NETMOD Working Group                                           L. Lhotka
Internet-Draft                                                    CZ.NIC
Intended status: Standards Track                               A. Lindem
Expires: May 4, 2018                                       Cisco Systems
                                                                   Y. Qu
                                            Futurewei Technologies, Inc.
                                                        October 31, 2017

        A YANG Data Model for Routing Management (NDMA Version)
                    draft-ietf-netmod-rfc8022bis-00
                    draft-ietf-netmod-rfc8022bis-01

Abstract

   This document contains a specification of three YANG modules and one
   submodule.  Together they form the core routing data model that
   serves as a framework for configuring and managing a routing
   subsystem.  It is expected that these modules will be augmented by
   additional YANG modules defining data models for control-plane
   protocols, route filters, and other functions.  The core routing data
   model provides common building blocks for such extensions -- routes,
   Routing Information Bases (RIBs), and control-plane protocols.

   This version of these YANG modules uses new names for these YANG
   models.  The main difference from the first version is that this
   version fully conforms to the Network Management Datastore
   Architecture (NMDA).  Consequently, this document obsoletes RFC 8022.
   Deprecated versions of the prior YANG modules are provided as the
   NDMA conpliant modules will replace the prior modules.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on May 4, 2018  . 2018.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology and Notation  . . . . . . . . . . . . . . . . . .   4   3
     2.1.  Glossary of New Terms . . . . . . . . . . . . . . . . . .   5   4
     2.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Prefixes in Data Node Names . . . . . . . . . . . . . . .   6   5
   3.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  The Design of the Core Routing Data Model . . . . . . . . . .   7   6
     4.1.  System-Controlled and User-Controlled List Entries  . . .   8   7
   5.  Basic Building Blocks . . . . . . . . . . . . . . . . . . . .   9   8
     5.1.  Route . . . . . . . . . . . . . . . . . . . . . . . . . .   9   8
     5.2.  Routing Information Base (RIB)  . . . . . . . . . . . . .   9
     5.3.  Control-Plane Protocol  . . . . . . . . . . . . . . . . .  10
       5.3.1.  Routing Pseudo-Protocols  . . . . . . . . . . . . . .  10
       5.3.2.  Defining New Control-Plane Protocols  . . . . . . . .  11  10
     5.4.  Parameters of IPv6 Router Advertisements  . . . . . . . .  11
   6.  Interactions with Other YANG Modules  . . . . . . . . . . . .  13  12
     6.1.  Module "ietf-interfaces"  . . . . . . . . . . . . . . . .  13  12
     6.2.  Module "ietf-ip"  . . . . . . . . . . . . . . . . . . . .  13
   7.  Routing Management YANG Module  . . . . . . . . . . . . . . .  14  13
   8.  IPv4 Unicast Routing Management YANG Module . . . . . . . . .  24  28
   9.  IPv6 Unicast Routing Management YANG Module . . . . . . . . .  29  36
     9.1.  IPv6 Router Advertisements Submodule  . . . . . . . . . .  34  44
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  41  54
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  42  55
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  43  56
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  43  56
     12.2.  Informative References . . . . . . . . . . . . . . . . .  44  57
   Appendix A.  Deprecated Models  . . . . . . . . . . . . . . . . .  45
     A.1.  Deprecated ietf-routing Model . . . . . . . . . . . . . .  45
     A.2.  Deprecated ietf-ipv4-unicast Model  . . . . . . . . . . .  58
     A.3.  Deprecated ietf-ipv6-unicast Model  . . . . . . . . . . .  64
     A.4.  Deprecated ietf-ipv6-router-advertisements Model  . . . .  69
   Appendix B.  The Complete Data Trees  . . . . . . . . . . . . . .  80  58
   Appendix C. B.  Minimum Implementation . . . . . . . . . . . . . . .  83  61
   Appendix D. C.  Example: Adding a New Control-Plane Protocol . . . .  84  61
   Appendix E. D.  Data Tree Example  . . . . . . . . . . . . . . . . .  86  64
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  94  72
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  94  72

1.  Introduction

   This document contains a specification of the following YANG modules:

   o  The "ietf-routing-2" "ietf-routing" module provides generic components of a routing
      data model.

   o  The "ietf-ipv4-unicast-routing-2" "ietf-ipv4-unicast-routing" module augments the "ietf-
      routing-2" "ietf-routing"
      module with additional data specific to IPv4 unicast.

   o  The "ietf-ipv6-unicast-routing-2" "ietf-ipv6-unicast-routing" module augments the "ietf-
      routing-2" "ietf-routing"
      module with additional data specific to IPv6 unicast.  Its
      submodule "ietf-ipv6-router-advertisements" also augments the
      "ietf-interfaces" [RFC7223] and "ietf-ip" [RFC7277] modules with
      IPv6 router configuration variables required by [RFC4861].

   These modules together define the so-called core routing data model,
   which is intended as a basis for future data model development
   covering more-sophisticated routing systems.  While these three
   modules can be directly used for simple IP devices with static
   routing (see Appendix C), B), their main purpose is to provide essential
   building blocks for more-complicated data models involving multiple
   control-plane protocols, multicast routing, additional address
   families, and advanced functions such as route filtering or policy
   routing.  To this end, it is expected that the core routing data
   model will be augmented by numerous modules developed by various IETF
   working groups.

   This version of these YANG modules uses new names for these YANG
   models.  The main difference from the first version is that this
   version fully conforms to the Network Management Datastore
   Architecture (NMDA) [I-D.ietf-netmod-revised-datastores].
   Consequently, this document obsoletes RFC 8022 [RFC8022].  Deprecated
   versions of the prior YANG modules are provided as the Appendix A
   NDMA conpliant modules will replace the prior modules.

2.  Terminology and Notation

   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 terms are defined in [RFC6241]:

   o  client

   o  message
   o  protocol operation

   o  server

   The following terms are defined in [RFC7950]:

   o  action

   o  augment

   o  configuration data

   o  container

   o  container with presence

   o  data model

   o  data node

   o  feature

   o  leaf

   o  list

   o  mandatory node

   o  module

   o  schema tree

   o  state data

   o  RPC (Remote Procedure Call) operation

2.1.  Glossary of New Terms

   core routing data model:  YANG data model comprising "ietf-routing-
      2", "ietf-ipv4-unicast-routing-2", "ietf-routing",
      "ietf-ipv4-unicast-routing", and "ietf-ipv6-unicast-routing-
      2" "ietf-ipv6-unicast-routing"
      modules.

   direct route:  a route to a directly connected network.

   Routing Information Base (RIB):  An object containing a list of
      routes together with other information.  See Section 5.2 for
      details.

   system-controlled entry:  An entry of a list in operational state
      ("config false") that is created by the systemindependently system independently of
      what has been explicitly configured.  See Section 4.1 for details.

   user-controlled entry:  An entry of a list in operational state data
      ("config false") that is created and deleted as a direct
      consequence of certain configuration changes.  See Section 4.1 for
      details.

2.2.  Tree Diagrams

   A simplified graphical representation of the complete data tree is
   presented in Appendix B, A, and similar diagrams of its various subtrees
   appear in the main text.

   o  Brackets "[" and "]" enclose list keys.

   o  Curly braces "{" and "}" contain names of optional features that
      make the corresponding node conditional.

   o  Abbreviations before data node names: "rw" means configuration
      (read-write), "ro" state data (read-only), "-x" RPC operations or
      actions, and "-n" notifications.

   o  Symbols after data node names: "?" means an optional node, "!" a
      container with presence, and "*" denotes a "list" or "leaf-list".

   o  Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

   o  Ellipsis ("...") stands for contents of subtrees that are not
      shown.

2.3.  Prefixes in Data Node Names

   In this document, names of data nodes, actions, and other data model
   objects are often used without a prefix, as long as it is clear from
   the context in which YANG module each name is defined.  Otherwise,
   names are prefixed using the standard prefix associated with the
   corresponding YANG module, as shown in Table 1.

           +--------+-----------------------------+-----------+

            +--------+---------------------------+-----------+
            | Prefix | YANG module               | Reference |
           +--------+-----------------------------+-----------+
            +--------+---------------------------+-----------+
            | if     | ietf-interfaces           | [RFC7223] |
            | ip     | ietf-ip                   | [RFC7277] |
            | rt     | ietf-routing-2 ietf-routing              | Section 7 |
            | v4ur   | ietf-ipv4-unicast-routing-2 ietf-ipv4-unicast-routing | Section 8 |
            | v6ur   | ietf-ipv6-unicast-routing-2 ietf-ipv6-unicast-routing | Section 9 |
            | yang   | ietf-yang-types           | [RFC6991] |
            | inet   | ietf-inet-types           | [RFC6991] |
           +--------+-----------------------------+-----------+
            +--------+---------------------------+-----------+

             Table 1: Prefixes and Corresponding YANG Modules

3.  Objectives

   The initial design of the core routing data model was driven by the
   following objectives:

   o  The data model should be suitable for the common address families
      -- in particular, IPv4 and IPv6 -- and for unicast and multicast
      routing, as well as Multiprotocol Label Switching (MPLS).

   o  A simple IP routing system, such as one that uses only static
      routing, should be configurable in a simple way, ideally without
      any need to develop additional YANG modules.

   o  On the other hand, the core routing framework must allow for
      complicated implementations involving multiple Routing Information
      Bases (RIBs) and multiple control-plane protocols, as well as
      controlled redistributions of routing information.

   o  Because device vendors will want to map the data models built on
      this generic framework to their proprietary data models and
      configuration interfaces, the framework should be flexible enough
      to facilitate that and accommodate data models with different
      logic.

4.  The Design of the Core Routing Data Model

   The core routing data model consists of three YANG modules and one
   submodule.  The first module, "ietf-routing-2", "ietf-routing", defines the generic
   components of a routing system.  The other two modules, "ietf-ipv4-
   unicast-routing-2"
   unicast-routing" and "ietf-ipv6-unicast-routing-2", "ietf-ipv6-unicast-routing", augment the
   "ietf-routing-2" "ietf-
   routing" module with additional data nodes that are needed for IPv4
   and IPv6 unicast routing, respectively.  The "ietf-ipv6-
   unicast-routing-2" "ietf-ipv6-unicast-
   routing" module has a submodule, "ietf-ipv6-router-
   advertisements", "ietf-ipv6-router-advertisements",
   that augments the "ietf-interfaces" [RFC7223] and "ietf-ip" [RFC7277]
   modules with configuration variables for IPv6 router advertisements
   as required by [RFC4861].

   Figures

   Figure 1   shows abridged views of the hierarchies.  See Appendix B A
   for the complete data trees.

   +--rw routing
      +--rw router-id?                 yang:dotted-quad
      +--ro interfaces
      |  +--ro interface*   if:interface-ref
      +--rw control-plane-protocols
      |  +--rw control-plane-protocol* [type name]
      |     +--rw type             identityref
      |     +--rw name             string
      |     +--rw description?     string
      |     +--rw static-routes
      |        +--rw v4ur:ipv4
      |        |     ...
      |        +--rw v6ur:ipv6
      |              ...
      +--rw ribs
         +--rw rib* [name]
            +--rw name              string
            +--rw address-family?   identityref
            +--ro default-rib?      boolean {multiple-ribs}?
            +--ro routes
            |  +--ro route*
            |        ...
            +---x active-route
            |  +---w input
            |  |  +---w v4ur:destination-address?   inet:ipv4-address
            |  |  +---w v6ur:destination-address?   inet:ipv6-address
            |  +--ro output
            |        ...
            +--rw description?      string

                         Figure 1: Data Hierarchy

   As can be seen from Figures 1, the core routing data model introduces
   several generic components of a routing framework: routes, RIBs
   containing lists of routes, and control-plane protocols.  Section 5
   describes these components in more detail.

4.1.  System-Controlled and User-Controlled List Entries

   The core routing data model defines several lists in the schema tree,
   such as "rib", that have to be populated with at least one entry in
   any properly functioning device, and additional entries may be
   configured by a client.

   In such a list, the server creates the required item as a so-called
   system-controlled entry in state data in the operational datastore
   [I-D.ietf-netmod-revised-datastores], i.e., inside read-only lists in
   the "routing" container.

   An example can be seen in Appendix E: D: the "/routing/ribs/rib" list
   has two system-controlled entries named "ipv4-master" and
   "ipv6-master".

   Additional entries may be created in the configuration by a client,
   e.g., via the NETCONF protocol.  These are so-called user-controlled
   entries.  If the server accepts a configured user-controlled entry,
   then this entry also appears in the state data version of the list.

   Corresponding entries in both versions of the list (in operational
   datastore and intended datastore [I-D.ietf-netmod-revised-datastores]
   have the same value of the list key.

   A client may also provide supplemental configuration of system-
   controlled entries.  To do so, the client creates a new entry in the
   configuration with the desired contents.  In order to bind this entry
   to the corresponding entry in the state data list in the operational
   datastore, the key of the configuration entry has to be set to the
   same value as the key of the state entry.

   Deleting a user-controlled entry from the configuration list results
   in the removal of the corresponding entry in the state data list.  In
   contrast, if client delets a system-controlled entry from the
   configuration list in the intended datastore, only the extra
   configuration specified in that entry is removed but the
   corresponding state data entry remains in the list in the operational
   datastore.

5.  Basic Building Blocks

   This section describes the essential components of the core routing
   data model.

5.1.  Route

   Routes are basic elements of information in a routing system.  The
   core routing data model defines only the following minimal set of
   route attributes:

   o  "destination-prefix": address prefix specifying the set of
      destination addresses for which the route may be used.  This
      attribute is mandatory.

   o  "route-preference": an integer value (also known as administrative
      distance) that is used for selecting a preferred route among
      routes with the same destination prefix.  A lower value means a
      more preferred route.

   o  "next-hop": determines the outgoing interface and/or next-hop
      address(es), or a special operation to be performed with a packet.

   Routes are primarily state data that appear as entries of RIBs
   (Section 5.2) but they may also be found in configuration data, for
   example, as manually configured static routes.  In the latter case,
   configurable route attributes are generally a subset of attributes
   defined for RIB routes.

5.2.  Routing Information Base (RIB)

   Every implementation of the core routing data model manages one or
   more Routing Information Bases (RIBs).  A RIB is a list of routes
   complemented with administrative data.  Each RIB contains only routes
   of one address family.  An address family is represented by an
   identity derived from the "rt:address-family" base identity.

   In the core routing data model, RIBs are state data represented as
   entries of the list "/routing/ribs/rib" in the operational datastore
   [I-D.ietf-netmod-revised-datastores].  The contents of RIBs are
   controlled and manipulated by control-plane protocol operations that
   may result in route additions, removals, and modifications.  This
   also includes manipulations via the "static" and/or "direct" pseudo-
   protocols; see Section 5.3.1.

   For every supported address family, exactly one RIB MUST be marked as
   the so-called default RIB to which control-plane protocols place
   their routes by default.

   Simple router implementations that do not advertise the feature
   "multiple-ribs" will typically create one system-controlled RIB per
   supported address family and mark it as the default RIB.

   More-complex router implementations advertising the "multiple-ribs"
   feature support multiple RIBs per address family that can be used for
   policy routing and other purposes.

   The following action (see Section 7.15 of [RFC7950]) is defined for
   the "rib" list:

   o  active-route -- return the active RIB route for the destination
      address that is specified as the action's input parameter.

5.3.  Control-Plane Protocol

   The core routing data model provides an open-ended framework for
   defining multiple control-plane protocol instances, e.g., for Layer 3
   routing protocols.  Each control-plane protocol instance MUST be
   assigned a type, which is an identity derived from the
   "rt:control-plane-protocol" base identity.  The core routing data
   model defines two identities for the direct and static pseudo-
   protocols (Section 5.3.1).

   Multiple control-plane protocol instances of the same type MAY be
   configured.

5.3.1.  Routing Pseudo-Protocols

   The core routing data model defines two special routing protocol
   types -- "direct" and "static".  Both are in fact pseudo-protocols,
   which means that they are confined to the local device and do not
   exchange any routing information with adjacent routers.

   Every implementation of the core routing data model MUST provide
   exactly one instance of the "direct" pseudo-protocol type.  It is the
   source of direct routes for all configured address families.  Direct
   routes are normally supplied by the operating system kernel, based on
   the configuration of network interface addresses; see Section 6.2.

   A pseudo-protocol of the type "static" allows for specifying routes
   manually.  It MAY be configured in zero or multiple instances,
   although a typical configuration will have exactly one instance.

5.3.2.  Defining New Control-Plane Protocols

   It is expected that future YANG modules will create data models for
   additional control-plane protocol types.  Such a new module has to
   define the protocol-specific configuration and state data, and it has
   to integrate it into the core routing framework in the following way:

   o  A new identity MUST be defined for the control-plane protocol, and
      its base identity MUST be set to "rt:control-plane-protocol" or to
      an identity derived from "rt:control-plane-protocol".

   o  Additional route attributes MAY be defined, preferably in one
      place by means of defining a YANG grouping.  The new attributes
      have to be inserted by augmenting the definitions of the node
       /rt:routing/rt:ribs/rt:rib/rt:routes/rt:route

      and possibly other places in the configuration, state data,
      notifications, and input/output parameters of actions or RPC
      operations.

   o  Configuration parameters and/or state data for the new protocol
      can be defined by augmenting the "control-plane-protocol" data
      node under "/routing".

   By using a "when" statement, the augmented configuration parameters
   and state data specific to the new protocol SHOULD be made
   conditional and valid only if the value of "rt:type" or
   "rt:source-protocol" is equal to (or derived from) the new protocol's
   identity.

   It is also RECOMMENDED that protocol-specific data nodes be
   encapsulated in an appropriately named container with presence.  Such
   a container may contain mandatory data nodes that are otherwise
   forbidden at the top level of an augment.

   The above steps are implemented by the example YANG module for the
   Routing Information Protocol (RIP) in Appendix D. C.

5.4.  Parameters of IPv6 Router Advertisements

   YANG module "ietf-ipv6-router-advertisements" (Section 9.1), which is
   a submodule of the "ietf-ipv6-unicast-routing-2" "ietf-ipv6-unicast-routing" module, augments the
   configuration and state data of IPv6 interfaces with definitions of
   the following variables as required by Section 6.2.1 of [RFC4861]:

   o  send-advertisements

   o  max-rtr-adv-interval

   o  min-rtr-adv-interval

   o  managed-flag

   o  other-config-flag

   o  link-mtu

   o  reachable-time

   o  retrans-timer

   o  cur-hop-limit
   o  default-lifetime

   o  prefix-list: a list of prefixes to be advertised.

      The following parameters are associated with each prefix in the
      list:

      *  valid-lifetime

      *  on-link-flag

      *  preferred-lifetime

      *  autonomous-flag

   NOTES:

   1.  The "IsRouter" flag, which is also required by [RFC4861], is
       implemented in the "ietf-ip" module [RFC7277] (leaf
       "ip:forwarding").

   2.  The original specification [RFC4861] allows the implementations
       to decide whether the "valid-lifetime" and "preferred-lifetime"
       parameters remain the same in consecutive advertisements or
       decrement in real time.  However, the latter behavior seems
       problematic because the values might be reset again to the
       (higher) configured values after a configuration is reloaded.
       Moreover, no implementation is known to use the decrementing
       behavior.  The "ietf-ipv6-router-advertisements" submodule
       therefore stipulates the former behavior with constant values.

6.  Interactions with Other YANG Modules

   The semantics of the core routing data model also depends on several
   configuration parameters that are defined in other YANG modules.

6.1.  Module "ietf-interfaces"

   The following boolean switch is defined in the "ietf-interfaces" YANG
   module [RFC7223]:

   /if:interfaces/if:interface/if:enabled

      If this switch is set to "false" for a network-layer interface,
      then all routing and forwarding functions MUST be disabled on this
      interface.

6.2.  Module "ietf-ip"

   The following boolean switches are defined in the "ietf-ip" YANG
   module [RFC7277]:

   /if:interfaces/if:interface/ip:ipv4/ip:enabled

      If this switch is set to "false" for a network-layer interface,
      then all IPv4 routing and forwarding functions MUST be disabled on
      this interface.

   /if:interfaces/if:interface/ip:ipv4/ip:forwarding

      If this switch is set to "false" for a network-layer interface,
      then the forwarding of IPv4 datagrams through this interface MUST
      be disabled.  However, the interface MAY participate in other IPv4
      routing functions, such as routing protocols.

   /if:interfaces/if:interface/ip:ipv6/ip:enabled

      If this switch is set to "false" for a network-layer interface,
      then all IPv6 routing and forwarding functions MUST be disabled on
      this interface.

   /if:interfaces/if:interface/ip:ipv6/ip:forwarding

      If this switch is set to "false" for a network-layer interface,
      then the forwarding of IPv6 datagrams through this interface MUST
      be disabled.  However, the interface MAY participate in other IPv6
      routing functions, such as routing protocols.

   In addition, the "ietf-ip" module allows for configuring IPv4 and
   IPv6 addresses and network prefixes or masks on network-layer
   interfaces.  Configuration of these parameters on an enabled
   interface MUST result in an immediate creation of the corresponding
   direct route.  The destination prefix of this route is set according
   to the configured IP address and network prefix/mask, and the
   interface is set as the outgoing interface for that route.

7.  Routing Management YANG Module

   <CODE BEGINS> file "ietf-routing-2@2017-10-06.yang" "ietf-routing@2017-10-30.yang"
   module ietf-routing-2 ietf-routing {
     yang-version "1.1";
     namespace "urn:ietf:params:xml:ns:yang:ietf-routing-2"; "urn:ietf:params:xml:ns:yang:ietf-routing";
     prefix "rt";

     import ietf-yang-types {
       prefix "yang";
     }

     import ietf-interfaces {
       prefix "if";
     }

     organization
       "IETF NETMOD - Networking Modeling Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/netmod/>
        WG List:  <mailto:rtgwg@ietf.org>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>
                  Acee Lindem
                  <mailto:acee@cisco.com>
                  Yingzhen Qu
                  <mailto:yingzhen.qu@huawei.com>";

     description
       "This YANG module defines essential components for the management
        of a routing subsystem.

        Copyright (c) 2017 IETF Trust and the persons
        identified as authors of the code.  All rights reserved.

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

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

     revision 2017-10-06 2017-10-30 {
       description
         "Network Managment Datastore Architecture (NDMA)
          Initial Revision
          Replaces ietf-routing.yang"; Revision";
       reference
         "RFC XXXX: A YANG Data Model for Routing Management
          (NDMA Version)";
     }

     revision 2016-11-04 {
          description
            "Initial revision.";
          reference
            "RFC 8022: A YANG Data Model for Routing Management";
     }

     /* Features */
     feature multiple-ribs {
       description
         "This feature indicates that the server supports user-defined
          RIBs.

          Servers that do not advertise this feature SHOULD provide
          exactly one system-controlled RIB per supported address family
          and make it also the default RIB.  This RIB then appears as an
          entry of the list /routing/ribs/rib.";
     }

     feature router-id {
       description
         "This feature indicates that the server supports configuration
          of an explicit 32-bit router ID that is used by some routing
          protocols.

          Servers that do not advertise this feature set a router ID
          algorithmically, usually to one of the configured IPv4
          addresses.  However, this algorithm is implementation
          specific.";
     }

     /* Identities */

     identity address-family {
       description
         "Base identity from which identities describing address
          families are derived.";
     }

     identity ipv4 {
       base address-family;
       description
         "This identity represents IPv4 address family.";
     }

     identity ipv6 {
       base address-family;
       description
         "This identity represents IPv6 address family.";
     }
     identity control-plane-protocol {
       description
         "Base identity from which control-plane protocol identities are
          derived.";
     }

     identity routing-protocol {
       base control-plane-protocol;
       description
         "Identity from which Layer 3 routing protocol identities are
          derived.";
     }

     identity direct {
       base routing-protocol;
       description
         "Routing pseudo-protocol that provides routes to directly
          connected networks.";
     }

     identity static {
       base routing-protocol;
       description
         "Static routing pseudo-protocol.";
     }

     /* Type Definitions */

     typedef route-preference {
       type uint32;
       description
         "This type is used for route preferences.";
     }

     /* Groupings */

     grouping address-family {
       description
         "This grouping provides a leaf identifying an address
          family.";
       leaf address-family {
         type identityref {
           base address-family;
         }
         mandatory "true";
         description
           "Address family.";
       }

     }

     grouping router-id {
       description
         "This grouping provides router ID.";
       leaf router-id {
         type yang:dotted-quad;
         description
           "A 32-bit number in the form of a dotted quad that is used by
            some routing protocols identifying a router.";
         reference
           "RFC 2328: OSPF Version 2.";
       }
     }

     grouping special-next-hop {
       description
         "This grouping provides a leaf with an enumeration of special
          next hops.";
       leaf special-next-hop {
         type enumeration {
           enum blackhole {
             description
               "Silently discard the packet.";
           }
           enum unreachable {
             description
               "Discard the packet and notify the sender with an error
                message indicating that the destination host is
                unreachable.";
           }
           enum prohibit {
             description
               "Discard the packet and notify the sender with an error
                message indicating that the communication is
                administratively prohibited.";
           }
           enum receive {
             description
               "The packet will be received by the local system.";
           }
         }
         description
           "Options for special next hops.";
       }
     }

     grouping next-hop-content {
       description
         "Generic parameters of next hops in static routes.";
       choice next-hop-options {
         mandatory "true";
         description
           "Options for next hops in static routes.

            It is expected that further cases will be added through
            augments from other modules.";
         case simple-next-hop {
           description
             "This case represents a simple next hop consisting of the
              next-hop address and/or outgoing interface.

              Modules for address families MUST augment this case with a
              leaf containing a next-hop address of that address
              family.";
           leaf outgoing-interface {
             type if:interface-ref;
             description
               "Name of the outgoing interface.";
           }
         }
         case special-next-hop {
           uses special-next-hop;
         }
         case next-hop-list {
           container next-hop-list {
             description
               "Container for multiple next-hops.";
             list next-hop {
               key "index";
               description
                 "An entry of a next-hop list.

                  Modules for address families MUST augment this list
                  with a leaf containing a next-hop address of that
                  address family.";
               leaf index {
                 type string;
                 description
                   "A user-specified identifier utilized to uniquely
                    reference the next-hop entry in the next-hop list.
                    The value of this index has no semantic meaning
                    other than for referencing the entry.";
               }
               leaf outgoing-interface {
                 type if:interface-ref;
                 description
                   "Name of the outgoing interface.";
               }
             }
           }
         }
       }
     }

     grouping next-hop-state-content {
       description
         "Generic parameters of next hops in state data.";
       choice next-hop-options {
         mandatory "true";
         description
           "Options for next hops in state data.

            It is expected that further cases will be added through
            augments from other modules, e.g., for recursive
            next hops.";
         case simple-next-hop {
           description
             "This case represents a simple next hop consisting of the
              next-hop address and/or outgoing interface.

              Modules for address families MUST augment this case with a
              leaf containing a next-hop address of that address
              family.";
           leaf outgoing-interface {
             type if:interface-ref;
             description
               "Name of the outgoing interface.";
           }
         }
         case special-next-hop {
           uses special-next-hop;
         }
         case next-hop-list {
           container next-hop-list {
             description
               "Container for multiple next hops.";
             list next-hop {
               description
                 "An entry of a next-hop list.

                  Modules for address families MUST augment this list
                  with a leaf containing a next-hop address of that
                  address family.";

               leaf outgoing-interface {
                 type if:interface-ref;
                 description
                   "Name of the outgoing interface.";
               }
             }
           }
         }
       }
     }

     grouping route-metadata {
       description
         "Common route metadata.";
       leaf source-protocol {
         type identityref {
           base routing-protocol;
         }
         mandatory "true";
         description
           "Type of the routing protocol from which the route
            originated.";
       }
       leaf active {
         type empty;
         description
           "Presence of this leaf indicates that the route is preferred
            among all routes in the same RIB that have the same
            destination prefix.";
       }
       leaf last-updated {
         type yang:date-and-time;
         description
           "Time stamp of the last modification of the route.  If the
            route was never modified, it is the time when the route was
            inserted into the RIB.";
       }
     }

     /* Configuration Data */

     container routing {
       description
         "Configuration parameters for the routing subsystem.";
       uses router-id {
         if-feature "router-id";
         description
           "Configuration of the global router ID.  Routing protocols
            that use router ID can use this parameter or override it
            with another value.";
       }
       container interfaces {
         config "false";
         description
           "Network-layer interfaces used for routing.";
         leaf-list interface {
           type if:interface-ref;
           description
             "Each entry is a reference to the name of a configured
              network-layer interface.";
         }
       }
       container control-plane-protocols {
         description
           "Configuration of control-plane protocol instances.";
         list control-plane-protocol {
           key "type name";
           description
             "Each entry contains configuration of a control-plane
              protocol instance.";
           leaf type {
             type identityref {
               base control-plane-protocol;
             }
             description
               "Type of the control-plane protocol - an identity derived
                from the 'control-plane-protocol' base identity.";
           }
           leaf name {
             type string;
             description
               "An arbitrary name of the control-plane protocol
                instance.";
           }
           leaf description {
             type string;
             description
               "Textual description of the control-plane protocol
                instance.";
           }
           container static-routes {
             when "derived-from-or-self(../type, 'rt:static')" {
               description
                 "This container is only valid for the 'static' routing
                  protocol.";
             }
             description
               "Configuration of the 'static' pseudo-protocol.

                Address-family-specific modules augment this node with
                their lists of routes.";
           }
         }
       }
       container ribs {
         description
           "Configuration of RIBs.";
         list rib {
           key "name";
           description
             "Each entry contains configuration for a RIB identified by
              the 'name' key.

              Entries having the same key as a system-controlled entry
              of the list /routing/ribs/rib are used for
              configuring parameters of that entry.  Other entries
              define additional user-controlled RIBs.";
           leaf name {
             type string;
             description
               "The name of the RIB.

                For system-controlled entries, the value of this leaf
                must be the same as the name of the corresponding entry
                in state data.

                For user-controlled entries, an arbitrary name can be
                used.";
           }
           uses address-family {
             description
               "Address family of the RIB.

                It is mandatory for user-controlled RIBs.  For
                system-controlled RIBs it can be omitted; otherwise, it
                must match the address family of the corresponding state
                entry.";
             refine "address-family" {
               mandatory "false";
             }
           }

           leaf default-rib {
             if-feature "multiple-ribs";
             type boolean;
             default "true";
             config "false";
             description
               "This flag has the value of 'true' if and only if the RIB
                is the default RIB for the given address family.

                By default, control-plane protocols place their routes
                in the default RIBs.";
           }
           container routes {
             config "false";
             description
               "Current content of the RIB.";
             list route {
               description
                 "A RIB route entry.  This data node MUST be augmented
                  with information specific for routes of each address
                  family.";
               leaf route-preference {
                 type route-preference;
                 description
                   "This route attribute, also known as administrative
                    distance, allows for selecting the preferred route
                    among routes with the same destination prefix.  A
                    smaller value means a more preferred route.";
               }
               container next-hop {
                 description
                   "Route's next-hop attribute.";
                 uses next-hop-state-content;
               }
               uses route-metadata;
             }
           }
           action active-route {
             description
               "Return the active RIB route that is used for the
                destination address.

                Address-family-specific modules MUST augment input
                parameters with a leaf named 'destination-address'.";
             output {
               container route {
                 description
                   "The active RIB route for the specified destination.

                    If no route exists in the RIB for the destination
                    address, no output is returned.

                    Address-family-specific modules MUST augment this
                    container with appropriate route contents.";
                 container next-hop {
                   description
                     "Route's next-hop attribute.";
                   uses next-hop-state-content;
                 }
                 uses route-metadata;
               }
             }
           }
           leaf description {
             type string;
             description
               "Textual description of the RIB.";
           }
         }
       }
     }
   }
   <CODE ENDS>

8.  IPv4 Unicast Routing Management YANG Module

   <CODE BEGINS> file "ietf-ipv4-unicast-routing-2@2017-10-06.yang"
   module ietf-ipv4-unicast-routing-2 {
     yang-version "1.1";
     namespace
        "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing-2";
     prefix "v4ur";

     import ietf-routing-2 {
       prefix "rt";
     }
     import ietf-inet-types

     /* Obsolete State Data */

     container routing-state {
       prefix "inet";
     }
     organization
       "IETF NETMOD - Networking Modeling Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/netmod/>
        WG List:  <mailto:rtgwg@ietf.org>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>
                  Acee Lindem
                  <mailto:acee@cisco.com>
                  Yingzhen Qu
                  <mailto:yingzhen.qu@huawei.com>";
       config false;
       status obsolete;
       description
       "This YANG module augments the 'ietf-routing-2' module with basic
        configuration and state
         "State data for IPv4 unicast routing.

        Copyright (c) 2017 IETF Trust and the persons
        identified as authors of the code.  All rights reserved.

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

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

     revision 2017-10-06 {
       description
         "Network Managment Datastore Architecture (NDMA)
          Initial Revision
          Replaces ietf-ipv4-unicast-routing.yang";
       reference
         "RFC XXXX: A YANG Data Model for Routing Management
          (NDMA Version)";
     }

     /* Identities */

     identity ipv4-unicast routing subsystem.";
       uses router-id {
       base rt:ipv4;
         status obsolete;
         description
         "This identity represents
           "Global router ID.

            It may be either configured or assigned algorithmically by
            the IPv4 unicast address family."; implementation.";
       }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route" {
       when "derived-from-or-self(../../rt:address-family, "
          + "'v4ur:ipv4-unicast')"
       container interfaces {
         status obsolete;
         description
           "This augment is valid only
           "Network-layer interfaces used for IPv4 unicast.";
       }
       description
         "This leaf augments an IPv4 unicast route.";
       leaf destination-prefix routing.";
         leaf-list interface {
           type inet:ipv4-prefix; if:interface-state-ref;
           status obsolete;
           description
           "IPv4 destination prefix.";
             "Each entry is a reference to the name of a configured
              network-layer interface.";
         }

       }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route/"
           + "rt:next-hop/rt:next-hop-options/rt:simple-next-hop" {
       when "derived-from-or-self(../../../rt:address-family, "
          + "'v4ur:ipv4-unicast')"
       container control-plane-protocols {
         status obsolete;
         description
           "This augment is valid only
           "Container for IPv4 unicast.";
       } the list of routing protocol instances.";
         list control-plane-protocol {
           key "type name";
           status obsolete;
           description
         "Augment 'simple-next-hop' case in IPv4 unicast routes.";
             "State data of a control-plane protocol instance.

              An implementation MUST provide exactly one
              system-controlled instance of the 'direct'
              pseudo-protocol.  Instances of other control-plane
              protocols MAY be created by configuration.";
           leaf next-hop-address type {
             type inet:ipv4-address; identityref {
               base control-plane-protocol;
             }
             status obsolete;
             description
           "IPv4 address
               "Type of the next hop.";
       } control-plane protocol.";
           }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route/"
           + "rt:next-hop/rt:next-hop-options/rt:next-hop-list/"
           + "rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family, "
          + "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv4 unicast.";
       }
       description
         "This leaf augments the 'next-hop-list' case of IPv4 unicast
          routes.";
           leaf address name {
             type inet:ipv4-address; string;
             status obsolete;
             description
           "IPv4 address
               "The name of the next-hop."; control-plane protocol instance.

                For system-controlled instances this name is
                persistent, i.e., it SHOULD NOT change across
                reboots.";
           }
         }

     augment
       "/rt:routing/rt:ribs/rt:rib/rt:active-route/rt:input" {
       when "derived-from-or-self(../rt:address-family, "
          + "'v4ur:ipv4-unicast')"
       }
       container ribs {
         status obsolete;
         description
           "This augment is valid only
           "Container for IPv4 unicast RIBs.";
       }
         list rib {
           key "name";
           min-elements 1;
           status obsolete;
           description
         "This augment adds
             "Each entry represents a RIB identified by the input parameter of 'name'
              key. All routes in a RIB MUST belong to the 'active-route'
          action."; same address
              family.

              An implementation SHOULD provide one system-controlled
              default RIB for each supported address family.";
           leaf destination-address name {
             type inet:ipv4-address; string;
             status obsolete;
             description
           "IPv4 destination address.";
       }
               "The name of the RIB.";
           }

     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route"
           uses address-family {
       when "derived-from-or-self(../../rt:address-family, "
          + "'v4ur:ipv4-unicast')"
             status obsolete;
             description
               "The address family of the RIB.";
           }
           leaf default-rib {
             if-feature "multiple-ribs";
             type boolean;
             default "true";
             status obsolete;
             description
               "This augment is valid flag has the value of 'true' if and only if the
                RIB is the default RIB for IPv4 unicast.";
       }
       description
         "This augment adds the destination prefix to given address family.

                By default, control-plane protocols place their routes
                in the reply default RIBs.";
           }
           container routes {
             status obsolete;
             description
               "Current content of the
          'active-route' action."; RIB.";
             list route {
               status obsolete;
               description
                 "A RIB route entry.  This data node MUST be augmented
                  with information specific for routes of each address
                  family.";
               leaf destination-prefix route-preference {
                 type inet:ipv4-prefix; route-preference;
                 status obsolete;
                 description
           "IPv4
                   "This route attribute, also known as administrative
                    distance, allows for selecting the preferred route
                    among routes with the same destination prefix.";
       } prefix.  A
                    smaller value means a more preferred route.";
               }

     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
           + "rt:simple-next-hop"
               container next-hop {
       when "derived-from-or-self(../../../rt:address-family, "
          + "'v4ur:ipv4-unicast')"
                 status obsolete;
                 description
                   "Route's next-hop attribute.";

                 uses next-hop-state-content {
                   status obsolete;
                   description
           "This augment is valid only for IPv4 unicast.";
                     "Route's next-hop attribute operational state.";
                 }
       description
         "Augment 'simple-next-hop' case in the reply to the
          'active-route' action.";
       leaf next-hop-address
               }
               uses route-metadata {
         type inet:ipv4-address;
                 status obsolete;
                 description
           "IPv4 address of the next hop.";
                   "Route metadata.";
               }
             }

     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
           + "rt:next-hop-list/rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family, "
          + "'v4ur:ipv4-unicast')"
           }
           action active-route {
             status obsolete;
             description
           "This augment
               "Return the active RIB route that is valid only used for IPv4 unicast.";
       }
       description
         "Augment 'next-hop-list' case in the reply to the
          'active-route' action.";
                destination address.

                Address-family-specific modules MUST augment input
                parameters with a leaf next-hop-address named 'destination-address'.";
             output {
         type inet:ipv4-address;
         description
           "IPv4 address of the next hop.";
       }
     }

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:static-routes"
               container route {
                 status obsolete;
                 description
         "This augment defines
                   "The active RIB route for the configuration of specified
                    destination.

                    If no route exists in the 'static'
          pseudo-protocol with data specific to IPv4 unicast."; RIB for the destination
                    address, no output is returned.

                    Address-family-specific modules MUST augment this
                    container ipv4 {
         description
           "Configuration of a 'static' pseudo-protocol instance
            consists of a list of routes.";
         list with appropriate route contents.";
                 container next-hop {
           key "destination-prefix";
                   status obsolete;
                   description
             "A list of static routes.";
           leaf destination-prefix
                     "Route's next-hop attribute.";
                   uses next-hop-state-content {
             type inet:ipv4-prefix;
             mandatory "true";
                     status obsolete;
                     description
               "IPv4 destination prefix.";
                       "Active route state data.";
                   }
           leaf description
                 }
                 uses route-metadata {
             type string;
                   status obsolete;
                   description
               "Textual description of the route.";
           }
           container next-hop {
             description
               "Configuration of next-hop.";
             uses rt:next-hop-content {
               augment "next-hop-options/simple-next-hop" {
                 description
                   "Augment 'simple-next-hop' case in IPv4 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv4-address;
                   description
                     "IPv4 address of the next hop.";
                 }
               }
               augment "next-hop-options/next-hop-list/next-hop-list/"
                     + "next-hop" {
                 description
                   "Augment 'next-hop-list' case in IPv4 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv4-address;
                   description
                     "IPv4 address of the next hop.";
                   "Active route metadata.";
                 }

               }
             }
           }
         }
       }
     }
   }
   <CODE ENDS>

9.  IPv6

8.  IPv4 Unicast Routing Management YANG Module

   <CODE BEGINS> file "ietf-ipv6-unicast-routing-2@2017-10-06.yang" "ietf-ipv4-unicast-routing@2017-10-14.yang"
   module ietf-ipv6-unicast-routing-2 ietf-ipv4-unicast-routing {
     yang-version "1.1";
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing-2";
        "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing";
     prefix "v6ur"; "v4ur";

     import ietf-routing-2 ietf-routing {
       prefix "rt";
     }

     import ietf-inet-types {
       prefix "inet";
     }

     include ietf-ipv6-router-advertisements-2 {
       revision-date 2017-10-06;
     }
     organization
       "IETF NETMOD - Networking Modeling Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/netmod/>
        WG List:  <mailto:rtgwg@ietf.org>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>
                  Acee Lindem
                  <mailto:acee@cisco.com>
                  Yingzhen Qu
                  <mailto:yingzhen.qu@huawei.com>";

     description
       "This YANG module augments the 'ietf-routing' module with basic
        configuration and state data for IPv6 IPv4 unicast routing.

        Copyright (c) 2017 IETF Trust and the persons
        identified as authors of the code.  All rights reserved.

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

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

     revision 2017-10-06 2017-10-14 {
       description
         "Network Managment Datastore Architecture (NDMA)
          Initial revision
          Replaces ietf-ipv6-unicast-routing.yang"; Revision";
       reference
         "RFC XXXX: A YANG Data Model for Routing Management
          (NDMA Version)";
     }

     revision 2016-11-04 {
          description
            "Initial revision.";
          reference
            "RFC 8022: A YANG Data Model for Routing Management";
     }

     /* Identities */

     identity ipv6-unicast ipv4-unicast {
       base rt:ipv6; rt:ipv4;
       description
         "This identity represents the IPv6 IPv4 unicast address family.";
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route" {
       when "derived-from-or-self(../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast.";
       }
       description
         "This leaf augments an IPv6 IPv4 unicast route.";
       leaf destination-prefix {
         type inet:ipv6-prefix; inet:ipv4-prefix;
         description
           "IPv6
           "IPv4 destination prefix.";
       }
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route/"
           + "rt:next-hop/rt:next-hop-options/rt:simple-next-hop" {

       when "derived-from-or-self(../../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast.";
       }
       description
         "Augment 'simple-next-hop' case in IPv6 IPv4 unicast routes.";
       leaf next-hop-address {
         type inet:ipv6-address; inet:ipv4-address;
         description
           "IPv6
           "IPv4 address of the next hop.";
       }
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route/"
           + "rt:next-hop/rt:next-hop-options/rt:next-hop-list/"
           + "rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast.";
       }
       description
         "This leaf augments the 'next-hop-list' case of IPv6 IPv4 unicast
          routes.";
       leaf address {
         type inet:ipv6-address; inet:ipv4-address;
         description
           "IPv6
           "IPv4 address of the next hop."; next-hop.";
       }
     }

     augment
       "/rt:routing/rt:ribs/rt:rib/rt:active-route/rt:input" {
       when "derived-from-or-self(../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast RIBs.";
       }
       description
         "This augment adds the input parameter of the 'active-route'
          action.";
       leaf destination-address {
         type inet:ipv6-address; inet:ipv4-address;
         description
           "IPv6
           "IPv4 destination address.";
       }
     }
     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route" {
       when "derived-from-or-self(../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast.";
       }
       description
         "This augment adds the destination prefix to the reply of the
          'active-route' action.";
       leaf destination-prefix {
         type inet:ipv6-prefix; inet:ipv4-prefix;
         description
           "IPv6
           "IPv4 destination prefix.";
       }
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
           + "rt:simple-next-hop" {
       when "derived-from-or-self(../../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast.";
       }
       description
         "Augment 'simple-next-hop' case in the reply to the
          'active-route' action.";
       leaf next-hop-address {
         type inet:ipv6-address; inet:ipv4-address;
         description
           "IPv6
           "IPv4 address of the next hop.";
       }
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
           + "rt:next-hop-list/rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" "'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv6 IPv4 unicast.";
       }
       description
         "Augment 'next-hop-list' case in the reply to the
          'active-route' action.";
       leaf next-hop-address {
         type inet:ipv6-address; inet:ipv4-address;
         description
           "IPv6
           "IPv4 address of the next hop.";
       }
     }

     /* Configuration data */

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:static-routes" {
       description
         "This augment defines the configuration of the 'static'
          pseudo-protocol with data specific to IPv6 IPv4 unicast.";
       container ipv6 ipv4 {
         description
           "Configuration of a 'static' pseudo-protocol instance
            consists of a list of routes.";
         list route {
           key "destination-prefix";
           description
             "A list of static routes.";
           leaf destination-prefix {
             type inet:ipv6-prefix; inet:ipv4-prefix;
             mandatory "true";
             description
               "IPv6
               "IPv4 destination prefix.";
           }
           leaf description {
             type string;
             description
               "Textual description of the route.";
           }
           container next-hop {
             description
               "Configuration of next-hop.";
             uses rt:next-hop-content {
               augment "next-hop-options/simple-next-hop" {
                 description
                   "Augment 'simple-next-hop' case in IPv6 IPv4 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv6-address; inet:ipv4-address;
                   description
                     "IPv6
                     "IPv4 address of the next hop.";
                 }
               }
               augment "next-hop-options/next-hop-list/next-hop-list/"
                     + "next-hop" {
                 description
                   "Augment 'next-hop-list' case in IPv6 IPv4 static
                    routes.";

                 leaf next-hop-address {
                   type inet:ipv6-address; inet:ipv4-address;
                   description
                     "IPv6
                     "IPv4 address of the next hop.";
                 }
               }
             }
           }
         }
       }
     }
   }
   <CODE ENDS>

9.1.  IPv6 Router Advertisements Submodule

   <CODE BEGINS>
   file "ietf-ipv6-router-advertisements-2@2017-10-06.yang"
   submodule ietf-ipv6-router-advertisements-2

     /* Obsolete State Data */

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route" {
     yang-version "1.1";
     belongs-to ietf-ipv6-unicast-routing-2
       when "derived-from-or-self(../../rt:address-family, "
            + "'v4ur:ipv4-unicast')" {
       prefix "v6ur";
         description
           "This augment is valid only for IPv4 unicast.";
       }

     import ietf-inet-types
       status obsolete;
       description
         "This leaf augments an IPv4 unicast route.";
       leaf destination-prefix {
       prefix "inet";
         type inet:ipv4-prefix;
         status obsolete;
         description
           "IPv4 destination prefix.";
       }

     import ietf-interfaces {
       prefix "if";
     }

     import ietf-ip
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route/"
             + "rt:next-hop/rt:next-hop-options/rt:simple-next-hop" {
       prefix "ip";
       when "derived-from-or-self(
               ../../../rt:address-family, 'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv4 unicast.";
       }

     organization
       "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/netmod/>
        WG List:  <mailto:netmod@ietf.org>

        WG Chair: Lou Berger
                  <mailto:lberger@labn.net>

        WG Chair: Kent Watsen
                  <mailto:kwatsen@juniper.net>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>

        Editor:   Acee Lindem
                  <mailto:acee@cisco.com>

        Editor:   Yingzhen Qu
                  <mailto:yingzhen.qu@huawei.com>";
       status obsolete;
       description
         "Augment 'simple-next-hop' case in IPv4 unicast routes.";
       leaf next-hop-address {
         type inet:ipv4-address;
         status obsolete;
         description
           "IPv4 address of the next hop.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route/"
             + "rt:next-hop/rt:next-hop-options/rt:next-hop-list/"
             + "rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family,
               'v4ur:ipv4-unicast')" {
         description
           "This YANG module augment is valid only for IPv4 unicast.";
       }
       status obsolete;
       description
         "This leaf augments the 'ietf-ip' module with
        configuration and state data 'next-hop-list' case of IPv4 unicast
          routes.";
       leaf address {
         type inet:ipv4-address;
         status obsolete;
         description
           "IPv4 address of IPv6 router advertisements.

        Copyright (c) 2017 IETF Trust and the persons identified as
        authors next-hop.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:input" {
       when "derived-from-or-self(../rt:address-family,
             'v4ur:ipv4-unicast')" {
         description
           "This augment is valid only for IPv4 unicast RIBs.";
       }
       status obsolete;
       description
         "This augment adds the input parameter of the code.  All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, 'active-route'
          action.";
       leaf destination-address {
         type inet:ipv4-address;
         status obsolete;
         description
           "IPv4 destination address.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:output/rt:route" {
       when "derived-from-or-self(../../rt:address-family,
               'v4ur:ipv4-unicast')" {
         description
           "This augment is permitted pursuant to, and subject
        to valid only for IPv4 unicast.";
       }
       status obsolete;
       description
         "This augment adds the license terms contained in, destination prefix to the Simplified BSD License
        set forth in Section 4.c reply of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://trustee.ietf.org/license-info).

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
        'OPTIONAL' in the module text are to be interpreted as
        described in RFC 2119.

        This version of this YANG module is part of RFC 8022;
        see the RFC itself for full legal notices.";

     reference
       "RFC 4861: Neighbor Discovery for IP version 6 (IPv6).";

     revision 2017-10-05
          'active-route' action.";
       leaf destination-prefix {
         type inet:ipv4-prefix;
         status obsolete;
         description
         "Network Managment Datastore Architecture (NDMA)
          Initial Revision
          Replaces ietf-ipv6-router-advertisements.yang";
       reference
         "RFC XXXX: A YANG Data Model for Routing Management
          (NDMA Version)";
           "IPv4 destination prefix.";
       }
     }
     augment "/if:interfaces/if:interface/ip:ipv6" "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
             + "rt:simple-next-hop" {
       description
         "Augment interface configuration with parameters of IPv6
          router advertisements.";
       container ipv6-router-advertisements
       when "derived-from-or-self(../../../rt:address-family,
               'v4ur:ipv4-unicast')" {
         description
           "Configuration of IPv6 Router Advertisements.";
           "This augment is valid only for IPv4 unicast.";
       }
       status obsolete;
       description
         "Augment 'simple-next-hop' case in the reply to the
          'active-route' action.";
       leaf send-advertisements next-hop-address {
         type boolean;
           default "false"; inet:ipv4-address;
         status obsolete;
         description
             "A flag indicating whether or not
           "IPv4 address of the router sends
              periodic Router Advertisements and responds to
              Router Solicitations.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvSendAdvertisements."; next hop.";
       }
         leaf max-rtr-adv-interval
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
             + "rt:next-hop-list/rt:next-hop-list/rt:next-hop" {
           type uint16
       when "derived-from-or-self(../../../../../rt:address-family,
               'v4ur:ipv4-unicast')" {
             range "4..1800";
           }
           units "seconds";
           default "600";
         description
             "The maximum time allowed between sending unsolicited
              multicast Router Advertisements from the interface.";
           reference
             "RFC 4861: Neighbor Discovery
           "This augment is valid only for IP version 6 (IPv6) -
              MaxRtrAdvInterval."; IPv4 unicast.";
       }
       status obsolete;
       description
         "Augment 'next-hop-list' case in the reply to the
          'active-route' action.";
       leaf min-rtr-adv-interval next-hop-address {
         type uint16 {
             range "3..1350";
           }
           units "seconds";
           must ". <= 0.75 * ../max-rtr-adv-interval" {
             description
               "The value MUST NOT be greater than 75% of
                'max-rtr-adv-interval'.";
           }
           description
             "The minimum time allowed between sending unsolicited
              multicast Router Advertisements from the interface.

              The default value to be used operationally if this
              leaf is not configured is determined as follows:

              - if max-rtr-adv-interval >= 9 seconds, the default
                value is 0.33 * max-rtr-adv-interval;

              - otherwise, it is 0.75 * max-rtr-adv-interval.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              MinRtrAdvInterval.";
         }
         leaf managed-flag {
           type boolean;
           default "false";
           description
             "The value to be placed in the 'Managed address
              configuration' flag field in the Router
              Advertisement.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvManagedFlag.";
         }
         leaf other-config-flag {
           type boolean;
           default "false";
           description
             "The value to be placed in the 'Other configuration'
              flag field in the Router Advertisement.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvOtherConfigFlag.";
         }
         leaf link-mtu {
           type uint32;
           default "0";
           description
             "The value to be placed in MTU options sent by the
              router. A value of zero indicates that no MTU options
              are sent.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvLinkMTU.";
         }
         leaf reachable-time {
           type uint32 {
             range "0..3600000";
           }
           units "milliseconds";
           default "0";
           description
             "The value to be placed in the Reachable Time field in
              the Router Advertisement messages sent by the router.
              A value of zero means unspecified (by this router).";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvReachableTime.";
         }
         leaf retrans-timer {
           type uint32;
           units "milliseconds";
           default "0";
           description
             "The value to be placed in the Retrans Timer field in
              the Router Advertisement messages sent by the router.
              A value of zero means unspecified (by this router).";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvRetransTimer.";
         }
         leaf cur-hop-limit {
           type uint8;
           description
             "The value to be placed in the Cur Hop Limit field in
              the Router Advertisement messages sent by the router.
              A value of zero means unspecified (by this router).

              If this parameter is not configured, the device SHOULD
              use the value specified in IANA Assigned Numbers that
              was in effect at the time of implementation.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvCurHopLimit.

              IANA: IP Parameters,
              http://www.iana.org/assignments/ip-parameters";
         }
         leaf default-lifetime {
           type uint16 {
             range "0..9000";
           }
           units "seconds";
           description
             "The value to be placed in the Router Lifetime field of
              Router Advertisements sent from the interface, in
              seconds. It MUST be either zero or between
              max-rtr-adv-interval and 9000 seconds.  A value of zero
              default indicates that the router is not to be used as
              a router.  These limits may be overridden by specific
              documents that describe how IPv6 operates over
              different link layers.

              If this parameter is not configured, the device SHOULD
              use a value of 3 * max-rtr-adv-interval.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvDefaultLifeTime.";
         }
         container prefix-list {
           description
             "Configuration of prefixes to be placed in Prefix
              Information options in Router Advertisement messages
              sent from the interface.

              Prefixes that are advertised by default but do not
              have their entries in the child 'prefix' list are
              advertised with the default values of all parameters.

              The link-local prefix SHOULD NOT be included in the
              list of advertised prefixes.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvPrefixList.";
           list prefix {
             key "prefix-spec";
             description
               "Configuration of an advertised prefix entry.";
             leaf prefix-spec {
               type inet:ipv6-prefix;
               description
                 "IPv6 address prefix.";
             }
             choice control-adv-prefixes {
               default "advertise";
               description
                 "Either the prefix is explicitly removed from the
                  set of advertised prefixes, or the parameters with
                  which it is advertised are specified (default
                  case).";
               leaf no-advertise {
                 type empty;
                 description
                   "The prefix will not be advertised.

                    This can be used for removing the prefix from
                    the default set of advertised prefixes.";
               }
               case advertise {
                 leaf valid-lifetime {
                   type uint32;
                   units "seconds";
                   default "2592000";
                   description
                     "The value to be placed in the Valid Lifetime
                      in the Prefix Information option.  The
                      designated value of all 1's (0xffffffff)
                       represents infinity.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvValidLifetime.";
                 }
                 leaf on-link-flag {
                   type boolean;
                   default "true";
                   description
                     "The value to be placed in the on-link flag
                      ('L-bit') field in the Prefix Information
                      option.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvOnLinkFlag.";
                 }
                 leaf preferred-lifetime {
                   type uint32;
                   units "seconds";
                   must ". <= ../valid-lifetime" {
                     description
                       "This value MUST NOT be greater than
                        valid-lifetime.";
                   }
                   default "604800";
                   description
                     "The value to be placed in the Preferred
                      Lifetime in the Prefix Information option.
                      The designated value of all 1's (0xffffffff)
                      represents infinity.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvPreferredLifetime.";
                 }
                 leaf autonomous-flag {
                   type boolean;
                   default "true";
                   description
                     "The value to be placed in the Autonomous Flag
                      field in the Prefix Information option.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvAutonomousFlag.";
                 }
               }
             }
           }
         }
       }
     }
   }
   <CODE ENDS>

10.  IANA Considerations

   This document registers the following namespace URIs in the "IETF XML
   Registry" [RFC3688]:

   URI: urn:ietf:params:xml:ns:yang:ietf-routing-2
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.

   URI: urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing-2
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.

   URI: urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing-2
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.

   This document registers the following YANG modules in the "YANG
   Module Names" registry [RFC6020]:

   Name:         ietf-routing-2
   Namespace:    urn:ietf:params:xml:ns:yang:ietf-routing-2
   Prefix:       rt
   Reference:    RFC 8022

   Name:         ietf-ipv4-unicast-routing-2
   Namespace:    urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing-2
   Prefix:       v4ur
   Reference:    RFC 8022

   Name:         ietf-ipv6-unicast-routing-2
   Namespace:    urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing-2
   Prefix:       v6ur
   Reference:    RFC 8022

   This document registers the following YANG submodule in the "YANG
   Module Names" registry [RFC6020]:

   Name:         ietf-ipv6-router-advertisements-2
   Module:       ietf-ipv6-unicast-routing-2
   Reference:    RFC 8022

11.  Security Considerations

   The YANG module defined in this memo is designed to be accessed via
   the NETCONF protocol [RFC6241].  The lowest NETCONF layer is the
   secure transport layer and the mandatory-to-implement secure
   transport is SSH [RFC6242].

   There are a number of data nodes defined in this 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.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   /routing/control-plane-protocols/control-plane-protocol:  This list
      specifies the control-plane protocols configured on a device.

   /routing/ribs/rib:  This list specifies the RIBs configured for the
      device.

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

   /routing/control-plane-protocols/control-plane-protocol:  This list
      specifies the control-plane protocols configured on a device.
      Refer to the control plane models for a list of sensitive
      information.

   /routing/ribs/rib:  This list specifies the RIB and their contents
      for the device.  Access to this information may disclose the
      network topology and or other information.

12.  References

12.1.  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, <https://www.rfc-
              editor.org/info/rfc2119>.

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

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, <https://www.rfc-
              editor.org/info/rfc4861>.

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

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

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

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

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

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

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

   [RFC8022]  Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", RFC 8022, DOI 10.17487/RFC8022, November
              2016, <https://www.rfc-editor.org/info/rfc8022>.

12.2.  Informative References

   [RFC6087]  Bierman, A., "Guidelines for Authors and Reviewers of YANG
              Data Model Documents", RFC 6087, DOI 10.17487/RFC6087,
              January 2011, <https://www.rfc-editor.org/info/rfc6087>.

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

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [I-D.ietf-netmod-revised-datastores]
              Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore
              Architecture", draft-ietf-netmod-revised-datastores-04
              (work in progress), August 2017.

Appendix A.  Deprecated Models

   This appendix contains the deprecated versions of ietf-routing, ietf-
   ipv4-unicast-routing, ietf-ipv6-unicast-routing, and ietf-ipv6-
   router-advertisements.

A.1.  Deprecated ietf-routing Model

   <CODE BEGINS> file "ietf-routing@2017-10-06.yang"
   module ietf-routing {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-routing";
     prefix rt;

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

     organization
       "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/netmod/>
        WG List:  <mailto:netmod@ietf.org>

        WG Chair: Lou Berger
                  <mailto:lberger@labn.net>

        WG Chair: Kent Watsen
                  <mailto:kwatsen@juniper.net>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>

        Editor:   Acee Lindem
                  <mailto:acee@cisco.com>";
     description
       "This YANG module defines essential components for the
        management of a routing subsystem.

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

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

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
        'OPTIONAL' in the module text are to be interpreted as
        described in RFC 2119.

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

     revision 2017-10-06 {
       description
         "Deprecated revision.";
       reference "RFC TBD: Revised YANG Data Model for Routing
                  Management";
     }

     revision 2016-11-04 {
          description
            "Initial revision.";
          reference
            "RFC 8022: A YANG Data Model for Routing Management";
     }

     feature multiple-ribs {
       status deprecated;
       description
         "This feature indicates that the server supports user-defined
          RIBs.

          Servers that do not advertise this feature SHOULD provide
          exactly one system-controlled RIB per supported address
          family and make it also the default RIB.  This RIB then
          appears as an entry of the list /routing-state/ribs/rib.";
     }

     feature router-id {
       status deprecated;
       description
         "This feature indicates that the server supports
          configuration of an explicit 32-bit router ID that is used
          by some routing protocols.

          Servers that do not advertise this feature set a router ID
          algorithmically, usually to one of the configured IPv4
          addresses.  However, this algorithm is implementation
          specific.";
     }

     identity address-family {
       status deprecated;
       description
         "Base identity from which identities describing address
          families are derived.";
     }

     identity ipv4 {
       base address-family;
       status deprecated;
       description
         "This identity represents IPv4 address family.";
     }

     identity ipv6 {
       base address-family;
       status deprecated;
       description
         "This identity represents IPv6 address family.";
     }

     identity control-plane-protocol {
       status deprecated;
       description
         "Base identity from which control-plane protocol identities
          are derived.";
     }

     identity routing-protocol {
       base control-plane-protocol;
       status deprecated;
       description
         "Identity from which Layer 3 routing protocol identities are
          derived.";
     }

     identity direct {
       base routing-protocol;
       status deprecated;
       description
         "Routing pseudo-protocol that provides routes to directly
          connected networks.";
     }

     identity static {
       base routing-protocol;
       status deprecated;
       description
         "Static routing pseudo-protocol.";
     }

     typedef route-preference {
       type uint32;
       status deprecated;
       description
         "This type is used for route preferences.";
     }

     grouping address-family {
       status deprecated;
       description
         "This grouping provides a leaf identifying an address
          family.";
       leaf address-family {
         type identityref {
           base address-family;
         }
         mandatory true;
         status deprecated;
         description
           "Address family.";
       }
     }

     grouping router-id {
       status deprecated;
       description
         "This grouping provides router ID.";
       leaf router-id {
         type yang:dotted-quad;
         status deprecated;
         description
           "A 32-bit number in the form of a dotted quad that is used
            by some routing protocols identifying a router.";
         reference "RFC 2328: OSPF Version 2.";
       }
     }

     grouping special-next-hop {
       status deprecated;
       description
         "This grouping provides a leaf with an enumeration of special
          next hops.";

       leaf special-next-hop {
         type enumeration {
           enum "blackhole" {
             status deprecated;
             description
               "Silently discard the packet.";
           }
           enum "unreachable" {
             status deprecated;
             description
               "Discard the packet and notify the sender with an error
                message indicating that the destination host is
                unreachable.";
           }
           enum "prohibit" {
             status deprecated;
             description
               "Discard the packet and notify the sender with an error
                message indicating that the communication is
                administratively prohibited.";
           }
           enum "receive" {
             status deprecated;
             description
               "The packet will be received by the local system.";
           }
         }
         status deprecated;
         description
           "Options for special next hops.";
       }
     }

     grouping next-hop-content {
       status deprecated;
       description
         "Generic parameters of next hops in static routes.";
       choice next-hop-options {
         mandatory true;
         status deprecated;
         description
           "Options for next hops in static routes.

            It is expected that further cases will be added through
            augments from other modules.";
         case simple-next-hop {
           status deprecated;
           description
             "This case represents a simple next hop consisting of the
              next-hop address and/or outgoing interface.

              Modules for address families MUST augment this case with
              a leaf containing a next-hop address of that address
              family.";
           leaf outgoing-interface {
             type if:interface-ref;
             status deprecated;
             description
               "Name of the outgoing interface.";
           }
         }
         case special-next-hop {
           status deprecated;
           uses special-next-hop;
         }
         case next-hop-list {
           status deprecated;
           container next-hop-list {
             status deprecated;
             description
               "Container for multiple next-hops.";
             list next-hop {
               key "index";
               status deprecated;
               description
                 "An entry of a next-hop list.

                  Modules for address families MUST augment this list
                  with a leaf containing a next-hop address of that
                  address family.";
               leaf index {
                 type string;
                 status deprecated;
                 description
                   "A user-specified identifier utilized to uniquely
                    reference the next-hop entry in the next-hop list.
                    The value of this index has no semantic meaning
                    other than for referencing the entry.";
               }
               leaf outgoing-interface {
                 type if:interface-ref;
                 status deprecated;
                 description
                   "Name of the outgoing interface.";
               }
             }

           }
         }
       }
     }

     grouping next-hop-state-content {
       status deprecated;
       description
         "Generic parameters of next hops in state data.";
       choice next-hop-options {
         mandatory true;
         status deprecated;
         description
           "Options for next hops in state data.

            It is expected that further cases will be added through
            augments from other modules, e.g., for recursive
            next hops.";
         case simple-next-hop {
           status deprecated;
           description
             "This case represents a simple next hop consisting of the
              next-hop address and/or outgoing interface.

              Modules for address families MUST augment this case with
              a leaf containing a next-hop address of that address
              family.";
           leaf outgoing-interface {
             type if:interface-state-ref;
             status deprecated;
             description
               "Name of the outgoing interface.";
           }
         }
         case special-next-hop {
           status deprecated;
           uses special-next-hop;
         }
         case next-hop-list {
           status deprecated;
           container next-hop-list {
             status deprecated;
             description
               "Container for multiple next hops.";
             list next-hop {
               status deprecated;
               description
                 "An entry of a next-hop list.

                  Modules for address families MUST augment this list
                  with a leaf containing a next-hop address of that
                  address family.";
               leaf outgoing-interface {
                 type if:interface-state-ref;
                 status deprecated;
                 description
                   "Name of the outgoing interface.";
               }
             }
           }
         }
       }
     }

     grouping route-metadata {
       status deprecated;
       description
         "Common route metadata.";
       leaf source-protocol {
         type identityref {
           base routing-protocol;
         }
         mandatory true;
         status deprecated;
         description
           "Type of the routing protocol from which the route
            originated.";
       }
       leaf active {
         type empty;
         status deprecated;
         description
           "Presence of this leaf indicates that the route is
            preferred among all routes in the same RIB that have the
            same destination prefix.";
       }
       leaf last-updated {
         type yang:date-and-time;
         status deprecated;
         description
           "Time stamp of the last modification of the route.  If the
            route was never modified, it is the time when the route
            was inserted into the RIB.";
       }
     }

     container routing-state {
       config false;
       status deprecated;
       description
         "State data of the routing subsystem.";
       uses router-id {
         status deprecated;
         description
           "Global router ID.

            It may be either configured or assigned algorithmically by
            the implementation.";
       }
       container interfaces {
         status deprecated;
         description
           "Network-layer interfaces used for routing.";
         leaf-list interface {
           type if:interface-state-ref;
           status deprecated;
           description
             "Each entry is a reference to the name of a configured
              network-layer interface.";
         }
       }
       container control-plane-protocols {
         status deprecated;
         description
           "Container for the list of routing protocol instances.";
         list control-plane-protocol {
           key "type name";
           status deprecated;
           description
             "State data of a control-plane protocol instance.

              An implementation MUST provide exactly one
              system-controlled instance of the 'direct'
              pseudo-protocol.  Instances of other control-plane
              protocols MAY be created by configuration.";
           leaf type {
             type identityref {
               base control-plane-protocol;
             }
             status deprecated;
             description
               "Type of the control-plane protocol.";
           }
           leaf name {
             type string;
             status deprecated;
             description
               "The name of the control-plane protocol instance.

                For system-controlled instances this name is
                persistent, i.e., it SHOULD NOT change across
                reboots.";
           }
         }
       }
       container ribs {
         status deprecated;
         description
           "Container for RIBs.";
         list rib {
           key "name";
           min-elements 1;
           status deprecated;
           description
             "Each entry represents a RIB identified by the 'name'
              key. All routes in a RIB MUST belong to the same address
              family.

              An implementation SHOULD provide one system-controlled
              default RIB for each supported address family.";
           leaf name {
             type string;
             status deprecated;
             description
               "The name of the RIB.";
           }
           uses address-family;
           leaf default-rib {
             if-feature "multiple-ribs";
             type boolean;
             default "true";
             status deprecated;
             description
               "This flag has the value of 'true' if and only if the
                RIB is the default RIB for the given address family.

                By default, control-plane protocols place their routes
                in the default RIBs.";
           }
           container routes {
             status deprecated;
             description
               "Current content of the RIB.";

             list route {
               status deprecated;
               description
                 "A RIB route entry.  This data node MUST be augmented
                  with information specific for routes of each address
                  family.";
               leaf route-preference {
                 type route-preference;
                 status deprecated;
                 description
                   "This route attribute, also known as administrative
                    distance, allows for selecting the preferred route
                    among routes with the same destination prefix.  A
                    smaller value means a more preferred route.";
               }
               container next-hop {
                 status deprecated;
                 description
                   "Route's next-hop attribute.";
                 uses next-hop-state-content;
               }
               uses route-metadata;
             }
           }
           action active-route {
             status deprecated;
             description
               "Return the active RIB route that is used for the
                destination address.

                Address-family-specific modules MUST augment input
                parameters with a leaf named 'destination-address'.";
             output {
               container route {
                 status deprecated;
                 description
                   "The active RIB route for the specified
                    destination.

                    If no route exists in the RIB for the destination
                    address, no output is returned.

                    Address-family-specific modules MUST augment this
                    container with appropriate route contents.";
                 container next-hop {
                   status deprecated;
                   description
                     "Route's next-hop attribute.";

                   uses next-hop-state-content;
                 }
                 uses route-metadata;
               }
             }
           }
         }
       }
     }
     container routing {
       status deprecated;
       description
         "Configuration parameters for the routing subsystem.";
       uses router-id {
         if-feature "router-id";
         status deprecated;
         description
           "Configuration of the global router ID.  Routing protocols
            that use router ID can use this parameter or override it
            with another value.";
       }
       container control-plane-protocols {
         status deprecated;
         description
           "Configuration of control-plane protocol instances.";
         list control-plane-protocol {
           key "type name";
           status deprecated;
           description
             "Each entry contains configuration of a control-plane
              protocol instance.";
           leaf type {
             type identityref {
               base control-plane-protocol;
             }
             status deprecated;
             description
               "Type of the control-plane protocol - an identity
                derived from the 'control-plane-protocol' base
                identity.";
           }
           leaf name {
             type string;
             status deprecated;
             description
               "An arbitrary name of the control-plane protocol
                instance.";
           }
           leaf description {
             type string;
             status deprecated;
             description
               "Textual description of the control-plane protocol
                instance.";
           }
           container static-routes {
             when "derived-from-or-self(../type, 'rt:static')" {
               description
                 "This container is only valid for the 'static'
                  routing protocol.";
             }
             status deprecated;
             description
               "Configuration of the 'static' pseudo-protocol.

                Address-family-specific modules augment this node with
                their lists of routes.";
           }
         }
       }
       container ribs {
         status deprecated;
         description
           "Configuration of RIBs.";
         list rib {
           key "name";
           status deprecated;
           description
             "Each entry contains configuration for a RIB identified
              by the 'name' key.

              Entries having the same key as a system-controlled entry
              of the list /routing-state/ribs/rib are used for
              configuring parameters of that entry.  Other entries
              define additional user-controlled RIBs.";
           leaf name {
             type string;
             status deprecated;
             description
               "The name of the RIB.

                For system-controlled entries, the value of this leaf
                must be the same as the name of the corresponding
                entry in state data.

                For user-controlled entries, an arbitrary name can be
                used.";
           }
           uses address-family {
             status deprecated;
             description
               "Address family of the RIB.

                It is mandatory for user-controlled RIBs.  For
                system-controlled RIBs it can be omitted; otherwise,
                it must match the address family of the corresponding
                state entry.";
             refine "address-family" {
               mandatory false;
             }
           }
           leaf description {
             type string; inet:ipv4-address;
         status deprecated;
             description
               "Textual obsolete;
         description
           "IPv4 address of the RIB.";
           }
         } next hop.";
       }
     }
   }
   <CODE ENDS>

A.2.  Deprecated ietf-ipv4-unicast Model

9.  IPv6 Unicast Routing Management YANG Module

   <CODE BEGINS> file "ietf-ipv4-unicast-routing@2017-10-06.yang" "ietf-ipv6-unicast-routing@2017-10-14.yang"
   module ietf-ipv4-unicast-routing ietf-ipv6-unicast-routing {
     yang-version 1.1; "1.1";
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing";
       "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing";
     prefix v4ur; "v6ur";

     import ietf-routing {
       prefix rt; "rt";
     }

     import ietf-inet-types {
       prefix inet; "inet";
     }

     include ietf-ipv6-router-advertisements {
       revision-date 2017-10-14;
     }

     organization
       "IETF NETMOD (NETCONF Data - Networking Modeling Language) Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/netmod/>   <http://tools.ietf.org/wg/netmod/>
        WG List:  <mailto:netmod@ietf.org>
        WG Chair: Lou Berger
                  <mailto:lberger@labn.net>

        WG Chair: Kent Watsen
                  <mailto:kwatsen@juniper.net>  <mailto:rtgwg@ietf.org>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>

        Editor:
                  Acee Lindem
                  <mailto:acee@cisco.com>";
                  <mailto:acee@cisco.com>
                  Yingzhen Qu
                  <mailto:yingzhen.qu@huawei.com>";

     description
       "This YANG module augments the 'ietf-routing' module with basic
        configuration and state data for IPv4 IPv6 unicast routing.

        Copyright (c) 2016 2017 IETF Trust and the persons
        identified as authors of the code.  All rights reserved.

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

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
        'OPTIONAL' in the module text are to be interpreted as
        described in RFC 2119.
        This version of this YANG module is part of RFC TBD; XXXX; see
        the RFC itself for full legal notices.";
     reference "RFC XXXX";

     revision 2017-10-06 2017-10-14 {
       description
         "Deprecated revision.";
         "Network Managment Datastore Architecture (NDMA) revision";
       reference
         "RFC TBD: Revised XXXX: A YANG Data Model for Routing
                  Management"; Management
          (NDMA Version)";
     }

     /* Identities */

     revision 2016-11-04 {
          description
            "Initial revision.";
          reference
            "RFC 8022: A YANG Data Model for Routing Management";
     }

     identity ipv4-unicast ipv6-unicast {
       base rt:ipv4;
       status deprecated; rt:ipv6;
       description
         "This identity represents the IPv4 IPv6 unicast address family.";
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route" "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route" {
       when "derived-from-or-self(../../rt:address-family, "
          + "'v4ur:ipv4-unicast')" "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast.";
       }
       status deprecated;
       description
         "This leaf augments an IPv4 IPv6 unicast route.";
       leaf destination-prefix {
         type inet:ipv4-prefix;
         status deprecated; inet:ipv6-prefix;
         description
           "IPv4
           "IPv6 destination prefix.";
       }
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route/" "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route/"
           + "rt:next-hop/rt:next-hop-options/rt:simple-next-hop" {
       when "derived-from-or-self(
               ../../../rt:address-family, 'v4ur:ipv4-unicast')" "derived-from-or-self(../../../rt:address-family, "
          + "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast.";

       }
       status deprecated;
       description
         "Augment 'simple-next-hop' case in IPv4 IPv6 unicast routes.";
       leaf next-hop-address {
         type inet:ipv4-address;
         status deprecated; inet:ipv6-address;
         description
           "IPv4
           "IPv6 address of the next hop.";
       }
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route/" "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route/"
           + "rt:next-hop/rt:next-hop-options/rt:next-hop-list/"
           + "rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family,
               'v4ur:ipv4-unicast')" "
          + "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast.";
       }
       status deprecated;
       description
         "This leaf augments the 'next-hop-list' case of IPv4 IPv6 unicast
          routes.";
       leaf address {
         type inet:ipv4-address;
         status deprecated; inet:ipv6-address;
         description
           "IPv4
           "IPv6 address of the next-hop."; next hop.";
       }
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:input"
       "/rt:routing/rt:ribs/rt:rib/rt:active-route/rt:input" {
       when "derived-from-or-self(../rt:address-family,
             'v4ur:ipv4-unicast')" "
          + "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast RIBs.";
       }
       status deprecated;
       description
         "This augment adds the input parameter of the 'active-route'
          action.";
       leaf destination-address {
         type inet:ipv4-address;
         status deprecated; inet:ipv6-address;
         description
           "IPv4
           "IPv6 destination address.";
       }
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/" "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route" {
       when "derived-from-or-self(../../rt:address-family,
               'v4ur:ipv4-unicast')" "
          + "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast.";
       }
       status deprecated;
       description
         "This augment adds the destination prefix to the reply of the
          'active-route' action.";
       leaf destination-prefix {
         type inet:ipv4-prefix;
         status deprecated; inet:ipv6-prefix;
         description
           "IPv4
           "IPv6 destination prefix.";
       }
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/" "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
           + "rt:simple-next-hop" {
       when "derived-from-or-self(../../../rt:address-family,
               'v4ur:ipv4-unicast')" "
          + "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast.";
       }
       status deprecated;
       description
         "Augment 'simple-next-hop' case in the reply to the
          'active-route' action.";
       leaf next-hop-address {
         type inet:ipv4-address;
         status deprecated; inet:ipv6-address;
         description
           "IPv4
           "IPv6 address of the next hop.";
       }
     }

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/" "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
           + "rt:next-hop-list/rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family,
               'v4ur:ipv4-unicast')" "
          + "'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv4 IPv6 unicast.";
       }
       status deprecated;
       description
         "Augment 'next-hop-list' case in the reply to the
          'active-route' action.";
       leaf next-hop-address {
         type inet:ipv4-address;
         status deprecated; inet:ipv6-address;
         description
           "IPv4
           "IPv6 address of the next hop.";
       }

     }

     /* Configuration data */

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:static-routes" {
       status deprecated;
       description
         "This augment defines the configuration of the 'static'
          pseudo-protocol with data specific to IPv4 IPv6 unicast.";
       container ipv4 ipv6 {
         status deprecated;
         description
           "Configuration of a 'static' pseudo-protocol instance
            consists of a list of routes.";
         list route {
           key "destination-prefix";
           status deprecated;
           description
             "A list of static routes.";
           leaf destination-prefix {
             type inet:ipv4-prefix; inet:ipv6-prefix;
             mandatory true;
             status deprecated; "true";
             description
               "IPv4
               "IPv6 destination prefix.";
           }
           leaf description {
             type string;
             status deprecated;
             description
               "Textual description of the route.";
           }
           container next-hop {
             status deprecated;
             description
               "Configuration of next-hop.";
             uses rt:next-hop-content {
               status deprecated;
               augment "next-hop-options/simple-next-hop" {
                 status deprecated;
                 description
                   "Augment 'simple-next-hop' case in IPv4 IPv6 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv4-address;
                   status deprecated; inet:ipv6-address;
                   description
                     "IPv4
                     "IPv6 address of the next hop.";
                 }
               }
               augment "next-hop-options/next-hop-list/" "next-hop-options/next-hop-list/next-hop-list/"
                     +
                       "next-hop-list/next-hop" "next-hop" {
                 status deprecated;
                 description
                   "Augment 'next-hop-list' case in IPv4 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv4-address;
                   status deprecated;
                   description
                     "IPv4 address of the next hop.";
                 }
               }

             }
           }
         }
       }
     }
   }
   <CODE ENDS>

A.3.  Deprecated ietf-ipv6-unicast Model

   <CODE BEGINS> file "ietf-ipv6-unicast-routing@2017-10-06.yang"
   module ietf-ipv6-unicast-routing {
     yang-version 1.1;
     namespace
        "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing";
     prefix v6ur;

     import ietf-routing {
       prefix rt;
     }
     import ietf-inet-types {
       prefix inet;
     }
     include ietf-ipv6-router-advertisements {
       revision-date 2017-10-06;
     }

     organization
       "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/netmod/>
        WG List:  <mailto:netmod@ietf.org>

        WG Chair: Lou Berger
                  <mailto:lberger@labn.net>

        WG Chair: Kent Watsen
                  <mailto:kwatsen@juniper.net>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>

        Editor:   Acee Lindem
                  <mailto:acee@cisco.com>";
     description
       "This YANG module augments the 'ietf-routing' module with basic
        configuration and state data for IPv6 unicast routing.

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

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

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
        'OPTIONAL' in the module text are to be interpreted as described
        in RFC 2119.

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

     revision 2017-10-06 {
       description
         "Deprecated revision.";
       reference "RFC TBD: Revised YANG Data Model for Routing
                  Management";
     }

     revision 2016-11-04 {
          description
            "Initial revision.";
          reference
            "RFC 8022: A YANG Data Model for Routing Management";
     }

     identity ipv6-unicast static
                    routes.";
                 leaf next-hop-address {
       base rt:ipv6;
       status deprecated;
                   type inet:ipv6-address;
                   description
         "This identity represents the IPv6 unicast
                     "IPv6 address family."; of the next hop.";
                 }
               }
             }
           }
         }
       }
     }

     /* Obsolete State Data */

     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route" {
       when "derived-from-or-self(../../rt:address-family,
               'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast.";
       }
       status deprecated; obsolete;
       description
         "This leaf augments an IPv6 unicast route.";
       leaf destination-prefix {
         type inet:ipv6-prefix;
         status deprecated; obsolete;
         description
           "IPv6 destination prefix.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route/"
             + "rt:next-hop/rt:next-hop-options/rt:simple-next-hop" {
       when "derived-from-or-self(../../../rt:address-family,
               'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast.";
       }
       status deprecated; obsolete;
       description
         "Augment 'simple-next-hop' case in IPv6 unicast routes.";
       leaf next-hop-address {
         type inet:ipv6-address;
         status deprecated; obsolete;
         description
           "IPv6 address of the next hop.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route/"
             + "rt:next-hop/rt:next-hop-options/rt:next-hop-list/"
             + "rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family,
               'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast.";
       }
       status deprecated; obsolete;
       description
         "This leaf augments the 'next-hop-list' case of IPv6 unicast
          routes.";
       leaf address {
         type inet:ipv6-address;
         status deprecated; obsolete;
         description
           "IPv6 address of the next hop.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/"
             + "rt:active-route/rt:input" {
       when "derived-from-or-self(../rt:address-family,
               'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast RIBs.";
       }
       status deprecated; obsolete;
       description
         "This augment adds the input parameter of the 'active-route'
          action.";
       leaf destination-address {
         type inet:ipv6-address;
         status deprecated; obsolete;
         description
           "IPv6 destination address.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:output/rt:route" {
       when "derived-from-or-self(../../rt:address-family,
             'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast.";
       }
       status deprecated; obsolete;
       description
         "This augment adds the destination prefix to the reply of the
          'active-route' action.";
       leaf destination-prefix {
         type inet:ipv6-prefix;
         status deprecated; obsolete;
         description
           "IPv6 destination prefix.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
             + "rt:simple-next-hop" {
       when "derived-from-or-self(../../../rt:address-family,
               'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast.";
       }
       status deprecated; obsolete;
       description
         "Augment 'simple-next-hop' case in the reply to the
          'active-route' action.";
       leaf next-hop-address {
         type inet:ipv6-address;
         status deprecated; obsolete;
         description
           "IPv6 address of the next hop.";
       }
     }
     augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
             + "rt:output/rt:route/rt:next-hop/rt:next-hop-options/"
             + "rt:next-hop-list/rt:next-hop-list/rt:next-hop" {
       when "derived-from-or-self(../../../../../rt:address-family,
               'v6ur:ipv6-unicast')" {
         description
           "This augment is valid only for IPv6 unicast.";
       }
       status deprecated; obsolete;
       description
         "Augment 'next-hop-list' case in the reply to the
          'active-route' action.";
       leaf next-hop-address {
         type inet:ipv6-address;
         status deprecated;
         description
           "IPv6 address of the next hop.";
       }
     }
     augment "/rt:routing/rt:control-plane-protocols/"
             + "rt:control-plane-protocol/rt:static-routes" {
       status deprecated;
       description
         "This augment defines the configuration of the 'static'
          pseudo-protocol with data specific to IPv6 unicast.";
       container ipv6 {
         status deprecated;
         description
           "Configuration of a 'static' pseudo-protocol instance
            consists of a list of routes.";
         list route {
           key "destination-prefix";
           status deprecated;
           description
             "A list of static routes.";
           leaf destination-prefix {
             type inet:ipv6-prefix;
             mandatory true;
             status deprecated;
             description
               "IPv6 destination prefix.";
           }
           leaf description {
             type string;
             status deprecated;
             description
               "Textual description of the route.";
           }
           container next-hop {
             status deprecated;
             description
               "Configuration of next-hop.";
             uses rt:next-hop-content {
               status deprecated;
               augment "next-hop-options/simple-next-hop" {
                 status deprecated;
                 description
                   "Augment 'simple-next-hop' case in IPv6 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv6-address;
                   status deprecated;
                   description
                     "IPv6 address of the next hop.";
                 }
               }
               augment "next-hop-options/next-hop-list/"
                       + "next-hop-list/next-hop" {
                 status deprecated;
                 description
                   "Augment 'next-hop-list' case in IPv6 static
                    routes.";
                 leaf next-hop-address {
                   type inet:ipv6-address;
                   status deprecated; obsolete;
         description
           "IPv6 address of the next hop.";
       }
     }
   }
           }
         }
       }
     }
   }
   <CODE ENDS>

A.4.  Deprecated ietf-ipv6-router-advertisements Model

9.1.  IPv6 Router Advertisements Submodule

   <CODE BEGINS> file "ietf-ipv6-router-advertisements@2017-10-06.yang" "ietf-ipv6-router-advertisements@2017-10-14.yang"
   submodule ietf-ipv6-router-advertisements {
     yang-version 1.1; "1.1";

     belongs-to ietf-ipv6-unicast-routing {
       prefix v6ur; "v6ur";
     }

     import ietf-inet-types {
       prefix inet; "inet";
     }

     import ietf-interfaces {
       prefix if; "if";
     }

     import ietf-ip {
       prefix ip; "ip";
     }

     organization
       "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/netmod/>
        WG List:  <mailto:netmod@ietf.org>

        WG Chair: Lou Berger
                  <mailto:lberger@labn.net>

        WG Chair: Kent Watsen
                  <mailto:kwatsen@juniper.net>

        Editor:   Ladislav Lhotka
                  <mailto:lhotka@nic.cz>

        Editor:   Acee Lindem
                  <mailto:acee@cisco.com>";
                  <mailto:acee@cisco.com>

        Editor:   Yingzhen Qu
                  <mailto:yingzhen.qu@huawei.com>";

     description
       "This YANG module augments the 'ietf-ip' module with
        configuration and state data of IPv6 router advertisements.

        Copyright (c) 2016 2017 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

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

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
        'OPTIONAL' in the module text are to be interpreted as
        described in RFC 2119.

        This version of this YANG module is part of RFC TBD; 8022;
        see the RFC itself for full legal notices.";

     reference
       "RFC 4861: Neighbor Discovery for IP version 6 (IPv6).";

     revision 2017-10-06 2017-10-14 {
       description
         "Deprecated revision.";
         "Network Managment Datastore Architecture (NDMA) Revision";
       reference
         "RFC TBD: Revised XXXX: A YANG Data Model for Routing Management"; Management
          (NDMA Version)";
     }

     revision 2016-11-04 {
          description
            "Initial revision.";
          reference
            "RFC 8022: A YANG Data Model for Routing Management";
     }

     augment "/if:interfaces-state/if:interface/ip:ipv6" "/if:interfaces/if:interface/ip:ipv6" {
       status deprecated;
       description
         "Augment interface state data configuration with parameters of IPv6
          router advertisements.";
       container ipv6-router-advertisements {
         status deprecated;
         description
           "Parameters
           "Configuration of IPv6 Router Advertisements.";
         leaf send-advertisements {
           type boolean;
           status deprecated;
           default "false";
           description
             "A flag indicating whether or not the router sends
              periodic Router Advertisements and responds to
              Router Solicitations.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvSendAdvertisements.";
         }
         leaf max-rtr-adv-interval {
           type uint16 {
             range "4..1800";
           }
           units "seconds";
           status deprecated;
           default "600";
           description
             "The maximum time allowed between sending unsolicited
              multicast Router Advertisements from the interface.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              MaxRtrAdvInterval.";
         }
         leaf min-rtr-adv-interval {
           type uint16 {
             range "3..1350";
             range "3..1350";
           }
           units "seconds";
           must ". <= 0.75 * ../max-rtr-adv-interval" {
             description
               "The value MUST NOT be greater than 75% of
                'max-rtr-adv-interval'.";
           }
           units "seconds";
           status deprecated;
           description
             "The minimum time allowed between sending unsolicited
              multicast Router Advertisements from the interface."; interface.

              The default value to be used operationally if this
              leaf is not configured is determined as follows:

              - if max-rtr-adv-interval >= 9 seconds, the default
                value is 0.33 * max-rtr-adv-interval;

              - otherwise, it is 0.75 * max-rtr-adv-interval.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              MinRtrAdvInterval.";
         }
         leaf managed-flag {
           type boolean;
           status deprecated;
           default "false";
           description
             "The value that is to be placed in the 'Managed address
              configuration' flag field in the Router
              Advertisement.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvManagedFlag.";
         }
         leaf other-config-flag {
           type boolean;
           status deprecated;
           default "false";
           description
             "The value that is to be placed in the 'Other configuration'
              flag field in the Router Advertisement.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvOtherConfigFlag.";
         }
         leaf link-mtu {
           type uint32;
           status deprecated;
           default "0";
           description
             "The value that is to be placed in MTU options sent by the
              router. A value of zero indicates that no MTU options
              are sent.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvLinkMTU.";
         }
         leaf reachable-time {
           type uint32 {
             range "0..3600000";
           }
           units "milliseconds";
           status deprecated;
           default "0";
           description
             "The value that is to be placed in the Reachable Time field in
              the Router Advertisement messages sent by the router.
              A value of zero means unspecified (by this router).";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvReachableTime.";
         }
         leaf retrans-timer {
           type uint32;
           units "milliseconds";
           status deprecated;
           default "0";
           description
             "The value that is to be placed in the Retrans Timer field in
              the Router Advertisement messages sent by the router.

              A value of zero means unspecified (by this router).";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvRetransTimer.";
         }
         leaf cur-hop-limit {
           type uint8;
           status deprecated;
           description
             "The value that is to be placed in the Cur Hop Limit field in
              the Router Advertisement messages sent by the router.
              A value of zero means unspecified (by this router)."; router).

              If this parameter is not configured, the device SHOULD
              use the value specified in IANA Assigned Numbers that
              was in effect at the time of implementation.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvCurHopLimit.

              IANA: IP Parameters,
              http://www.iana.org/assignments/ip-parameters";
         }
         leaf default-lifetime {
           type uint16 {
             range "0..9000";
           }
           units "seconds";
           status deprecated;
           description
             "The value that is to be placed in the Router Lifetime field of
              Router Advertisements sent from the interface, in
              seconds. It MUST be either zero or between
              max-rtr-adv-interval and 9000 seconds.  A value of zero
              default indicates that the router is not to be
              used as to be used as
              a router.  These limits may be overridden by specific
              documents that describe how IPv6 operates over
              different link layers.

              If this parameter is not configured, the device SHOULD
              use a default router."; value of 3 * max-rtr-adv-interval.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvDefaultLifeTime.";
         }
         container prefix-list {
           status deprecated;
           description
             "A list
             "Configuration of prefixes that are to be placed in Prefix
              Information options in Router Advertisement messages
              sent from the interface.

              By default, these are all prefixes

              Prefixes that are advertised by default but do not
              have their entries in the router
              advertises via routing protocols as being on-link for child 'prefix' list are
              advertised with the
              interface from which default values of all parameters.

              The link-local prefix SHOULD NOT be included in the advertisement is sent.";
              list of advertised prefixes.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvPrefixList.";
           list prefix {
             key "prefix-spec";
             status deprecated;
             description
               "Advertised
               "Configuration of an advertised prefix entry and its parameters."; entry.";
             leaf prefix-spec {
               type inet:ipv6-prefix;
               status deprecated;
               description
                 "IPv6 address prefix.";
             }
             choice control-adv-prefixes {
               default "advertise";
               description
                 "Either the prefix is explicitly removed from the
                  set of advertised prefixes, or the parameters with
                  which it is advertised are specified (default
                  case).";
               leaf no-advertise {
                 type empty;
                 description
                   "The prefix will not be advertised.

                    This can be used for removing the prefix from
                    the default set of advertised prefixes.";
               }
               case advertise {
                 leaf valid-lifetime {
                   type uint32;
                   units "seconds";
               status deprecated;
                   default "2592000";
                   description
                     "The value that is to be placed in the Valid Lifetime
                      in the Prefix Information option.  The
                      designated value of all 1's (0xffffffff)
                       represents infinity.

                  An implementation SHOULD keep this value constant in
                  consecutive advertisements except when it is
                  explicitly changed in configuration."; infinity.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvValidLifetime.";
                 }
                 leaf on-link-flag {
                   type boolean;
               status deprecated;
                   default "true";
                   description
                     "The value that is to be placed in the on-link flag
                      ('L-bit') field in the Prefix Information
                      option.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvOnLinkFlag.";
                 }
                 leaf preferred-lifetime {
                   type uint32;
                   units "seconds";
                   must ". <= ../valid-lifetime" {
                     description
                       "This value MUST NOT be greater than
                        valid-lifetime.";
                   }
             leaf preferred-lifetime {
               type uint32;
               units "seconds";
               status deprecated;
                   default "604800";
                   description
                     "The value that is to be placed in the Preferred
                      Lifetime in the Prefix Information option, in seconds. option.
                      The designated value of all 1's (0xffffffff)
                      represents
                  infinity.

                  An implementation SHOULD keep this value constant in
                  consecutive advertisements except when it is
                  explicitly changed in configuration."; infinity.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvPreferredLifetime.";
                 }
                 leaf autonomous-flag {
                   type boolean;
               status deprecated;
                   default "true";
                   description
                     "The value that is to be placed in the Autonomous Flag
                      field in the Prefix Information option.";
                   reference
                     "RFC 4861: Neighbor Discovery for IP version 6
                      (IPv6) - AdvAutonomousFlag.";
                 }
               }
             }
           }
         }
       }
     }

     /* Obsolete State Data */

     augment "/if:interfaces/if:interface/ip:ipv6" "/if:interfaces-state/if:interface/ip:ipv6" {
       status deprecated; obsolete;
       description
         "Augment interface configuration state data with parameters of IPv6 router
          advertisements.";
       container ipv6-router-advertisements {
         status deprecated; obsolete;
         description
           "Configuration
           "Parameters of IPv6 Router Advertisements.";
         leaf send-advertisements {
           type boolean;
           default "false";
           status deprecated; obsolete;
           description
             "A flag indicating whether or not the router sends periodic
              Router Advertisements and responds to Router
              Solicitations.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvSendAdvertisements.";
         }
         leaf max-rtr-adv-interval {
           type uint16 {
             range "4..1800";
           }
           units "seconds";
           default "600";
           status deprecated; obsolete;
           description
             "The maximum time allowed between sending unsolicited
              multicast Router Advertisements from the interface.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              MaxRtrAdvInterval.";
         }
         leaf min-rtr-adv-interval {
           type uint16 {
             range "3..1350";
           }
           units "seconds";
           must ". <= 0.75 * ../max-rtr-adv-interval"
           status obsolete;
           description
             "The minimum time allowed between sending unsolicited
              multicast Router Advertisements from the interface.";
         }
         leaf managed-flag {
           type boolean;
           status obsolete;
           description
             "The value MUST NOT be greater than 75% that is placed in the 'Managed address
              configuration' flag field in the Router Advertisement.";
         }
         leaf other-config-flag {
           type boolean;
           status obsolete;
           description
             "The value that is placed in the 'Other configuration' flag
              field in the Router Advertisement.";
         }
         leaf link-mtu {
           type uint32;
           status obsolete;
           description
             "The value that is placed in MTU options sent by the
              router.  A value of
                'max-rtr-adv-interval'."; zero indicates that no MTU options are
              sent.";
         }
         leaf reachable-time {
           type uint32 {
             range "0..3600000";
           }
           units "milliseconds";
           status obsolete;
           description
             "The value that is placed in the Reachable Time field in
              the Router Advertisement messages sent by the router.  A
              value of zero means unspecified (by this router).";
         }
         leaf retrans-timer {
           type uint32;
           units "milliseconds";
           status deprecated; obsolete;
           description
             "The minimum time allowed between sending unsolicited
              multicast Router Advertisements from the interface.

              The default value to be used operationally if this leaf is
              not configured that is determined as follows:

              - if max-rtr-adv-interval >= 9 seconds, placed in the default Retrans Timer field in the
              Router Advertisement messages sent by the router.  A value is 0.33 * max-rtr-adv-interval;

              - otherwise, it is 0.75 * max-rtr-adv-interval.";

           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              MinRtrAdvInterval.";
              of zero means unspecified (by this router).";
         }
         leaf managed-flag cur-hop-limit {
           type boolean;
           default "false"; uint8;
           status deprecated; obsolete;
           description
             "The value to be that is placed in the 'Managed address
              configuration' flag Cur Hop Limit field in the
              Router Advertisement.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvManagedFlag."; Advertisement messages sent by the router.  A value
              of zero means unspecified (by this router).";
         }
         leaf other-config-flag default-lifetime {
           type boolean;
           default "false"; uint16 {
             range "0..9000";
           }
           units "seconds";
           status deprecated; obsolete;
           description
             "The value to be that is placed in the 'Other configuration' flag Router Lifetime field of
              Router Advertisements sent from the interface, in seconds.
              A value of zero indicates that the router is not to be
              used as a default router.";
         }
         container prefix-list {
           status obsolete;
           description
             "A list of prefixes that are placed in Prefix Information
              options in Router Advertisement.";
           reference
             "RFC 4861: Neighbor Discovery Advertisement messages sent from the
              interface.

              By default, these are all prefixes that the router
              advertises via routing protocols as being on-link for IP version 6 (IPv6) -
              AdvOtherConfigFlag.";
         } the
              interface from which the advertisement is sent.";
           list prefix {
             key "prefix-spec";
             status obsolete;
             description
               "Advertised prefix entry and its parameters.";
             leaf link-mtu prefix-spec {
               type uint32;
           default "0"; inet:ipv6-prefix;
               status deprecated; obsolete;
               description
             "The value to be placed in MTU options sent by the router.
              A value of zero indicates that no MTU options are sent.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvLinkMTU.";
                 "IPv6 address prefix.";
             }
             leaf reachable-time valid-lifetime {
               type uint32 {
             range "0..3600000";
           } uint32;
               units "milliseconds";
           default "0"; "seconds";
               status deprecated; obsolete;
               description
                 "The value to be that is placed in the Reachable Time field Valid Lifetime in the
              Router Advertisement messages sent by the router.  A
                  Prefix Information option.  The designated value of zero means unspecified (by
                  all 1's (0xffffffff) represents infinity.

                  An implementation SHOULD keep this router).";

           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvReachableTime."; value constant in
                  consecutive advertisements except when it is
                  explicitly changed in configuration.";
             }
             leaf retrans-timer on-link-flag {
               type uint32;
           units "milliseconds";
           default "0"; boolean;
               status deprecated; obsolete;
               description
                 "The value to be that is placed in the Retrans Timer on-link flag ('L-bit')
                  field in the
              Router Advertisement messages sent by the router.  A value
              of zero means unspecified (by this router).";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvRetransTimer."; Prefix Information option.";
             }
             leaf cur-hop-limit preferred-lifetime {
               type uint8; uint32;
               units "seconds";
               status deprecated; obsolete;
               description
                 "The value to be that is placed in the Cur Hop Limit field Preferred Lifetime in
                  the
              Router Advertisement messages sent by the router.  A Prefix Information option, in seconds.  The
                  designated value of zero means unspecified (by this router).

              If this parameter is not configured, the device all 1's (0xffffffff) represents
                  infinity.

                  An implementation SHOULD use
              the keep this value specified constant in IANA Assigned Numbers that was
                  consecutive advertisements except when it is
                  explicitly changed in
              effect at the time of implementation.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvCurHopLimit.

              IANA: IP Parameters,
              http://www.iana.org/assignments/ip-parameters"; configuration.";
             }
             leaf default-lifetime autonomous-flag {
               type uint16 {
             range "0..9000";
           }
           units "seconds"; boolean;
               status deprecated; obsolete;
               description
                 "The value to be that is placed in the Router Lifetime Autonomous Flag field of
              Router Advertisements sent from
                  in the interface, Prefix Information option.";
             }
           }
         }
       }
     }
   }
   <CODE ENDS>

10.  IANA Considerations

   [RFC8022] registered the following namespace URIs in seconds.
              It MUST be either zero or between max-rtr-adv-interval and
              9000 seconds.  A value of zero indicates that the router "IETF XML
   Registry" [RFC3688]:

   URI: urn:ietf:params:xml:ns:yang:ietf-routing
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is not to be used as a default router.  These limits may
              be overridden by specific documents that describe how IPv6
              operates over different link layers.

              If this parameter an XML namespace.

   URI: urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is not configured, an XML namespace.

   URI: urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing
   Registrant Contact: The IESG.
   XML: N/A; the device SHOULD use
              a value of 3 * max-rtr-adv-interval.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvDefaultLifeTime.";
         }
         container prefix-list {
           status deprecated;
           description
             "Configuration of prefixes to be placed requested URI is an XML namespace.

   [RFC8022] registered the following YANG modules in Prefix
              Information options the "YANG Module
   Names" registry [RFC6020]:

   Name:         ietf-routing
   Namespace:    urn:ietf:params:xml:ns:yang:ietf-routing
   Prefix:       rt
   Reference:    RFC 8022
   Name:         ietf-ipv4-unicast-routing
   Namespace:    urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing
   Prefix:       v4ur
   Reference:    RFC 8022

   Name:         ietf-ipv6-unicast-routing
   Namespace:    urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing
   Prefix:       v6ur
   Reference:    RFC 8022

   This document registers the following YANG submodule in Router Advertisement messages sent
              from the interface.

              Prefixes that "YANG
   Module Names" registry [RFC6020]:

   Name:         ietf-ipv6-router-advertisements
   Module:       ietf-ipv6-unicast-routing
   Reference:    RFC 8022

11.  Security Considerations

   The YANG module defined in this memo is designed to be accessed via
   the NETCONF protocol [RFC6241].  The lowest NETCONF layer is the
   secure transport layer and the mandatory-to-implement secure
   transport is SSH [RFC6242].

   There are advertised by default but do not have
              their entries a number of data nodes defined in the child 'prefix' list this YANG module which
   are advertised
              with writable/creatable/deletable (i.e., config true, which is the default values of all parameters.

              The link-local prefix SHOULD NOT
   default).  These data nodes may be included 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.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   /routing/control-plane-protocols/control-plane-protocol:  This list
              of advertised prefixes.";
           reference
             "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) -
              AdvPrefixList.";
      specifies the control-plane protocols configured on a device.

   /routing/ribs/rib:  This list prefix {
             key "prefix-spec";
             status deprecated;
             description
               "Configuration of an advertised prefix entry.";
             leaf prefix-spec {
               type inet:ipv6-prefix;
               status deprecated;
               description
                 "IPv6 address prefix.";
             }
             choice control-adv-prefixes {
               default "advertise";
               status deprecated;
               description
                 "Either specifies the prefix is explicitly removed from RIBs configured for the
                  set
      device.

   Some of advertised prefixes, or the parameters with
                  which it readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is advertised thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are specified (default case).";
               leaf no-advertise {
                 type empty;
                 status deprecated;
                 description
                   "The prefix will not be advertised. the subtrees and data
   nodes and their sensitivity/vulnerability:

   /routing/control-plane-protocols/control-plane-protocol:  This list
      specifies the control-plane protocols configured on a device.
      Refer to the control plane models for a list of sensitive
      information.

   /routing/ribs/rib:  This can be used for removing list specifies the prefix from RIB and their contents
      for the
                    default set of advertised prefixes.";
               }
               case advertise {
                 status deprecated;
                 leaf valid-lifetime {
                   type uint32;
                   units "seconds";
                   default "2592000";
                   status deprecated;
                   description
                     "The value device.  Access to be placed in this information may disclose the Valid Lifetime
      network topology and or other information.

12.  References

12.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in
                      the Prefix Information option.  The designated
                      value of all 1's (0xffffffff) represents
                      infinity.";
                   reference
                     "RFC 4861: Neighbor RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
              editor.org/info/rfc2119>.

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

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6
                      (IPv6) (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007, <https://www.rfc-
              editor.org/info/rfc4861>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - AdvValidLifetime.";
                 }
                 leaf on-link-flag {
                   type boolean;
                   default "true";
                   status deprecated;
                   description
                     "The value to be placed in A Data Modeling Language for
              the on-link flag
                      ('L-bit') field in Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010, <https://www.rfc-
              editor.org/info/rfc6020>.

   [RFC6242]  Wasserman, M., "Using the Prefix Information
                      option.";
                   reference
                     "RFC 4861: Neighbor Discovery NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

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

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

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

   [RFC7277]  Bjorklund, M., "A YANG Data Model for IP version 6
                      (IPv6) - AdvOnLinkFlag.";
                 }
                 leaf preferred-lifetime {
                   type uint32;
                   units "seconds";
                   must ". <= ../valid-lifetime" {
                     description
                       "This value MUST NOT be greater than
                        valid-lifetime.";
                   }
                   default "604800";
                   status deprecated;
                   description Management",
              RFC 7277, DOI 10.17487/RFC7277, June 2014,
              <https://www.rfc-editor.org/info/rfc7277>.

   [RFC7950]  Bjorklund, M., Ed., "The value to be placed in the Preferred Lifetime
                      in the Prefix Information option.  The designated
                      value of all 1's (0xffffffff) represents
                      infinity.";
                   reference
                     "RFC 4861: Neighbor Discovery YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8022]  Lhotka, L. and A. Lindem, "A YANG Data Model for IP version 6
                      (IPv6) - AdvPreferredLifetime.";
                 }
                 leaf autonomous-flag {
                   type boolean;
                   default "true";
                   status deprecated;
                   description
                     "The value to be placed in the Autonomous Flag
                      field in the Prefix Information option.";
                   reference
                     "RFC 4861: Neighbor Discovery Routing
              Management", RFC 8022, DOI 10.17487/RFC8022, November
              2016, <https://www.rfc-editor.org/info/rfc8022>.

12.2.  Informative References

   [RFC6087]  Bierman, A., "Guidelines for IP version 6
                      (IPv6) - AdvAutonomousFlag.";
                 }
               }
             }
           }
         }
       }
     }
   }
   <CODE ENDS> Authors and Reviewers of YANG
              Data Model Documents", RFC 6087, DOI 10.17487/RFC6087,
              January 2011, <https://www.rfc-editor.org/info/rfc6087>.

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

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [I-D.ietf-netmod-revised-datastores]
              Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore
              Architecture", draft-ietf-netmod-revised-datastores-05
              (work in progress), October 2017.

Appendix B. A.  The Complete Data Trees

   This appendix presents the complete tree of the core routing data
   model.  See Section 2.2 for an explanation of the symbols used.  The
   data type of every leaf node is shown near the right end of the
   corresponding line.

   module: ietf-routing-2 ietf-routing
   +--rw routing
      +--rw router-id?                 yang:dotted-quad
      +--ro interfaces
      |  +--ro interface*   if:interface-ref
      +--rw control-plane-protocols
      |  +--rw control-plane-protocol* [type name]
      |     +--rw type             identityref
      |     +--rw name             string
      |     +--rw description?     string
      |     +--rw static-routes
      |        +--rw v4ur:ipv4
      |        |  +--rw v4ur:route* [destination-prefix]
      |        |     +--rw v4ur:destination-prefix    inet:ipv4-prefix
      |        |     +--rw v4ur:description?          string
      |        |     +--rw v4ur:next-hop
      |        |        +--rw (v4ur:next-hop-options)
      |        |           +--:(v4ur:simple-next-hop)
      |        |           |  +--rw v4ur:outgoing-interface?
      |        |           |             if:interface-ref
      |        |           |  +--rw v4ur:next-hop-address?
      |        |           |             inet:ipv4-address
      |        |           +--:(v4ur:special-next-hop)
      |        |           |  +--rw v4ur:special-next-hop?  enumeration
      |        |           +--:(v4ur:next-hop-list)
      |        |              +--rw v4ur:next-hop-list
      |        |                 +--rw v4ur:next-hop* [index]
      |        |                    +--rw v4ur:index             string
      |        |                    +--rw v4ur:outgoing-interface?
      |        |                               if:interface-ref
      |        |                    +--rw v4ur:next-hop-address?
      |        |                               inet:ipv4-address
      |        +--rw v6ur:ipv6
      |           +--rw v6ur:route* [destination-prefix]
      |              +--rw v6ur:destination-prefix    inet:ipv6-prefix
      |              +--rw v6ur:description?          string
      |              +--rw v6ur:next-hop
      |                 +--rw (v6ur:next-hop-options)
      |                    +--:(v6ur:simple-next-hop)
      |                    |  +--rw v6ur:outgoing-interface?
      |                    |             if:interface-ref
      |                    |  +--rw v6ur:next-hop-address?
      |                    |             inet:ipv6-address
      |                    +--:(v6ur:special-next-hop)
      |                    |  +--rw v6ur:special-next-hop?  enumeration
      |                    +--:(v6ur:next-hop-list)
      |                       +--rw v6ur:next-hop-list
      |                          +--rw v6ur:next-hop* [index]
      |                             +--rw v6ur:index             string
      |                             +--rw v6ur:outgoing-interface?
      |                                        if:interface-ref
      |                             +--rw v6ur:next-hop-address?
      |                                        inet:ipv6-address
      +--rw ribs
         +--rw rib* [name]
            +--rw name              string
            +--rw address-family?   identityref
            +--ro default-rib?      boolean {multiple-ribs}?
            +--ro routes
            |  +--ro route*
            |     +--ro route-preference?          route-preference
            |     +--ro next-hop
            |     |  +--ro (next-hop-options)
            |     |     +--:(simple-next-hop)
            |     |     |  +--ro outgoing-interface?
            |     |     |  |       if:interface-ref
            |     |     |  +--ro v4ur:next-hop-address?
            |     |     |  |       inet:ipv4-address
            |     |     |  +--ro v6ur:next-hop-address?
            |     |     |             inet:ipv6-address
            |     |     +--:(special-next-hop)
            |     |     |  +--ro special-next-hop?        enumeration
            |     |     +--:(next-hop-list)
            |     |        +--ro next-hop-list
            |     |           +--ro next-hop*
            |     |              +--ro outgoing-interface?
            |     |              |       if:interface-ref
            |     |              +--ro v4ur:address?
            |     |              |       inet:ipv4-address
            |     |              +--ro v6ur:address?
            |     |                       inet:ipv6-address
            |     +--ro source-protocol            identityref
            |     +--ro active?                    empty
            |     +--ro last-updated?              yang:date-and-time
            |     +--ro v4ur:destination-prefix?   inet:ipv4-prefix
            |     +--ro v6ur:destination-prefix?   inet:ipv6-prefix
            +---x active-route
            |  +---w input
            |  |  +---w v4ur:destination-address?   inet:ipv4-address
            |  |  +---w v6ur:destination-address?   inet:ipv6-address
            |  +--ro output
            |     +--ro route
            |        +--ro next-hop
            |        |  +--ro (next-hop-options)
            |        |     +--:(simple-next-hop)
            |        |     |  +--ro outgoing-interface?
            |        |     |  |       if:interface-ref
            |        |     |  +--ro v4ur:next-hop-address?
            |        |     |  |          inet:ipv4-address
            |        |     |  +--ro v6ur:next-hop-address?
            |        |     |             inet:ipv6-address
            |        |     +--:(special-next-hop)
            |        |     |  +--ro special-next-hop?      enumeration
            |        |     +--:(next-hop-list)
            |        |        +--ro next-hop-list
            |        |           +--ro next-hop*
            |        |              +--ro outgoing-interface?
            |        |              |       if:interface-ref
            |        |              +--ro v4ur:next-hop-address?
            |        |              |       inet:ipv4-address
            |        |              +--ro v6ur:next-hop-address?
            |        |                      inet:ipv6-address
            |        +--ro source-protocol          identityref
            |        +--ro active?                  empty
            |        +--ro last-updated?            yang:date-and-time
            |        +--ro v4ur:destination-prefix? inet:ipv4-prefix
            |        +--ro v6ur:destination-prefix? inet:ipv6-prefix
            +--rw description?      string
   module: ietf-ipv6-unicast-routing-2 ietf-ipv6-unicast-routing
     augment /if:interfaces/if:interface/ip:ipv6:
   +--rw ipv6-router-advertisements
      +--rw send-advertisements?    boolean
      +--rw max-rtr-adv-interval?   uint16
      +--rw min-rtr-adv-interval?   uint16
      +--rw managed-flag?           boolean
      +--rw other-config-flag?      boolean
      +--rw link-mtu?               uint32
      +--rw reachable-time?         uint32
      +--rw retrans-timer?          uint32
      +--rw cur-hop-limit?          uint8
      +--rw default-lifetime?       uint16
      +--rw prefix-list
         +--rw prefix* [prefix-spec]
            +--rw prefix-spec           inet:ipv6-prefix
            +--rw (control-adv-prefixes)?
               +--:(no-advertise)
               |  +--rw no-advertise?         empty
               +--:(advertise)
                  +--rw valid-lifetime?       uint32
                  +--rw on-link-flag?         boolean
                  +--rw preferred-lifetime?   uint32
                  +--rw autonomous-flag?      boolean

Appendix C. B.  Minimum Implementation

   Some parts and options of the core routing model, such as user-
   defined RIBs, are intended only for advanced routers.  This appendix
   gives basic non-normative guidelines for implementing a bare minimum
   of available functions.  Such an implementation may be used for hosts
   or very simple routers.

   A minimum implementation does not support the feature
   "multiple-ribs".  This means that a single system-controlled RIB is
   available for each supported address family -- IPv4, IPv6, or both.
   These RIBs are also the default RIBs.  No user-controlled RIBs are
   allowed.

   In addition to the mandatory instance of the "direct" pseudo-
   protocol, a minimum implementation should support configuring
   instance(s) of the "static" pseudo-protocol.

   For hosts that are never intended to act as routers, the ability to
   turn on sending IPv6 router advertisements (Section 5.4) should be
   removed.

   Platforms with severely constrained resources may use deviations for
   restricting the data model, e.g., limiting the number of "static"
   control-plane protocol instances.

Appendix D. C.  Example: Adding a New Control-Plane Protocol

   This appendix demonstrates how the core routing data model can be
   extended to support a new control-plane protocol.  The YANG module
   "example-rip" shown below is intended as an illustration rather than
   a real definition of a data model for the Routing Information
   Protocol (RIP).  For the sake of brevity, this module does not obey
   all the guidelines specified in [RFC6087].  See also Section 5.3.2.

   module example-rip {

     yang-version "1.1";

     namespace "http://example.com/rip";

     prefix "rip";
     import ietf-interfaces {
       prefix "if";
     }

     import ietf-routing-2 ietf-routing {
       prefix "rt";
     }

     identity rip {
       base rt:routing-protocol;
       description
         "Identity for the Routing Information Protocol (RIP).";
     }

     typedef rip-metric {
       type uint8 {
         range "0..16";
       }
     }

     grouping route-content {
       description
         "This grouping defines RIP-specific route attributes.";
       leaf metric {
         type rip-metric;
       }
       leaf tag {
         type uint16;
         default "0";
         description
           "This leaf may be used to carry additional info, e.g.,
            autonomous system (AS) number.";
       }
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route" {
       when "derived-from-or-self(rt:source-protocol, 'rip:rip')" {
         description
           "This augment is only valid for a route whose source
            protocol is RIP.";
       }
       description
         "RIP-specific route attributes.";
       uses route-content;
     }

     augment "/rt:routing/rt:ribs/rt:rib/rt:active-route/"
           + "rt:output/rt:route" {

       description
         "RIP-specific route attributes in the output of 'active-route'
          RPC.";
       uses route-content;
     }

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol" {
       when "derived-from-or-self(rt:type,'rip:rip')" {
         description
           "This augment is only valid for a routing protocol instance
            of type 'rip'.";
       }
       container rip {
         presence "RIP configuration";
         description
           "RIP instance configuration.";
         container interfaces {
           description
             "Per-interface RIP configuration.";
           list interface {
             key "name";
             description
               "RIP is enabled on interfaces that have an entry in this
                list, unless 'enabled' is set to 'false' for that
                entry.";
             leaf name {
               type if:interface-ref;
             }
             leaf enabled {
               type boolean;
               default "true";
             }
             leaf metric {
               type rip-metric;
               default "1";
             }
           }
         }
         leaf update-interval {
           type uint8 {
             range "10..60";
           }
           units "seconds";
           default "30";
           description
             "Time interval between periodic updates.";
         }

       }
     }
   }

Appendix E. D.  Data Tree Example

   This section contains an example of an instance data tree in the JSON
   encoding [RFC7951], containing both configuration and state data.
   The data conforms to a data model that is defined by the following
   YANG library specification [RFC7895]:

   {
     "ietf-yang-library:modules-state": {
       "module-set-id": "c2e1f54169aa7f36e1a6e8d0865d441d3600f9c4",
       "module": [
         {
           "name": "ietf-routing-2", "ietf-routing",
           "revision": "2017-09-13",
           "feature": [
             "multiple-ribs",
             "router-id"
           ],
           "namespace": "urn:ietf:params:xml:ns:yang:ietf-routing-2", "urn:ietf:params:xml:ns:yang:ietf-routing",
           "conformance-type": "implement"
         },
         {
           "name": "ietf-ipv4-unicast-routing-2", "ietf-ipv4-unicast-routing",
           "revision": "2017-09-13",
           "namespace":
             "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing-2",
             "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing",
           "conformance-type": "implement"
         },
         {
           "name": "ietf-ipv6-unicast-routing-2", "ietf-ipv6-unicast-routing",
           "revision": "2017-09-13",
           "namespace":
             "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing-3",
           "conformance-type": "implement"
         },
         {
           "name": "ietf-interfaces",
           "revision": "2014-05-08",
           "namespace": "urn:ietf:params:xml:ns:yang:ietf-interfaces",
           "conformance-type": "implement"
         },
         {
           "name": "ietf-inet-types",
           "namespace": "urn:ietf:params:xml:ns:yang:ietf-inet-types",
           "revision": "2013-07-15",
           "conformance-type": "import"
         },
         {
           "name": "ietf-yang-types",
           "namespace": "urn:ietf:params:xml:ns:yang:ietf-yang-types",
           "revision": "2013-07-15",
           "conformance-type": "import"
         },
         {
           "name": "iana-if-type",
           "namespace": "urn:ietf:params:xml:ns:yang:iana-if-type",
           "revision": "",
           "conformance-type": "implement"
         },
         {
           "name": "ietf-ip",
           "revision": "2014-06-16",
           "namespace": "urn:ietf:params:xml:ns:yang:ietf-ip",
           "conformance-type": "implement"
         }
       ]
     }
   }

   A simple network setup as shown in Figure 2 is assumed: router "A"
   uses static default routes with the "ISP" router as the next hop.
   IPv6 router advertisements are configured only on the "eth1"
   interface and disabled on the upstream "eth0" interface.

                   +-----------------+
                   |                 |
                   |    Router ISP   |
                   |                 |
                   +--------+--------+
                            |2001:db8:0:1::2
                            |192.0.2.2
                            |
                            |
                            |2001:db8:0:1::1
                        eth0|192.0.2.1
                   +--------+--------+
                   |                 |
                   |     Router A    |
                   |                 |
                   +--------+--------+
                        eth1|198.51.100.1
                            |2001:db8:0:2::1
                            |

                Figure 2: Example of Network Configuration

   The instance data tree could then be as follows:

   {
     "ietf-interfaces:interfaces": {
       "interface": [
         {
           "name": "eth0",
           "type": "iana-if-type:ethernetCsmacd",
           "description": "Uplink to ISP.",
           "ietf-ip:ipv4": {
             "address": [
               {
                 "ip": "192.0.2.1",
                 "prefix-length": 24
               }
             ],
             "forwarding": true
           },
           "ietf-ip:ipv6": {
             "address": [
               {
                 "ip": "2001:0db8:0:1::1",
                 "prefix-length": 64
               }
             ],
             "forwarding": true,
             "autoconf": {
               "create-global-addresses": false
             }
           }
         },
         {
           "name": "eth1",
           "type": "iana-if-type:ethernetCsmacd",
           "description": "Interface to the internal network.",
           "ietf-ip:ipv4": {
             "address": [
               {
                 "ip": "198.51.100.1",
                 "prefix-length": 24
               }
             ],
             "forwarding": true
           },
           "ietf-ip:ipv6": {
             "address": [
               {
                 "ip": "2001:0db8:0:2::1",
                 "prefix-length": 64
               }
             ],
             "forwarding": true,
             "autoconf": {
               "create-global-addresses": false
             },
             "ietf-ipv6-unicast-routing-2:
                 ipv6-router-advertisements-2":
             "ietf-ipv6-unicast-routing:
                 ipv6-router-advertisements": {
               "send-advertisements": true
             }
           }
         }
       ]
     },
     "ietf-interfaces:interfaces-state": {
       "interface": [
         {
           "name": "eth0",
           "type": "iana-if-type:ethernetCsmacd",
           "phys-address": "00:0C:42:E5:B1:E9",
           "oper-status": "up",
           "statistics": {
             "discontinuity-time": "2015-10-24T17:11:27+02:00"
           },
           "ietf-ip:ipv4": {
             "forwarding": true,
             "mtu": 1500,
             "address": [
               {
                 "ip": "192.0.2.1",
                 "prefix-length": 24
               }
             ]
           },
           "ietf-ip:ipv6": {
             "forwarding": true,
             "mtu": 1500,
             "address": [
               {
                 "ip": "2001:0db8:0:1::1",
                 "prefix-length": 64
               }
             ],
             "ietf-ipv6-unicast-routing-2:
                ipv6-router-advertisements-2":
             "ietf-ipv6-unicast-routing:
                ipv6-router-advertisements": {
               "send-advertisements": false
             }
           }
         },
         {
           "name": "eth1",
           "type": "iana-if-type:ethernetCsmacd",
           "phys-address": "00:0C:42:E5:B1:EA",
           "oper-status": "up",
           "statistics": {
             "discontinuity-time": "2015-10-24T17:11:29+02:00"
           },
           "ietf-ip:ipv4": {
             "forwarding": true,
             "mtu": 1500,
             "address": [
               {
                 "ip": "198.51.100.1",
                 "prefix-length": 24
               }
             ]
           },
           "ietf-ip:ipv6": {
             "forwarding": true,
             "mtu": 1500,
             "address": [
               {
                 "ip": "2001:0db8:0:2::1",
                 "prefix-length": 64
               }
             ],
             "ietf-ipv6-unicast-routing-2:
                ipv6-router-advertisements-2":
             "ietf-ipv6-unicast-routing:
                ipv6-router-advertisements": {
               "send-advertisements": true,
               "prefix-list": {
                 "prefix": [
                   {
                     "prefix-spec": "2001:db8:0:2::/64"
                   }
                 ]
               }
             }
           }
         }
       ]
     },
     "ietf-routing-2:routing":
     "ietf-routing:routing": {
       "router-id": "192.0.2.1",
       "control-plane-protocols": {
         "control-plane-protocol": [
           {
             "type": "ietf-routing-2:static", "ietf-routing:static",
             "name": "st0",
             "description":
               "Static routing is used for the internal network.",
             "static-routes": {
               "ietf-ipv4-unicast-routing-2:ipv4":
               "ietf-ipv4-unicast-routing:ipv4": {
                 "route": [
                   {
                     "destination-prefix": "0.0.0.0/0",
                     "next-hop": {
                       "next-hop-address": "192.0.2.2"
                     }
                   }
                 ]
               },
               "ietf-ipv6-unicast-routing-2:ipv6":
               "ietf-ipv6-unicast-routing:ipv6": {
                 "route": [
                   {
                     "destination-prefix": "::/0",
                     "next-hop": {
                       "next-hop-address": "2001:db8:0:1::2"
                     }
                   }
                 ]
               }

             }
           }
         ]
       }
           "ribs": {
         "rib": [
           {
             "name": "ipv4-master",
             "address-family":
               "ietf-ipv4-unicast-routing-2:ipv4-unicast",
               "ietf-ipv4-unicast-routing:ipv4-unicast",
             "default-rib": true,
             "routes": {
               "route": [
                 {
                   "ietf-ipv4-unicast-routing-2:destination-prefix":
                   "ietf-ipv4-unicast-routing:destination-prefix":
                     "192.0.2.1/24",
                   "next-hop": {
                     "outgoing-interface": "eth0"
                   },
                   "route-preference": 0,
                   "source-protocol": "ietf-routing-2:direct", "ietf-routing:direct",
                   "last-updated": "2015-10-24T17:11:27+02:00"
                 },
                 {
                   "ietf-ipv4-unicast-routing-2:destination-prefix":
                   "ietf-ipv4-unicast-routing:destination-prefix":
                     "198.51.100.0/24",
                   "next-hop": {
                     "outgoing-interface": "eth1"
                   },
                   "source-protocol": "ietf-routing-2:direct", "ietf-routing:direct",
                   "route-preference": 0,
                   "last-updated": "2015-10-24T17:11:27+02:00"
                 },
                 {
                   "ietf-ipv4-unicast-routing-2:destination-prefix":
                   "ietf-ipv4-unicast-routing:destination-prefix":
                     "0.0.0.0/0",
                   "source-protocol": "ietf-routing-2:static", "ietf-routing:static",
                   "route-preference": 5,
                   "next-hop": {
                     "ietf-ipv4-unicast-routing-2:next-hop-address":
                     "ietf-ipv4-unicast-routing:next-hop-address":
                       "192.0.2.2"
                   },
                   "last-updated": "2015-10-24T18:02:45+02:00"
                 }
               ]
             }
           },
           {
             "name": "ipv6-master",
             "address-family":
               "ietf-ipv6-unicast-routing-2:ipv6-unicast",
               "ietf-ipv6-unicast-routing:ipv6-unicast",
             "default-rib": true,
             "routes": {
               "route": [
                 {
                   "ietf-ipv6-unicast-routing-2:destination-prefix":
                   "ietf-ipv6-unicast-routing:destination-prefix":
                     "2001:db8:0:1::/64",
                   "next-hop": {
                     "outgoing-interface": "eth0"
                   },
                   "source-protocol": "ietf-routing-2:direct", "ietf-routing:direct",
                   "route-preference": 0,
                   "last-updated": "2015-10-24T17:11:27+02:00"
                 },
                 {
                   "ietf-ipv6-unicast-routing-2:destination-prefix":
                   "ietf-ipv6-unicast-routing:destination-prefix":
                     "2001:db8:0:2::/64",
                   "next-hop": {
                     "outgoing-interface": "eth1"
                   },
                   "source-protocol": "ietf-routing-2:direct", "ietf-routing:direct",
                   "route-preference": 0,
                   "last-updated": "2015-10-24T17:11:27+02:00"
                 },
                 {
                   "ietf-ipv6-unicast-routing-2:destination-prefix":
                   "ietf-ipv6-unicast-routing:destination-prefix":
                     "::/0",
                   "next-hop": {
                     "ietf-ipv6-unicast-routing-2:next-hop-address":
                     "ietf-ipv6-unicast-routing:next-hop-address":
                       "2001:db8:0:1::2"
                   },
                   "source-protocol": "ietf-routing-2:static", "ietf-routing:static",
                   "route-preference": 5,
                   "last-updated": "2015-10-24T18:02:45+02:00"
                 }
               ]
             }
           }
         ]
       }
     },
   }

Acknowledgments

   The authors wish to thank Nitin Bahadur, Martin Bjorklund, Dean
   Bogdanovic, Jeff Haas, Joel Halpern, Wes Hardaker, Sriganesh Kini,
   David Lamparter, Andrew McGregor, Jan Medved, Xiang Li, Stephane
   Litkowski, Thomas Morin, Tom Petch, Yingzhen Qu, Bruno Rijsman,
   Juergen Schoenwaelder, Phil Shafer, Dave Thaler, Yi Yang,
   Derek Man-Kit Yeung, and Jeffrey Zhang for their helpful comments and
   suggestions.

Authors' Addresses

   Ladislav Lhotka
   CZ.NIC

   EMail: lhotka@nic.cz

   Acee Lindem
   Cisco Systems

   EMail: acee@cisco.com

   Yingzhen Qu
   Futurewei Technologies, Inc.
   2330 Central Expressway
   Santa Clara  CA 95050
   USA

   EMail: yingzhen.qu@huawei.com