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Versions: (draft-tissa-netmod-oam) 00 01 02 03 04 05 06 draft-ietf-lime-yang-oam-model

Network Working Group                                    T. Senevirathne
Internet-Draft                                                   N. Finn
Intended status: Standards Track                           D. Kumar, Ed.
Expires: February 5, 2016                                       S. Salam
                                                                   Cisco
                                                              Q. Wu, Ed.
                                                                 M. Wang
                                                                  Huawei
                                                          August 4, 2015


Generic YANG Data Model for Operations, Administration, and Maintenance
                                 (OAM)
                   draft-tissa-lime-yang-oam-model-06

Abstract

   This document presents base YANG Data model for OAM.  It provides a
   protocol-independent and technology-independent abstraction of key
   OAM constructs.  Based model presented here can be extended to
   include technology specific details.  This is leading to uniformity
   between OAM technologies and support nested OAM workflows (i.e.,
   performing OAM functions at different layers through a unified
   interface).

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://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 February 5, 2016.

Copyright Notice

   Copyright (c) 2015 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
   (http://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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   4
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Architecture of Generic YANG Model for OAM  . . . . . . . . .   6
   4.  Overview of the OAM Model . . . . . . . . . . . . . . . . . .   7
     4.1.  Maintenance Domain (MD) configuration . . . . . . . . . .   8
     4.2.  Maintenance Association (MA) configuration  . . . . . . .   8
     4.3.  Maintenance Endpoint (MEP) configuration  . . . . . . . .   9
     4.4.  rpc definitions . . . . . . . . . . . . . . . . . . . . .   9
     4.5.  OAM data hierarchy  . . . . . . . . . . . . . . . . . . .  12
   5.  OAM YANG Module . . . . . . . . . . . . . . . . . . . . . . .  17
   6.  Base Mode . . . . . . . . . . . . . . . . . . . . . . . . . .  41
     6.1.  MEP Address . . . . . . . . . . . . . . . . . . . . . . .  41
     6.2.  MEP ID for Base Mode  . . . . . . . . . . . . . . . . . .  42
     6.3.  Maintenance Domain  . . . . . . . . . . . . . . . . . . .  42
     6.4.  Maintenance Association . . . . . . . . . . . . . . . . .  42
   7.  Note  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  43
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  43
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  44
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  44
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  44
     11.2.  Informative References . . . . . . . . . . . . . . . . .  45
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  46

1.  Introduction

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

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

   2.  Troubleshoot failures (Fault verification and localization).

   3.  Monitor Performance



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

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

   [IEEE802.1Q] Connectivity Fault Management is a well-established OAM
   standard that is widely adopted for Ethernet networks.  ITU-T
   [Y.1731][Y.1731], MEF Service OAM, MPLS-TP [RFC6371], TRILL
   [RFC7455][RFC7455] all define OAM methods based on manageability
   frame work of [IEEE802.1Q] [IEEE802.1Q]CFM.

   Given the wide adoption of the underlying OAM concepts defined in
   [IEEE802.1Q][IEEE802.1Q] CFM, it is a reasonable choice to develop
   the unified management framework based on those concepts.  In this
   document, we take the [IEEE802.1Q][IEEE802.1Q] CFM model and extend
   it to a technology independent framework and build the corresponding
   YANG model accordingly.  The YANG model presented in this document is
   the base model and supports generic continuity check, connectivity
   verification and path discovery.  The generic YANG model for OAM is
   designed such that it can be extended to cover various technologies.
   Technology dependent nodes and RPC (remote process call) 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 MPLS [RFC4379] uses IP addresses or
   the label stack 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 purposes: first
   it keeps each YANG model smaller and 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).

   All implementations that follow the YANG framework presented in this
   document MUST implement the generic YANG model presented here.

   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 Ping
   command or a Traceroute 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 an IP ping from device A to
   Device B failed.  Between device A and B there are IEEE 802.1 bridges



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   a,b and c.  Let's assume a,b and c are using [IEEE802.1Q] CFM.  A
   user upon detecting the IP layer ping failures may decide to drill
   down to the Ethernet layer and issue the corresponding fault
   verification (LBM) and fault isolation (LTM) tools, using the same
   API.  This ability to go down to the same portion of path atlower
   layer for Fault localization and troubleshooting is referred to as
   "nested OAM workflow" and is a useful concept that leads to efficient
   network troubleshooting and maintenance.  The OAM YANG model
   presented in this document facilitates that without needing changes
   to the underlying protocols.

2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   The following notations are used within the data tree and carry the
   meaning as below.

   Each node is printed as:

   <status> <flags> <name> <opts> <type>

   <status> is one of:
        +  for current
        x  for deprecated
        o  for obsolete


   <flags> is one of:

       rw for configuration data
       ro for non-configuration data
       -x for rpcs
       -n for notifications


   <name> is the name of the node

   If the node is augmented into the tree from another module, its name
   is printed as <prefix>:<name>.









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   <opts> is one of:

        ?  for an optional leaf or choice
        !  for a presence container
        *  for a leaf-list or list
        [<keys>] for a list's keys

   <type> is the name of the type for leafs and leaf-lists

   In this document, these words will appear with that interpretation
   only when in ALL CAPS.  Lower case uses of these words are not to be
   interpreted as carrying RFC-2119 significance.

2.1.  Terminology

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

   ECMP  - Equal Cost Multipath.

   LBM   - Loopback Message [IEEE802.1Q].

   MP    - Maintenance Point [IEEE802.1Q].

   MEP   - Maintenance End Point [RFC7174] [IEEE802.1Q] [RFC6371].

   MIP   - Maintenance Intermediate Point [RFC7174] [IEEE802.1Q]
         [RFC6371].

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

   MD    - Maintenance Domain [IEEE802.1Q]

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

   CV    - Connectivity Verification [RFC7276].Connectivity
         Verifications are also referred to as path verification and



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         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.

3.  Architecture of Generic YANG Model for OAM

   In this document we define a generic YANG model for OAM.  The YANG
   model defined here is generic such that other technologies can extend
   it for technology specific needs.  The Generic YANG model acts as the
   root for other OAM YANG models.  This allows users to traverse
   between OAM of different technologies at ease through a uniform API
   set.  This is also provides a nested OAM workflow.  Figure 1 depicts
   the relationship of different OAM YANG models to the Generic YANG
   Model for OAM.  Some technologies may have different sub-
   technologies.  As an example, consider Network Virtualization
   Overlays.  These could employ either VXLAN or NVGRE as encapsulation.
   The Generic YANG model for 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.

   Figure 1 depicts relationship of different YANG modules.

                           +-+-+-+-+-+
                           |  gen    |
                           |OAM YANG |
                           +-+-+-+-+-+
                                |
                                O
                                |
        +---------------------------------------------------------+
        |              |               |         |                |
    +-+-+-+-+-+   +-+-+-+-+-+   +-+-+-+-+-+ +-+-+-+-+-+      +-+-+-+-+-+
    | TRILL   |   | NVO3    |   | MPLS    | | IP      | . . .|  foo    |
    |OAM YANG |   |OAM YANG |   |OAM YANG | |OAM YANG |      |OAM YANG |
    +-+-+-+-+-+   +-+-+-+-+-+   +-+-+-+-+-+ +-+-+-+-+-+      +-+-+-+-+-+
          |             |             |           |              |
          |       +-+-+-+-+-+   +-+-+-+-+-+       |          +-+-+-+-+-+
          |       | NVO3    |   | MPLS    |       |     . . .|  foo    |
          |       |sub tech |   |sub tech |       |          |sub tech |
          |       +-+-+-+-+-+   +-+-+-+-+-+       |          +-+-+-+-+-+
          |             |             |           |              |
          |             |             |           |              |
        +------------------------------------------------------------+
        |                      Uniform API                           |
        +------------------------------------------------------------+

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




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4.  Overview of the OAM Model

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

   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
   Association (MA).  In IP, the MA can be per IP Subnet, in NVO3 this
   can be per VNI and for TRILL this can be per Fine-Grained Label or
   for VPLS this can be per VPLS instance.

   Under each MA, there can be two or more MEPs (Maintenance Association
   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 vertical direction orthogonal to the Maintenance Domain,
   presented are the commands.  Those, in YANG terms, are the rpc
   commands.  These rpc commands provide uniform APIs for continuity
   check,connectivity verification, path discovery and their equivalents
   as well as other OAM commands.

   The generic YANG model defined here does not require explicit
   configuration of OAM entities prior to using any of the OAM tools.The
   OAM tools used here are limited to OAM toolset specified in section
   5.1 of [RFC7276].  Users of Ping and Traceroute tools within IP
   devices are expecting ability to use OAM tools with no explicit
   configuration.  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 and Addresses of MEP 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 such as NVO3,
   MPLS and future extensions 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.






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4.1.  Maintenance Domain (MD) configuration

   The container "domains" is the top level container within the gen-oam
   module.  Within the container "domains", separate list is maintained
   per MD.  The MD list uses the key MD-name-string for indexing.  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.  MD-name-
   format indicates the format of the augmented MD-names.  MD-name is
   presented as choice/case construct.  Thus, it is easily augmentable
   by derivative work.

       module: ietf-gen-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

4.2.  Maintenance Association (MA) configuration

   Within a given Maintenance Domain there can be one or more
   Maintenance Associations (MA).  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-gen-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)



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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.

      module: ietf-gen-oam
         +--rw domains
            +--rw domain* [technology MD-name-string]
               +--rw technology        identityref
               .
               .
               +--rw MAs
                  +--rw MA* [MA-name-string]
                     +--rw MA-name-string       MA-name-string
                     .
                     .
                     +--rw MEP* [mep-name]
                     |  +--rw mep-name             MEP-name
                     |  +--rw (MEP-ID)?
                     |  |  +--:(MEP-ID-int)
                     |  |     +--rw MEP-ID-int?          int32
                     |  |  +--:(MEP-ID-tlv)
                     |  |     +--rw MEP-ID-type?         int16
                     |  |     +--rw MEP-ID-len?          int16
                     |  |     +--rw MEP-ID-value?        binary
                     |  +--rw MEP-ID-format?       identityref
                     |  +--rw (mp-address)?
                     |  |  +--:(mac-address)
                     |  |  |  +--rw mac-address?   yang:mac-address
                     |  |  +--:(ipv4-address)
                     |  |  |  +--rw ipv4-address?  inet:ipv4-address
                     |  |  +--:(ipv6-address)
                     |  |     +--rw ipv6-address?  inet:ipv6-address
          .          .
          .          .
          .          .

      Snippet of data hierarchy related to Maintenance Endpoint (MEP)

4.4.  rpc definitions

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





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   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 for the complete
   data hierarchy and Section 5 for the YANG model.















































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      module: ietf-gen-oam
         +--rw domains
               +--rw domain* [technology MD-name-string]
               +--rw technology        identityref
         .
         .
      rpcs:
         +---x continuity-check
         |  +--ro input
         |  |  +--ro technology             identityref
         |  |  +--ro MD-name-string         MD-name-string
         |  |  +--ro MA-name-string?        MA-name-string
         |  |  +--ro (flow-entropy)?
         |  |  |  +--:(flow-entropy-null)
         |  |  |     +--ro flow-entropy-null?     empty
         |  |  +--ro priority?              uint8
         |  |  +--ro ttl?                   uint8
         |  |  +--ro session-type           enumeration
         |  |  +--ro ecmp-choice?           ecmp-choices
         |  |  +--ro sub-type?              identityref
         |  |  +--ro outgoing-interfaces* [interface]
         |  |  |  +--ro interface          if:interface-ref
         |  |  +--ro source-mep?            MEP-name
         |  |  +--ro destination-mp
         |  |  |  +--ro (mp-address)?
         |  |  |  |  +--:(mac-address)
         |  |  |  |  |  +--ro mac-address?     yang:mac-address
         |  |  |  |  +--:(ipv4-address)
         |  |  |  |  |  +--ro ipv4-address?    inet:ipv4-address
         |  |  |  |  +--:(ipv6-address)
         |  |  |  |     +--ro ipv6-address?    inet:ipv6-address
         |  |  |  +--ro (MEP-ID)?
         |  |  |  |  +--:(MEP-ID-int)
         |  |  |  |     +--ro MEP-ID-int?      int32
         |  |  |  +--ro MEP-ID-format?   identityref
         |  |  +--ro count?                 uint32
         |  |  +--ro interval?              Interval
         |  |  +--ro packet-size?           uint32
         |  +--ro output
         |     +--ro tx-packt-count?    oam-counter32
         |     +--ro rx-packet-count?   oam-counter32
         |     +--ro min-delay?         oam-counter32
         |     +--ro average-delay?     oam-counter32
         |     +--ro max-delay?         oam-counter32

      Snippet of data hierarchy related to rpc call continuity-check





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4.5.  OAM data hierarchy

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

   module: ietf-gen-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 mep-direction        MEP-direction
                  +--rw interval?            Interval
                  +--rw loss-threshold?      uint32
                  +--rw ttl?                 uint8
                  +--rw (flow-entropy)?
                  |  +--:(flow-entropy-null)
                  |     +--rw flow-entropy-null?   empty
                  +--rw priority?            uint8
                  +--rw MEP* [mep-name]
                  |  +--rw mep-name             MEP-name
                  |  +--rw (MEP-ID)?
                  |  |  +--:(MEP-ID-int)
                  |  |  |  +--rw MEP-ID-int?          int32
                  |  |  +--:(MEP-ID-tlv)
                  |  |     +--rw MEP-ID-type?         int16
                  |  |     +--rw MEP-ID-len?          int16
                  |  |     +--rw MEP-ID-value?        binary
                  |  +--rw MEP-ID-format?       identityref
                  |  +--rw (mp-address)?
                  |  |  +--:(mac-address)
                  |  |  |  +--rw mac-address?         yang:mac-address
                  |  |  +--:(ipv4-address)
                  |  |  |  +--rw ipv4-address?        inet:ipv4-address



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                  |  |  +--:(ipv6-address)
                  |  |     +--rw ipv6-address?        inet:ipv6-address
                  |  +--rw (connectivity-context)?
                  |  |  +--:(context-null)
                  |  |     +--rw context-null?        empty
                  |  +--rw Interface?                 if:interface-ref
                  |  +--rw (topology)?
                  |  |  +--:(topo-null)
                  |  |     +--rw topo-null?           empty
                  |  +--ro admin-status?        leafref
                  |  +--ro oper-status?         leafref
                  |  +--rw (flow-entropy)?
                  |  |  +--:(flow-entropy-null)
                  |  |     +--rw flow-entropy-null?   empty
                  |  +--rw priority?            uint8
                  |  +--rw session* [session-cookie]
                  |     +--rw session-cookie             uint32
                  |     +--rw ttl?                       uint8
                  |     +--rw interval?                  Interval
                  |     +--rw enable?                    boolean
                  |     +--rw ecmp-choice?               ecmp-choices
                  |     +--rw source-mep?                MEP-name
                  |     +--rw destination-mep
                  |     |  +--rw (MEP-ID)?
                  |     |  |  +--:(MEP-ID-int)
                  |     |  |  |  +--rw MEP-ID-int?      int32
                  |     |  |  +--:(MEP-ID-tlv)
                  |     |  |     +--rw MEP-ID-type?     int16
                  |     |  |     +--rw MEP-ID-len?      int16
                  |     |  |     +--rw MEP-ID-value?    binary
                  |     |  +--rw MEP-ID-format?         identityref
                  |     +--rw destination-mep-address
                  |     |  +--rw (mp-address)?
                  |     |     +--:(mac-address)
                  |     |     |  +--rw mac-address?    yang:mac-address
                  |     |     +--:(ipv4-address)
                  |     |     |  +--rw ipv4-address?   inet:ipv4-address
                  |     |     +--:(ipv6-address)
                  |     |        +--rw ipv6-address?   inet:ipv6-address
                  |     +--rw (connectivity-context)?
                  |     |  +--:(context-null)
                  |     |     +--rw context-null?              empty
                  |     +--rw (flow-entropy)?
                  |     |  +--:(flow-entropy-null)
                  |     |     +--rw flow-entropy-null?         empty
                  |     +--rw priority?                  uint8
                  |     +--rw outgoing-interface* [interface]
                  |        +--rw interface         leafref



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                  +--rw MIP* [interface]
                  |  +--rw interface               if:interface-ref
                  +--rw related-oam-layer* [offset]
                     +--rw offset            int32
                     +--rw technology        identityref
                     +--rw MD-name-string    MD-name-string
                     +--rw MA-name-string?   MA-name-string
   rpcs:
      +---x continuity-check
      |  +--ro input
      |  |  +--ro technology             identityref
      |  |  +--ro MD-name-string         MD-name-string
      |  |  +--ro MA-name-string?        MA-name-string
      |  |  +--ro (flow-entropy)?
      |  |  |  +--:(flow-entropy-null)
      |  |  |     +--ro flow-entropy-null?     empty
      |  |  +--ro priority?              uint8
      |  |  +--ro ttl?                   uint8
      |  |  +--ro session-type-enum?     enumeration
      |  |  +--ro ecmp-choice?           ecmp-choices
      |  |  +--ro sub-type?              identityref
      |  |  +--ro outgoing-interfaces* [interface]
      |  |  |  +--ro interface           if:interface-ref
      |  |  +--ro source-mep?            MEP-name
      |  |  +--ro destination-mp
      |  |  |  +--ro (mp-address)?
      |  |  |  |  +--:(mac-address)
      |  |  |  |  |  +--ro mac-address?     yang:mac-address
      |  |  |  |  +--:(ipv4-address)
      |  |  |  |  |  +--ro ipv4-address?    inet:ipv4-address
      |  |  |  |  +--:(ipv6-address)
      |  |  |  |     +--ro ipv6-address?    inet:ipv6-address
      |  |  |  +--ro (MEP-ID)?
      |  |  |  |  +--:(MEP-ID-int)
      |  |  |  |  |  +--ro MEP-ID-int?      int32
      |  |  |  |  +--:(MEP-ID-tlv)
      |  |  |  |     +--ro MEP-ID-type?     int16
      |  |  |  |     +--ro MEP-ID-len?      int16
      |  |  |  |     +--ro MEP-ID-value?    binary
      |  |  |  +--ro MEP-ID-format?      identityref
      |  |  +--ro count?                 uint32
      |  |  +--ro interval?              Interval
      |  |  +--ro packet-size?           uint32
      |  +--ro output
      |     +--ro tx-packt-count?    oam-counter32
      |     +--ro rx-packet-count?   oam-counter32
      |     +--ro min-delay?         oam-counter32
      |     +--ro average-delay?     oam-counter32



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      |     +--ro max-delay?         oam-counter32
      +---x continuity-verification     {connectivity-verification}?
      |  +--ro input
      |  |  +--ro technology             identityref
      |  |  +--ro MD-name-string         MD-name-string
      |  |  +--ro MA-name-string?        MA-name-string
      |  |  +--ro (flow-entropy)?
      |  |  |  +--:(flow-entropy-null)
      |  |  |     +--ro flow-entropy-null?     empty
      |  |  +--ro priority?              uint8
      |  |  +--ro ttl?                   uint8
      |  |  +--ro session-type-enum?     enumeration
      |  |  +--ro ecmp-choice?           ecmp-choices
      |  |  +--ro sub-type?              identityref
      |  |  +--ro outgoing-interfaces* [interface]
      |  |  |  +--ro interface           if:interface-ref
      |  |  +--ro source-mep?            MEP-name
      |  |  +--ro destination-mp
      |  |  |  +--ro (mp-address)?
      |  |  |  |  +--:(mac-address)
      |  |  |  |  |  +--ro mac-address?     yang:mac-address
      |  |  |  |  +--:(ipv4-address)
      |  |  |  |  |  +--ro ipv4-address?    inet:ipv4-address
      |  |  |  |  +--:(ipv6-address)
      |  |  |  |     +--ro ipv6-address?    inet:ipv6-address
      |  |  |  +--ro (MEP-ID)?
      |  |  |  |  +--:(MEP-ID-int)
      |  |  |  |  |  +--ro MEP-ID-int?      int32
      |  |  |  |  +--:(MEP-ID-tlv)
      |  |  |  |     +--ro MEP-ID-type?     int16
      |  |  |  |     +--ro MEP-ID-len?      int16
      |  |  |  |     +--ro MEP-ID-value?    binary
      |  |  |  +--ro MEP-ID-format?      identityref
      |  |  +--ro count?                 uint32
      |  |  +--ro interval?              Interval
      |  |  +--ro packet-size?           uint32
      |  +--ro output
      |     +--ro tx-packt-count?    oam-counter32
      |     +--ro rx-packet-count?   oam-counter32
      |     +--ro min-delay?         oam-counter32
      |     +--ro average-delay?     oam-counter32
      |     +--ro max-delay?         oam-counter32
      +---x path-discovery
         +--ro input
         |  +--ro technology             identityref
         |  +--ro MD-name-string         MD-name-string
         |  +--ro MA-name-string?        MA-name-string
         |  +--ro (flow-entropy)?



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         |  |  +--:(flow-entropy-null)
         |  |     +--ro flow-entropy-null?     empty
         |  +--ro priority?              uint8
         |  +--ro ttl?                   uint8
         |  +--ro session-type-enum?     enumeration
         |  +--ro command-sub-type?      identityref
         |  +--ro ecmp-choice?           ecmp-choices
         |  +--ro outgoing-interfaces* [interface]
         |  |  +--ro interface           if:interface-ref
         |  +--ro source-mep?            MEP-name
         |  +--ro destination-mp
         |  |  +--ro (mp-address)?
         |  |  |  +--:(mac-address)
         |  |  |  |  +--ro mac-address?     yang:mac-address
         |  |  |  +--:(ipv4-address)
         |  |  |  |  +--ro ipv4-address?    inet:ipv4-address
         |  |  |  +--:(ipv6-address)
         |  |  |     +--ro ipv6-address?    inet:ipv6-address
         |  |  +--ro (MEP-ID)?
         |  |  |  +--:(MEP-ID-int)
         |  |  |  |  +--ro MEP-ID-int?      int32
         |  |  |  +--:(MEP-ID-tlv)
         |  |  |     +--ro MEP-ID-type?     int16
         |  |  |     +--ro MEP-ID-len?      int16
         |  |  |     +--ro MEP-ID-value?    binary
         |  |  +--ro MEP-ID-format?      identityref
         |  +--ro count?                 uint32
         |  +--ro interval?              Interval
         +--ro output
            +--ro response* [response-index]
               +--ro response-index     uint8
               +--ro ttl?               uint8
               +--ro destination-mp
               |  +--ro (mp-address)?
               |  |  +--:(mac-address)
               |  |  |  +--ro mac-address?     yang:mac-address
               |  |  +--:(ipv4-address)
               |  |  |  +--ro ipv4-address?    inet:ipv4-address
               |  |  +--:(ipv6-address)
               |  |     +--ro ipv6-address?    inet:ipv6-address
               |  +--ro (MEP-ID)?
               |  |  +--:(MEP-ID-int)
               |  |  |  +--ro MEP-ID-int?      int32
               |  |  +--:(MEP-ID-tlv)
               |  |     +--ro MEP-ID-type?     int16
               |  |     +--ro MEP-ID-len?      int16
               |  |     +--ro MEP-ID-value?    binary
               |  +--ro MEP-ID-format?   identityref



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               +--ro tx-packt-count?    oam-counter32
               +--ro rx-packet-count?   oam-counter32
               +--ro min-delay?         oam-counter32
               +--ro average-delay?     oam-counter32
               +--ro max-delay?         oam-counter32
   notifications:
      +---n defect-condition-notification
         +--ro technology          identityref
         +--ro MD-name-string      MD-name-string
         +--ro MA-name-string?     MA-name-string
         +--ro mep-name?           MEP-name
         +--ro defect-type?        identityref
         +--ro generating-mepid
         |  +--ro (MEP-ID)?
         |  |  +--:(MEP-ID-int)
         |  |  |  +--ro MEP-ID-int?      int32
         |  |  +--:(MEP-ID-tlv)
         |  |     +--ro MEP-ID-type?     int16
         |  |     +--ro MEP-ID-len?      int16
         |  |     +--ro MEP-ID-value?    binary
         |  +--ro MEP-ID-format?         identityref
         +--ro (error)?
            +--:(error-null)
            |  +--ro error-null?         empty
            +--:(error-code)
               +--ro error-code?         int3
               +--ro error-code?         int32

                           data hierarchy of OAM

5.  OAM YANG Module

   <CODE BEGINS> file "ietf-gen-oam.yang"

      module ietf-gen-oam {
     namespace "urn:ietf:params:xml:ns:yang:ietf-gen-oam";
     prefix goam;

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




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     organization "IETF LIME Working Group";
     contact
       "Tissa Senevirathne tsenevir@cisco.com";
     description
       "This YANG module defines the generic configuration,
        statistics and rpc for OAM to be used within IETF in
        a protocol indpendent manner. Functional level
        abstraction is indendent 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";

     revision 2015-04-09 {
       description
         "Initial revision. - 04 version";
       reference "draft-tissa-lime-oam";
     }

     /* features */
     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.";
     }

     /* Identities */

     identity technology-types {
       description
         "this is the base identy of technology types which are
          vpls, nvo3, TRILL, ipv4, ipv6, mpls, etc";
     }

     identity ipv4 {
       base technology-types;
       description
         "technology of ipv4";
     }


     identity ipv6 {
       base technology-types;
       description



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         "technology of ipv6";
     }

     identity command-sub-type {
       description
         "defines different rpc command subtypes, e.g rfc792 IP
          ping, rfc4379 LSP ping, rfc6905 trill OAM, this is
          optional for most cases";
     }

     identity icmp-rfc792 {
       base command-sub-type;
       description
         "Defines the command subtypes for ICMP ping";
       reference "RFC 792";
     }

     identity name-format {
       description
         "This defines the name format, IEEE 8021Q 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 MEPD-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 rdi,
          mis-connection defect, loss of continuity";
     }
     identity remote-rdi {



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       base defect-types;
       description
         " Indicates the aggregate health of the remote MEPs. ";
     }

     identity remote-mep-error{
       base defect-types;
       description
         " Indicates that one or more of the remote MEPs is
   reporting a failure ";
     }
     identity invalue-oam-error{
       base defect-types;
       description
    "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-error{
       base defect-types;
       description
   " Indicates that one or more cross-connect oam messages has been
   received and that 3.5 times that OAM message transmission
   interval has not yet expired.
   ";
     }

     /* typedefs */
     typedef MEP-direction {
       type enumeration {
         enum "Up" {
           value 0;
   description
     "Indicates when OAM frames are transmitted towards and
   received from the bridging/routing function.";
         }
         enum "Down" {
           value 1;
   description
     "Indicates when OAM frames are transmitted towards and
   received from the wire.";
         }
       }
       description
         "MEP direction.";
     }




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     typedef MEP-name {
       type string;
       description
         "Generic administrative name for a MEP";
     }

     typedef Interval {
       type uint32;
       units "milliseconds";
       default "1000";
       description
         "Interval between packets in milliseconds.
          0 means no packets are sent.";
     }

     typedef ecmp-choices {
       type enumeration {
         enum "ecmp-use-platform-hash" {
           value 0;
   description
     "Use Platform hashing.";
         }
         enum "ecmp-use-round-robin" {
           value 1;
   description
     "Use round robin hashing.";
         }
       }
       description
         "Equal cost multi Path Choices";
     }

     typedef MD-name-string {
       type string;
       default "";
       description
         "Generic administrative name for an MD";
     }

     typedef MA-name-string {
       type string;
       default "";
       description
         "Generic administrative name for an MA";
     }

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



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       description
         "defines 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 (eg to 0-7)";
     }

     /* groupings */

     grouping topology {
       choice topology {
         case topo-null {
           description
             "this is a placeholder when no topology is needed";
           leaf topo-null {
              type empty;
              description
                "there is no topology define, it will be defined
                 in technology specific model.";
           }
         }
         description
           "Topology choices";
       }
       description
         "Topology";
     }

     grouping error-message {
       choice error {
         case error-null {
           description
             "this is a placeholder when no error status is needed";
           leaf error-null {
              type empty;
              description
                "there is no error define, it will be defined in
                 technology specific model.";
           }
         }
         case error-code {
           description



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             "this is a placeholder to display error code.";
           leaf error-code {
              type int32;
              description
                "error code is integer value specific to technology.";
           }
         }
         description
           "Error Message choices.";
       }
       description
         "Error Message.";
     }

     grouping mp-address {
       choice mp-address {
         case mac-address {
           leaf mac-address {
             type yang:mac-address;
     description
       "MAC Address";
           }
   description
     "MAC Address based MP Addressing.";
         }
         case ipv4-address {
           leaf ipv4-address {
             type inet:ipv4-address;
     description
       "Ipv4 Address";
           }
   description
     "Ip Address based MP Addressing.";
         }
         case ipv6-address {
           leaf ipv6-address {
             type inet:ipv6-address;
     description
       "Ipv6 Address";
           }
   description
     "ipv6 Address based MP Addressing.";
         }
         description
           "MP Addressing.";
       }
       description
         "MP Address";



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     }

     grouping maintenance-domain-id {
       description
         "Grouping containing leaves sufficient to identify an MD";
       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
           "Name format.";
       }
       choice MD-name {
         case MD-name-null {
           leaf MD-name-null {
     when "../../../MD-name-format = name-format-null" {
        description
          "MD name format is equal to null format.";
     }
             type empty;
     description
       "MD name Null.";
           }
         }
         description
           "MD name.";
       }
       description
         "MD name";
     }



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

     grouping MA-name {
       description
         "MA name";
       leaf MA-name-format {
         type identityref {
           base name-format;
         }
         description
           "Ma name format";
       }
       choice MA-name {
         case MA-name-null {
           leaf MA-name-null {
             when "../../../MA-name-format = name-format-null" {
     description
       "MA";
     }
     type empty;
     description
       "empty";
           }
         }
         description
           "MA name";
       }
     }

     grouping MEP-ID {
       choice MEP-ID {
         default "MEP-ID-int";
         case MEP-ID-int {
           leaf MEP-ID-int {
             type int32;
     description
       "MEP ID in integer format";
           }
         }
         case MEP-ID-tlv {



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            leaf MEP-ID-type {
      type int16;
      description
        "Type of MEP-ID";
            }
    leaf MEP-ID-len {
      type int16;
      description
        "Length of MEP-ID value";
    }
    leaf MEP-ID-value {
       type binary {
         length "12..255";
       }
       description
         "Value please refer RFC6428.";
    }
         }
         description
           "MEP-ID";
       }
       leaf MEP-ID-format {
         type identityref {
           base identifier-format;
         }
         description
           "MEP ID format.";
       }
       description
         "MEP-ID";
     }

     grouping MEP {
       description
         "Defines elements within the MEP";
       leaf mep-name {
         type MEP-name;
         mandatory true;
         description
           "Generic administrative name of the MEP";
       }
       uses MEP-ID;

       uses mp-address;
       uses connectivity-context;
       leaf Interface {
         type if:interface-ref;
         description



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           "Interface name as defined by ietf-interfaces";
       }
       uses topology;
     }

     grouping session-type {
       description
         "This object indicates the current session
          definition.";
       leaf session-type-enum {
         type enumeration {
           enum proactive {
             description
               "The current session is proactive";
           }
           enum on-demand {
             description
               "The current session is on-demand.";
           }
         }
         description
           "session type enum";
       }
     }

     grouping monitor-stats {
       leaf tx-packt-count {
         type oam-counter32;
         description
           "Transmitted Packet count";
       }
       leaf rx-packet-count {
         type oam-counter32;
         description
           "Received packet count";
       }
       leaf min-delay {
         type oam-counter32;
         units milliseconds;
         description
           "Delay is specified in milliseconds";
       }
       leaf average-delay {
         type oam-counter32;
         units millisecond;
         description
           "average delay in milliseconds";
       }



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       leaf max-delay {
         type oam-counter32;
         units millisecond;
         description
           "Maximum delay in milliseconds";
       }
       description
         "Monitor Statistics";
     }

     grouping MIP {
       description
         "defines MIP";
       leaf interface {
         type if:interface-ref;
         description
            "Interface";
       }
     }

     grouping related-oam-layer {
       leaf offset {
         type int32 {
           range "-255..255";
         }
         description
           "defines offset (in MD levels) to a related OAM layer
            +1 is the layer immediately above
            -1 is the layer immediately below";
       }
       uses maintenance-domain-id;
       uses ma-identifier;
       description
         "related OAM layer";
     }

     grouping interface-status {
       description
         "collection of interface related status";
       leaf admin-status {
         type leafref {
           path "/if:interfaces-state/if:interface/if:admin-status";
         }
         config false;
         description
           "oper status from ietf-interface module";
       }
       leaf oper-status {



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         type leafref {
           path "/if:interfaces-state/if:interface/if:oper-status";
         }
         config false;
         description
           "oper status from ietf-interface module";
       }
     }

     grouping connectivity-context {
       description
         "Grouping defining the connectivity context for an MA; for
          example, a VRF for IP, or an LSP for MPLS.  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 define";
           }
         }
         description
           "connectivity context";
       }
     }

     grouping priority {
       description
         "Priority used in transmitted packets; for example, in the
          TOS/DSCP field in IP or the Traffic Class field in MPLS";
       leaf priority {
         type uint8;
         description
           "priority";
       }
     }

     grouping flow-entropy {
       description
         "defines the grouping statement for flow-entropy";
       choice flow-entropy {
         default "flow-entropy-null";
         case flow-entropy-null {
           description



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             "this is a place holder when no flow entropy is needed";
           leaf flow-entropy-null {
             type empty;
             description
               "there is no flow entropy defined";
           }
         }
         description
           "Flow entropy";
       }
     }

     grouping measurement-timing-group {
        description
        "This grouping includes objects used for
         proactive and on-demand
         scheduling of PM measurement sessions.";

        container start-time {
           description
   "This container defines the session start time.";
   choice start-time {
     description
     "Measurement sessions tart time can be immediate, relative, or
     absolute.";
     container immediate {
               presence "Start the measurement session immediately.";
               description
               "Start Time of probe immediately.";
     }
     leaf absolute {
       type yang:date-and-time;
       description
       "This objects specifies the scheduled start time
        to perform the on-demand monitoring operations.";
     }
           }
        }

        container stop-time {
   description
   "This container defines the session stop time.";
   choice stop-time {
      description
      "Measurement session stop time can be none, or absolute.";
      container none {
                 presence "Never end the measurement session.";
                 description



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                 "Stop time is never to end.";

      }

      leaf absolute {
        type yang:date-and-time;
        description
          "This objects specifies the scheduled stop time
            to perform the on-demand monitoring operations.";
      }
           }
        }
     }

     container domains {
       description
         "Contains configuration related data. Within the container
          is list of fault domains. Wihin each domian has List of MA.";
       list domain {
         key "technology MD-name-string";
         ordered-by system;
         description
           "Define the list of Domains within the IETF-OAM";
         uses maintenance-domain-id;
         uses MD-name;
         leaf md-level {
           type MD-level;
           description
             "Defines the MD-Level";
         }
         container MAs {
           description
             "This container defines MA, within that have multiple MA
              and within MA have MEP, MIP";
           list MA {
     key "MA-name-string";
             ordered-by system;
             uses ma-identifier;
             uses MA-name;
             uses connectivity-context;
             leaf mep-direction {
               type MEP-direction;
               mandatory true;
               description
                 "Direction for MEPs in this MA";
             }
             leaf interval {
       type Interval;



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               default "0";
               description
                 "Defines default Keepalive/CC Interval.  May be
                  overridden for specific sessions if supported by the
                  protocol.";
             }
             leaf loss-threshold {
       type uint32;
               default "3";
               description
                 "number of consecutive Keepalive/CC messages missed
                  before declaring loss of continuity fault. This is
                  monitored per each remote MEP session";
             }
             leaf ttl {
               type uint8;
               default "255";
       description
         "Time to Live";
             }
             uses flow-entropy {
               description
                 "Default flow entropy in this MA, which may be
                  overridden for particular MEPs, sessions or
                  operations";
             }
             uses priority {
               description
                 "Default priority for this MA, which may be overridden
                  for particular MEPs, sessions or operations.";
             }
             list MEP {
               key "mep-name";
               ordered-by system;
               description
                 "contain list of MEPS";
               uses MEP;
               uses interface-status {
                 description
                   "status of associated interface";
               }
               uses flow-entropy;
               uses priority;
               list session {
                 key "session-cookie";
                 ordered-by user;
                 description
                   "Monitoring session to/from a particular remote MEP.



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                    Depending on the protocol, this could represent 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 MEPs or multiple sessions to
                      the same remote MEP.";
                 }
                 leaf ttl {
                   type uint8;
                   default "255";
     description
       "Time to Live.";
                 }
                 leaf interval {
                   type Interval;
                   description
                     "Transmission interval for CC packets for this
                      session.";
                 }
                 leaf enable {
            type boolean;
                   default "false";
                   description
                     "enable or disable a monitor session";
                 }
                 leaf ecmp-choice {
                   type ecmp-choices;
                   description
                     "0 means use the specified interface
                      1 means use round robin";
                 }
                 leaf source-mep {
                   type MEP-name;
                   description
                     "Source MEP for this session, if applicable";
                 }
                 container destination-mep {
                   uses MEP-ID;
     description
        "Destination MEP";
                 }
                 container destination-mep-address {



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                   uses mp-address;
     description
        "Destination MEP Address";
                 }
                 uses connectivity-context;
                 uses flow-entropy;
                 uses priority;
                 list outgoing-interface {
                   key "interface";
                   leaf interface {
                     type if:interface-ref;
       description
         "Outgoing Interface";
                   }
     description
       "outgoing interfaces";
                 }
               }
             }
             list MIP {
               key "interface";
               uses MIP;
       description
         "Maintenance Intermediate Point";
             }
             list related-oam-layer {
               key "offset";
               description
                 "List of OAM layers above and below that are related to
                  current MA. This allow users to easily navigate up and
                  down to efficiently troubleshoot a connectivity
                  issue";
               uses related-oam-layer;
             }
     description
        "Maintenance Association list";
           }
         }
       }
     }

     notification defect-condition-notification {
       description
         "When defect condition is met this notificiation is sent";
      uses maintenance-domain-id {
         description
           "defines the MD (Maintenance Domain) identifier, which is the
            Generic MD-name-string and the technology.";



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       }
       uses ma-identifier;
       leaf mep-name {
         type MEP-name;
         description
           "Indicate which MEP is seeing the error";
       }
       leaf defect-type {
         type identityref {
           base defect-types;
         }
         description
           "The currently active defects on the specific MEP.";
       }
       container generating-mepid {
         uses MEP-ID;
         description
           "Who is generating the error (if known) if
            unknown make it 0.";
       }
       uses error-message {
         description
            "Error message to indicate more details.";
       }
     }
     rpc continuity-check {
       description
         "Generates continuity-check as per RFC7276 Table 4.";
       input {
         uses maintenance-domain-id {
           description
             "defines the MD (Maintenance Domain) identifier, which is
              the generic
              MD-name-string and the technology.";
         }
         uses ma-identifier {
           description
             "identfies the Maintenance association";
         }
         uses flow-entropy;
         uses priority;
         leaf ttl {
           type uint8;
           default "255";
    description
      "Time to Live";
         }
         uses session-type;



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         leaf ecmp-choice {
           type ecmp-choices;
           description
             "0 means use the specified interface
              1 means use round robin";
         }
         leaf sub-type {
           type identityref {
             base command-sub-type;
           }
           description
             "defines different command types";
         }
         list outgoing-interfaces {
           key "interface";
           leaf interface {
             type if:interface-ref;
     description
       "outgoing interface";
           }
   description
     "outgoing Interfaces";
         }
         leaf source-mep {
           type MEP-name;
   description
     "Source MEP";
         }
         container destination-mp {
           uses mp-address;
           uses MEP-ID {
             description "Only applicable if the destination is a MEP";
           }
   description
     "Destination MEP";
         }
         leaf count {
           type uint32;
           default "3";
           description


             "Number of ping echo request message to send";
         }
         leaf interval {
           type Interval;
           description
             "Interval between echo requests";



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         }
         leaf packet-size {
           type uint32 {
             range "64..10000";
           }
           default "64";
           description
             "Size of ping echo request 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 {
         uses maintenance-domain-id {
           description
             "defines the MD (Maintenance Domain) identifier, which is
              the generic
              MD-name-string and the technology.";
         }
         uses ma-identifier {
           description
             "identfies the Maintenance association";
         }
         uses flow-entropy;
         uses priority;
         leaf ttl {
           type uint8;
           default "255";
   description
     "Time to Live";
         }
         uses session-type;
         leaf ecmp-choice {
           type ecmp-choices;
           description
             "0 means use the specified interface
              1 means use round robin";
         }



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         leaf sub-type {
           type identityref {
             base command-sub-type;
           }
           description
             "defines different command types";
         }
         list outgoing-interfaces {
           key "interface";
           leaf interface {
             type if:interface-ref;
     description
       "outgoing interface";
           }
   description
     "outgoing Interfaces";
         }
         leaf source-mep {
           type MEP-name;
   description
     "Source MEP";
         }
         container destination-mp {
           uses mp-address;
           uses MEP-ID {
             description "Only applicable if the destination is a MEP";
           }
   description
     "Destination MEP";
         }
         leaf count {
           type uint32;
           default "3";
           description
             "Number of ping echo request message to send";
         }
         leaf interval {
           type Interval;
           description
             "Interval between echo requests";
         }
         leaf packet-size {
           type uint32 {
             range "64..10000";
           }
           default "64";
           description
             "Size of ping echo request packets, in octets";



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         }
       }
       output {
         uses monitor-stats {
           description
             "Stats of continuity check.";
         }
       }
     }
     rpc path-discovery {
       description
         "Generates Trace-route or Path Trace and return response.
          Referencing RFC7276 for common Toolset name, for IP it's
          Traceroute, for MPLS OAM it's Traceroute mode, for
          MPLS-TP OAM it's Route Tracing, for Pseudowire OAM it's
          LSP Ping, 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 valune";
       input {
         uses maintenance-domain-id {
           description
             "defines the MD (Maintenance Domain) identifier, which is
              the generic MD-name-string and the technology.";
         }
         uses ma-identifier {
           description
             "identfies the Maintenance association";
         }
         uses flow-entropy;
         uses priority;
         leaf ttl {
           type uint8;
           default "255";
   description
     "Time to Live";
         }
         uses session-type;
         leaf command-sub-type {
           type identityref {


             base command-sub-type;
           }
           description
             "defines different command types";
         }
         leaf ecmp-choice {



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           type ecmp-choices;
           description
             "0 means use the specified interface
              1 means use round robin";
         }
         list outgoing-interfaces {
           key "interface";
           leaf interface {
             type if:interface-ref;
     description
       "Interface.";
           }
   description
     "Outgoing interface list.";
         }
         leaf source-mep {
           type MEP-name;
   description
     "Source MEP";
         }
         container destination-mp {
           uses mp-address;
           uses MEP-ID {
             description "Only applicable if the destination is a MEP";
           }
   description
     "Destination 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 send at each TTL.";
         }
         leaf interval {
           type Interval;
           description
             "Interval between echo requests";
         }
       }
       output {
         list response {
           key "response-index";
           leaf response-index {
     type uint8;
             description



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               "Arbitrary index for the response.  In protocols that
                guarantee there is only a single response at each TTL
                (eg IP Traceroute), the TTL can be used as the response
                index.";
           }
           leaf ttl {
             type uint8;
     description
       "Time to Live";
           }
   description
      "Time to Live";
           container destination-mp {
             description "MP from which the response has been received";
             uses mp-address;
             uses MEP-ID {
               description
                 "Only applicable if the destination is a MEP";
             }
           }
           uses monitor-stats {
             description
               "If count is 1, there is a single delay value reported.";
           }
         }
         description
           "List of response.";
       }
     }
   }

                            YANG module of OAM

   <CODE ENDS>

6.  Base Mode

   The Base Mode 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.





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6.2.  MEP ID for Base Mode

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

   MEPID is 2 octet field by default.  It is never used on the wire
   except when using CCM.  Ping, traceroute and session monitoring does
   not use the MEPID on its message header.  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 we propose to use MEP ID zero (0) 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.

   [IEEE802.1Q] CFM defines MEP ID as an unsigned integer in the range 1
   to 8191.  In this document we propose to 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 Domain

   Default MD-LEVEL is set to 3.

6.4.  Maintenance Association

   MAID [IEEE802.1Q] has a flexible format and includes two parts:
   Maintenance Domain Name and Short MA name.  In the Based Mode of
   operation, the value of the Maintenance Domain Name must be the
   character string "GenericBaseMode" (excluding the quotes ").  In Base
   Mode operation Short MA Name format is set to 2-octet integer format
   (value 3 in Short MA Format field [IEEE802.1Q]) and Short MA name set
   to 65532 (0xFFFC).

7.  Note

   This section will be removed or subject to change in the future if
   any agreement is reached.  As per investigation of RFC7276 for
   performance Monitoring for Loss and Delay are defined for MPLS
   OAM(RFC6374[RFC6374]), OWAMP (RFC4656[RFC4656]) and TWAMP
   (RFC5357[RFC5357]) and TRILL OAM (RFC7456[RFC7456]).  In case of



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   Performance Monitoring Statistics are common between these
   technologies thus generic Yang model for Performance will be worked
   out through separate draft with Augmentation of Generic LIME model.
   In case of Other Function, it's technology specific and thus should
   be dealt in technology specific Yang model instead of Generic Model.

8.  Security Considerations

   The YANG module defined in this memo is designed to be accessed via
   the NETCONF protocol [RFC6241] [RFC6241].  The lowest NETCONF layer
   is the secure transport layer and the mandatory-to-implement secure
   transport is SSH [RFC6242] [RFC6242].  The NETCONF access control
   model [RFC6536] [RFC6536] provides the means to restrict access for
   particular NETCONF users to a pre-configured subset of all available
   NETCONF 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 or vulnerable
   in some network environments.  Write operations (e.g., <edit-config>)
   to these data nodes without proper protection can have a negative
   effect on network operations.

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

   /goam:domains/goam:domain/

   /goam:domains/goam:domain/goam:MAs/goam:MA/

   /goam:domains/goam:domain/goam:MAs/goam:MA/goam:MEP

   /goam:domains/goam:domain/goam:MAs/goam:MA/goam:MEP/goam: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.

9.  IANA Considerations

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






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   URI: urn:ietf:params:xml:ns:yang:ietf-gen-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-gen-oam namespace: urn:ietf:params:xml:ns:yang:ietf-gen-oam
     prefix: goam 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 participated and contributed to
   this document.

11.  References

11.1.  Normative References

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

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

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://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,
              <http://www.rfc-editor.org/info/rfc6241>.




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

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

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

11.2.  Informative References

   [IEEE802.1Q]
              "Media Access Control (MAC) Bridges and Virtual Bridged
              Local Area Networks", IEEE Std 802.1Q-2011, August 2011.

   [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", RFC 4379,
              DOI 10.17487/RFC4379, February 2006,
              <http://www.rfc-editor.org/info/rfc4379>.

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

   [RFC4656]  Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
              Zekauskas, "A One-way Active Measurement Protocol
              (OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006,
              <http://www.rfc-editor.org/info/rfc4656>.

   [RFC5357]  Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
              Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
              RFC 5357, DOI 10.17487/RFC5357, October 2008,
              <http://www.rfc-editor.org/info/rfc5357>.

   [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,
              <http://www.rfc-editor.org/info/rfc6291>.







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   [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,
              <http://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, <http://www.rfc-editor.org/info/rfc6371>.

   [RFC6374]  Frost, D. and S. Bryant, "Packet Loss and Delay
              Measurement for MPLS Networks", RFC 6374,
              DOI 10.17487/RFC6374, September 2011,
              <http://www.rfc-editor.org/info/rfc6374>.

   [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,
              <http://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,
              <http://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,
              <http://www.rfc-editor.org/info/rfc7455>.

   [RFC7456]  Mizrahi, T., Senevirathne, T., Salam, S., Kumar, D., and
              D. Eastlake 3rd, "Loss and Delay Measurement in
              Transparent Interconnection of Lots of Links (TRILL)",
              RFC 7456, DOI 10.17487/RFC7456, March 2015,
              <http://www.rfc-editor.org/info/rfc7456>.

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

Authors' Addresses








Senevirathne, et al.    Expires February 5, 2016               [Page 46]


Internet-Draft         Generic YANG Model for OAM            August 2015


   Tissa Senevirathne
   CISCO Systems
   375 East Tasman Drive.
   San Jose, CA  95134
   USA

   Phone: 408-853-2291
   Email: tsenevir@cisco.com


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

   Email: nfinn@cisco.com


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

   Email: dekumar@cisco.com


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

   Email: ssalam@cisco.com


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

   Email: bill.wu@huawei.com







Senevirathne, et al.    Expires February 5, 2016               [Page 47]


Internet-Draft         Generic YANG Model for OAM            August 2015


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

   Email: wangzitao@huawei.com












































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