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Versions: (draft-ietf-lime-yang-oam-model) 00 01 02 03 04 05 06 07 Draft is active
In: Auth48
Network Working Group                                           D. Kumar
Internet-Draft                                                     Cisco
Intended status: Standards Track                                   Q. Wu
Expires: August 29, 2018                                         M. Wang
                                                                  Huawei
                                                       February 25, 2018


      Generic YANG Data Model for Connection Oriented Operations,
             Administration, and Maintenance(OAM) protocols
         draft-ietf-lime-yang-connection-oriented-oam-model-07

Abstract

   This document presents a base YANG Data model for connection-oriented
   Operations, Administration, and Maintenance(OAM) protocols.  It
   provides a technology-independent abstraction of key OAM constructs
   for such protocols.  The model presented here can be extended to
   include technology specific details.  This guarantees uniformity in
   the management of OAM protocols and provides support for nested OAM
   workflows (i.e., performing OAM functions at different levels through
   a unified interface).

   The YANG model in this document conforms to the Network Management
   Datastore Architecture.

Status of This Memo

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

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

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

   This Internet-Draft will expire on August 29, 2018.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   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 . . . . . . . . . . . . . .   4
     2.1.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   5
     2.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   6
     2.3.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Architecture of Generic YANG Model for connection-oriented
       OAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Overview of the Connection-Oriented OAM YANG Model  . . . . .   7
     4.1.  Maintenance Domain (MD) configuration . . . . . . . . . .   8
     4.2.  Maintenance Association (MA) configuration  . . . . . . .   9
     4.3.  Maintenance Endpoint (MEP) configuration  . . . . . . . .   9
     4.4.  RPC definitions . . . . . . . . . . . . . . . . . . . . .  10
     4.5.  Notifications . . . . . . . . . . . . . . . . . . . . . .  13
     4.6.  Monitor statistics  . . . . . . . . . . . . . . . . . . .  13
     4.7.  OAM data hierarchy  . . . . . . . . . . . . . . . . . . .  13
   5.  OAM YANG Module . . . . . . . . . . . . . . . . . . . . . . .  17
   6.  Base Mode . . . . . . . . . . . . . . . . . . . . . . . . . .  41
     6.1.  MEP Address . . . . . . . . . . . . . . . . . . . . . . .  41
     6.2.  MEP ID for Base Mode  . . . . . . . . . . . . . . . . . .  41
     6.3.  Maintenance Association . . . . . . . . . . . . . . . . .  41
   7.  Connection-oriented OAM YANG model applicability  . . . . . .  42
     7.1.  Generic YANG Model extension for TRILL OAM  . . . . . . .  42
       7.1.1.  MD Configuration Extension  . . . . . . . . . . . . .  42
       7.1.2.  MA Configuration Extension  . . . . . . . . . . . . .  43
       7.1.3.  MEP Configuration Extension . . . . . . . . . . . . .  44
       7.1.4.  RPC extension . . . . . . . . . . . . . . . . . . . .  44
     7.2.  Generic YANG Model extension for MPLS-TP OAM  . . . . . .  45
       7.2.1.  MD Configuration Extension  . . . . . . . . . . . . .  45
       7.2.2.  MA Configuration Extension  . . . . . . . . . . . . .  47
       7.2.3.  MEP Configuration Extension . . . . . . . . . . . . .  47
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  48
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  49
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  49
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  49
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  49
     11.2.  Informative References . . . . . . . . . . . . . . . . .  51



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   Appendix A.  Contributors' Addresses  . . . . . . . . . . . . . .  52
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  53

1.  Introduction

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

   1.  Monitor network connections (Connectivity Verification,
       Continuity Check).

   2.  Troubleshoot failures (Fault verification and localization).

   3.  Monitor Performance

   An overview of OAM tools is presented in [RFC7276].  Over the years,
   many technologies have developed similar tools for fault and
   performance management.

   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] ).
   The YANG Data model for OAM protocols using connectionless
   communications is specified in
   [I-D.ietf-lime-yang-connectionless-oam].

   [IEEE802.1Q] Connectivity Fault Management is a well-established OAM
   standard that is widely adopted for Ethernet networks.  ITU-T
   [G.8013], MEF Service OAM [MEF-17], MPLS-TP [RFC6371]and TRILL
   [RFC7455] all define OAM mechanisms based on the manageability frame
   work of CFM [IEEE802.1Q].

   Given the wide adoption of the underlying OAM concepts defined in CFM
   [IEEE802.1Q], it is a reasonable choice to develop the unified
   management framework for connection-oriented OAM based on those
   concepts.  In this document, we take the CFM [IEEE802.1Q] model and
   extend it to a technology independent framework and define the
   corresponding YANG model accordingly.  The YANG model presented in
   this document is the base model for connection-oriented OAM protocols
   and supports generic continuity check, connectivity verification and
   path discovery (traceroute).  The generic YANG model for connection-
   oriented OAM is designed to be extensible to other connection-



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   oriented technologies.  Technology dependent nodes and remote process
   call (RPC) commands are defined in technology specific YANG models,
   which use and extend the base model defined here.  As an example,
   VXLAN uses source UDP port number for flow entropy, while TRILL uses
   either MAC addresses, the VLAN tag or fine grain label, and/or IP
   addresses for flow entropy in the hashing for multipath selection.
   To capture this variation, corresponding YANG models would define the
   applicable structures as augmentation to the generic base model
   presented here.  This accomplishes three goals: First it keeps each
   YANG model smaller and more manageable.  Second, it allows
   independent development of corresponding YANG models.  Third,
   implementations can limit support to only the applicable set of YANG
   models. (e.g.  TRILL RBridge may only need to implement Generic model
   and the TRILL YANG model).

   The YANG data model presented in this document is generated at the
   management layer.  Encapsulations and state machines may differ
   according to each OAM protocol.  A user who wishes to issues a
   Continuity Check command or a Loopback or initiate a performance
   monitoring session can do so in the same manner regardless of the
   underlying protocol or technology or specific vendor implementation.

   As an example, consider a scenario where connectivity from device A
   loopback to device B fails.  Between device A and B there are IEEE
   802.1 bridges a, b and c.  Let's assume a,b and c are using CFM
   [IEEE802.1Q].  A user upon detecting the loopback failure, may decide
   to drill down to the lower level at different segments of the path
   and issue the corresponding fault verification (LBM) and fault
   isolation (LTM) tools, using the same API.  This ability to drill
   down to a lower layer of the protocol stack at a specific segment
   within a path for fault localization and troubleshooting is referred
   to as "nested OAM workflow".  It is a useful concept that leads to
   efficient network troubleshooting and maintenance workflows.  The
   connection-oriented OAM YANG model presented in this document
   facilitates that without needing changes to the underlying protocols.

   The YANG model in this document conforms to the Network Management
   Datastore Architecture defined in
   [I-D.ietf-netmod-revised-datastores].

2.  Conventions used in this document

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP14, [RFC2119], [RFC8174] when, and only when, they appear in all
   capitals, as shown here.




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   Many of the terms used in this document (including those set out in
   Section 2.1 and Section 2.2) are specific to the world of OAM.  This
   document does not attempt to explain the terms, but does assume that
   the reader is familiar with the concepts.  For a good overview, read
   [IEEE802.1Q].  For an example of how these OAM terms appear in IETF
   work, see [RFC6371].

2.1.  Abbreviations

   CCM   - Continuity Check Message [IEEE802.1Q].

   ECMP  - Equal Cost Multipath.

   LBM   - Loopback Message [IEEE802.1Q].

   LTM   - Linktrace Message [IEEE802.1Q].

   MP    - Maintenance Point [IEEE802.1Q].

   MEP   - Maintenance End Point [RFC7174] (Maintenance association End
         Point [IEEE802.1Q], MEG End Points [RFC6371]).

   MIP   - Maintenance Intermediate Point [RFC7174] (Maintenance domain
         Intermediate Point [IEEE802.1Q], MEG Intermediate Point
         [RFC6371]).

   MA    - Maintenance Association [IEEE802.1Q] [RFC7174].

   MD    - Maintenance Domain [IEEE802.1Q]

   MEG   - Maintenance Entity Group [RFC6371]

   MTV   - Multi-destination Tree Verification Message.

   OAM   - Operations, Administration, and Maintenance [RFC6291].

   TRILL - Transparent Interconnection of Lots of Links [RFC6325].

   CFM   - Connectivity Fault Management [RFC7174] [IEEE802.1Q].

   RPC   - Remote Process Call.

   CC    - Continuity Check [RFC7276].

   CV    - Connectivity Verification [RFC7276].






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2.2.  Terminology

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

   Connectivity Verification  - Connectivity Verification is used to
      verify that a destination is connected.  It is also referred to as
      path verification and used to verify not only that the two MPs are
      connected, but also that they are connected through the expected
      path, allowing detection of unexpected topology changes.

   Proactive OAM  - The proactive OAM refers to OAM actions which are
      carried out continuously to permit proactive reporting of fault.
      Proactive OAM method requires persistent configuration.

   On-demand OAM  - The on-demand OAM refers to OAM actions which are
      initiated via manual intervention for a limited time to carry out
      diagnostics.  The on-demand OAM method requires only transient
      configuration.

2.3.  Tree Diagrams

   Tree diagrams used in this document follow the notation defined in
   [I-D.ietf-netmod-yang-tree-diagrams].

3.  Architecture of Generic YANG Model for connection-oriented OAM

   In this document we define a generic YANG model for connection-
   oriented OAM protocols.  The YANG model defined here is generic in a
   sense that other technologies can extend it for technology-specific
   needs.  The Generic YANG model for connection-oriented OAM acts as
   the root for other OAM YANG models.  This allows users to traverse
   between different OAM protocols with ease through a uniform API set.
   This also enables a nested OAM workflow.  Figure 1 depicts the
   relationship of different OAM YANG models to the Generic YANG Model
   for connection-oriented OAM.  The Generic YANG model for connection-
   oriented OAM provides a framework where technology-specific YANG
   models can inherit constructs from the base YANG models without
   needing to redefine them within the sub-technology.











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                            +----------+
                            |Connection|
                            | Oriented |
                            |  gen     |
                            |OAM YANG  |
                            +-+-+-+-+-++
                                 |
                                 |
                                 |
         +------------------------------------------+
         |                       |                  |
     +-+-+-+-+-+          +-+-+-+-+-+          +-+-+-+-+-+
     | TRILL   |          | MPLS-TP |     . . .|  foo    |
     |OAM YANG |          |OAM YANG |          |OAM YANG |
     +-+-+-+-+-+          +-+-+-+-+-+          +-+-+-+-+-+
           |                    |                  |
           |                    |              +-+-+-+-+-+
           |                    |         . . .|  foo    |
           |                    |              |sub tech |
           |                    |              +-+-+-+-+-+
           |                    |                  |
           |                    |                  |
    +-------------------------------------------------------+
    |                      Uniform API                      |
    +-------------------------------------------------------+

        Relationship of OAM YANG model to generic (base) YANG model

4.  Overview of the Connection-Oriented OAM YANG Model

   In this document we adopt the concepts of the CFM [IEEE802.1Q] model
   and structure it such that it can be adapted to different connection-
   oriented OAM protocols.

   At the top of the Model is the Maintenance Domain.  Each Maintenance
   Domain is associated with a Maintenance Name and a Domain Level.

   Under each Maintenance Domain there is one or more Maintenance
   Associations (MA).  In TRILL, the MA can correspond to Fine-Grained
   Label.

   Under each MA, there can be two or more MEPs (Maintenance End
   Points).  MEPs are addressed by their respective technology specific
   address identifiers.  The YANG model presented here provides
   flexibility to accommodate different addressing schemes.

   In the management protocol direction orthogonal to the Maintenance
   Domain, presented are the commands.  Those, in YANG terms, are the



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   RPC commands.  These RPC commands provide uniform APIs for continuity
   check, connectivity verification, path discovery(traceroute) and
   their equivalents as well as other OAM commands.

   The OAM entities in the generic YANG model defined here will be
   either explicitly or implicitly configured using any of the OAM
   tools.  The OAM tools used here are limited to the OAM toolset
   specified in section 5.1 of [RFC7276].  In order to facilitate zero-
   touch experience, this document defines a default mode of OAM.  The
   default mode of OAM is referred to as the Base Mode and specifies
   default values for each of model parameters, such as Maintenance
   Domain Level, Name of the Maintenance Association, Addresses of MEPs
   and so on.  The default values of these depend on the technology.
   Base Mode for TRILL is defined in [RFC7455].  Base mode for other
   technologies and future extensions developed in IETF will be defined
   in their corresponding documents.

   It is important to note that, no specific enhancements are needed in
   the YANG model to support Base Mode.  Implementations that comply
   with this document, by default implement the data nodes of the
   applicable technology.  Data nodes of the Base Mode are read-only
   nodes.

4.1.  Maintenance Domain (MD) configuration

   The container "domains" is the top level container within the gen-oam
   module.  Within the container "domains", a separate list is
   maintained per MD.  The MD list uses the key "md-name-string" for
   indexing.  The "md-name-string" is a leaf and derived from type
   string.  Additional name formats as defined in [IEEE802.1Q] or other
   standards can be included by association of the "md-name-format" with
   an identity-ref.  The "md-name-format" indicates the format of the
   augmented "md-name".  The "md-name" is presented as choice/case
   construct.  Thus, it is easily augmentable by derivative work.

       module: ietf-connection-oriented-oam
       +--rw domains
          +--rw domain* [technology md-name-string]
             +--rw technology        identityref
             +--rw md-name-string    md-name-string
             +--rw md-name-format?   identityref
             +--rw (md-name)?
             |  +--:(md-name-null)
             |     +--rw md-name-null? empty
             +--rw md-level?           md-level

             Snippet of data hierarchy related to OAM domains




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4.2.  Maintenance Association (MA) configuration

   Within a given Maintenance Domain there can be one or more
   Maintenance Associations (MA(s)).  MAs are represented as a list and
   indexed by the "ma-name-string".  Similar to "md-name" defined
   previously, additional name formats can be added by augmenting the
   name-format identity-ref and adding applicable case statements to
   "ma-name".

      module: ietf-connection-oriented-oam
       +--rw domains
          +--rw domain* [technology md-name-string]
             .
             .
             +--rw mas
                +--rw ma* [ma-name-string]
                   +--rw ma-name-string          ma-name-string
                   +--rw ma-name-format?         identityref
                   +--rw (ma-name)?
                   |  +--:(ma-name-null)
                   |     +--rw ma-name-null?     empty

    Snippet of data hierarchy related to Maintenance Associations (MA)

4.3.  Maintenance Endpoint (MEP) configuration

   Within a given Maintenance Association (MA), there can be one or more
   Maintenance End Points (MEP).  MEPs are represented as a list within
   the data hierarchy and indexed by the key "mep-name".






















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      module: ietf-connection-oriented-oam
       +--rw domains
          +--rw domain* [technology md-name-string]
             +--rw technology                  identityref
             .
             .
             +--rw mas
                +--rw ma* [ma-name-string]
                   .
                   .
                   +--rw mep* [mep-name]
                   |  +--rw mep-name         mep-name
                   |  +--rw (mep-id)?
                   |  |  +--:(mep-id-int)
                   |  |     +--rw mep-id-int?      int32
                   |  +--rw mep-id-format?   identityref
                   |  +--rw (mep-address)?
                   |  |  +--:(mac-address)
                   |  |  |  +--rw mac-address?     yang:mac-address
                   |  |  +--:(ip-address)
                   |  |     +--rw ip-address?      inet:ip-address
                     .          .
                     .          .
                     .          .

      Snippet of data hierarchy related to Maintenance Endpoint (MEP)

4.4.  RPC definitions

   The RPC model facilitates issuing commands to a "server" (in this
   case to the device that need to execute the OAM command) and
   obtaining a response.  RPC model defined here abstracts OAM specific
   commands in a technology independent manner.

   There are several RPC commands defined for the purpose of OAM.  In
   this section we present a snippet of the continuity check command for
   illustration purposes.  Please refer to Section 4.5 for the complete
   data hierarchy and Section 5 for the YANG model.

   module: ietf-connection-oriented-oam
       +--rw domains
             +--rw domain* [technology md-name-string]
             +--rw technology        identityref
       .
       .
   rpcs:
     +---x continuity-check {continuity-check}?
     |  +---w input



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     |  |  +---w technology?             identityref
     |  |  +---w md-name-string -> /domains/domain/md-name-string
     |  |  +---w md-level?      -> /domains/domain/md-level
     |  |  +---w ma-name-string -> /domains/domain/mas/ma/ma-name-string
     |  |  +---w cos-id?                 uint8
     |  |  +---w ttl?                    uint8
     |  |  +---w sub-type?               identityref
     |  |  +---w source-mep?    -> /domains/domain/mas/ma/mep/mep-name
     |  |  +---w destination-mep
     |  |  |  +---w (mep-address)?
     |  |  |  |  +--:(mac-address)
     |  |  |  |  |  +---w mac-address?     yang:mac-address
     |  |  |  |  +--:(ip-address)
     |  |  |  |     +---w ip-address?      inet:ip-address
     |  |  |  +---w (mep-id)?
     |  |  |  |  +--:(mep-id-int)
     |  |  |  |     +---w mep-id-int?      int32
     |  |  |  +---w mep-id-format?   identityref
     |  |  +---w count?                  uint32
     |  |  +---w cc-transmit-interval?   time-interval
     |  |  +---w packet-size?            uint32
     |  +--ro output
     |     +--ro (monitor-stats)?
     |        +--:(monitor-null)
     |           +--ro monitor-null?   empty
     +---x continuity-verification {connectivity-verification}?
     |  +---w input
     |  |  +---w md-name-string -> /domains/domain/md-name-string
     |  |  +---w md-level?      -> /domains/domain/md-level
     |  |  +---w ma-name-string -> /domains/domain/mas/ma/ma-name-string
     |  |  +---w cos-id?            uint8
     |  |  +---w ttl?               uint8
     |  |  +---w sub-type?          identityref
     |  |  +---w source-mep?    -> /domains/domain/mas/ma/mep/mep-name
     |  |  +---w destination-mep
     |  |  |  +---w (mep-address)?
     |  |  |  |  +--:(mac-address)
     |  |  |  |  |  +---w mac-address?     yang:mac-address
     |  |  |  |  +--:(ip-address)
     |  |  |  |     +---w ip-address?      inet:ip-address
     |  |  |  +---w (mep-id)?
     |  |  |  |  +--:(mep-id-int)
     |  |  |  |     +---w mep-id-int?      int32
     |  |  |  +---w mep-id-format?   identityref
     |  |  +---w count?             uint32
     |  |  +---w interval?          time-interval
     |  |  +---w packet-size?       uint32
     |  +--ro output



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     |     +--ro (monitor-stats)?
     |        +--:(monitor-null)
     |           +--ro monitor-null?   empty
     +---x traceroute {traceroute}?
        +---w input
        |  +---w md-name-string -> /domains/domain/md-name-string
        |  +---w md-level?      -> /domains/domain/md-level
        |  +---w ma-name-string -> /domains/domain/mas/ma/ma-name-string
        |  +---w cos-id?             uint8
        |  +---w ttl?                uint8
        |  +---w command-sub-type?   identityref
        |  +---w source-mep?    -> /domains/domain/mas/ma/mep/mep-name
        |  +---w destination-mep
        |  |  +---w (mep-address)?
        |  |  |  +--:(mac-address)
        |  |  |  |  +---w mac-address?     yang:mac-address
        |  |  |  +--:(ip-address)
        |  |  |     +---w ip-address?      inet:ip-address
        |  |  +---w (mep-id)?
        |  |  |  +--:(mep-id-int)
        |  |  |     +---w mep-id-int?      int32
        |  |  +---w mep-id-format?   identityref
        |  +---w count?              uint32
        |  +---w interval?           time-interval
        +--ro output
           +--ro response* [response-index]
              +--ro response-index     uint8
              +--ro ttl?               uint8
              +--ro destination-mep
              |  +--ro (mep-address)?
              |  |  +--:(mac-address)
              |  |  |  +--ro mac-address?     yang:mac-address
              |  |  +--:(ip-address)
              |  |     +--ro ip-address?      inet:ip-address
              |  +--ro (mep-id)?
              |  |  +--:(mep-id-int)
              |  |     +--ro mep-id-int?      int32
              |  +--ro mep-id-format?   identityref
              +--ro mip {mip}?
              |  +--ro interface?     if:interface-ref
              |  +--ro (mip-address)?
              |     +--:(mac-address)
              |     |  +--ro mac-address?   yang:mac-address
              |     +--:(ip-address)
              |        +--ro ip-address?    inet:ip-address
              +--ro (monitor-stats)?
                 +--:(monitor-null)
                    +--ro monitor-null?      empty



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      Snippet of data hierarchy related to RPC call continuity-check

4.5.  Notifications

   Notification is sent on detecting defect condition and on clearing
   defect with Maintenance Domain Name, MA Name, defect-type (The
   currently active defects), generating-mepid, and defect-message to
   indicate more details.

4.6.  Monitor statistics

   Grouping for monitoring statistics is to be used by technology
   specific YANG modules which Augment Generic YANG Model to provide
   statistics due to pro-active OAM like CCM Messages.  For example CCM
   Transmit, CCM Receive, CCM Errors, etc.

4.7.  OAM data hierarchy

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

 module: ietf-connection-oriented-oam
     +--rw domains
        +--rw domain* [technology md-name-string]
           +--rw technology        identityref
           +--rw md-name-string    md-name-string
           +--rw md-name-format?   identityref
           +--rw (md-name)?
           |  +--:(md-name-null)
           |     +--rw md-name-null?     empty
           +--rw md-level?         md-level
           +--rw mas
              +--rw ma* [ma-name-string]
                 +--rw ma-name-string    ma-name-string
                 +--rw ma-name-format?   identityref
                 +--rw (ma-name)?
                 |  +--:(ma-name-null)
                 |     +--rw ma-name-null?     empty
                 +--rw (connectivity-context)?
                 |  +--:(context-null)
                 |     +--rw context-null?     empty
                 +--rw cos-id?           uint8
                 +--rw cc-enable?        boolean
                 +--rw mep* [mep-name]
                 |  +--rw mep-name         mep-name
                 |  +--rw (mep-id)?
                 |  |  +--:(mep-id-int)
                 |  |     +--rw mep-id-int?      int32



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                 |  +--rw mep-id-format?   identityref
                 |  +--rw (mep-address)?
                 |  |  +--:(mac-address)
                 |  |  |  +--rw mac-address?     yang:mac-address
                 |  |  +--:(ip-address)
                 |  |     +--rw ip-address?      inet:ip-address
                 |  +--rw cos-id?          uint8
                 |  +--rw cc-enable?       boolean
                 |  +--rw session* [session-cookie]
                 |     +--rw session-cookie             uint32
                 |     +--rw destination-mep
                 |     |  +--rw (mep-id)?
                 |     |  |  +--:(mep-id-int)
                 |     |  |     +--rw mep-id-int?      int32
                 |     |  +--rw mep-id-format?   identityref
                 |     +--rw destination-mep-address
                 |     |  +--rw (mep-address)?
                 |     |     +--:(mac-address)
                 |     |     |  +--rw mac-address?   yang:mac-address
                 |     |     +--:(ip-address)
                 |     |        +--rw ip-address?    inet:ip-address
                 |     +--rw cos-id?                    uint8
                 +--rw mip* [name] {mip}?
                    +--rw name           string
                    +--rw interface?     if:interface-ref
                    +--rw (mip-address)?
                       +--:(mac-address)
                       |  +--rw mac-address?   yang:mac-address
                       +--:(ip-address)
                          +--rw ip-address?    inet:ip-address

   rpcs:
     +---x continuity-check {continuity-check}?
     |  +---w input
     |  |  +---w technology?             identityref
     |  |  +---w md-name-string -> /domains/domain/md-name-string
     |  |  +---w md-level?      -> /domains/domain/md-level
     |  |  +---w ma-name-string -> /domains/domain/mas/ma/ma-name-string
     |  |  +---w cos-id?                 uint8
     |  |  +---w ttl?                    uint8
     |  |  +---w sub-type?               identityref
     |  |  +---w source-mep?    -> /domains/domain/mas/ma/mep/mep-name
     |  |  +---w destination-mep
     |  |  |  +---w (mep-address)?
     |  |  |  |  +--:(mac-address)
     |  |  |  |  |  +---w mac-address?     yang:mac-address
     |  |  |  |  +--:(ip-address)
     |  |  |  |     +---w ip-address?      inet:ip-address



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     |  |  |  +---w (mep-id)?
     |  |  |  |  +--:(mep-id-int)
     |  |  |  |     +---w mep-id-int?      int32
     |  |  |  +---w mep-id-format?   identityref
     |  |  +---w count?                  uint32
     |  |  +---w cc-transmit-interval?   time-interval
     |  |  +---w packet-size?            uint32
     |  +--ro output
     |     +--ro (monitor-stats)?
     |        +--:(monitor-null)
     |           +--ro monitor-null?   empty
     +---x continuity-verification {connectivity-verification}?
     |  +---w input
     |  |  +---w md-name-string -> /domains/domain/md-name-string
     |  |  +---w md-level?      -> /domains/domain/md-level
     |  |  +---w ma-name-string -> /domains/domain/mas/ma/ma-name-string
     |  |  +---w cos-id?            uint8
     |  |  +---w ttl?               uint8
     |  |  +---w sub-type?          identityref
     |  |  +---w source-mep?    -> /domains/domain/mas/ma/mep/mep-name
     |  |  +---w destination-mep
     |  |  |  +---w (mep-address)?
     |  |  |  |  +--:(mac-address)
     |  |  |  |  |  +---w mac-address?     yang:mac-address
     |  |  |  |  +--:(ip-address)
     |  |  |  |     +---w ip-address?      inet:ip-address
     |  |  |  +---w (mep-id)?
     |  |  |  |  +--:(mep-id-int)
     |  |  |  |     +---w mep-id-int?      int32
     |  |  |  +---w mep-id-format?   identityref
     |  |  +---w count?             uint32
     |  |  +---w interval?          time-interval
     |  |  +---w packet-size?       uint32
     |  +--ro output
     |     +--ro (monitor-stats)?
     |        +--:(monitor-null)
     |           +--ro monitor-null?   empty
     +---x traceroute {traceroute}?
        +---w input
        |  +---w md-name-string -> /domains/domain/md-name-string
        |  +---w md-level?      -> /domains/domain/md-level
        |  +---w ma-name-string -> /domains/domain/mas/ma/ma-name-string
        |  +---w cos-id?             uint8
        |  +---w ttl?                uint8
        |  +---w command-sub-type?   identityref
        |  +---w source-mep?    -> /domains/domain/mas/ma/mep/mep-name
        |  +---w destination-mep
        |  |  +---w (mep-address)?



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        |  |  |  +--:(mac-address)
        |  |  |  |  +---w mac-address?     yang:mac-address
        |  |  |  +--:(ip-address)
        |  |  |     +---w ip-address?      inet:ip-address
        |  |  +---w (mep-id)?
        |  |  |  +--:(mep-id-int)
        |  |  |     +---w mep-id-int?      int32
        |  |  +---w mep-id-format?   identityref
        |  +---w count?              uint32
        |  +---w interval?           time-interval
        +--ro output
           +--ro response* [response-index]
              +--ro response-index     uint8
              +--ro ttl?               uint8
              +--ro destination-mep
              |  +--ro (mep-address)?
              |  |  +--:(mac-address)
              |  |  |  +--ro mac-address?     yang:mac-address
              |  |  +--:(ip-address)
              |  |     +--ro ip-address?      inet:ip-address
              |  +--ro (mep-id)?
              |  |  +--:(mep-id-int)
              |  |     +--ro mep-id-int?      int32
              |  +--ro mep-id-format?   identityref
              +--ro mip {mip}?
              |  +--ro interface?     if:interface-ref
              |  +--ro (mip-address)?
              |     +--:(mac-address)
              |     |  +--ro mac-address?   yang:mac-address
              |     +--:(ip-address)
              |        +--ro ip-address?    inet:ip-address
              +--ro (monitor-stats)?
                 +--:(monitor-null)
                    +--ro monitor-null?      empty

   notifications:
     +---n defect-condition-notification
     |  +--ro technology?         identityref
     |  +--ro md-name-string -> /domains/domain/md-name-string
     |  +--ro ma-name-string -> /domains/domain/mas/ma/ma-name-string
     |  +--ro mep-name?      -> /domains/domain/mas/ma/mep/mep-name
     |  +--ro defect-type?        identityref
     |  +--ro generating-mepid
     |  |  +--ro (mep-id)?
     |  |  |  +--:(mep-id-int)
     |  |  |     +--ro mep-id-int?      int32
     |  |  +--ro mep-id-format?   identityref
     |  +--ro (defect)?



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     |     +--:(defect-null)
     |     |  +--ro defect-null?        empty
     |     +--:(defect-code)
     |        +--ro defect-code?        int32
     +---n defect-cleared-notification
        +--ro technology?         identityref
        +--ro md-name-string -> /domains/domain/md-name-string
        +--ro ma-name-string -> /domains/domain/mas/ma/ma-name-string
        +--ro mep-name?      -> /domains/domain/mas/ma/mep/mep-name
        +--ro defect-type?        identityref
        +--ro generating-mepid
        |  +--ro (mep-id)?
        |  |  +--:(mep-id-int)
        |  |     +--ro mep-id-int?      int32
        |  +--ro mep-id-format?   identityref
        +--ro (defect)?
           +--:(defect-null)
           |  +--ro defect-null?        empty
           +--:(defect-code)
              +--ro defect-code?        int32

                           data hierarchy of OAM

5.  OAM YANG Module

   This module imports typedefs from [RFC6991] and [I-D.ietf-netmod-
   rfc7223bis], and it references [RFC6371],[RFC6905], [RFC7276].

   RFC Ed.: update the date below with the date of RFC publication and
   remove this note.

   <CODE BEGINS> file "ietf-connection-oriented-oam@2018-02-07.yang"

module ietf-connection-oriented-oam {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-connection-oriented-oam";
  prefix co-oam;

  import ietf-yang-types {
    prefix yang;
  }
  import ietf-inet-types {
    prefix inet;
  }
  import ietf-interfaces {
    prefix if;
  }




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  organization
    "IETF LIME Working Group";
  contact
    "WG Web:    http://tools.ietf.org/wg/lime
     WG List:   mailto:lime@ietf.org
     Editor:    Deepak Kumar dekumar@cisco.com
     Editor:    Qin Wu bill.wu@huawei.com
     Editor:    Zitao Wang wangzitao@huawei.com";
  description
    "This YANG module defines the generic configuration,
     statistics and rpc for connection oriented OAM
     to be used within IETF in a protocol independent manner.
     Functional level abstraction is independent
     with YANG modeling. It is assumed that each protocol
     maps corresponding abstracts to its native format.
     Each protocol may extend the YANG model defined
     here to include protocol specific extensions

     Copyright (c) 2018 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

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

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

  revision 2018-02-07 {
    description
      "Initial revision.";
    reference
      "RFC xxxx: Generic YANG Data Model for Connection
       Oriented OAM protocols";
  }

  feature connectivity-verification {
    description
      "This feature indicates that the server supports
       executing connectivity verification OAM command and
       returning a response. Servers that do not advertise
       this feature will not support executing
       connectivity verification command or rpc model for
       connectivity verification command.";
  }



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  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 model for
       continuity check command.";
  }

  feature traceroute {
    description
      "This feature indicates that the server supports
       executing traceroute OAM command and
       returning a response. Servers that do not advertise
       this feature will not support executing
       traceroute command or rpc model for
       traceroute command.";
  }

  feature mip {
    description
      "This feature indicates that the Maintenance
       Intermediate Point(MIP) needs to be explicit configured";
  }

  identity technology-types {
    description
      "This is the base identity of technology types which are
       TRILL, MPLS-TP, etc";
  }

  identity command-sub-type {
    description
      "Defines different rpc command subtypes,
       e.g rfc6905 trill OAM, this is optional for most cases";
    reference
      "RFC 6905: Requirements for OAM in Transparent
       Interconnection of Lots of Links (TRILL)";

  }

  identity on-demand {
    base command-sub-type;
    description
      "On demand activation - indicates that the tool is activated
       manually to detect a specific anomaly.
       On-demand OAM method requires only transient configuration.";



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    reference
      "RFC 7276: An Overview of Operations, Administration, and
       Maintenance (OAM) Tools";
  }

  identity proactive {
    base command-sub-type;
    description
      "Proactive activation - indicates that the tool is activated on a
       continual basis, where messages are sent periodically, and errors
       are detected when a certain number of expected messages are not
       received. Proactive OAM method requires persistent
       configuration.";
    reference
      "RFC 7276: An Overview of Operations, Administration, and
       Maintenance (OAM) Tools";
  }

  identity name-format {
    description
      "This defines the name format, IEEE 8021ag CFM defines varying
       styles of names. It is expected name format as an identity ref
       to be extended with new types.";
  }

  identity name-format-null {
    base name-format;
    description
      "Defines name format as null";
  }

  identity identifier-format {
    description
      "Identifier-format identity can be augmented to define other
       format identifiers used in MEP-ID etc";
  }

  identity identifier-format-integer {
    base identifier-format;
    description
      "Defines identifier-format to be integer";
  }

  identity defect-types {
    description
      "Defines different defect types, e.g.
       Remote Defect Indication (rdi), loss of continuity";
  }



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  identity rdi {
    base defect-types;
    description
      "The Remote Defect Indication (rdi) indicates the
       aggregate health of the remote Maintenance End Points (MEPs).";
  }

  identity remote-mep-defect {
    base defect-types;
    description
      "Indicates that one or more of the remote
       Maintenance End Points(MEPs)is reporting a failure ";
  }

  identity loss-of-continuity {
    base defect-types;
    description
      "Indicate there is no proactive Continuity Check (CC)
       OAM packets from the source Maintenance End Point
       (MEP) (and in the case of Connectivity
       Verification , this includes the
       requirement to have the expected unique,
       technology dependent source MEP
       identifier) received within the interval.";
    reference
      "RFC 6371: Operations, Administration, and Maintenance
       Framework for MPLS-Based Transport Networks";
  }

  identity cv-defect {
    base defect-types;
    description
      "This function should support monitoring between
       the Maintenance End Points (MEPs) and,
       in addition, between a MEP and Maintenance Intermediate
       Point (MIP). When performing Connectivity Verification,
       the need for the Continuity Check and Connectivity
       Verification (CC-V) messages to include unique
       identification of the MEG that is being monitored and
       the MEP that originated the message.";
    reference
      "RFC 6371: Operations, Administration, and Maintenance
       Framework for MPLS-Based Transport Networks";
  }

  identity invalid-oam-defect {
    base defect-types;
    description



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      "Indicates that one or more invalid OAM messages has been
       received and that 3.5 times that OAM message transmission
       interval has not yet expired.";
  }

  identity cross-connect-defect {
    base defect-types;
    description
      "Indicates that one or more cross-connect defect
       (for example, a service ID does not match the VLAN.)
       messages has been received and that 3.5 times that OAM message
       transmission interval has not yet expired.";
  }

  typedef mep-name {
    type string;
    description
      "Generic administrative name for a Maintenance End Point
       (MEP).";
  }

  typedef time-interval {
    type decimal64 {
      fraction-digits 2;
    }
    units "milliseconds";
    description
      "Time interval between packets in milliseconds.
       Time interval should not be less than 0.
       0 means no packets are sent.";
  }

  typedef md-name-string {
    type string;
    description
      "Generic administrative name for Maintenance Domain (MD).";
  }

  typedef ma-name-string {
    type string;
    description
      "Generic administrative name for a
       Maintenance Association (MA).";
  }

  typedef oam-counter32 {
    type yang:zero-based-counter32;
    description



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      "Define 32 bit counter for OAM.";
  }

  typedef md-level {
    type uint32 {
      range "0..255";
    }
    description
      "Maintenance Domain level.  The level may be restricted in
       certain protocols (e.g., protocol in layer 0 to layer 7).";
  }

  grouping maintenance-domain-reference {
    description
      "This grouping uniquely identifies a maintenance domain.";
    leaf maintenance-domain {
      type leafref {
        path "/co-oam:domains/co-oam:domain/co-oam:md-name-string";
      }
      description
        "A reference to a specific Maintenance Domain.";
    }
  }

  grouping maintenance-association-reference {
    description
      "This grouping uniquely identifies a
       maintenance association. It consists
       of a maintence-domain-reference and
       a maintenance-association leafref";
    uses maintenance-domain-reference;
    leaf maintenance-association {
      type leafref {
        path "/co-oam:domains/co-oam:domain[co-oam:md-name-string "
        +"= current()/../maintenance-domain]/co-oam:mas"
        +"/co-oam:ma/co-oam:ma-name-string";
      }
      description
        "A reference to a specific Maintenance Association.";
    }
  }

  grouping maintenance-association-end-point-reference {
    description
      "This grouping uniquely identifies
       a maintenance association. It consists
       of a maintence-association-reference and
       a maintenance-association-end-point leafref";



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    uses maintenance-association-reference;
    leaf maintenance-association-end-point {
      type leafref {
        path "/co-oam:domains/co-oam:domain[co-oam:md-name-string "
        +"= current()/../maintenance-domain]/co-oam:mas"
        +"/co-oam:ma[co-oam:ma-name-string = "
        +"current()/../maintenance-association]"
        +"/co-oam:mep/co-oam:mep-name";
      }
      description
        "A reference to a specific Maintenance
         association End Point.";
    }
  }

  grouping time-to-live {
    leaf ttl {
      type uint8;
      description
        "Time to Live.";
    }
    description
      "Time to Live grouping.";
  }

  grouping defect-message {
    choice defect {
      case defect-null {
        description
          "This is a placeholder when no defect status is needed";
        leaf defect-null {
          type empty;
          description
            "There is no defect to be defined, it will be defined in
             technology specific model.";
        }
      }
      case defect-code {
        description
          "This is a placeholder to display defect code.";
        leaf defect-code {
          type int32;
          description
            "Defect code is integer value specific to a technology.";
        }
      }
      description
        "Defect Message choices.";



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    }
    description
      "Defect Message.";
  }

  grouping mep-address {
    choice mep-address {
      default ip-address;
      case mac-address {
        leaf mac-address {
          type yang:mac-address;
          description
            "MAC Address.";
        }
        description
          "MAC Address based Maintenance End Point (MEP) Addressing.";
      }
      case ip-address {
        leaf ip-address {
          type inet:ip-address;
          description
            "IP Address.";
        }
        description
          "IP Address based Maintenance End Point(MEP) Addressing.";
      }
      description
        "Maintenance End Point (MEP) Addressing.";
    }
    description
      "Grouping for Maintenance End Point(MEP) Address";
  }

  grouping mip-address {
    choice mip-address {
      default ip-address;
      case mac-address {
        leaf mac-address {
          type yang:mac-address;
          description
            "MAC Address of Maintenance Intermediate Point";
        }
        description
          "MAC Address based Maintenance Intermediate
           Point (MIP) Addressing.";
      }
      case ip-address {
        leaf ip-address {



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          type inet:ip-address;
          description
            "IP Address.";
        }
        description
          "IP Address based Maintenance Intermediate Point(MIP)
           Addressing.";
      }
      description
        "Maintenance Intermediate Point (MIP) Addressing.";
    }
    description
      "Maintenance Intermediate Point (MIP) Address.";
  }

  grouping maintenance-domain-id {
    description
      "Grouping containing leaves sufficient to identify
       a Maintenance Domain.";
    leaf technology {
      type identityref {
        base technology-types;
      }
      mandatory true;
      description
        "Defines the technology.";
    }
    leaf md-name-string {
      type md-name-string;
      mandatory true;
      description
        "Defines the generic administrative maintenance domain name.";
    }
  }

  grouping md-name {
    leaf md-name-format {
      type identityref {
        base name-format;
      }
      description
        "Maintenance Domain Name format.";
    }
    choice md-name {
      case md-name-null {
        leaf md-name-null {
          when "derived-from-or-self(../md-name-format,"
          +"'name-format-null')" {



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            description
              "Maintenance Domain (MD) name
               format is equal to null format.";
          }
          type empty;
          description
            "Maintenance Domain (MD) name Null.";
        }
      }
      description
        "Maintenance Domain (MD) name.";
    }
    description
      "Maintenance Domain (MD) name.";
  }

  grouping ma-identifier {
    description
      "Grouping containing leaves sufficient to identify
       an Maintenance Association (MA).";
    leaf ma-name-string {
      type ma-name-string;
      description
        "Maintenance Association (MA) name string.";
    }
  }

  grouping ma-name {
    description
      "Maintenance Association (MA) name.";
    leaf ma-name-format {
      type identityref {
        base name-format;
      }
      description
        "Maintenance Association (MA) name format.";
    }
    choice ma-name {
      case ma-name-null {
        leaf ma-name-null {
          when "derived-from-or-self(../ma-name-format, "
          +"'name-format-null')" {
            description
              "Maintenance Association (MA).";
          }
          type empty;
          description
            "Empty";



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        }
      }
      description
        "Maintenance Association) name(MA).";
    }
  }

  grouping mep-id {
    choice mep-id {
      default "mep-id-int";
      case mep-id-int {
        leaf mep-id-int {
          type int32;
          description
            "Maintenance End Point (MEP) ID
             in integer format.";
        }
      }
      description
        "Maintenance End Point (MEP) ID.";
    }
    leaf mep-id-format {
      type identityref {
        base identifier-format;
      }
      description
        "Maintenance End Point (MEP) ID format.";
    }
    description
      "Maintenance End Point (MEP) ID.";
  }

  grouping mep {
    description
      "Defines elements within the
       Maintenance End Point (MEP).";
    leaf mep-name {
      type mep-name;
      mandatory true;
      description
        "Generic administrative name of the
         Maintenance End Point (MEP).";
    }
    uses mep-id;
    uses mep-address;
  }

  grouping monitor-stats {



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    description
      "grouping for monitoring statistics, this will be augmented
       by others who use this component";
    choice monitor-stats {
      default "monitor-null";
      case monitor-null {
        description
          "This is a place holder when
           no monitoring statistics is needed";
        leaf monitor-null {
          type empty;
          description
            "There is no monitoring statistics to be defined.";
        }
      }
      description
        "Define the monitor stats.";
    }
  }

  grouping connectivity-context {
    description
      "Grouping defining the connectivity context for an
       Maintenance Association (MA), for example,
       an LSP for MPLS-TP. This will be
       augmented by each protocol who use this component.";
    choice connectivity-context {
      default "context-null";
      case context-null {
        description
          "This is a place holder when no context is needed.";
        leaf context-null {
          type empty;
          description
            "There is no context to be defined.";
        }
      }
      description
        "Connectivity context.";
    }
  }

  grouping cos {
    description
      "Grouping for Priority used in transmitted packets,
       for example, in the CoS field in MPLS-TP.";
    leaf cos-id {
      type uint8;



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      description
        "Class of Service(CoS) id, this value is used to indicate
         Class of Service information .";
    }
  }

  grouping mip-grouping {
    uses mip-address;
    description
      "Grouping for Maintenance Intermediate Point(MIP)
       configuration.";
  }

  container domains {
    description
      "Contains configuration related data. Within the
       container there is a list of fault domains. each
       domian has a List of Maintenance Association
       (MA).";
    list domain {
      key "technology md-name-string";
      description
        "Define a list of Domains within the
         ietf-connection-oriented-oam module.";
      uses maintenance-domain-id;
      uses md-name;
      leaf md-level {
        type md-level;
        description
          "Define the MD-Level.";
      }
      container mas {
        description
          "This container defines Maintenance Association (MA),
           within that have multiple MA and within MA have
           Maintenance End Point (MEP).";
        list ma {
          key "ma-name-string";
          uses ma-identifier;
          uses ma-name;
          uses connectivity-context;
          uses cos {
            description
              "Default class of service for this
               Maintenance Association (MA),
               which may be overridden for particular
               Maintenance End Points (MEPs),
               sessions or operations.";



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          }
          leaf cc-enable {
            type boolean;
            description
              "Indicate whether the
               Continuity Check (CC) is enabled.";
          }
          list mep {
            key "mep-name";
            description
              "Contain a list of Maintenance End Points (MEPs)";
            uses mep;
            uses cos;
            leaf cc-enable {
              type boolean;
              description
                "Indicate whether the Continuity Check (CC)is enabled.";
            }
            list session {
              key "session-cookie";
              description
                "Monitoring session to/from a particular
                 remote Maintenance End Point (MEP).
                 Depending on the protocol, this could represent
                 Continuity Check (CC) messages received from
                 a single remote MEP (if the protocol uses
                 multicast CCs) or a target to which
                 unicast echo request CCs are sent and from which
                 responses are received (if the protocol uses a

                 unicast request/response mechanism).";
              leaf session-cookie {
                type uint32;
                description
                  "Cookie to identify different sessions, when there
                   are multiple remote Maintenance End Point(MEP)
                   or multiple sessions tothe same remote MEP.";
              }
              container destination-mep {
                uses mep-id;
                description
                  "Destination Maintenance End Point(MEP).";
              }
              container destination-mep-address {
                uses mep-address;
                description
                  "Destination Maintenance End Point (MEP) Address.";
              }



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              uses cos;
            }
          }
          list mip {
            if-feature "mip";
            key "name";
            leaf name {
              type string;
              description
                "Identifier of Maintenance intermediate point";
            }
            leaf interface {
              type if:interface-ref;
              description
                "Interface";
            }
            uses mip-grouping;
            description
              "List for Maintenance Intermediate Point (MIP).";
          }
          description
            "Maintenance Association list.";
        }
      }
    }
  }
  notification defect-condition-notification {
    description
      "Upon the defect condition is met, this
       notification is sent";
    leaf technology {
      type identityref {
        base technology-types;
      }
      description
        "The technology";
    }
    leaf md-name-string {
      type leafref {
        path "/domains/domain/md-name-string";
      }
      mandatory true;
      description
        "Indicate which Maintenance Domain(MD)
         does the defect belong to.";
    }
    leaf ma-name-string {
      type leafref {



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        path "/domains/domain/mas/ma/ma-name-string";
      }
      mandatory true;
      description
        "Indicate which Maintenance Association (MA)
         is the defect associated with.";
    }
    leaf mep-name {
      type leafref {
        path "/domains/domain/mas/ma/mep/mep-name";
      }
      description
        "Indicate which Maintenance End Point(MEP)
         is seeing the defect.";
    }
    leaf defect-type {
      type identityref {
        base defect-types;
      }
      description
        "The currently active defects on the specific
         Maintenance End Point (MEP).";
    }
    container generating-mepid {
      uses mep-id;
      description
        "Indicate who is generating the defect (if known). If
         unknown set it as 0.";
    }
    uses defect-message {
      description
        "The defect message to indicate more details.";
    }
  }
  notification defect-cleared-notification {
    description
      "Upon defect cleared is met, this notification is sent";
    leaf technology {
      type identityref {
        base technology-types;
      }
      description
        "The technology.";
    }
    leaf md-name-string {
      type leafref {
        path "/domains/domain/md-name-string";
      }



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      mandatory true;
      description
        "Indicate which Maintenance Domain (MD)
         does the defect belong to";
    }
    leaf ma-name-string {
      type leafref {
        path "/domains/domain/mas/ma/ma-name-string";
      }
      mandatory true;
      description
        "Indicate which Maintenance Association (MA)
         is the defect associated with.";
    }
    leaf mep-name {
      type leafref {
        path "/domains/domain/mas/ma/mep/mep-name";
      }
      description
        "Indicate which Maintenance End Point (MEP)
         is seeing the defect.";
    }
    leaf defect-type {
      type identityref {
        base defect-types;
      }
      description
        "The currently active defects on the
         specific Maintenance End Point (MEP).";
    }
    container generating-mepid {
      uses mep-id;
      description
        "Indicate who is generating the defect (if known). if
         unknown set it as 0.";
    }
    uses defect-message {
      description
        "Defect message to indicate more details.";
    }
  }
  rpc continuity-check {
    if-feature "continuity-check";
    description
      "Generates continuity-check as per RFC7276 Table 4.";
    input {
      leaf technology {
        type identityref {



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          base technology-types;
        }
        description
          "The technology";
      }
      leaf md-name-string {
        type leafref {
          path "/domains/domain/md-name-string";
        }
        mandatory true;
        description
          "Indicate which Maintenance Domain (MD)
           does the defect belong to.";
      }
      leaf md-level {
        type leafref {
          path "/domains/domain/md-level";
        }
        description
          "The maintenance domain level.";
      }
      leaf ma-name-string {
        type leafref {
          path "/domains/domain/mas/ma/ma-name-string";
        }
        mandatory true;
        description
          "Indicate which MA is the defect associated with";
      }
      uses cos;
      uses time-to-live;
      leaf sub-type {
        type identityref {
          base command-sub-type;
        }
        description
          "Defines different command types.";
      }
      leaf source-mep {
        type leafref {
          path "/domains/domain/mas/ma/mep/mep-name";
        }
        description
          "Source Maintenance End Point (MEP).";
      }
      container destination-mep {
        uses mep-address;
        uses mep-id {



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          description
            "Only applicable if the destination is
             a Maintenance End Point (MEP).";
        }
        description
          "Destination Maintenance End Point (MEP).";
      }
      leaf count {
        type uint32;
        default "3";
        description
          "Number of continuity-check message to be sent.";
      }
      leaf cc-transmit-interval {
        type time-interval;
        description
          "Time interval between echo requests.";
      }
      leaf packet-size {
        type uint32 {
          range "64..10000";
        }
        description
          "Size of continuity-check packets, in octets.";
      }
    }
    output {
      uses monitor-stats {
        description
          "Stats of continuity check.";
      }
    }
  }
  rpc continuity-verification {
    if-feature "connectivity-verification";
    description
      "Generates continuity-verification as per RFC7276 Table 4.";
    input {
      leaf md-name-string {
        type leafref {
          path "/domains/domain/md-name-string";
        }
        mandatory true;
        description
          "Indicate which MD (Maintenance Domain)
           does the defect belong to.";
      }
      leaf md-level {



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        type leafref {
          path "/domains/domain/md-level";
        }
        description
          "The maintenance domain level.";
      }
      leaf ma-name-string {
        type leafref {
          path "/domains/domain/mas/ma/ma-name-string";
        }
        mandatory true;
        description
          "Indicate which Maintenance Association (MA)
           is the defect associated with.";
      }
      uses cos;
      uses time-to-live;
      leaf sub-type {
        type identityref {
          base command-sub-type;
        }
        description
          "Defines different command types.";
      }
      leaf source-mep {
        type leafref {
          path "/domains/domain/mas/ma/mep/mep-name";
        }
        description
          "Source Maintenance End Point(MEP).";
      }
      container destination-mep {
        uses mep-address;
        uses mep-id {
          description
            "Only applicable if the destination
             is a Maintenance End Point (MEP).";
        }
        description
          "Destination Maintenance End Point(MEP).";
      }
      leaf count {
        type uint32;
        default "3";
        description
          "Number of continuity-verification message to be sent.";
      }
      leaf interval {



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        type time-interval;
        description
          "Time interval between echo requests.";
      }
      leaf packet-size {
        type uint32 {
          range "64..10000";
        }
        description
          "Size of continuity-verification packets, in octets";
      }
    }
    output {
      uses monitor-stats {
        description
          "Stats of continuity check.";
      }
    }
  }
  rpc traceroute {
    if-feature "traceroute";
    description
      "Generates Traceroute or Path Trace and return response.
       Referencing RFC7276 for common Toolset name, for
       MPLS-TP OAM, it's Route Tracing, and for TRILL OAM, it's
       Path Tracing tool. Starts with TTL of one and increment
       by one at each hop. Untill destination reached or TTL
       reach max value.";
    input {
      leaf md-name-string {
        type leafref {
          path "/domains/domain/md-name-string";
        }
        mandatory true;
        description
          "Indicate which Maintenance Domain (MD)
           does the defect belong to.";
      }
      leaf md-level {
        type leafref {
          path "/domains/domain/md-level";
        }
        description
          "The maintenance domain level.";
      }
      leaf ma-name-string {
        type leafref {
          path "/domains/domain/mas/ma/ma-name-string";



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        }
        mandatory true;
        description
          "Indicate which Maintenance Association (MA)
           is the defect associated with.";
      }
      uses cos;
      uses time-to-live;
      leaf command-sub-type {
        type identityref {
          base command-sub-type;
        }
        description
          "Defines different command types.";
      }
      leaf source-mep {
        type leafref {
          path "/domains/domain/mas/ma/mep/mep-name";
        }
        description
          "Source Maintenance End Point (MEP).";
      }
      container destination-mep {
        uses mep-address;
        uses mep-id {
          description
            "Only applicable if the destination is a
             Maintenance End Point (MEP).";
        }
        description
          "Destination Maintenance End Point (MEP).";
      }
      leaf count {
        type uint32;
        default "1";
        description
          "Number of traceroute probes to send. In protocols where a
           separate message is sent at each TTL, this is the number
           of packets to be sent at each TTL.";
      }
      leaf interval {
        type time-interval;
        description
          "Time interval between echo requests.";
      }
    }
    output {
      list response {



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        key "response-index";
        leaf response-index {
          type uint8;
          description
            "Arbitrary index for the response.  In protocols that
             guarantee there is only a single response at each TTL,
             the TTL can be used as the response index.";
        }
        uses time-to-live;
        container destination-mep {
          description
            "Maintenance End Point (MEP) from
             which the response has been received";
          uses mep-address;
          uses mep-id {
            description
              "Only applicable if the destination is a
               Maintenance End Point (MEP).";
          }
        }
        container mip {
          if-feature "mip";
          leaf interface {
            type if:interface-ref;
            description
              "Maintenance Intermediate Point (MIP) interface.";
          }
          uses mip-address;
          description
            "Maintenance Intermediate Point (MIP)
             responding with traceroute";
        }
        uses monitor-stats {
          description
            "Stats of traceroute.";
        }
        description
          "List of response.";
      }
    }
  }
}

   <CODE ENDS>







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6.  Base Mode

   The Base Mode ('default mode' described in section 4) defines default
   configuration that MUST be present in the devices that comply with
   this document.  Base Mode allows users to have "zero-touch"
   experience.  Several parameters require technology specific
   definition.

6.1.  MEP Address

   In the Base Mode of operation, the MEP Address is by default the IP
   address of the interface on which the MEP is located.

6.2.  MEP ID for Base Mode

   In the Base Mode of operation, each device creates a single MEP
   associated with a virtual OAM port with no physical layer (NULL PHY).
   The MEP-ID associated with this MEP is zero (0).  The choice of MEP-
   ID zero is explained below.

   MEP-ID is 2 octet field by default.  It is never used on the wire
   except when using CCM.  It is important to have method that can
   derive MEP-ID of base mode in an automatic manner with no user
   intervention.  IP address cannot be directly used for this purpose as
   the MEP-ID is much smaller field.  For Base Mode of operation MEP-ID
   zero (0) is set as the default MEP-ID.

   CCM packet use MEP-ID on the payload.  CCM MUST NOT be used in the
   Base Mode.  Hence CCM MUST be disabled on the Maintenance Association
   of the Base Mode.

   If CCM is required, users MUST configure a separate Maintenance
   association and assign unique value for the corresponding MEP IDs.

   CFM [IEEE802.1Q] defines MEP ID as an unsigned integer in the range 1
   to 8191.  In this document we propose extend the range to 0 to 65535.
   Value 0 is reserved for MEP-ID of Base Mode operation and MUST NOT be
   used for other purposes.

6.3.  Maintenance Association

   The ID of the Maintenance Association (MA-ID) [IEEE802.1Q] has a
   flexible format and includes two parts: Maintenance Domain Name and
   Short MA name.  In the Base Mode of operation, the value of the
   Maintenance Domain Name must be the character string
   "GenericBaseMode" (excluding the quotes ").  In the Base Mode
   operation, the Short MA Name format is set to 2-octet integer format




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   (value 3 in Short MA Format field [IEEE802.1Q]) and the Short MA name
   set to 65532 (0xFFFC).

7.  Connection-oriented OAM YANG model applicability

   "ietf-connection-oriented-oam" model defined in this document
   provides technology-independent abstraction of key OAM constructs for
   connection-oriented protocols.  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
   connection-oriented OAM model.

   This section demonstrates the usability of the connection-oriented
   YANG OAM data model to various connection-oriented OAM technologies,
   e.g., TRILL and MPLS-TP.  Note that, in this section, we only present
   several snippets of technology-specific model extensions for
   illustrative purposes.  The complete model extensions should be
   worked on in respective protocol working groups.

7.1.  Generic YANG Model extension for TRILL OAM

   The TRILL OAM YANG module (I-D.trill-yang-oam) is augmenting
   connection-oriented OAM module for both configuration and RPC
   commands.

   In addition,the TRILL OAM YANG module also requires the base TRILL
   module ([I-D.ietf-trill-yang]) to be supported as there is a strong
   relationship between those modules.

   The configuration extensions for connection-oriented OAM include MD
   configuration extension, Technology type extension, MA configuration
   extension, Connectivity-Context Extension, MEP Configuration
   Extension, ECMP extension.  In the RPC extension, the continuity-
   check and path-discovery RPC are extended with TRILL specific
   parameters.

7.1.1.  MD Configuration Extension

   MD level configuration parameters are management information which
   can be inherited in the TRILL OAM model and set by connection-
   oriented base model as default values.  For example domain name can
   be set to area-ID in the TRILL OAM case.  In addition, at the
   Maintenance Domain level (i.e., at root level), domain data node can
   be augmented with technology type.

   Note that MD level configuration parameters provides context
   information for the management system to correlate faults, defects,



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   network failures with location information, which helps quickly
   identify root causes of network failures.

7.1.1.1.  Technology Type Extension

   No TRILL technology type has been defined in the connection-oriented
   base model.  Therefore a technology type extension is required in the
   TRILL OAM model.  The technology type "trill" is defined as an
   identity that augments the base "technology-types" defined in the
   connection-oriented base model:

      identity trill{
       base co-oam:technology-types;
       description
        "trill type";
      }

7.1.2.  MA Configuration Extension

   MA level configuration parameters are management information which
   can be inherited in the TRILL OAM model and set by connection-
   oriented base model as default values.  In addition, at the
   Maintenance Association(MA) level (i.e.,at the second level), MA data
   node can be augmented with connectivity-context extension.

   Note that MA level configuration parameters provides context
   information for the management system to correlate faults, defects,
   network failures with location information, which helps quickly
   identify root causes of network failures.

7.1.2.1.  Connectivity-Context Extension

   In TRILL OAM, one example of connectivity-context is either a 12 bit
   VLAN ID or a 24 bit Fine Grain Label.  The connection-oriented base
   model defines a placeholder for context-id.  This allows other
   technologies to easily augment that to include technology specific
   extensions.  The snippet below depicts an example of augmenting
   connectivity-context to include either VLAN ID or Fine Grain Label.

      augment /co-oam:domains/co-oam:domain
   /co-oam:mas/co-oam:ma/co-oam:connectivity-context:
            +--:(connectivity-context-vlan)
            |  +--rw connectivity-context-vlan?   vlan
            +--:(connectivity-context-fgl)
               +--rw connectivity-context-fgl?    fgl






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7.1.3.  MEP Configuration Extension

   The MEP configuration definition in the connection-oriented base
   model already supports configuring the interface of MEP with either
   MAC address or IP address.  In addition, the MEP address can be
   represented using a 2 octet RBridge Nickname in TRILL OAM . Hence,
   the TRILL OAM model augments the MEP configuration in base model to
   add a nickname case into the MEP address choice node as follows:

   augment /co-oam:domains/co-oam:domain
   /co-oam:mas/co-oam:ma/co-oam:mep/co-oam:mep-address:
            +--:( mep-address-trill)
            |  +--rw mep-address-trill?  tril-rb-nickname

   In addition, at the Maintenance Association Endpoint(MEP) level
   (i.e.,at the third level), MEP data node can be augmented with ECMP
   extension.

7.1.3.1.  ECMP Extension

   Since TRILL supports ECMP path selection, flow-entropy in TRILL is
   defined as a 96 octet field in the LIME model extension for TRILL
   OAM.  The snippet below illustrates its extension.

    augment /co-oam:domains/co-oam:domain
   /co-oam:mas/co-oam:ma/co-oam:mep:
               +--rw flow-entropy-trill?   flow-entropy-trill
      augment /co-oam:domains/co-oam:domain
   /co-oam:mas/co-oam:ma/co-oam:mep/co-oam:session:
               +--rw flow-entropy-trill?   flow-entropy-trill

7.1.4.  RPC extension

   In the TRILL OAM YANG model, the continuity-check and path-discovery
   RPC commands are extended with TRILL specific requirements.  The
   snippet below depicts an example of illustrates the TRILL OAM RPC
   extension.














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      augment /co-oam:continuity-check/co-oam:input:
            +--ro (out-of-band)?
            |  +--:(ipv4-address)
            |  |  +--ro ipv4-address?      inet:ipv4-address
            |  +--:(ipv6-address)
            |  |  +--ro ipv6-address?      inet:ipv6-address
            |  +--:(trill-nickname)
            |     +--ro trill-nickname?    tril-rb-nickname
            +--ro diagnostic-vlan?   boolean
      augment /co-oam:continuity-check/co-oam:input:
               +--ro flow-entropy-trill?   flow-entropy-trill
      augment /co-oam:continuity-check/co-oam:output:
            +--ro upstream-rbridge?   tril-rb-nickname
            +--ro next-hop-rbridge*   tril-rb-nickname
      augment /co-oam:path-discovery/co-oam:input:
            +--ro (out-of-band)?
            |  +--:(ipv4-address)
            |  |  +--ro ipv4-address?      inet:ipv4-address
            |  +--:(ipv6-address)
            |  |  +--ro ipv6-address?      inet:ipv6-address
            |  +--:(trill-nickname)
            |     +--ro trill-nickname?    tril-rb-nickname
            +--ro diagnostic-vlan?   boolean
      augment /co-oam:path-discovery/co-oam:input:
               +--ro flow-entropy-trill?   flow-entropy-trill
      augment /co-oam:path-discovery/co-oam:output/co-oam:response:
            +--ro upstream-rbridge?   tril-rb-nickname
            +--ro next-hop-rbridge*   tril-rb-nickname

7.2.  Generic YANG Model extension for MPLS-TP OAM

   The MPLS-TP OAM YANG module can augment the connection-oriented OAM
   Module with some technology-specific details.  And the
   [mpls-tp-oam-yang] presents the YANG Data model for MPLS-TP OAM.

   The configuration extensions for connection-oriented OAM include MD
   configuration extension, Technology type extension, Sub Technology
   Type Extension, MA configuration extension, MEP Configuration
   Extension.

7.2.1.  MD Configuration Extension

   MD level configuration parameters are management information which
   can be inherited in the MPLS-TP OAM model and set by the connection-
   oriented OAM base model as default values.  For example domain name
   can be set to area-ID or the provider's Autonomous System Number(ASN)
   [RFC6370] in the MPLS-TP OAM case.  In addition, at the Maintenance




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   Domain level (i.e.,at root level), domain data node can be augmented
   with technology type and sub-technology type.

   Note that MD level configuration parameters provides context
   information for the management system to correlate faults, defects,
   network failures with location information, which helps quickly
   identify root causes of network failures

7.2.1.1.  Technology Type Extension

   No MPLS-TP technology type has been defined in the connection-
   oriented base model, hence it is required in the MPLS-TP OAM model.
   The technology type "mpls-tp" is defined as an identity that augments
   the base "technology-types" defined in the connection-oriented base
   model:

       identity mpls-tp{
             base co-oam:technology-types;
             description
              "mpls-tp type";
            }

7.2.1.2.  Sub Technology Type Extension

   In MPLS-TP, since different encapsulation types such as IP/UDP
   Encapsulation, PW-ACH encapsulation can be employed, the "technology-
   sub-type" data node is defined and added into the MPLS-TP OAM model
   to further identify the encapsulation types within the MPLS-TP OAM
   model.  Based on it, we also define a technology sub-type for IP/UDP
   encapsulation and PW-ACH encapsulation.  Other Encapsulation types
   can be defined in the same way.  The snippet below depicts an example
   of several encapsulation types.



















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   identity technology-sub-type {
         description
         "certain implementations can have different
          encapsulation types such as ip/udp, pw-ach and so on.
          Instead of defining separate models for each
          encapsulation, we define a technology sub-type to
       further identify different encapsulations.
       Technology sub-type is associated at the MA level"; }

              identity technology-sub-type-udp {
                base technology-sub-type;
                description
                  "technology sub-type is IP/UDP encapsulation";
              }

              identity technology-sub-type-ach {
                base technology-sub-type;
                description
                  "technology sub-type is PW-ACH encapsulation";
              }
              }

         augment "/co-oam:domains/co-oam:domain"
               +"/co-oam:mas/co-oam:ma {
                leaf technology-sub-type {
                  type identityref {
                    base technology-sub-type;
                  }
                }
              }

7.2.2.  MA Configuration Extension

   MA level configuration parameters are management information which
   can be inherited in the MPLS-TP OAM model and set by the connection-
   oriented OAM base model as default values.  One example of MA Name
   could be MEG LSP ID or MEG Section ID or MEG PW ID[RFC6370].

   Note that MA level configuration parameters provides context
   information for the management system to correlate faults, defects,
   network failures with location information, which helps quickly
   identify root causes of network failures.

7.2.3.  MEP Configuration Extension

   In MPLS-TP, MEP-ID is either a variable length label value in case of
   G-ACH encapsulation or a 2 octet unsigned integer value in case of
   IP/UDP encapsulation.  One example of MEP-ID is MPLS-TP LSP_MEP_ID



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   [RFC6370].  In the connection-oriented base model, MEP-ID is defined
   as a choice/case node which can supports an int32 value, and the same
   definition can be used for MPLS-TP with no further modification.  In
   addition, at the Maintenance Association Endpoint(MEP) level (i.e.,at
   the third level), MEP data node can be augmented with Session
   extension and interface extension.

8.  Security Considerations

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

   The NETCONF access control model [RFC6536] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There are a number of data nodes defined in the YANG module which are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive 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.  These are the subtrees and data nodes and
   their sensitivity/vulnerability:

   /co-oam:domains/co-oam:domain/

   /co-oam:domains/co-oam:domain/co-oam:mas/co-oam:ma

   /co-oam:domains/co-oam:domain/co-oam:mas/co-oam:ma/co-oam:mep

   /co-oam:domains/co-oam:domain/co-oam:mas/co-oam:ma/co-oam:mep/
   co-oam:session

   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.







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9.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in RFC 3688, the following registration is
   requested to be made:

     URI: urn:ietf:params:xml:ns:yang:ietf-connection-oriented-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 [RFC6020].


  name:         ietf-connection-oriented-oam
  namespace:    urn:ietf:params:xml:ns:yang:ietf-connection-oriented-oam
  prefix:       co-oam
  reference:    RFC XXXX

10.  Acknowledgments

   Giles Heron came up with the idea of developing a YANG model as a way
   of creating a unified OAM API set (interface), work in this document
   is largely an inspiration of that.  Alexander Clemm provided many
   valuable tips, comments and remarks that helped to refine the YANG
   model presented in this document.

   Carlos Pignataro, David Ball,Mahesh Jethanandani,Benoit
   Claise,Ladislav Lhotka,GUBALLA JENS,Yuji Tochio,Gregory Mirsky, Huub
   van Helvoort, Tom Taylor, Dapeng Liu,Mishael Wexler, Adi Molkho
   participated and contributed to this document.

11.  References

11.1.  Normative References

   [IEEE802.1Q]
              "Connectivity Fault Management", IEEE Std 802.1Q-2014,
              2014.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.





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

   [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>.

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

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

   [RFC6370]  Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
              Profile (MPLS-TP) Identifiers", RFC 6370,
              DOI 10.17487/RFC6370, September 2011,
              <https://www.rfc-editor.org/info/rfc6370>.

   [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>.

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

   [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>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.







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11.2.  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-lime-yang-connectionless-oam]
              Kumar, D., Wang, Z., Wu, Q., Rahman, R., and S. Raghavan,
              "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 (work in progress), November 2017.

   [I-D.ietf-netmod-revised-datastores]
              Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore
              Architecture", draft-ietf-netmod-revised-datastores-10
              (work in progress), January 2018.

   [I-D.ietf-netmod-yang-tree-diagrams]
              Bjorklund, M. and L. Berger, "YANG Tree Diagrams", draft-
              ietf-netmod-yang-tree-diagrams-06 (work in progress),
              February 2018.

   [I-D.ietf-trill-yang]
              Weiguo, H., Yizhou, L., Kumar, D., Durrani, M., Zhai, H.,
              and L. Xia, "TRILL YANG Data Model", draft-ietf-trill-
              yang-04 (work in progress), December 2015.

   [I-D.ietf-trill-yang-oam]
              Kumar, D., Senevirathne, T., Finn, N., Salam, S., Xia, L.,
              and H. Weiguo, "YANG Data Model for TRILL Operations,
              Administration, and Maintenance (OAM)", draft-ietf-trill-
              yang-oam-05 (work in progress), March 2017.

   [MEF-17]   "Service OAM Requirements & Framework - Phase 1", METRO
              ETHERNET FORUM MEF 17, 2007.

   [mpls-tp-oam-yang]
              Zhang, L., Zheng, L., Aldrin, S., and G. Mirsky, "YANG
              Data Model for MPLS-TP Operations, Administration, and
              Maintenance", draft-zhang-mpls-tp-yang-oam (work in
              progress), 2016.






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   [RFC6291]  Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
              D., and S. Mansfield, "Guidelines for the Use of the "OAM"
              Acronym in the IETF", BCP 161, RFC 6291,
              DOI 10.17487/RFC6291, June 2011,
              <https://www.rfc-editor.org/info/rfc6291>.

   [RFC6325]  Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
              Ghanwani, "Routing Bridges (RBridges): Base Protocol
              Specification", RFC 6325, DOI 10.17487/RFC6325, July 2011,
              <https://www.rfc-editor.org/info/rfc6325>.

   [RFC6371]  Busi, I., Ed. and D. Allan, Ed., "Operations,
              Administration, and Maintenance Framework for MPLS-Based
              Transport Networks", RFC 6371, DOI 10.17487/RFC6371,
              September 2011, <https://www.rfc-editor.org/info/rfc6371>.

   [RFC6905]  Senevirathne, T., Bond, D., Aldrin, S., Li, Y., and R.
              Watve, "Requirements for Operations, Administration, and
              Maintenance (OAM) in Transparent Interconnection of Lots
              of Links (TRILL)", RFC 6905, DOI 10.17487/RFC6905, March
              2013, <https://www.rfc-editor.org/info/rfc6905>.

   [RFC7174]  Salam, S., Senevirathne, T., Aldrin, S., and D. Eastlake
              3rd, "Transparent Interconnection of Lots of Links (TRILL)
              Operations, Administration, and Maintenance (OAM)
              Framework", RFC 7174, DOI 10.17487/RFC7174, May 2014,
              <https://www.rfc-editor.org/info/rfc7174>.

   [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>.

   [RFC7455]  Senevirathne, T., Finn, N., Salam, S., Kumar, D., Eastlake
              3rd, D., Aldrin, S., and Y. Li, "Transparent
              Interconnection of Lots of Links (TRILL): Fault
              Management", RFC 7455, DOI 10.17487/RFC7455, March 2015,
              <https://www.rfc-editor.org/info/rfc7455>.

Appendix A.  Contributors' Addresses










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      Tissa Senevirathne
      Consultant

      Email: tsenevir@gmail.com

      Norman Finn
      CISCO Systems
      510 McCarthy Blvd
      Milpitas, CA  95035
      USA

      Email: nfinn@cisco.com

      Samer Salam
      CISCO Systems
      595 Burrard St. Suite 2123
      Vancouver, BC  V7X 1J1
      Canada

      Email: ssalam@cisco.com

Authors' Addresses

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

   Email: dekumar@cisco.com


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

   Email: bill.wu@huawei.com


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

   Email: wangzitao@huawei.com



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