Network Working Group                                     A. Lindem, Ed.
Internet-Draft                                             Cisco Systems
Intended status: Informational                            L. Berger, Ed.
Expires: May 1, 2017                             LabN Consulting, L.L.C.
                                                           D. Bogdanovic

                                                                C. Hopps
                                                        Deutsche Telekom
                                                        October 28, 2016


               Network Device YANG Organizational Models
                    draft-ietf-rtgwg-device-model-01

Abstract

   This document presents an approach for organizing YANG models in a
   comprehensive structure that may be used to configure and operate
   network devices.  The structure is itself represented as a YANG
   model, with all of the related component models logically organized
   in a way that is operationally intuitive, but this model is not
   expected to be implemented.  The identified component modules are
   expected to be defined and implemented on common network devices.

   This document is derived from work submitted to the IETF by members
   of the informal OpenConfig working group of network operators and is
   a product of the Routing Area YANG Architecture design team.

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 May 1, 2017.







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Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (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
     1.1.  Status of Work and Open Issues  . . . . . . . . . . . . .   4
   2.  Module Overview . . . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  Interface Model Components  . . . . . . . . . . . . . . .   7
     2.2.  System Management . . . . . . . . . . . . . . . . . . . .   9
     2.3.  Network Services  . . . . . . . . . . . . . . . . . . . .  10
     2.4.  OAM Protocols . . . . . . . . . . . . . . . . . . . . . .  11
     2.5.  Routing . . . . . . . . . . . . . . . . . . . . . . . . .  11
     2.6.  MPLS  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   5.  Network Device Model Structure  . . . . . . . . . . . . . . .  13
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  20
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22

1.  Introduction

   "Operational Structure and Organization of YANG Models"
   [I-D.openconfig-netmod-model-structure], highlights the value of
   organizing individual, self-standing YANG [RFC6020] models into a
   more comprehensive structure.  This document builds on that work and
   presents a derivative structure for use in representing the
   networking infrastructure aspects of physical and virtual devices.
   [I-D.openconfig-netmod-model-structure] and earlier versions of this
   document presented a single device-centric model root, this document
   no longer contains this element.  Such an element would have
   translated to a single device management model that would be the root




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   of all other models and was judged to be overly restrictive in terms
   of definition, implementation, and operation.

   The document presents a notional network device YANG organizational
   structure that provides a conceptual framework for the models that
   may be used to configure and operate network devices.  The structure
   is itself presented as a YANG module, with all of the related
   component modules logically organized in a way that is operationally
   intuitive.  This network device model is not expected to be
   implemented, but rather provide as context for the identified
   representative component modules with are expected to be defined, and
   supported on typical network devices.

   This document refers to two new modules that are expected to be
   implemented.  These models are defined to support the configuration
   and operation of network-devices that allow for the partitioning of
   resources from both, or either, management and networking
   perspectives.  Two forms of resource partitioning are referenced:

   The first form provides a logical partitioning of a network device
   where each partition is separately managed as essentially an
   independent network element which is 'hosted' by the base network
   device.  These hosted network elements are referred to as logical
   network elements, or LNEs, and are supported by the logical-network-
   element module defined in [I-D.ietf-rtgwg-lne-model].  The module is
   used to identify LNEs and associate resources from the network-device
   with each LNE.  LNEs themselves are represented in YANG as
   independent network devices; each accessed independently.
   Optionally, and when supported by the implementation, they may also
   be accessed from the host system.  Examples of vendor terminology for
   an LNE include logical system or logical router, and virtual switch,
   chassis, or fabric.

   The second form provides support what is commonly referred to as
   Virtual Routing and Forwarding (VRF) instances as well as Virtual
   Switch Instances (VSI), see [RFC4026].  In this form of resource
   partitioning multiple control plane and forwarding/bridging instances
   are provided by and managed via a single (physical or logical)
   network device.  This form of resource partitioning is referred to as
   Network Instances and are supported by the network-instance module
   defined in [I-D.ietf-rtgwg-ni-model].  Configuration and operation of
   each network-instance is always via the network device and the
   network-instance module.

   This document was motivated by, and derived from,
   [I-D.openconfig-netmod-model-structure].  The requirements from that
   document have been combined with the requirements from "Consistent
   Modeling of Operational State Data in YANG",



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   [I-D.openconfig-netmod-opstate], into "NETMOD Operational State
   Requirements", [I-D.ietf-netmod-opstate-reqs].  This document is
   aimed at the requirement related to a common model-structure,
   currently Requirement 7, and also aims to provide a modeling base for
   Operational State representation.

   The approach taken in this (and the original) document is to organize
   the models describing various aspects of network infrastructure,
   focusing on devices, their subsystems, and relevant protocols
   operating at the link and network layers.  The proposal does not
   consider a common model for higher level network services.  We focus
   on the set of models that are commonly used by network operators, and
   suggest a corresponding organization.

   A significant portion of the text and model contained in this
   document was taken from the -00 of
   [I-D.openconfig-netmod-model-structure].

1.1.  Status of Work and Open Issues

   This version of the document and structure are a product of the
   Routing Area YANG Architecture design team and is very much a work in
   progress rather than a final proposal.  This version is a major
   change from the prior version and this change was enabled by the work
   on the previously mentioned Schema Mount.

   Schema Mount enables a dramatic simplification of the presented
   device model, particularly for "lower-end" devices which are unlikely
   to support multiple network instances or logical network elements.
   Should structural-mount/YSDL not be available, the more explicit tree
   structure presented in earlier versions of this document will need to
   be utilized.

   The top open issues are:

   1.  This document will need to match the evolution and
       standardization of [I-D.openconfig-netmod-opstate] or
       [I-D.ietf-netmod-opstate-reqs] by the Netmod WG.

   2.  Interpretation of different policy containers requires
       clarification.

   3.  It may make sense to use the identityref structuring with
       hardware and QoS model.

   4.  Which document(s) define the base System management, network
       services, and oam protocols modules is TBD.  This includes the




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       possibility of simply using RFC7317 in place of the presented
       System management module.

   5.  The model will be updated once the "opstate" requirements are
       addressed.

2.  Module Overview

   In this document, we consider network devices that support protocols
   and functions defined within the IETF Routing Area, e.g, routers,
   firewalls and hosts.  Such devices may be physical or virtual, e.g.,
   a classic router with custom hardware or one residing within a
   server-based virtual machine implementing a virtual network function
   (VNF).  Each device may sub-divide their resources into logical
   network elements (LNEs) each of which provides a managed logical
   device.  Examples of vendor terminology for an LNE include logical
   system or logical router, and virtual switch, chassis, or fabric.
   Each LNE may also support virtual routing and forwarding (VRF) and
   virtual switching instance (VSI) functions, which are referred to
   below as a network instances (NIs).  This breakdown is represented in
   Figure 1.


              ,''''''''''''''''''''''''''''''''''''''''''''''`.
              |      Network Device (Physical or Virtual)     |
              | .....................   ..................... |
              | :  Logical Network  :   :  Logical Network  : |
              | :      Element      :   :      Element      : |
              | :+-----+-----+-----+:   :+-----+-----+-----+: |
              | :| Net | Net | Net |:   :| Net | Net | Net |: |
              | :|Inst.|Inst.|Inst.|:   :|Inst.|Inst.|Inst.|: |
              | :+-----+-----+-----+:   :+-----+-----+-----+: |
              | :  | |   | |   | |  :   :  | |   | |   | |  : |
              | :..|.|...|.|...|.|..:   :..|.|...|.|...|.|..: |
              |    | |   | |   | |         | |   | |   | |    |
               `'''|'|'''|'|'''|'|'''''''''|'|'''|'|'''|'|'''''
                   | |   | |   | |         | |   | |   | |
                      Interfaces              Interfaces

   Figure 1: Module Element Relationships

   A model for LNEs is described in [I-D.ietf-rtgwg-lne-model] and the
   model for network instances is covered in [I-D.ietf-rtgwg-ni-model].

   The presented notional network device module can itself be thought of
   as a "meta-model" as it describes the relationships between
   individual models.  We choose to represent it also as a simple YANG
   module consisting of other models, which are in fact independent top



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   level individual models.  Although it is never expected to be
   implemented.

   The presented modules do not follow the hierarchy of any Particular
   implementation, and hence is vendor-neutral.  Nevertheless, the
   structure should be familiar to network operators and also readily
   mapped to vendor implementations.

   The overall structure is:

       module: ietf-network-device
          +--rw modules-state            [RFC7895]
          |
          +--rw interfaces               [RFC7223]
          +--rw hardware
          +--rw qos
          |
          +--rw system-management        [RFC7317 or derived]
          +--rw network-services
          +--rw oam-protocols
          |
          +--rw routing                  [I-D.ietf-netmod-routing-cfg]
          +--rw mpls
          +--rw ieee-dot1Q
          |
          +--rw acls                     [I-D.ietf-netmod-acl-model]
          +--rw key-chains               [I-D.ietf-rtgwg-yang-key-chain]
          |
          +--rw logical-network-elements [I-D.ietf-rtgwg-lne-model]
          +--rw network-instances        [I-D.ietf-rtgwg-ni-model]

   The network device is composed of top level modules that can be used
   to configure and operate a network device.  (This is a significant
   difference from earlier versions of this document where there was a
   strict model hierarchy.)  Importantly the network device structure is
   the same for a physical network device or a logical network device,
   such as those instantiated via the logical-network-element model.
   Extra spacing is included to denote different types of modules
   included.

   YANG library [RFC7895] is included as it used to identify details of
   the top level modules supported by the (physical or logical) network
   device.  Th ability to identify supported modules is particularly
   important for LNEs which may have a set of supported modules which
   differs from the set supported by the host network device.

   The interface management model [RFC7223] is included at the top
   level.  The hardware module is a placeholder for a future device-



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   specific configuration and operational state data model.  For
   example, a common structure for the hardware model might include
   chassis, line cards, and ports, but we leave this unspecified.  The
   quality of service (QoS) section is also a placeholder module for
   device configuration and operational state data which relates to the
   treatment of traffic across the device.  This document references
   augmentations to the interface module to support LNEs and NIs.
   Similar elements, although perhaps only for LNEs, may also need to be
   included as part of the definition of the future hardware and QoS
   modules.

   System management, network services, and oam protocols represent new
   top level modules that are used to organize data models of similar
   functions.  Additional information on each is provided below.

   The routing and MPLS modules provide core support for the
   configuration and operation of a devices control plane and data plane
   functions.  IEEE dot1Q [IEEE-8021Q] is an example of another module
   that provides similar functions for VLAN bridging, and other similar
   modules are also possible.  Each of these modules is expected to be
   LNE and NI unaware, and to be instantiated as needed as part of the
   LNE and NI configuration and operation supported by the logical-
   network-element and network-instance modules.  (Note that this is a
   change from [I-D.ietf-netmod-routing-cfg] which is currently defined
   with VRF/NI semantics.)

   The access control list (ACL) and key chain modules are included as
   examples of other top level modules that may be supported by a
   network device.

   The logical network element and network instance modules enable LNEs
   and NIs respectively and are defined below.

2.1.  Interface Model Components

   Interfaces are a crucial part of any network device's configuration
   and operational state.  They generally include a combination of raw
   physical interfaces, link-layer interfaces, addressing configuration,
   and logical interfaces that may not be tied to any physical
   interface.  Several system services, and layer 2 and layer 3
   protocols may also associate configuration or operational state data
   with different types of interfaces (these relationships are not shown
   for simplicity).  The interface management model is defined by
   [RFC7223].

   The logical-network-element and network-instance modules defined in
   [I-D.ietf-rtgwg-lne-model] and [I-D.ietf-rtgwg-ni-model] augment the
   existing interface management model in two ways: The first, by the



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   logical-network-element module, adds an identifier which is used on
   physical interface types to identify an associated LNE.  The second,
   by the network-instance module, adds a name which is used on
   interface or sub-interface types to identify an associated network
   instance.  Similarly, this name is also added for IPv4 and IPv6
   types, as defined in [RFC7277].

   The interface related augmentations are as follows:

       module: ietf-logical-network-element
       augment /if:interfaces/if:interface:
          +--rw bind-lne-name?   string

       module: ietf-network-instance
       augment /if:interfaces/if:interface:
          +--rw bind-network-instance-name?   string
       augment /if:interfaces/if:interface/ip:ipv4:
          +--rw bind-network-instance-name?   string
       augment /if:interfaces/if:interface/ip:ipv6:
          +--rw bind-network-instance-name?   string

   The following is an example of envisioned combined usage.  The
   interfaces container includes a number of commonly used components as
   examples:



























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             +--rw if:interfaces
             |  +--rw interface* [name]
             |     +--rw name                       string
             |     +--rw lne:bind-lne-name?         string
             |     +--rw ethernet
             |     |  +--rw ni:bind-network-instance-name? string
             |     |  +--rw aggregates
             |     |  +--rw rstp
             |     |  +--rw lldp
             |     |  +--rw ptp
             |     +--rw vlans
             |     +--rw tunnels
             |     +--rw ipv4
             |     |  +--rw ni:bind-network-instance-name? string
             |     |  +--rw arp
             |     |  +--rw icmp
             |     |  +--rw vrrp
             |     |  +--rw dhcp-client
             |     +--rw ipv6
             |        +--rw ni:bind-network-instance-name? string
             |        +--rw vrrp
             |        +--rw icmpv6
             |        +--rw nd
             |        +--rw dhcpv6-client

   The [RFC7223] defined interface model is structured to include all
   interfaces in a flat list, without regard to logical or virtual
   instances (e.g., VRFs) supported on the device.  The bind-lne-name
   and bind-network-instance-name leaves provide the association between
   an interface and its associated LNE and NI (e.g., VRF or VSI).

2.2.  System Management

   [Editor's note: need to discuss and resolve relationship between this
   structure and RFC7317 and determine if 7317 is close enough to simply
   use as is.]

   System management is expected to reuse definitions contained in
   [RFC7317].  It is expected to be instantiated per device and LNE.
   Its structure is shown below:

       module: ietf-network-device
          +--rw system-management
          |  +--rw system-management-global
          |  +--rw system-management-protocol* [type]
          |     +--rw type    identityref





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   System-management-global is used for configuration information and
   state that is independent of a particular management protocol.
   System-management-protocol is a list of management protocol specific
   elements.  The type-specific sub-modules are expected to be defined.

   The following is an example of envisioned usage:

       module: ietf-network-device
          +--rw system-management
             +--rw system-management-global
             |  +--rw statistics-collection
             |  ...
             +--rw system-management-protocol* [type]
             |  +--rw type=syslog
             |  +--rw type=dns
             |  +--rw type=ntp
             |  +--rw type=ssh
             |  +--rw type=tacacs
             |  +--rw type=snmp
             |  +--rw type=netconf


2.3.  Network Services

   A device may provide different network services to other devices, for
   example a device my act as a DHCP server.  The model may be
   instantiated per device, LNE, and NI.  An identityref is used to
   identify the type of specific service being provided and its
   associated configuration and state information.  The defined
   structure is as follows:

       module: ietf-network-device
          +--rw network-services
          |  +--rw network-service* [type]
          |     +--rw type    identityref

   The following is an example of envisioned usage: Examples shown below
   include a device-based Network Time Protocol (NTP) server, a Domain
   Name System (DNS) server, and a Dynamic Host Configuration Protocol
   (DHCP) server:

       module: ietf-network-device
          +--rw network-services
             +--rw network-service* [type]
                +--rw type=ntp-server
                +--rw type=dns-server
                +--rw type=dhcp-server




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2.4.  OAM Protocols

   OAM protocols that may run within the context of a device are grouped
   within the oam-protocols model.  The model may be instantiated per
   device, LNE, and NI.  An identifyref is used to identify the
   information and state that may relate to a specific OAM protocol.
   The defined structure is as follows:

       module: ietf-network-device
          +--rw oam-protocols
             +--rw oam-protocol* [type]
                +--rw type    identityref


   The following is an example of envisioned usage.  Examples shown
   below include Bi-directional Forwarding Detection (BFD), Ethernet
   Connectivity Fault Management (CFM), and Two-Way Active Measurement
   Protocol (TWAMP):

       module: ietf-network-device
          +--rw oam-protocols
             +--rw oam-protocol* [type]
                +--rw type=bfd
                +--rw type=cfm
                +--rw type=twamp

2.5.  Routing

   Routing protocol and IP forwarding configuration and operation
   information is modeled via a routing model, such as the one defined
   in [I-D.ietf-netmod-routing-cfg].

   The routing module is expected to include all IETF defined control
   plane protocols, such as BGP, OSPF, LDP and RSVP-TE.  It is also
   expected to support configuration and operation of or more routing
   information bases (RIB).  A RIB is a list of routes complemented with
   administrative data.  Finally, policy is expected to be represented
   within each control plane protocol and RIB.

   The anticipated structure is as follows:











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      module: ietf-network-device
          +--rw rt:routing                 [I-D.ietf-netmod-routing-cfg]
             +--rw control-plane-protocol* [type]
             |  +--rw type      identityref
             |  +--rw policy
             +--rw rib* [name]
                +--rw name           string
                +--rw description?   string
                +--rw policy

2.6.  MPLS

   MPLS data plane related information is grouped together, as with the
   previously discussed modules, is unaware of VRFs/NIs.  The model may
   be instantiated per device, LNE, and NI.  MPLS control plane
   protocols are expected to be included in Section 2.5.  MPLS may reuse
   and build on [I-D.openconfig-mpls-consolidated-model] or other
   emerging models and has an anticipated structure as follows:

     module: ietf-network-device
          +--rw mpls
             +--rw global
             +--rw lsps* [type]
                +--rw type    identityref

   Type refers to LSP type, such as static, traffic engineered or
   routing congruent.  The following is an example of such usage:

     module: ietf-network-device
          +--rw mpls
             +--rw global
             +--rw lsps* [type]
                 +--rw type=static
                 +--rw type=constrained-paths
                 +--rw type=igp-congruent

3.  Security Considerations

   The network-device model structure described in this document does
   not define actual configuration and state data, hence it is not
   directly responsible for security risks.

   Each of the component models that provide the corresponding
   configuration and state data should be considered sensitive from a
   security standpoint since they generally manipulate aspects of
   network configurations.  Each component model should be carefully
   evaluated to determine its security risks, along with mitigations to
   reduce such risks.



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   LNE portion is TBD

   NI portion is TBD

4.  IANA Considerations

   This YANG model currently uses a temporary ad-hoc namespace.  If it
   is placed or redirected for the standards track, an appropriate
   namespace URI will be registered in the "IETF XML Registry"
   [RFC3688].  The YANG structure modules will be registered in the
   "YANG Module Names" registry [RFC6020].

5.  Network Device Model Structure

   <CODE BEGINS> file "ietf-network-device@2016-05-01.yang"
   module ietf-network-device {

     yang-version "1";

     // namespace
     namespace "urn:ietf:params:xml:ns:yang:ietf-network-device";

     prefix "nd";

     // import some basic types

     // meta
     organization "IETF RTG YANG Design Team Collaboration
                   with OpenConfig";

     contact
         "Routing Area YANG Architecture Design Team -
          <rtg-dt-yang-arch@ietf.org>";

     description
       "This module describes a model structure for YANG
        configuration and operational state data models. Its intent is
        to describe how individual device protocol and feature models
        fit together and interact.";

     revision "2016-05-01" {
       description
         "IETF Routing YANG Design Team Meta-Model";
       reference "TBD";
     }

     // extension statements




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     // identity statements

     identity oam-protocol-type {
         description
             "Base identity for derivation of OAM protocols";
     }

     identity network-service-type {
         description
             "Base identity for derivation of network services";
     }

      identity system-management-protocol-type {
         description
             "Base identity for derivation of system management
              protocols";
      }

      identity oam-service-type {
         description
             "Base identity for derivation of Operations,
              Administration, and Maintenance (OAM) services.";
      }

      identity control-plane-protocol-type {
         description
             "Base identity for derivation of control-plane protocols";
      }

      identity mpls-lsp-type {
         description
             "Base identity for derivation of MPLS LSP typs";
      }

     // typedef statements

     // grouping statements

     grouping ribs {
       description
         "Routing Information Bases (RIBs) supported by a
          network-instance";
       container ribs {
           description
               "RIBs supported by a network-instance";
           list rib {
               key "name";
               min-elements "1";



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               description
                   "Each entry represents a RIB identified by the
                  'name' key. All routes in a RIB must belong to the
                   same address family.

                   For each routing instance, an implementation should
                   provide one system-controlled default RIB for each
                   supported address family.";
               leaf name {
                   type string;
                   description
                       "The name of the RIB.";
               }
               reference "draft-ietf-netmod-routing-cfg";
               leaf description {
                   type string;
                   description
                       "Description of the RIB";
               }
               // Note that there is no list of interfaces within
               container policy {
                   description "Policy specific to RIB";
               }
           }
       }
     }

     // top level device definition statements
     container ietf-yang-library {
       description
         "YANG Module Library as defined in
          draft-ietf-netconf-yang-library";
     }

     container interfaces {
       description
        "Interface list as defined by RFC7223/RFC7224";
     }

     container hardware {
       description
         "Hardware / vendor-specific data relevant to the platform.
         This container is an anchor point for platform-specific
         configuration and operational state data.  It may be further
         organized into chassis, line cards, ports, etc.  It is
         expected that vendor or platform-specific augmentations
         would be used to populate this part of the device model";
     }



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     container qos {
       description "QoS features, for example policing, shaping, etc.";
     }

     container system-management {
         description
           "System management for physical or virtual device.";
         container system-management-global {
             description "System management - with reuse of RFC 7317";
         }
         list system-management-protocol {
             key "type";
             leaf type {
                 type identityref {
                     base system-management-protocol-type;
                 }
                 mandatory true;
                 description
                     "Syslog, ssh, TACAC+, SNMP, NETCONF, etc.";
             }
             description "List of system management protocol
                          configured for a logical network
                          element.";
         }
     }

     container network-services {
         description
             "Container for list of configured network
              services.";
         list network-service {
             key "type";
             description
                 "List of network services configured for a
                  network instance.";
             leaf type {
                 type identityref {
                     base network-service-type;
                 }
                 mandatory true;
                 description
                     "The network service type supported within
                      a network instance, e.g., NTP server, DNS
                      server, DHCP server, etc.";
             }
         }
     }




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     container oam-protocols {
         description
             "Container for configured OAM protocols.";
         list oam-protocol {
             key "type";
             leaf type {
                 type identityref {
                     base oam-protocol-type;
                 }
                 mandatory true;
                 description
                     "The Operations, Administration, and
                      Maintenance (OAM) protocol type, e.g., BFD,
                      TWAMP, CFM, etc.";
             }
             description
                 "List of configured OAM protocols.";
         }
     }

     container routing {
       description
         "The YANG Data Model for Routing Management revised to be
          Network Instance / VRF independent. ";
       // Note that there is no routing or network instance
       list control-plane-protocol {
           key "type";
           description
               "List of control plane protocols configured for
                a network instance.";
           leaf type {
               type identityref {
                   base control-plane-protocol-type;
               }
               description
                   "The control plane protocol type, e.g., BGP,
                    OSPF IS-IS, etc";
           }
           container policy {
               description
                   "Protocol specific policy,
                   reusing [RTG-POLICY]";
           }
       }
       list rib {
           key "name";
           min-elements "1";
           description



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               "Each entry represents a RIB identified by the
              'name' key. All routes in a RIB must belong to the
               same address family.

               For each routing instance, an implementation should
               provide one system-controlled default RIB for each
               supported address family.";
           leaf name {
               type string;
               description
                   "The name of the RIB.";
           }
           reference "draft-ietf-netmod-routing-cfg";
           leaf description {
               type string;
               description
                   "Description of the RIB";
           }
           // Note that there is no list of interfaces within
           container policy {
               description "Policy specific to RIB";
           }
       }
     }

     container mpls {
         description "MPLS and TE configuration";
         container global {
             description "Global MPLS configuration";
         }
         list lsps {
             key "type";
             description
                 "List of LSP types.";
             leaf type {
                 type identityref {
                     base mpls-lsp-type;
                 }
                 mandatory true;
                 description
                     "MPLS and Traffic Engineering protocol LSP types,
                      static, LDP/SR (igp-congruent),
                      RSVP TE (constrained-paths) , etc.";
             }
         }
     }

     container ieee-dot1Q {



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       description
         "The YANG Data Model for VLAN bridges as defined by the IEEE";
     }

     container ietf-acl {
       description "Packet Access Control Lists (ACLs) as specified
                      in draft-ietf-netmod-acl-model";
     }

     container ietf-key-chain {
       description "Key chains as specified in
                    draft-ietf-rtgwg-yang-key-chain;";
     }

     container logical-network-element {
       description
         "This module is used to support multiple logical network
          elements on a single physical or virtual system.";
     }

     container network-instance {
       description
         "This module is used to support multiple network instances
          within a single physical or virtual device.  Network
          instances are commonly know as VRFs (virtual routing
          and forwarding) and VSIs (virtual switching instances).";
     }
     // rpc statements

     // notification statements

   }
   <CODE ENDS>

6.  References

6.1.  Normative References

   [I-D.ietf-rtgwg-lne-model]
              Berger, L., Hopps, C., Lindem, A., and D. Bogdanovic,
              "Logical Network Element Model", draft-ietf-rtgwg-lne-
              model-00 (work in progress), June 2016.

   [I-D.ietf-rtgwg-ni-model]
              Berger, L., Hopps, C., Lindem, A., and D. Bogdanovic,
              "Network Instance Model", draft-ietf-rtgwg-ni-model-00
              (work in progress), June 2016.




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

   [RFC4026]  Andersson, L. and T. Madsen, "Provider Provisioned Virtual
              Private Network (VPN) Terminology", RFC 4026,
              DOI 10.17487/RFC4026, March 2005,
              <http://www.rfc-editor.org/info/rfc4026>.

   [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>.

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

   [RFC7277]  Bjorklund, M., "A YANG Data Model for IP Management",
              RFC 7277, DOI 10.17487/RFC7277, June 2014,
              <http://www.rfc-editor.org/info/rfc7277>.

   [RFC7317]  Bierman, A. and M. Bjorklund, "A YANG Data Model for
              System Management", RFC 7317, DOI 10.17487/RFC7317, August
              2014, <http://www.rfc-editor.org/info/rfc7317>.

6.2.  Informative References

   [I-D.ietf-netmod-acl-model]
              Bogdanovic, D., Koushik, K., Huang, L., and D. Blair,
              "Network Access Control List (ACL) YANG Data Model",
              draft-ietf-netmod-acl-model-09 (work in progress), October
              2016.

   [I-D.ietf-netmod-opstate-reqs]
              Watsen, K. and T. Nadeau, "Terminology and Requirements
              for Enhanced Handling of Operational State", draft-ietf-
              netmod-opstate-reqs-04 (work in progress), January 2016.

   [I-D.ietf-netmod-routing-cfg]
              Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", draft-ietf-netmod-routing-cfg-24 (work in
              progress), October 2016.

   [I-D.ietf-rtgwg-yang-key-chain]
              Lindem, A., Qu, Y., Yeung, D., Chen, I., Zhang, Z., and Y.
              Yang, "Routing Key Chain YANG Data Model", draft-ietf-
              rtgwg-yang-key-chain-10 (work in progress), October 2016.



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   [I-D.openconfig-mpls-consolidated-model]
              George, J., Fang, L., eric.osborne@level3.com, e., and R.
              Shakir, "MPLS / TE Model for Service Provider Networks",
              draft-openconfig-mpls-consolidated-model-02 (work in
              progress), October 2015.

   [I-D.openconfig-netmod-model-structure]
              Shaikh, A., Shakir, R., D'Souza, K., and L. Fang,
              "Operational Structure and Organization of YANG Models",
              draft-openconfig-netmod-model-structure-00 (work in
              progress), March 2015.

   [I-D.openconfig-netmod-opstate]
              Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling
              of Operational State Data in YANG", draft-openconfig-
              netmod-opstate-01 (work in progress), July 2015.

   [IEEE-8021Q]
              Holness, M., "IEEE 802.1Q YANG Module Specifications",
              IEEE-Draft http://www.ieee802.org/1/files/public/docs2015/
              new-mholness-yang-8021Q-0515-v04.pdf, May 2015.

   [RFC7895]  Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
              Library", RFC 7895, DOI 10.17487/RFC7895, June 2016,
              <http://www.rfc-editor.org/info/rfc7895>.

Appendix A.  Acknowledgments

   This document is derived from draft-openconfig-netmod-model-
   structure-00.  We thank the Authors of that document and acknowledge
   their indirect contribution to this work.  The authors include: Anees
   Shaikh, Rob Shakir, Kevin D'Souza, Luyuan Fang, Qin Wu, Stephane
   Litkowski and Gang Yan.

   This work was discussed in and produced by the Routing Area Yang
   Architecture design team.  Members at the time of writing included
   Acee Lindem, Anees Shaikh, Christian Hopps, Dean Bogdanovic, Lou
   Berger, Qin Wu, Rob Shakir, Stephane Litkowski, and Gang Yan.

   The identityref approach was proposed by Mahesh Jethanandani.

   The RFC text was produced using Marshall Rose's xml2rfc tool.









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Authors' Addresses

   Acee Lindem (editor)
   Cisco Systems
   301 Midenhall Way
   Cary, NC  27513
   USA

   Email: acee@cisco.com


   Lou Berger (editor)
   LabN Consulting, L.L.C.

   Email: lberger@labn.net


   Dean Bogdanovic

   Email: ivandean@gmail.com


   Christan Hopps
   Deutsche Telekom

   Email: chopps@chopps.org

























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