            "MAC Address based TP Addressing.";
        }
        case ipv4-address {
          leaf ipv4-address-location {
            type inet:ipv4-address;
            description
              "Ipv4 Address";
          }
          description
            "IP Address based TP Addressing.";
        }
        case ipv6-address {
          leaf ipv6-address-location {
            type inet:ipv6-address;
            description
              "IPv6 Address";
          }
          description
            "IPv6 Address based TP Addressing.";
        }
        case as-number {
          leaf as-number-location {
            type inet:as-number;
            description
              "AS number location";
          }
          description
            "AS number for point to multipoint OAM";
        }
        case router-id {



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          leaf router-id-location {
            type rt:router-id;
            description
              "System id location";
          }

          description
            "System ID";
        }
        description
          "TP location.";
      }
      description
        "List of neighboring test points in the same layer that are related to current test
         point. If the neighboring test-point is placed after the current test point, the
         position is specified as +1. If neighboring test-point
         is placed before the current test point, the position is specified
         as -1, if no neighboring test points placed before or after the current
         test point in the same layer, the position is specified as 0.";
    }
    description
      "Connectionless OAM related neighboring test points list.";
  }
  grouping tp-technology {
    choice technology {
      default "technology-null";
      case technology-null {
        description
          "This is a placeholder when no technology is needed.";
        leaf tech-null {
          type empty;
          description
            "There is no technology to be defined.";
        }
      }
      description
        "Technology choice.";
    }
    description
      "OAM Technology";
  }
  grouping tp-tools {
    description
      "Test Point OAM Toolset.";
    container tp-tools {
      leaf continuity-check {
        type boolean;
        mandatory true;



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        description
          "A flag indicating whether or not the
           continuity check function is supported.";
        reference

          "RFC 792: INTERNET CONTROL MESSAGE PROTOCOL.
           RFC 4443: Internet Control Message Protocol (ICMPv6)
           for the Internet Protocol Version 6 (IPv6) Specification.
           RFC 5880: Bidirectional Forwarding Detection.
           RFC 5881: BFD for IPv4 and IPv6.
           RFC 5883: BFD for Multihop Paths.

           RFC 5884: BFD for MPLS Label Switched Paths.
           RFC 5885: BFD for PW VCCV.
           RFC 6450: Multicast Ping Protocol.
           RFC 8029: Detecting Multiprotocol Label Switched
          (MPLS) Data-Plane Failures.";
      }
      leaf path-discovery {
        type boolean;
        mandatory true;
        description
          "A flag indicating whether or not the
           path discovery function is supported.";
        reference
          "RFC 792: INTERNET CONTROL MESSAGE PROTOCOL.
           RFC 4443: Internet Control Message Protocol (ICMPv6)
           for the Internet Protocol Version 6 (IPv6) Specification.
           RFC 4884: Extended ICMP to Support Multi-part Message.
           RFC 5837:Extending ICMP for Interface.
           and Next-Hop Identification.
           RFC 8029: Detecting Multiprotocol Label Switched (MPLS)
           Data-Plane Failures.";
      }
      description
        "Container for test point OAM tools set.";
    }
  }
  grouping test-point-location-info {
    uses tp-technology;
    uses tp-tools;
    anydata root {
      yangmnt:mount-point "root";
      description
        "Root for models supported per
         test point";
    }
    uses connectionless-oam-tps;



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    description
      "Test point Location";
  }
  grouping test-point-locations {
    description
      "Group of test point locations.";
        leaf tp-location-type {
      type identityref {
        base tp-address-technology-type;
      }
      description
        "Test point location type.";
    }
  container ipv4-location-type {
  when "derived-from-or-self(../tp-location-type,"+
  "'cl-oam:ipv4-address-type')" {
   description
   "When test point location type is equal to ipv4 address.";
    }
  container test-point-ipv4-location-list {
          list test-point-locations {
            key "ipv4-location ni";
            leaf ipv4-location {
              type inet:ipv4-address;
              description
                "IPv4 Address.";
            }
            leaf ni {
              type routing-instance-ref;
              description
                "The ni is used to describe the
                 corresponding network instance";
            }
            uses test-point-location-info;
            description
              "List of test point locations.";
          }
          description
            "Serves as top-level container
             for test point location list.";
        }
        description
           "ipv4 location type container.";
      }
 container ipv6-location-type {
   when "derived-from-or-self(../tp-location-type,"+
    "'cl-oam:ipv6-address-type')" {
     description



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  "when test point location is equal to ipv6 address";
   }
 container test-point-ipv6-location-list {
          list test-point-locations {
            key "ipv6-location ni";
            leaf ipv6-location {
              type inet:ipv6-address;
              description
                "IPv6 Address.";
            }
            leaf ni {
              type routing-instance-ref;
              description
                "The ni is used to describe the
                 corresponding network instance";
            }
            uses test-point-location-info;
            description
              "List of test point locations.";
          }
          description
            "Serves as top-level container
             for test point location list.";
        }
        description
           "ipv6 location type container.";
      }
      container mac-location-type {
       when "derived-from-or-self(../tp-location-type,"+
       "'cl-oam:mac-address-type')" {
       description
       "when test point location type is equal to mac address.";
       }
      container test-point-mac-address-location-list {
          list test-point-locations {
            key "mac-address-location";
            leaf mac-address-location {
              type yang:mac-address;
              description
                "MAC Address";
            }
            uses test-point-location-info;
            description
              "List of test point locations.";
          }
          description
            "Serves as top-level container
             for test point location list.";



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        }
        description
           "mac address location type container.";
      }
container group-as-number-location-type {
   when "derived-from-or-self(../tp-location-type,"+
   "'cl-oam:as-number-address-type')" {
   description
   "when test point location type is equal to as-number.";
}
 container test-point-as-number-location-list {
          list test-point-locations {
            key "as-number-location";
            leaf as-number-location {
              type inet:as-number;
              description
              "AS number for point to multi point OAM.";
            }
            leaf ni {
              type routing-instance-ref;
              description
                "The ni is used to describe the
                 corresponding network instance";
            }
            uses test-point-location-info;
            description
              "List of test point locations.";
          }
          description
            "Serves as top-level container
             for test point location list.";
        }
        description
           "as number location type container.";
      }
container group-router-id-location-type {
when "derived-from-or-self(../tp-location-type,"+
  "'cl-oam:router-id-address-type')" {
  description
  "when test point location type is equal to system-info.";
   }
        container test-point-system-info-location-list {
          list test-point-locations {
            key "router-id-location";
            leaf router-id-location {
              type rt:router-id;
              description
                "System Id.";



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            }
            leaf ni {
              type routing-instance-ref;
              description
                "The ni is used to describe the
                 corresponding network instance";
            }
            uses test-point-location-info;
            description
              "List of test point locations.";
          }
          description
            "Serves as top-level container for
             test point location list.";
        }
        description
           "system ID location type container.";
      }
  }
  augment "/nd:networks/nd:network/nd:node" {
    description
      "augments the /networks/network/node path defined in the
      ietf-network module (I-D.ietf-i2rs-yang-network-topo) with
      test-point-locations grouping.";
      uses test-point-locations;
  }
  grouping timestamp {
    description
      "Grouping for timestamp.";
    leaf timestamp-type {
      type identityref {
      base lime:timestamp-type;
      }
      description
        "Type of Timestamp, such as Truncated PTP, NTP.";
    }
 container timestamp-64bit {
  when "derived-from-or-self(../timestamp-type, 'cl-oam:truncated-ptp')"+
  "or derived-from-or-self(../timestamp-type,'cl-oam:ntp64')" {
   description
   "Only applies when Truncated PTP or 64bit NTP Timestamp.";
  }
      leaf timestamp-sec {
      type uint32;
      description
        "Absolute timestamp in seconds as per IEEE1588v2
         or seconds part in 64-bit NTP timestamp.";
       }



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      leaf timestamp-nanosec {
      type uint32;
      description
        "Fractional part in nanoseconds as per IEEE1588v2
         or Fractional part in 64-bit NTP timestamp.";
      }
      description
      "Container for 64bit timestamp.See section 4.2.1 of
      draft-ietf-ntp-packet-timestamps for NTP 64-bit Timestamp
      Format and section 4.3 of draft-ietf-ntp-packet-timestamps
      for The PTP Truncated Timestamp Format.";
    }
 container timestamp-80bit {
 when "derived-from-or-self(../timestamp-type, 'cl-oam:ptp80')"{
         description
          "Only applies when 80bit PTP Timestamp.";
        }
  if-feature ptp-long-format;
      leaf timestamp-sec {
      type uint64 {
      range "0..281474976710655";
      }
      description
        "48bit Timestamp in seconds as per IEEE1588v2.";
       }
      leaf timestamp-nanosec {
      type uint32;
      description
        "Fractional part in nanoseconds as per IEEE1588v2.";
      }
      description
      "Container for 80bit timestamp.";
    }
 container ntp-timestamp-32bit {
 when "derived-from-or-self(../timestamp-type, 'cl-oam:truncated-ntp')"{
  description
   "Only applies when 32 bit NTP Short format Timestamp.";
   }
  if-feature ntp-short-format;
      leaf timestamp-sec {
      type uint16;
      description
        "Timestamp in seconds as per short format NTP.";
       }
      leaf timestamp-nanosec {
      type uint16;
      description
        "Truncated Fractional part in 16-bit NTP timestamp.";



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      }
      description
      "Container for 32bit timestamp.See section 4.2.2 of
     draft-ietf-ntp-packet-timestamps for NTP 32-bit Timestamp
      Format.";
    }
 container icmp-timestamp-32bit {
 when "derived-from-or-self(../timestamp-type, 'cl-oam:icmp-ntp')"{
  description
  "Only applies when Truncated NTP or 64bit NTP Timestamp.";
  }
  if-feature icmp-timestamp;
      leaf timestamp-millisec {
      type uint32;

      description
        "timestamp in milliseconds for ICMP timestamp.";
       }
      description
      "Container for 32bit timestamp.See RFC792 for ICMP
       timestamp format.";
    }
  }
  grouping path-discovery-data {
    description
      "Path discovery related data output from nodes.";
    container src-test-point {
      description
        "Source test point.";
      uses tp-address-ni;
    }
    container dest-test-point {
      description
        "Destination test point.";
      uses tp-address-ni;
    }
    leaf sequence-number {
      type uint64;
      default "0";
      description
        "Sequence number in data packets. A value of
        zero indicates that no sequence number is sent.";
    }
    leaf hop-cnt {
      type uint8;
      default "0";
      description
        "Hop count. A value of zero indicates



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        that no hop count is sent";
    }
    uses session-packet-statistics;
    uses session-error-statistics;
    uses session-delay-statistics;
    uses session-jitter-statistics;
    container path-verification {
      description
        "Optional path verification related information.";
      leaf flow-info {
        type string;
        description
          "Informations that refers to the flow.";
      }
      uses session-path-verification-statistics;
    }
    container path-trace-info {
      description
        "Optional path trace per-hop test point information.
         The path trace information list has typically a single
         element for per-hop cases such as path-discovery RPC operation
         but allows a list of hop related information for other types of
         data retrieval methods.";
      list path-trace-info-list {
        key "index";
        description
          "Path trace information list.";
        leaf index {
          type uint32;
          description
            "Trace information index.";
        }
        uses tp-address-ni;
        uses timestamp;
        leaf ingress-intf-name {
          type if:interface-ref;
          description
            "Ingress interface name";
        }
        leaf egress-intf-name {
          type if:interface-ref;
          description
            "Egress interface name";
        }
        leaf queue-depth {
          type uint32;
          description
            "Length of the queue of the interface from where



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             the packet is forwarded out.  The queue depth could
             be the current number of memory buffers used by the
             queue and a packet can consume one or more memory buffers
             thus constituting device-level information.";
        }
        leaf transit-delay {
          type uint32;
          description
            "Time in nano seconds
             packet spent transiting a node.";
        }
        leaf app-meta-data {
          type uint64;
          description

            "Application specific
             data added by node.";
        }
      }
    }
  }
  grouping continuity-check-data {
    description
      "Continuity check data output from nodes.";
    container src-test-point {
      description
        "Source test point.";
      uses tp-address-ni;
      leaf egress-intf-name {
        type if:interface-ref;
        description
          "Egress interface name.";
      }
    }
    container dest-test-point {
      description
      "Destination test point.";
      uses tp-address-ni;
      leaf ingress-intf-name {
        type if:interface-ref;
        description
          "Ingress interface name.";
      }
    }
    leaf sequence-number {
      type uint64;
      default "0";
      description



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       "Sequence number in data packets. A value of
       zero indicates that no sequence number is sent.";
    }
    leaf hop-cnt {
      type uint8;
      default "0";
      description
        "Hop count. A value of zero indicates
         that no hop count is sent";
    }
    uses session-packet-statistics;
    uses session-error-statistics;
    uses session-delay-statistics;
    uses session-jitter-statistics;
  }
  container cc-session-statistics-data {
    if-feature "continuity-check";
    config false;
    list cc-session-statistics {
       key type;
       leaf type {
        type identityref {
         base traffic-type;
        }
        description
         "Type of traffic.";
       }
        container cc-ipv4-sessions-statistics {
        when "../type = 'ipv4'" {
         description
          "Only applies when traffic type is Ipv4.";
        }
      description
       "CC ipv4 sessions";
      uses cc-session-statistics;
      }
       container cc-ipv6-sessions-statistics {
        when "../type = 'ipv6'" {
         description
          "Only applies when traffic type is Ipv6.";
        }
      description
        "CC ipv6 sessions";
      uses cc-session-statistics;
      }
       description
      "List of CC session statistics data.";
      }



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    description
    "CC operational information.";
  }
}

   <CODE ENDS>

6.  Connectionless model applicability

   The "ietf-connectionless-oam" model defined in this document provides
   a technology-independent abstraction of key OAM constructs for OAM
   protocols that use connectionless communication.  This model can be
   further extended to include technology-specific details, e.g., adding
   new data nodes with technology specific functions and parameters into
   proper anchor points of the base model, so as to develop a
   technology-specific connectionless OAM model.

   This section demonstrates the usability of the connectionless YANG
   OAM data model to various connectionless OAM technologies, e.g., BFD,
   LSP ping.  Note that, in this section, several snippets of
   technology-specific model extensions are presented for illustrative
   purposes.  The complete model extensions should be worked on in
   respective protocol working groups.

6.1.  BFD Extension

   RFC 7276 defines BFD as a connection-oriented protocol.  It is used
   to monitor a connectionless protocol in the case of basic BFD for IP.

6.1.1.  Augment Method

   The following sections shows how the "ietf-connectionless-oam" model
   can be extended to cover BFD technology.  For this purpose, a set of
   extension are introduced such as technology-type extension and test-
   point attributes extension.

   Note that a dedicated BFD YANG data model [I-D.ietf-bfd-yang] is also
   standardized.  Augmentation of the "ietf-connectionless-oam" model
   with BFD specific details provides an alternative approach that
   provides a unified view of management information across various OAM
   protocols.  The BFD specific details can be the grouping defined in
   the BFD model avoiding duplication of effort.

6.1.1.1.  Technology type extension

   No BFD technology type has been defined in the "ietf-connectionless-
   oam" model.  Therefore a technology type extension is required in the
   model Extension.



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   The snippet below depicts an example of adding the "bfd" type as an
   augment to the ietf-connectionless-oam" model:

   augment "/nd:networks/nd:network/nd:node/"
   +"coam:location-type/coam:ipv4-location-type"
   +"/coam:test-point-ipv4-location-list/"
   +"coam:test-point-locations/coam:technology"
   {
       leaf bfd{
      type string;
     }
   }

6.1.1.2.  Test point attributes extension

   To support BFD, the "ietf-connectionless-oam" model can be extended
   by adding specific parameters into the "test-point-locations" list
   and/or adding a new location type such as "BFD over MPLS TE" under
   "location-type".

6.1.1.2.1.  Define and insert new nodes into corresponding test-point-
            location

   In the "ietf-connectionless-oam" model, multiple "test-point-
   location" lists are defined under the "location-type" choice node.
   Therefore, to derive a model for some BFD technologies ( such as ip
   single-hop, ip multi-hops, etc), data nodes for BFD specific details
   need to be added into corresponding "test-point-locations" list.  In
   this section, some groupings which are defined in [I-D.ietf-bfd-yang]
   are reused as follows:

   The snippet below shows how the "ietf-connectionless-oam" model can
   be extended to support "BFD IP Single-Hop":


















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   augment "/nd:networks/nd:network/nd:node/"
   +"coam:location-type/coam:ipv4-location-type"
   +"/coam:test-point-ipv4-location-list/"
           +"coam:test-point-locations"
   {
           container session-cfg {
             description "BFD IP single-hop session configuration";
             list sessions {
               key "interface dest-addr";
               description "List of IP single-hop sessions";
               leaf interface {
                 type if:interface-ref;
                 description
                   "Interface on which the BFD session is running.";
               }
               leaf dest-addr {
                 type inet:ip-address;
                 description "IP address of the peer";
               }
               uses bfd:bfd-grouping-common-cfg-parms;
               uses bfd:bfd-grouping-echo-cfg-parms;
             }
           }
   }

   Similar augmentations can be defined to support other BFD
   technologies such as BFD IP Multi-Hop, BFD over MPLS, etc.

6.1.1.2.2.  Add new location-type cases

   In the "ietf-connectionless-oam" model, If there is no appropriate
   "location type" case that can be extended, a new "location-type" case
   can be defined and inserted into the "location-type" choice node.

   Therefore, the model user can flexibly add "location-type" to support
   other type of test point which are not defined in the "ietf-
   connectionless-oam" model.  In this section, a new "location-type"
   case is added and some groupings that are defined in
   [I-D.ietf-bfd-yang] are reused as follows:

   The snippet below shows how the "ietf-connectionless-oam" model can
   be extended to support "BFD over MPLS-TE":









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   augment "/nd:networks/nd:network/nd:node/coam:location-type"{
    case te-location{
     list test-point-location-list{
      key "tunnel-name";
      leaf tunnel-name{
       type leafref{
    path "/te:te/te:tunnels/te:tunnel/te:name";
   }
   description
   "point to a te instance.";
      }
       uses bfd:bfd-grouping-common-cfg-parms;
           uses bfd-mpls:bfd-encap-cfg;
     }
    }
   }

   Similar augmentations can be defined to support other BFD
   technologies such as BFD over LAG, etc.

6.1.2.  Schema Mount

   An alternative method is using the schema mount mechanism [I-D.ietf-
   netmod-schema-mount] in the "ietf-connectionless-oam" model.  Within
   the "test-point-locations" list, a "root" attribute is defined to
   provide a mount point for models mounted per "test-point-locations".
   Therefore, the "ietf-connectionless-oam" model can provide a place in
   the node hierarchy where other OAM YANG data models can be attached,
   without any special extension in the "ietf-connectionless-oam" YANG
   data models [I-D.ietf-netmod-schema-mount].  Note that the limitation
   of the Schema Mount method is it is not allowed to specify certain
   modules that are required to be mounted under a mount point.

   The snippet below depicts the definition of the "root" attribute.

         anydata root {
          yangmnt:mount-point root;
          description
         "Root for models supported per
           test point";
         }

   The following section shows how the "ietf-connectionless-oam" model
   can use schema mount to support BFD technology.







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6.1.2.1.  BFD Modules be populated in schema-mount

   To support BFD technology, "ietf-bfd-ip-sh" and "ietf-bfd-ip-mh" YANG
   modules might be populated in the "schema-mounts" container:

      <schema-mounts
          xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-schema-mount">
        <mount-point>
          <module> ietf-connectionless-oam </module>
          <name>root</name>
          <use-schema>
            <name>root</name>
          </use-schema>
        </mount-point>
        <schema>
          <name>root</name>
          <module>
            <name>ietf-bfd-ip-sh </name>
            <revision>2016-07-04</revision>
            <namespace>
              urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh
            </namespace>
            <conformance-type>implement</conformance-type>
          </module>
          <module>
            <name>ietf-bfd-ip-mh </name>
            <revision> 2016-07-04</revision>
            <namespace>
              urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh
            </namespace>
            <conformance-type>implement</conformance-type>
          </module>
        </schema>
      </schema-mounts>

   and the "ietf-connectionless-oam" module might have:















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   <ietf-connectionless-oam
   uri="urn:ietf:params:xml:ns:yang:ietf-connectionless-oam">
      ......
    <test-point-locations>
     <ipv4-location>192.0.2.1</ipv4-location>
      ......
     <root>
      <ietf-bfd-ip-sh uri="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh">
       <ip-sh>
        foo
        ......
       </ip-sh>
      </ietf-bfd-ip-sh>
      <ietf-bfd-ip-mh uri="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh">
       <ip-mh>
        foo
        ......
       </ip-mh>
      </ietf-bfd-ip-mh>
     </root>
    </test-point-locations>
   </ietf-connectionless-oam>

6.2.  LSP Ping extension

6.2.1.  Augment Method

   The following sections shows how the "ietf-connectionless-oam" model
   can be extended to support LSP ping technology.  For this purpose, a
   set of extensions are introduced such as the "technology-type"
   extension and the test-point "attributes" extension.

   Note that an LSP Ping YANG data model is being specified
   [I-D.zheng-mpls-lsp-ping-yang-cfg].  As with BFD, users can choose to
   use the "ietf-connectioless-oam" as basis and augment the "ietf-
   connectionless-oam" model with LSP Ping specific details in the model
   extension to provide a unified view across different technologies.
   The LSP Ping specific details can be the grouping defined in the LSP
   ping model to avoid duplication of effort.

6.2.1.1.  Technology type extension

   No LSP Ping technology type has been defined in the "ietf-
   connectionless-oam" model.  Therefore a technology type extension is
   required in the model extension.

   The snippet below depicts an example of augmenting the "ietf-
   connectionless-oam" with "lsp-ping" type:



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   augment "/nd:networks/nd:network/nd:node/"
   +"coam:location-type/coam:ipv4-location-type"
   +"/coam:test-point-ipv4-location-list/"
           +"coam:test-point-locations/coam:technology"
   {
      leaf lsp-ping{
      type string;
     }
   }

6.2.1.2.  Test point attributes extension

   To support LSP Ping, the "ietf-connectionless-oam" model can be
   extended and add LSP Ping specific parameters can be defined and
   under "test-point-locations" list.

   Users can reuse the attributes or groupings which are defined in
   [I-D.zheng-mpls-lsp-ping-yang-cfg] as follows:

   The snippet below depicts an example of augmenting the "test-point-
   locations" list with lsp ping attributes:

   augment "/nd:networks/nd:network/nd:node/"
   +"coam:location-type/coam:ipv4-location-type"
   +"/coam:test-point-ipv4-location-list/"
           +"coam:test-point-locations"
   {
   list lsp-ping {
            key "lsp-ping-name";
            leaf lsp-ping-name {
             type string {
               length "1..31";
            }
           mandatory "true";
           description "LSP Ping test name.";
           ......
         }

6.2.2.  Schema Mount

   An alternative method is using schema mount mechanism
   [I-D.ietf-netmod-schema-mount] in the "ietf-connectionless-oam".
   Within the "test-point-locations" list, a "root" attribute is defined
   to provide a mounted point for models mounted per "test-point-
   locations".  Therefore, the "ietf-connectionless-oam" model can
   provide a place in the node hierarchy where other OAM YANG data
   models can be attached, without any special extension in the "ietf-
   connectionless-oam" YANG data models [I-D.ietf-netmod-schema-mount].



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   Note that the limitation of the Schema Mount method is it is not
   allowed to specify certain modules that are required to be mounted
   under a mount point.

   The snippet below depicts the definition of "root" attribute.

         anydata root {
          yangmnt:mount-point root;
          description
         "Root for models supported per
           test point";
         }

   The following section shows how the "ietf-connectionless-oam" model
   can use schema mount to support LSP-PING technology.

6.2.2.1.  LSP-PING Modules be populated in schema-mount

   To support LSP-PING technology, "ietf-lspping" YANG module
   [I-D.zheng-mpls-lsp-ping-yang-cfg] might be populated in the "schema-
   mounts" container:

      <schema-mounts
          xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-schema-mount">
        <mount-point>
          <module> ietf-connectionless-oam </module>
          <name>root</name>
          <use-schema>
            <name>root</name>
          </use-schema>
        </mount-point>
        <schema>
          <name>root</name>
          <module>
            <name>ietf-lspping </name>
            <revision>2016-03-18</revision>
            <namespace>
              urn:ietf:params:xml:ns:yang: ietf-lspping
            </namespace>
            <conformance-type>implement</conformance-type>
          </module>
        </schema>
      </schema-mounts>

   and the "ietf-connectionless-oam" module might have:






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   <ietf-connectionless-oam
   uri="urn:ietf:params:xml:ns:yang:ietf-connectionless-oam">
      ......
    <test-point-locations>
     <ipv4-location> 192.0.2.1</ipv4-location>
      ......
     <root>
      <ietf-lspping uri="urn:ietf:params:xml:ns:yang:ietf-lspping">
       <lsp-pings>
        foo
        ......
       </lsp-pings>
      </ietf-lspping>
     </root>
    </test-point-locations>
   </ietf-connectionless-oam>

7.  Security Considerations

   The YANG module defined in this document 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.

   The vulnerable "config true" subtrees and data nodes are the
   following:

      /nd:networks/nd:network/nd:node/cl-oam:location-type/cl-oam:ipv4-
      location-type/cl-oam:test-point-ipv4-location-list/cl-oam:test-
      point-locations/

      /nd:networks/nd:network/nd:node/cl-oam:location-type/cl-oam:ipv6-
      location-type/cl-oam:test-point-ipv6-location-list/cl-oam:test-
      point-locations/



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      /nd:networks/nd:network/nd:node/cl-oam:location-type/cl-oam:mac-
      location-type/cl-oam:test-point-mac-address-location-list/cl-
      oam:test-point-locations/

      /nd:networks/nd:network/nd:node/cl-oam:location-type/cl-oam:group-
      as-number-location-type/cl-oam:test-point-as-number-location-list/
      cl-oam:test-point-locations/

      /nd:networks/nd:network/nd:node/cl-oam:location-type/cl-oam:group-
      router-id-location-type/cl-oam:test-point-system-info-location-
      list/cl-oam:test-point-locations/

   Unauthorized access to any of these lists can adversely affect OAM
   management system handling of end-to-end OAM and coordination of OAM
   within underlying network layers.  This may lead to inconsistent
   configuration, reporting, and presentation for the OAM mechanisms
   used to manage the network.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

      /coam:cc-session-statistics-data/cl-oam:cc-ipv4-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-count/

      /coam:cc-session-statistics-data/cl-oam:cc-ipv4-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-up-count/

      /coam:cc-session-statistics-data/cl-oam:cc-ipv4-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam: session-down-
      count/

      /coam:cc-session-statistics-data/cl-oam:cc-ipv4-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-admin-down-
      count/

      /coam:cc-session-statistics-data/cl-oam:cc-ipv6-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-count/

      /coam:cc-session-statistics-data/cl-oam:cc-ipv6-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-up-count//

      /coam:cc-session-statistics-data/cl-oam:cc-ipv6-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-down-count/





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      /coam:cc-session-statistics-data/cl-oam:cc-ipv6-sessions-
      statistics/cl-oam:cc-session-statistics/cl-oam:session-admin-down-
      count/

8.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in [RFC3688], the following registration is
   requested to be made:

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

   URI: urn:ietf:params:xml:ns:yang:ietf-connectionless-oam
   Registrant Contact: The IESG.
   XML: N/A, the requested URI is an XML namespace.

   This document registers a YANG module in the YANG Module Names
   registry [RFC7950].

            Name: ietf-lime-common-types
            Namespace: urn:ietf:params:xml:ns:yang:ietf-lime-time-types
            Prefix: lime
            Reference: RFC XXXX

          Name: ietf-connectionless-oam
          Namespace: urn:ietf:params:xml:ns:yang:ietf-connectionless-oam
          Prefix: cl-oam
          Reference: RFC XXXX

9.  Acknowlegements

   The authors of this document would like to thank Elwyn Davies, Alia
   Atlas, Brian E Carpenter, Greg Mirsky, Adam Roach, Alissa Cooper,
   Eric Rescorla, Ben Campbell, Benoit Claise, Kathleen Moriarty, Carlos
   Pignataro, and others for their substantive review and comments, and
   proposals to stabilize and improve the document.

10.  References

10.1.  Normative References

   [I-D.ietf-i2rs-yang-network-topo]
              Clemm, A., Medved, J., Varga, R., Bahadur, N.,
              Ananthakrishnan, H., and X. Liu, "A Data Model for Network
              Topologies", draft-ietf-i2rs-yang-network-topo-17 (work in
              progress), October 2017.



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   [I-D.ietf-rtgwg-ni-model]
              Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
              Liu, "YANG Network Instances", draft-ietf-rtgwg-ni-
              model-04 (work in progress), September 2017.

   [I-D.ietf-rtgwg-routing-types]
              Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger,
              "Routing Area Common YANG Data Types", draft-ietf-rtgwg-
              routing-types-17 (work in progress), October 2017.

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

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
              Control Message Protocol (ICMPv6) for the Internet
              Protocol Version 6 (IPv6) Specification", STD 89,
              RFC 4443, DOI 10.17487/RFC4443, March 2006,
              <https://www.rfc-editor.org/info/rfc4443>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC5905]  Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
              "Network Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
              <https://www.rfc-editor.org/info/rfc5905>.

   [RFC6021]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6021, DOI 10.17487/RFC6021, October 2010,
              <https://www.rfc-editor.org/info/rfc6021>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

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

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <https://www.rfc-editor.org/info/rfc6536>.




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   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7223]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 7223, DOI 10.17487/RFC7223, May 2014,
              <https://www.rfc-editor.org/info/rfc7223>.

   [RFC792]   Postel, J., "Internet Control Message Protocol", RFC 792,
              September 1981.

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

   [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
              Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
              Switched (MPLS) Data-Plane Failures", RFC 8029,
              DOI 10.17487/RFC8029, March 2017,
              <https://www.rfc-editor.org/info/rfc8029>.

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

10.2.  Informative References

   [G.800]    "Unified functional architecture of transport networks",
              ITU-T Recommendation G.800, 2016.

   [G.8013]   "OAM functions and mechanisms for Ethernet based
              networks", ITU-T Recommendation G.8013/Y.1731, 2013.

   [I-D.ietf-bfd-yang]
              Rahman, R., Zheng, L., Jethanandani, M., Networks, J., and
              G. Mirsky, "YANG Data Model for Bidirectional Forwarding
              Detection (BFD)", draft-ietf-bfd-yang-07 (work in
              progress), October 2017.

   [I-D.ietf-lime-yang-connection-oriented-oam-model]
              Kumar, D., Wu, Q., and Z. Wang, "Generic YANG Data Model
              for Connection Oriented Operations, Administration, and
              Maintenance(OAM) protocols", draft-ietf-lime-yang-
              connection-oriented-oam-model-00 (work in progress), June
              2017.






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   [I-D.ietf-lime-yang-connectionless-oam-methods]
              Kumar, D., Wang, Z., Wu, Q., Rahman, R., and S. Raghavan,
              "Retrieval Methods YANG Data Model for the Management of
              Operations, Administration, and Maintenance (OAM)
              Protocols that use Connectionless Communications", draft-
              ietf-lime-yang-connectionless-oam-methods-13 (work in
              progress), November 2017.

   [I-D.ietf-netmod-schema-mount]
              Bjorklund, M. and L. Lhotka, "YANG Schema Mount", draft-
              ietf-netmod-schema-mount-08 (work in progress), October
              2017.

   [I-D.ietf-ntp-packet-timestamps]
              Mizrahi, T., Fabini, J., and A. Morton, "Guidelines for
              Defining Packet Timestamps", draft-ietf-ntp-packet-
              timestamps-00 (work in progress), October 2017.

   [I-D.zheng-mpls-lsp-ping-yang-cfg]
              Zheng, L., Aldrin, S., Zheng, G., Mirsky, G., and R.
              Rahman, "YANG Data Model for LSP-Ping", draft-zheng-mpls-
              lsp-ping-yang-cfg-06 (work in progress), October 2017.

   [IEEE.1588]
              "IEEE Standard for a Precision Clock Synchronization
              Protocol for Networked Measurement and Control Systems",
              IEEE IEEE Std 1588-2008, 2008.

   [RFC5462]  Andersson, L. and R. Asati, "Multiprotocol Label Switching
              (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
              Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
              2009, <https://www.rfc-editor.org/info/rfc5462>.

   [RFC6136]  Sajassi, A., Ed. and D. Mohan, Ed., "Layer 2 Virtual
              Private Network (L2VPN) Operations, Administration, and
              Maintenance (OAM) Requirements and Framework", RFC 6136,
              DOI 10.17487/RFC6136, March 2011,
              <https://www.rfc-editor.org/info/rfc6136>.

   [RFC7276]  Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
              Weingarten, "An Overview of Operations, Administration,
              and Maintenance (OAM) Tools", RFC 7276,
              DOI 10.17487/RFC7276, June 2014,
              <https://www.rfc-editor.org/info/rfc7276>.







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Authors' Addresses

   Deepak Kumar
   CISCO Systems
   510 McCarthy Blvd
   Milpitas, CA  95035
   USA

   Email: dekumar@cisco.com


   Michael Wang
   Huawei Technologies, Co., Ltd
   101 Software Avenue, Yuhua District
   Nanjing  210012
   China

   Email: wangzitao@huawei.com


   Qin Wu (editor)
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: bill.wu@huawei.com


   Reshad Rahman
   Cisco Systems
   2000 Innovation Drive
   Kanata, Ontario  K2K 3E8
   Canada

   Email: rrahman@cisco.com


   Srihari Raghavan
   Cisco Systems
   Tril Infopark Sez, Ramanujan IT City
   Neville Block, 2nd floor, Old Mahabalipuram Road
   Chennai, Tamil Nadu  600113
   India

   Email: srihari@cisco.com





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