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rfc:rfc8349

Internet Engineering Task Force (IETF) L. Lhotka Request for Comments: 8349 CZ.NIC Obsoletes: 8022 A. Lindem Category: Standards Track Cisco Systems ISSN: 2070-1721 Y. Qu

                                                                Huawei
                                                            March 2018
      A YANG Data Model for Routing Management (NMDA Version)

Abstract

 This document specifies 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.
 The YANG modules in this document conform to the Network Management
 Datastore Architecture (NMDA).  This document obsoletes RFC 8022.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8349.

Lhotka, et al. Standards Track [Page 1] RFC 8349 YANG Routing Management March 2018

Copyright Notice

 Copyright (c) 2018 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (https://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Lhotka, et al. Standards Track [Page 2] RFC 8349 YANG Routing Management March 2018

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
 2.  Terminology and Notation  . . . . . . . . . . . . . . . . . .   4
   2.1.  Glossary of New Terms . . . . . . . . . . . . . . . . . .   5
   2.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   6
   2.3.  Prefixes in Data Node Names . . . . . . . . . . . . . . .   6
 3.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   6
 4.  The Design of the Core Routing Data Model . . . . . . . . . .   7
   4.1.  System-Controlled and User-Controlled List Entries  . . .   8
 5.  Basic Building Blocks . . . . . . . . . . . . . . . . . . . .   9
   5.1.  Routes  . . . . . . . . . . . . . . . . . . . . . . . . .   9
   5.2.  Routing Information Base (RIB)  . . . . . . . . . . . . .  10
   5.3.  Control-Plane Protocol  . . . . . . . . . . . . . . . . .  11
     5.3.1.  Routing Pseudo-Protocols  . . . . . . . . . . . . . .  11
     5.3.2.  Defining New Control-Plane Protocols  . . . . . . . .  11
   5.4.  Parameters of IPv6 Router Advertisements  . . . . . . . .  12
 6.  Interactions with Other YANG Modules  . . . . . . . . . . . .  13
   6.1.  Module "ietf-interfaces"  . . . . . . . . . . . . . . . .  13
   6.2.  Module "ietf-ip"  . . . . . . . . . . . . . . . . . . . .  14
 7.  Routing Management YANG Module  . . . . . . . . . . . . . . .  15
 8.  IPv4 Unicast Routing Management YANG Module . . . . . . . . .  29
 9.  IPv6 Unicast Routing Management YANG Module . . . . . . . . .  37
   9.1.  IPv6 Router Advertisements Submodule  . . . . . . . . . .  45
 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  56
 11. Security Considerations . . . . . . . . . . . . . . . . . . .  57
 12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  58
   12.1.  Normative References . . . . . . . . . . . . . . . . . .  58
   12.2.  Informative References . . . . . . . . . . . . . . . . .  60
 Appendix A.  The Complete Schema Tree . . . . . . . . . . . . . .  61
 Appendix B.  Minimum Implementation . . . . . . . . . . . . . . .  66
 Appendix C.  Example: Adding a New Control-Plane Protocol . . . .  67
 Appendix D.  Data Tree Example  . . . . . . . . . . . . . . . . .  70
 Appendix E.  NETCONF Get Data Reply Example . . . . . . . . . . .  77
 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  80
 Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  80

Lhotka, et al. Standards Track [Page 3] RFC 8349 YANG Routing Management March 2018

1. Introduction

 This document specifies the following YANG modules:
 o  The "ietf-routing" module provides generic components of a routing
    data model.
 o  The "ietf-ipv4-unicast-routing" module augments the "ietf-routing"
    module with additional data specific to IPv4 unicast.
 o  The "ietf-ipv6-unicast-routing" module augments the "ietf-routing"
    module with additional data specific to IPv6 unicast.  Its
    submodule, "ietf-ipv6-router-advertisements", also augments the
    "ietf-interfaces"  [RFC8343] and "ietf-ip" [RFC8344] modules with
    IPv6 router configuration variables required by [RFC4861].
 These modules together define the 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 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.
 The YANG modules in this document conform to the Network Management
 Datastore Architecture (NMDA) [RFC8342].  This document obsoletes
 RFC 8022 [RFC8022].

2. Terminology and Notation

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.
 The following terms are defined in [RFC8342]:
 o  client
 o  server
 o  configuration

Lhotka, et al. Standards Track [Page 4] RFC 8349 YANG Routing Management March 2018

 o  system state
 o  operational state
 o  intended configuration
 The following terms are defined in [RFC7950]:
 o  action
 o  augment
 o  container
 o  data model
 o  data node
 o  feature
 o  leaf
 o  list
 o  mandatory node
 o  module
 o  presence container
 o  schema tree
 o  RPC (Remote Procedure Call) operation

2.1. Glossary of New Terms

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

Lhotka, et al. Standards Track [Page 5] RFC 8349 YANG Routing Management March 2018

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

 Tree diagrams used in this document follow the notation defined in
 [RFC8340].

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           | [RFC8343] |
          | ip     | ietf-ip                   | [RFC8344] |
          | rt     | ietf-routing              | Section 7 |
          | v4ur   | ietf-ipv4-unicast-routing | Section 8 |
          | v6ur   | 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.

Lhotka, et al. Standards Track [Page 6] RFC 8349 YANG Routing Management March 2018

 o  On the other hand, the core routing framework must allow for
    complicated implementations involving multiple 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 such mapping 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", defines the generic
 components of a routing system.  The other two modules --
 "ietf-ipv4-unicast-routing" and "ietf-ipv6-unicast-routing" --
 augment the "ietf-routing" module with additional data nodes that are
 needed for IPv4 and IPv6 unicast routing, respectively.  The
 "ietf-ipv6-unicast-routing" module has a submodule,
 "ietf-ipv6-router-advertisements", that augments the
 "ietf-interfaces" [RFC8343] and "ietf-ip" [RFC8344] modules with
 configuration variables for IPv6 Router Advertisements as required by
 [RFC4861].

Lhotka, et al. Standards Track [Page 7] RFC 8349 YANG Routing Management March 2018

 Figure 1 shows abridged views of the hierarchies.  See Appendix 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 Figure 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.

Lhotka, et al. Standards Track [Page 8] RFC 8349 YANG Routing Management March 2018

 In such a list, the server creates the required item as a
 "system-controlled entry" in the operational state, i.e., inside
 read-only lists in the "routing" container.
 An example can be seen in Appendix D: the "/routing/ribs/rib" list
 has two system-controlled entries -- "ipv4-master" and "ipv6-master".
 Additional entries called "user-controlled entries" may be created in
 the configuration by a client, e.g., via the Network Configuration
 Protocol (NETCONF).  If the server accepts a configured
 user-controlled entry, then this entry also appears in the
 operational state version of the list.
 Corresponding entries in both versions of the list (in the intended
 configuration and the operational state) [RFC8342] 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 operational state, the key of the
 configuration entry has to be set to the same value as the key of the
 operational state entry.
 Deleting a user-controlled entry from the intended configuration
 results in the removal of the corresponding entry in the operational
 state list.  In contrast, if a client deletes a system-controlled
 entry from the intended configuration, only the extra configuration
 specified in that entry is removed; the corresponding operational
 state entry is not removed.

5. Basic Building Blocks

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

5.1. Routes

 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.

Lhotka, et al. Standards Track [Page 9] RFC 8349 YANG Routing Management March 2018

 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 indicates a route that is more preferred.
 o  "next-hop": determines the outgoing interface and/or next-hop
    address(es), or a special operation to be performed on a packet.
 Routes are primarily system state and appear as entries in 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 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 represented as entries in
 the list "/routing/ribs/rib" in the operational state.  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 "default RIB", in which control-plane protocols place their
 routes by default.
 Simple router implementations that do not advertise the
 "multiple-ribs" feature 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.

Lhotka, et al. Standards Track [Page 10] RFC 8349 YANG Routing Management March 2018

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 new modules will have
 to define the protocol-specific data nodes, and they will have to
 integrate 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".

Lhotka, et al. Standards Track [Page 11] RFC 8349 YANG Routing Management March 2018

 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 schema tree.
 o  Data nodes for the new protocol can be defined by augmenting the
    "control-plane-protocol" data node under "/routing".
 By using a "when" statement, the augmented data nodes 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); see Appendix C.

5.4. Parameters of IPv6 Router Advertisements

 The YANG module "ietf-ipv6-router-advertisements" (Section 9.1),
 which is a submodule of the "ietf-ipv6-unicast-routing" module,
 augments the schema tree 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

Lhotka, et al. Standards Track [Page 12] RFC 8349 YANG Routing Management March 2018

 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 [RFC8344] (leaf
     "ip:forwarding").
 2.  The Neighbor Discovery 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 [RFC8343]:
 /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.

Lhotka, et al. Standards Track [Page 13] RFC 8349 YANG Routing Management March 2018

6.2. Module "ietf-ip"

 The following boolean switches are defined in the "ietf-ip" YANG
 module [RFC8344]:
 /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.

Lhotka, et al. Standards Track [Page 14] RFC 8349 YANG Routing Management March 2018

7. Routing Management YANG Module

 <CODE BEGINS> file "ietf-routing@2018-03-13.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";
     description
       "An 'ietf-interfaces' module version that is compatible with
        the Network Management Datastore Architecture (NMDA)
        is required.";
   }
   organization
     "IETF NETMOD (Network Modeling) Working Group";
   contact
     "WG Web:   <https://datatracker.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.  The model fully conforms to the Network
      Management Datastore Architecture (NMDA).
      Copyright (c) 2018 IETF Trust and the persons
      identified as authors of the code.  All rights reserved.
      Redistribution and use in source and binary forms, with or
      without modification, is permitted pursuant to, and subject
      to the license terms contained in, the Simplified BSD License
      set forth in Section 4.c of the IETF Trust's Legal Provisions
      Relating to IETF Documents
      (https://trustee.ietf.org/license-info).

Lhotka, et al. Standards Track [Page 15] RFC 8349 YANG Routing Management March 2018

      This version of this YANG module is part of RFC 8349; see
      the RFC itself for full legal notices.";
   revision 2018-03-13 {
     description
       "Network Management Datastore Architecture (NMDA) revision.";
     reference
       "RFC 8349: A YANG Data Model for Routing Management
                  (NMDA 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 also make it the default RIB.  This RIB then appears as an
        entry in the list '/routing/ribs/rib'.";
   }
   feature router-id {
     description
       "This feature indicates that the server supports 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.";
   }

Lhotka, et al. Standards Track [Page 16] RFC 8349 YANG Routing Management March 2018

   identity ipv4 {
     base address-family;
     description
       "This identity represents an IPv4 address family.";
   }
   identity ipv6 {
     base address-family;
     description
       "This identity represents an 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 */

Lhotka, et al. Standards Track [Page 17] RFC 8349 YANG Routing Management March 2018

   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 a 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.";

Lhotka, et al. Standards Track [Page 18] RFC 8349 YANG Routing Management March 2018

         }
         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 in a next-hop list.
                Modules for address families MUST augment this list

Lhotka, et al. Standards Track [Page 19] RFC 8349 YANG Routing Management March 2018

                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 state parameters of next hops.";
     choice next-hop-options {
       mandatory true;
       description
         "Options for next hops.
          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;

Lhotka, et al. Standards Track [Page 20] RFC 8349 YANG Routing Management March 2018

       }
       case next-hop-list {
         container next-hop-list {
           description
             "Container for multiple next hops.";
           list next-hop {
             description
               "An entry in 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
         "The 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
         "Timestamp 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.";

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     }
   }
   /* Data nodes */
   container routing {
     description
       "Configuration parameters for the routing subsystem.";
     uses router-id {
       if-feature "router-id";
       description
         "Support for the global router ID.  Routing protocols
          that use a 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
         "Support for control-plane protocol instances.";
       list control-plane-protocol {
         key "type name";
         description
           "Each entry contains 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.";
         }

Lhotka, et al. Standards Track [Page 22] RFC 8349 YANG Routing Management March 2018

         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
             "Support for the 'static' pseudo-protocol.
              Address-family-specific modules augment this node with
              their lists of routes.";
         }
       }
     }
     container ribs {
       description
         "Support for RIBs.";
       list rib {
         key "name";
         description
           "Each entry contains a configuration for a RIB identified
            by the 'name' key.
            Entries having the same key as a system-controlled entry
            in 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 the operational state.
              For user-controlled entries, an arbitrary name can be
              used.";
         }
         uses address-family {
           description
             "The address family of the system-controlled RIB.";

Lhotka, et al. Standards Track [Page 23] RFC 8349 YANG Routing Management March 2018

         }
         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 contents of the RIB.";
           list route {
             description
               "A RIB route entry.  This data node MUST be augmented
                with information specific to 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 indicates a route that is
                  more preferred.";
             }
             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 {

Lhotka, et al. Standards Track [Page 24] RFC 8349 YANG Routing Management March 2018

             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.";
         }
       }
     }
   }
   /*
    * The subsequent data nodes are obviated and obsoleted
    * by the Network Management Datastore Architecture
    * as described in RFC 8342.
    */
   container routing-state {
     config false;
     status obsolete;
     description
       "State data of the routing subsystem.";
     uses router-id {
       status obsolete;
       description
         "Global router ID.
          It may be either configured or assigned algorithmically by
          the implementation.";
     }
     container interfaces {
       status obsolete;
       description

Lhotka, et al. Standards Track [Page 25] RFC 8349 YANG Routing Management March 2018

         "Network-layer interfaces used for routing.";
       leaf-list interface {
         type if:interface-state-ref;
         status obsolete;
         description
           "Each entry is a reference to the name of a configured
            network-layer interface.";
       }
     }
     container control-plane-protocols {
       status obsolete;
       description
         "Container for the list of routing protocol instances.";
       list control-plane-protocol {
         key "type name";
         status obsolete;
         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 obsolete;
           description
             "Type of the control-plane protocol.";
         }
         leaf name {
           type string;
           status obsolete;
           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 obsolete;
       description
         "Container for RIBs.";
       list rib {

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         key "name";
         min-elements 1;
         status obsolete;
         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 obsolete;
           description
             "The name of the RIB.";
         }
         uses address-family {
           status obsolete;
           description
             "The address family of the RIB.";
         }
         leaf default-rib {
           if-feature "multiple-ribs";
           type boolean;
           default "true";
           status obsolete;
           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 obsolete;
           description
             "Current contents of the RIB.";
           list route {
             status obsolete;
             description
               "A RIB route entry.  This data node MUST be augmented
                with information specific to routes of each address
                family.";
             leaf route-preference {
               type route-preference;
               status obsolete;
               description
                 "This route attribute, also known as 'administrative

Lhotka, et al. Standards Track [Page 27] RFC 8349 YANG Routing Management March 2018

                  distance', allows for selecting the preferred route
                  among routes with the same destination prefix.  A
                  smaller value indicates a route that is
                  more preferred.";
             }
             container next-hop {
               status obsolete;
               description
                 "Route's next-hop attribute.";
               uses next-hop-state-content {
                 status obsolete;
                 description
                   "Route's next-hop attribute operational state.";
               }
             }
             uses route-metadata {
               status obsolete;
               description
                 "Route metadata.";
             }
           }
         }
         action active-route {
           status obsolete;
           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 obsolete;
               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 obsolete;
                 description
                   "Route's next-hop attribute.";
                 uses next-hop-state-content {
                   status obsolete;

Lhotka, et al. Standards Track [Page 28] RFC 8349 YANG Routing Management March 2018

                   description
                     "Active route state data.";
                 }
               }
               uses route-metadata {
                 status obsolete;
                 description
                   "Active route metadata.";
               }
             }
           }
         }
       }
     }
   }
 }
 <CODE ENDS>

8. IPv4 Unicast Routing Management YANG Module

 <CODE BEGINS> file "ietf-ipv4-unicast-routing@2018-03-13.yang"
 module ietf-ipv4-unicast-routing {
   yang-version "1.1";
   namespace
     "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing";
   prefix "v4ur";
   import ietf-routing {
     prefix "rt";
     description
       "An 'ietf-routing' module version that is compatible with
        the Network Management Datastore Architecture (NMDA)
        is required.";
   }
   import ietf-inet-types {
     prefix "inet";
   }
   organization
     "IETF NETMOD (Network Modeling) Working Group";
   contact
     "WG Web:   <https://datatracker.ietf.org/wg/netmod/>
      WG List:  <mailto:rtgwg@ietf.org>
      Editor:   Ladislav Lhotka
                <mailto:lhotka@nic.cz>

Lhotka, et al. Standards Track [Page 29] RFC 8349 YANG Routing Management March 2018

                Acee Lindem
                <mailto:acee@cisco.com>
                Yingzhen Qu
                <mailto:yingzhen.qu@huawei.com>";
   description
     "This YANG module augments the 'ietf-routing' module with basic
      parameters for IPv4 unicast routing.  The model fully conforms
      to the Network Management Datastore Architecture (NMDA).
      Copyright (c) 2018 IETF Trust and the persons
      identified as authors of the code.  All rights reserved.
      Redistribution and use in source and binary forms, with or
      without modification, is permitted pursuant to, and subject
      to the license terms contained in, the Simplified BSD License
      set forth in Section 4.c of the IETF Trust's Legal Provisions
      Relating to IETF Documents
      (https://trustee.ietf.org/license-info).
      This version of this YANG module is part of RFC 8349; see
      the RFC itself for full legal notices.";
   revision 2018-03-13 {
     description
       "Network Management Datastore Architecture (NMDA) revision.";
     reference
       "RFC 8349: A YANG Data Model for Routing Management
                  (NMDA Version)";
   }
   revision 2016-11-04 {
        description
          "Initial revision.";
        reference
          "RFC 8022: A YANG Data Model for Routing Management";
   }
   /* Identities */
   identity ipv4-unicast {
     base rt:ipv4;
     description
       "This identity represents the IPv4 unicast address family.";
   }
   augment "/rt:routing/rt:ribs/rt:rib/rt:routes/rt:route" {
     when "derived-from-or-self(../../rt:address-family, "

Lhotka, et al. Standards Track [Page 30] RFC 8349 YANG Routing Management March 2018

        + "'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     description
       "This leaf augments an IPv4 unicast route.";
     leaf destination-prefix {
       type inet:ipv4-prefix;
       description
         "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, "
        + "'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     description
       "Augments the 'simple-next-hop' case in IPv4 unicast routes.";
     leaf next-hop-address {
       type inet:ipv4-address;
       description
         "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, "
        + "'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 {
       type inet:ipv4-address;
       description
         "IPv4 address of the next hop.";
     }
   }
   augment

Lhotka, et al. Standards Track [Page 31] RFC 8349 YANG Routing Management March 2018

     "/rt:routing/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.";
     }
     description
       "This augment adds the input parameter of the 'active-route'
        action.";
     leaf destination-address {
       type inet:ipv4-address;
       description
         "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, "
        + "'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     description
       "This augment adds the destination prefix to the reply of the
        'active-route' action.";
     leaf destination-prefix {
       type inet:ipv4-prefix;
       description
         "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, "
        + "'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     description
       "Augments the 'simple-next-hop' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {
       type inet:ipv4-address;
       description
         "IPv4 address of the next hop.";

Lhotka, et al. Standards Track [Page 32] RFC 8349 YANG Routing Management March 2018

     }
   }
   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')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     description
       "Augments the 'next-hop-list' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {
       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" {
     description
       "This augment defines the 'static' pseudo-protocol
        with data specific to IPv4 unicast.";
     container ipv4 {
       description
         "Support for 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:ipv4-prefix;
           mandatory true;
           description
             "IPv4 destination prefix.";
         }
         leaf description {
           type string;
           description
             "Textual description of the route.";
         }
         container next-hop {
           description
             "Support for next-hop.";

Lhotka, et al. Standards Track [Page 33] RFC 8349 YANG Routing Management March 2018

           uses rt:next-hop-content {
             augment "next-hop-options/simple-next-hop" {
               description
                 "Augments the '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
                 "Augments the 'next-hop-list' case in IPv4 static
                  routes.";
               leaf next-hop-address {
                 type inet:ipv4-address;
                 description
                   "IPv4 address of the next hop.";
               }
             }
           }
         }
       }
     }
   }
   /*
    * The subsequent data nodes are obviated and obsoleted
    * by the Network Management Datastore Architecture
    * as described in RFC 8342.
    */
   augment "/rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route" {
     when "derived-from-or-self(../../rt:address-family, "
          + "'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     status obsolete;
     description
       "This leaf augments an IPv4 unicast route.";
     leaf destination-prefix {
       type inet:ipv4-prefix;
       status obsolete;
       description
         "IPv4 destination prefix.";
     }

Lhotka, et al. Standards Track [Page 34] RFC 8349 YANG Routing Management March 2018

   }
   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, 'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     status obsolete;
     description
       "Augments the '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 augment is valid only for IPv4 unicast.";
     }
     status obsolete;
     description
       "This leaf augments the 'next-hop-list' case of IPv4 unicast
        routes.";
     leaf address {
       type inet:ipv4-address;
       status obsolete;
       description
         "IPv4 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,
             'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast RIBs.";
     }
     status obsolete;
     description
       "This augment adds the input parameter of the 'active-route'
        action.";

Lhotka, et al. Standards Track [Page 35] RFC 8349 YANG Routing Management March 2018

     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 valid only for IPv4 unicast.";
     }
     status obsolete;
     description
       "This augment adds the destination prefix to the reply of the
        'active-route' action.";
     leaf destination-prefix {
       type inet:ipv4-prefix;
       status obsolete;
       description
         "IPv4 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,
             'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     status obsolete;
     description
       "Augments the 'simple-next-hop' case in the reply to the
        'active-route' action.";
     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: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,

Lhotka, et al. Standards Track [Page 36] RFC 8349 YANG Routing Management March 2018

             'v4ur:ipv4-unicast')" {
       description
         "This augment is valid only for IPv4 unicast.";
     }
     status obsolete;
     description
       "Augments the 'next-hop-list' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {
       type inet:ipv4-address;
       status obsolete;
       description
         "IPv4 address of the next hop.";
     }
   }
 }
 <CODE ENDS>

9. IPv6 Unicast Routing Management YANG Module

 <CODE BEGINS> file "ietf-ipv6-unicast-routing@2018-03-13.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";
     description
       "An 'ietf-routing' module version that is compatible with
        the Network Management Datastore Architecture (NMDA)
        is required.";
   }
   import ietf-inet-types {
     prefix "inet";
     description
       "An 'ietf-interfaces' module version that is compatible with
        the Network Management Datastore Architecture (NMDA)
        is required.";
   }
   include ietf-ipv6-router-advertisements {
     revision-date 2018-03-13;
   }

Lhotka, et al. Standards Track [Page 37] RFC 8349 YANG Routing Management March 2018

   organization
     "IETF NETMOD (Network Modeling) Working Group";
   contact
     "WG Web:   <https://datatracker.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
      parameters for IPv6 unicast routing.  The model fully conforms
      to the Network Management Datastore Architecture (NMDA).
      Copyright (c) 2018 IETF Trust and the persons
      identified as authors of the code.  All rights reserved.
      Redistribution and use in source and binary forms, with or
      without modification, is permitted pursuant to, and subject
      to the license terms contained in, the Simplified BSD License
      set forth in Section 4.c of the IETF Trust's Legal Provisions
      Relating to IETF Documents
      (https://trustee.ietf.org/license-info).
      This version of this YANG module is part of RFC 8349; see
      the RFC itself for full legal notices.";
   revision 2018-03-13 {
     description
       "Network Management Datastore Architecture (NMDA) revision.";
     reference
       "RFC 8349: A YANG Data Model for Routing Management
                  (NMDA Version)";
   }
   /* Identities */
   revision 2016-11-04 {
        description
          "Initial revision.";
        reference
          "RFC 8022: A YANG Data Model for Routing Management";
   }

Lhotka, et al. Standards Track [Page 38] RFC 8349 YANG Routing Management March 2018

   identity ipv6-unicast {
     base rt:ipv6;
     description
       "This identity represents the IPv6 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')" {
       description
         "This augment is valid only for IPv6 unicast.";
     }
     description
       "This leaf augments an IPv6 unicast route.";
     leaf destination-prefix {
       type inet:ipv6-prefix;
       description
         "IPv6 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')" {
       description
         "This augment is valid only for IPv6 unicast.";
     }
     description
       "Augments the 'simple-next-hop' case in IPv6 unicast routes.";
     leaf next-hop-address {
       type inet:ipv6-address;
       description
         "IPv6 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')" {
       description
         "This augment is valid only for IPv6 unicast.";
     }
     description
       "This leaf augments the 'next-hop-list' case of IPv6 unicast
        routes.";

Lhotka, et al. Standards Track [Page 39] RFC 8349 YANG Routing Management March 2018

     leaf address {
       type inet:ipv6-address;
       description
         "IPv6 address of the 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')" {
       description
         "This augment is valid only for IPv6 unicast RIBs.";
     }
     description
       "This augment adds the input parameter of the 'active-route'
        action.";
     leaf destination-address {
       type inet:ipv6-address;
       description
         "IPv6 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')" {
       description
         "This augment is valid only for IPv6 unicast.";
     }
     description
       "This augment adds the destination prefix to the reply of the
        'active-route' action.";
     leaf destination-prefix {
       type inet:ipv6-prefix;
       description
         "IPv6 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')" {
       description
         "This augment is valid only for IPv6 unicast.";

Lhotka, et al. Standards Track [Page 40] RFC 8349 YANG Routing Management March 2018

     }
     description
       "Augments the 'simple-next-hop' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {
       type inet:ipv6-address;
       description
         "IPv6 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')" {
       description
         "This augment is valid only for IPv6 unicast.";
     }
     description
       "Augments the 'next-hop-list' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {
       type inet:ipv6-address;
       description
         "IPv6 address of the next hop.";
     }
   }
   /* Data node augmentations */
   augment "/rt:routing/rt:control-plane-protocols/"
         + "rt:control-plane-protocol/rt:static-routes" {
     description
       "This augment defines the 'static' pseudo-protocol
        with data specific to IPv6 unicast.";
     container ipv6 {
       description
         "Support for 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;
           mandatory true;
           description

Lhotka, et al. Standards Track [Page 41] RFC 8349 YANG Routing Management March 2018

             "IPv6 destination prefix.";
         }
         leaf description {
           type string;
           description
             "Textual description of the route.";
         }
         container next-hop {
           description
             "Next hop for the route.";
           uses rt:next-hop-content {
             augment "next-hop-options/simple-next-hop" {
               description
                 "Augments the 'simple-next-hop' case in IPv6 static
                  routes.";
               leaf next-hop-address {
                 type inet:ipv6-address;
                 description
                   "IPv6 address of the next hop.";
               }
             }
             augment "next-hop-options/next-hop-list/next-hop-list/"
                   + "next-hop" {
               description
                 "Augments the 'next-hop-list' case in IPv6 static
                  routes.";
               leaf next-hop-address {
                 type inet:ipv6-address;
                 description
                   "IPv6 address of the next hop.";
               }
             }
           }
         }
       }
     }
   }
   /*
    * The subsequent data nodes are obviated and obsoleted
    * by the Network Management Datastore Architecture
    * as described in RFC 8342.
    */
   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.";

Lhotka, et al. Standards Track [Page 42] RFC 8349 YANG Routing Management March 2018

     }
     status obsolete;
     description
       "This leaf augments an IPv6 unicast route.";
     leaf destination-prefix {
       type inet:ipv6-prefix;
       status 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 obsolete;
     description
       "Augments the 'simple-next-hop' case in IPv6 unicast routes.";
     leaf next-hop-address {
       type inet:ipv6-address;
       status 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 obsolete;
     description
       "This leaf augments the 'next-hop-list' case of IPv6 unicast
        routes.";
     leaf address {
       type inet:ipv6-address;
       status obsolete;
       description
         "IPv6 address of the next hop.";
     }
   }
   augment "/rt:routing-state/rt:ribs/rt:rib/"

Lhotka, et al. Standards Track [Page 43] RFC 8349 YANG Routing Management March 2018

           + "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 obsolete;
     description
       "This augment adds the input parameter of the 'active-route'
        action.";
     leaf destination-address {
       type inet:ipv6-address;
       status 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 obsolete;
     description
       "This augment adds the destination prefix to the reply of the
        'active-route' action.";
     leaf destination-prefix {
       type inet:ipv6-prefix;
       status 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 obsolete;
     description
       "Augments the 'simple-next-hop' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {

Lhotka, et al. Standards Track [Page 44] RFC 8349 YANG Routing Management March 2018

       type inet:ipv6-address;
       status 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 obsolete;
     description
       "Augments the 'next-hop-list' case in the reply to the
        'active-route' action.";
     leaf next-hop-address {
       type inet:ipv6-address;
       status obsolete;
       description
         "IPv6 address of the next hop.";
     }
   }
 }
 <CODE ENDS>

9.1. IPv6 Router Advertisements Submodule

 <CODE BEGINS> file "ietf-ipv6-router-advertisements@2018-03-13.yang"
 submodule ietf-ipv6-router-advertisements {
   yang-version "1.1";
   belongs-to ietf-ipv6-unicast-routing {
     prefix "v6ur";
   }
   import ietf-inet-types {
     prefix "inet";
   }
   import ietf-interfaces {
     prefix "if";
     description
       "An 'ietf-interfaces' module version that is compatible with

Lhotka, et al. Standards Track [Page 45] RFC 8349 YANG Routing Management March 2018

        the Network Management Datastore Architecture (NMDA)
        is required.";
   }
   import ietf-ip {
     prefix "ip";
     description
       "An 'ietf-ip' module version that is compatible with
        the Network Management Datastore Architecture (NMDA)
        is required.";
   }
   organization
     "IETF NETMOD (Network Modeling) Working Group";
   contact
     "WG Web:   <https://datatracker.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-ip' module with
      parameters for IPv6 Router Advertisements.  The model fully
      conforms to the Network Management Datastore
      Architecture (NMDA).
      Copyright (c) 2018 IETF Trust and the persons
      identified as authors of the code.  All rights reserved.
      Redistribution and use in source and binary forms, with or
      without modification, is permitted pursuant to, and subject
      to the license terms contained in, the Simplified BSD License
      set forth in Section 4.c of the IETF Trust's Legal Provisions
      Relating to IETF Documents
      (https://trustee.ietf.org/license-info).
      This version of this YANG module is part of RFC 8349; see
      the RFC itself for full legal notices.";
   reference
     "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)";
   revision 2018-03-13 {

Lhotka, et al. Standards Track [Page 46] RFC 8349 YANG Routing Management March 2018

     description
       "Network Management Datastore Architecture (NMDA) revision.";
     reference
       "RFC 8349: A YANG Data Model for Routing Management
                  (NMDA Version)";
   }
   revision 2016-11-04 {
        description
          "Initial revision.";
        reference
          "RFC 8022: A YANG Data Model for Routing Management";
   }
   augment "/if:interfaces/if:interface/ip:ipv6" {
     description
       "Augments interface configuration with parameters of IPv6
        Router Advertisements.";
     container ipv6-router-advertisements {
       description
         "Support for IPv6 Router Advertisements.";
       leaf send-advertisements {
         type boolean;
         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..65535";
         }
         units "seconds";
         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";

Lhotka, et al. Standards Track [Page 47] RFC 8349 YANG Routing Management March 2018

         }
         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:
  1. if max-rtr-adv-interval >= 9 seconds, the default

value is 0.33 * max-rtr-adv-interval;

  1. 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

Lhotka, et al. Standards Track [Page 48] RFC 8349 YANG Routing Management March 2018

            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 IANA-specified value for the default IPv4
            Time to Live (TTL) parameter that was in effect at the
            time of implementation.";
         reference
           "RFC 3232: Assigned Numbers: RFC 1700 is Replaced by
                      an On-line Database
            RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
                      - AdvCurHopLimit

Lhotka, et al. Standards Track [Page 49] RFC 8349 YANG Routing Management March 2018

            IANA: IP Parameters
                  (https://www.iana.org/assignments/ip-parameters)";
       }
       leaf default-lifetime {
         type uint16 {
           range "0..65535";
         }
         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
            indicates that the router 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 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
           "Support for 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
             "Support for an advertised prefix entry.";
           leaf prefix-spec {
             type inet:ipv6-prefix;
             description
               "IPv6 address prefix.";
           }

Lhotka, et al. Standards Track [Page 50] RFC 8349 YANG Routing Management March 2018

           choice control-adv-prefixes {
             default "advertise";
             description
               "Either (1) the prefix is explicitly removed from the
                set of advertised prefixes or (2) the parameters with
                which the prefix 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.";
                 }

Lhotka, et al. Standards Track [Page 51] RFC 8349 YANG Routing Management March 2018

                 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";
               }
             }
           }
         }
       }
     }
   }
   /*
    * The subsequent data nodes are obviated and obsoleted
    * by the Network Management Datastore Architecture
    * as described in RFC 8342.
    */
   augment "/if:interfaces-state/if:interface/ip:ipv6" {
     status obsolete;
     description
       "Augments interface state data with parameters of IPv6
        Router Advertisements.";
     container ipv6-router-advertisements {
       status obsolete;
       description
         "Parameters of IPv6 Router Advertisements.";
       leaf send-advertisements {
         type boolean;
         status obsolete;
         description
           "A flag indicating whether or not the router sends
            periodic Router Advertisements and responds to
            Router Solicitations.";

Lhotka, et al. Standards Track [Page 52] RFC 8349 YANG Routing Management March 2018

       }
       leaf max-rtr-adv-interval {
         type uint16 {
           range "4..1800";
         }
         units "seconds";
         status obsolete;
         description
           "The maximum time allowed between sending unsolicited
            multicast Router Advertisements from the interface.";
       }
       leaf min-rtr-adv-interval {
         type uint16 {
           range "3..1350";
         }
         units "seconds";
         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 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 zero indicates that no MTU options
            are sent.";
       }
       leaf reachable-time {
         type uint32 {
           range "0..3600000";
         }
         units "milliseconds";

Lhotka, et al. Standards Track [Page 53] RFC 8349 YANG Routing Management March 2018

         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 obsolete;
         description
           "The value that is placed in the Retrans Timer field in the
            Router Advertisement messages sent by the router.  A value
            of zero means unspecified (by this router).";
       }
       leaf cur-hop-limit {
         type uint8;
         status obsolete;
         description
           "The value that is 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).";
       }
       leaf default-lifetime {
         type uint16 {
           range "0..9000";
         }
         units "seconds";
         status obsolete;
         description
           "The value that is placed in the 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 messages sent from the
            interface.
            By default, these are all prefixes that the router
            advertises via routing protocols as being on-link for the
            interface from which the advertisement is sent.";
         list prefix {
           key "prefix-spec";
           status obsolete;

Lhotka, et al. Standards Track [Page 54] RFC 8349 YANG Routing Management March 2018

           description
             "Advertised prefix entry and its parameters.";
           leaf prefix-spec {
             type inet:ipv6-prefix;
             status obsolete;
             description
               "IPv6 address prefix.";
           }
           leaf valid-lifetime {
             type uint32;
             units "seconds";
             status obsolete;
             description
               "The value that is 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.";
           }
           leaf on-link-flag {
             type boolean;
             status obsolete;
             description
               "The value that is placed in the on-link flag ('L-bit')
                field in the Prefix Information option.";
           }
           leaf preferred-lifetime {
             type uint32;
             units "seconds";
             status obsolete;
             description
               "The value that is placed in the Preferred Lifetime in
                the Prefix Information option, in seconds.  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.";
           }
           leaf autonomous-flag {
             type boolean;
             status obsolete;
             description
               "The value that is placed in the Autonomous Flag field
                in the Prefix Information option.";

Lhotka, et al. Standards Track [Page 55] RFC 8349 YANG Routing Management March 2018

           }
         }
       }
     }
   }
 }
 <CODE ENDS>

10. IANA Considerations

 [RFC8022] registered the following namespace URIs in the "IETF XML
 Registry" [RFC3688].  IANA has updated the references to refer to
 this document.
 URI: urn:ietf:params:xml:ns:yang:ietf-routing
 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
 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
 Registrant Contact: The IESG.
 XML: N/A; the requested URI is an XML namespace.
 [RFC8022] registered the following YANG modules in the "YANG Module
 Names" registry [RFC6020].  IANA has updated (1) the modules per this
 document and (2) the references to refer to this document.
 Name:      ietf-routing
 Namespace: urn:ietf:params:xml:ns:yang:ietf-routing
 Prefix:    rt
 Reference: RFC 8349
 Name:      ietf-ipv4-unicast-routing
 Namespace: urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing
 Prefix:    v4ur
 Reference: RFC 8349
 Name:      ietf-ipv6-unicast-routing
 Namespace: urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing
 Prefix:    v6ur
 Reference: RFC 8349

Lhotka, et al. Standards Track [Page 56] RFC 8349 YANG Routing Management March 2018

 This document registers the following YANG submodule in the "YANG
 Module Names" registry [RFC6020]:
 Name:      ietf-ipv6-router-advertisements
 Module:    ietf-ipv6-unicast-routing
 Reference: RFC 8349

11. Security Considerations

 The YANG modules specified in this document define a schema for data
 that is designed to be accessed via network management protocols such
 as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
 is the secure transport layer, and the mandatory-to-implement secure
 transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
 is HTTPS, and the mandatory-to-implement secure transport is TLS
 [RFC5246].
 The NETCONF access control model [RFC8341] provides the means to
 restrict access for particular NETCONF or RESTCONF users to a
 preconfigured subset of all available NETCONF or RESTCONF protocol
 operations and content.
 There are a number of data nodes defined in these YANG modules that
 are writable/creatable/deletable (i.e., config true, which is the
 default).  These data nodes may be considered sensitive or vulnerable
 in some network environments.  Write operations (e.g., edit-config)
 to these data nodes without proper protection can have a negative
 effect on network operations.  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 these YANG modules 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.

Lhotka, et al. Standards Track [Page 57] RFC 8349 YANG Routing Management March 2018

 /routing/ribs/rib:  This list specifies the RIBs and their contents
    for the device.  Access to this information may disclose the
    network topology and/or other information.
 Some of the RPC operations in this YANG module may be considered
 sensitive or vulnerable in some network environments.  It is thus
 important to control access to these operations.  These are the
 operations and their sensitivity/vulnerability:
 /routing/ribs/rib/active-route:  The output from this RPC operation
    returns the route that is being used for a specified destination.
    Access to this information may disclose the network topology or
    relationship (e.g., client/provider).  Additionally, the routes
    used by a network device may be used to mount a subsequent attack
    on traffic traversing the network device.

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>.
 [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
            (TLS) Protocol Version 1.2", RFC 5246,
            DOI 10.17487/RFC5246, August 2008,
            <https://www.rfc-editor.org/info/rfc5246>.
 [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
            the Network Configuration Protocol (NETCONF)", RFC 6020,
            DOI 10.17487/RFC6020, October 2010,
            <https://www.rfc-editor.org/info/rfc6020>.
 [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
            and A. Bierman, Ed., "Network Configuration Protocol
            (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
            <https://www.rfc-editor.org/info/rfc6241>.

Lhotka, et al. Standards Track [Page 58] RFC 8349 YANG Routing Management March 2018

 [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>.
 [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
            RFC 6991, DOI 10.17487/RFC6991, July 2013,
            <https://www.rfc-editor.org/info/rfc6991>.
 [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>.
 [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
            Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
            <https://www.rfc-editor.org/info/rfc8040>.
 [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in
            RFC 2119 Key Words", BCP 14, RFC 8174,
            DOI 10.17487/RFC8174, May 2017,
            <https://www.rfc-editor.org/info/rfc8174>.
 [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
            Access Control Model", STD 91, RFC 8341,
            DOI 10.17487/RFC8341, March 2018,
            <https://www.rfc-editor.org/info/rfc8341>.
 [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
            and R. Wilton, "Network Management Datastore Architecture
            (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
            <https://www.rfc-editor.org/info/rfc8342>.
 [RFC8343]  Bjorklund, M., "A YANG Data Model for Interface
            Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
            <https://www.rfc-editor.org/info/rfc8343>.
 [RFC8344]  Bjorklund, M., "A YANG Data Model for IP Management",
            RFC 8344, DOI 10.17487/RFC8344, March 2018,
            <https://www.rfc-editor.org/info/rfc8344>.

Lhotka, et al. Standards Track [Page 59] RFC 8349 YANG Routing Management March 2018

 [W3C.REC-xml-20081126]
            Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
            F. Yergeau, "Extensible Markup Language (XML) 1.0
            (Fifth Edition)", World Wide Web Consortium Recommendation
            REC-xml-20081126, November 2008,
            <https://www.w3.org/TR/2008/REC-xml-20081126>.

12.2. Informative References

 [RFC7224]  Bjorklund, M., "IANA Interface Type YANG Module",
            RFC 7224, DOI 10.17487/RFC7224, May 2014,
            <https://www.rfc-editor.org/info/rfc7224>.
 [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>.
 [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
            BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
            <https://www.rfc-editor.org/info/rfc8340>.
 [YANG-Guidelines]
            Bierman, A., "Guidelines for Authors and Reviewers of YANG
            Data Model Documents", Work in Progress,
            draft-ietf-netmod-rfc6087bis-20, March 2018.

Lhotka, et al. Standards Track [Page 60] RFC 8349 YANG Routing Management March 2018

Appendix A. The Complete Schema Tree

 This appendix presents the complete tree of the core routing data
 model.  See [RFC8340] 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
   +--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

Lhotka, et al. Standards Track [Page 61] RFC 8349 YANG Routing Management March 2018

   |  |              +--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

Lhotka, et al. Standards Track [Page 62] RFC 8349 YANG Routing Management March 2018

   |        |     +--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
   o--ro routing-state
      o--ro router-id?                 yang:dotted-quad
      o--ro interfaces
      |  o--ro interface*   if:interface-state-ref

Lhotka, et al. Standards Track [Page 63] RFC 8349 YANG Routing Management March 2018

      o--ro control-plane-protocols
      |  o--ro control-plane-protocol* [type name]
      |     o--ro type    identityref
      |     o--ro name    string
      o--ro ribs
         o--ro rib* [name]
            o--ro name              string
            o--ro address-family    identityref
            o--ro default-rib?      boolean {multiple-ribs}?
            o--ro routes
            |  o--ro route*
            |     o--ro route-preference?          route-preference
            |     o--ro next-hop
            |     |  o--ro (next-hop-options)
            |     |     o--:(simple-next-hop)
            |     |     |  o--ro outgoing-interface?
            |     |     |  |       if:interface-ref
            |     |     |  o--ro v4ur:next-hop-address?
            |     |     |  |       inet:ipv4-address
            |     |     |  o--ro v6ur:next-hop-address?
            |     |     |          inet:ipv6-address
            |     |     o--:(special-next-hop)
            |     |     |  o--ro special-next-hop?        enumeration
            |     |     o--:(next-hop-list)
            |     |        o--ro next-hop-list
            |     |           o--ro next-hop*
            |     |              o--ro outgoing-interface?
            |     |              |       if:interface-ref
            |     |              o--ro v4ur:address?
            |     |              |       inet:ipv4-address
            |     |              o--ro v6ur:address?
            |     |                      inet:ipv6-address
            |     o--ro source-protocol            identityref
            |     o--ro active?                    empty
            |     o--ro last-updated?              yang:date-and-time
            |     o--ro v4ur:destination-prefix?   inet:ipv4-prefix
            |     o--ro v6ur:destination-prefix?   inet:ipv6-prefix
            o---x active-route
               o---w input
               |  o---w v4ur:destination-address?   inet:ipv4-address
               |  o---w v6ur:destination-address?   inet:ipv6-address
               o--ro output

Lhotka, et al. Standards Track [Page 64] RFC 8349 YANG Routing Management March 2018

                  o--ro route
                     o--ro next-hop
                     |  o--ro (next-hop-options)
                     |     o--:(simple-next-hop)
                     |     |  o--ro outgoing-interface?
                     |     |  |       if:interface-ref
                     |     |  o--ro v4ur:next-hop-address?
                     |     |  |       inet:ipv4-address
                     |     |  o--ro v6ur:next-hop-address?
                     |     |          inet:ipv6-address
                     |     o--:(special-next-hop)
                     |     |  o--ro special-next-hop?
                     |     |          enumeration
                     |     o--:(next-hop-list)
                     |        o--ro next-hop-list
                     |           o--ro next-hop*
                     |              o--ro outgoing-interface?
                     |              |       if:interface-ref
                     |              o--ro v4ur:next-hop-address?
                     |              |       inet:ipv4-address
                     |              o--ro v6ur:next-hop-address?
                     |                      inet:ipv6-address
                     o--ro source-protocol            identityref
                     o--ro active?                    empty
                     o--ro last-updated?
                     |       yang:date-and-time
                     o--ro v4ur:destination-prefix?
                     |       inet:ipv4-prefix
                     o--ro v6ur:destination-prefix?
                             inet:ipv6-prefix
 module: 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

Lhotka, et al. Standards Track [Page 65] RFC 8349 YANG Routing Management March 2018

              +--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
   augment /if:interfaces-state/if:interface/ip:ipv6:
     o--ro ipv6-router-advertisements
        o--ro send-advertisements?    boolean
        o--ro max-rtr-adv-interval?   uint16
        o--ro min-rtr-adv-interval?   uint16
        o--ro managed-flag?           boolean
        o--ro other-config-flag?      boolean
        o--ro link-mtu?               uint32
        o--ro reachable-time?         uint32
        o--ro retrans-timer?          uint32
        o--ro cur-hop-limit?          uint8
        o--ro default-lifetime?       uint16
        o--ro prefix-list
           o--ro prefix* [prefix-spec]
              o--ro prefix-spec           inet:ipv6-prefix
              o--ro valid-lifetime?       uint32
              o--ro on-link-flag?         boolean
              o--ro preferred-lifetime?   uint32
              o--ro autonomous-flag?      boolean

Appendix 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 "multiple-ribs"
 feature.  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.

Lhotka, et al. Standards Track [Page 66] RFC 8349 YANG Routing Management March 2018

 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 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 [YANG-Guidelines].  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 {
     prefix "rt";
   }
   identity rip {
     base rt:routing-protocol;
     description
       "Identity for the Routing Information Protocol (RIP).";
   }
   typedef rip-metric {
     type uint8 {
       range "0..16";
     }
   }

Lhotka, et al. Standards Track [Page 67] RFC 8349 YANG Routing Management March 2018

   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 information,
          e.g., an 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 an
        '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 {

Lhotka, et al. Standards Track [Page 68] RFC 8349 YANG Routing Management March 2018

         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.";
       }
     }
   }
 }

Lhotka, et al. Standards Track [Page 69] RFC 8349 YANG Routing Management March 2018

Appendix D. Data Tree Example

 This section contains an example of an instance data tree from the
 operational state, in JSON encoding [RFC7951].  (This example
 includes "iana-if-type", which is defined in [RFC7224].)
 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",
          "revision": "2018-03-13",
          "feature": [
            "multiple-ribs",
            "router-id"
          ],
          "namespace": "urn:ietf:params:xml:ns:yang:ietf-routing",
          "conformance-type": "implement"
        },
        {
          "name": "ietf-ipv4-unicast-routing",
          "revision": "2018-03-13",
          "namespace":
            "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing",
          "conformance-type": "implement"
        },
        {
          "name": "ietf-ipv6-unicast-routing",
          "revision": "2018-03-13",
          "namespace":
            "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing",
          "conformance-type": "implement",
          "submodule": [
            {
              "name": "ietf-ipv6-router-advertisements",
              "revision": "2018-03-13"
            }
          ]
        },
        {
          "name": "ietf-interfaces",
          "revision": "2018-02-20",
          "namespace": "urn:ietf:params:xml:ns:yang:ietf-interfaces",
          "conformance-type": "implement"

Lhotka, et al. Standards Track [Page 70] RFC 8349 YANG Routing Management March 2018

        },
        {
          "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": "2014-05-08",
          "conformance-type": "implement"
        },
        {
          "name": "ietf-ip",
          "revision": "2018-02-22",
          "namespace": "urn:ietf:params:xml:ns:yang:ietf-ip",
          "conformance-type": "implement"
        }
      ]
    }
  }

Lhotka, et al. Standards Track [Page 71] RFC 8349 YANG Routing Management March 2018

 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.",
         "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

Lhotka, et al. Standards Track [Page 72] RFC 8349 YANG Routing Management March 2018

             }
           ]
         },
         "ietf-ip:ipv6": {
           "forwarding": true,
           "mtu": 1500,
           "address": [
             {
               "ip": "2001:0db8:0:1::1",
               "prefix-length": 64
             }
           ],
           "autoconf": {
             "create-global-addresses": false
           },
           "ietf-ipv6-unicast-routing:ipv6-router-advertisements": {
             "send-advertisements": false
           }
         }
       },
       {
         "name": "eth1",
         "type": "iana-if-type:ethernetCsmacd",
         "description": "Interface to the internal network.",
         "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
             }
           ],

Lhotka, et al. Standards Track [Page 73] RFC 8349 YANG Routing Management March 2018

           "autoconf": {
             "create-global-addresses": false
           },
           "ietf-ipv6-unicast-routing:ipv6-router-advertisements": {
             "send-advertisements": true,
             "prefix-list": {
               "prefix": [
                 {
                   "prefix-spec": "2001:db8:0:2::/64"
                 }
               ]
             }
           }
         }
       }
     ]
   },
   "ietf-routing:routing": {
     "router-id": "192.0.2.1",
     "control-plane-protocols": {
       "control-plane-protocol": [
         {
           "type": "ietf-routing:static",
           "name": "st0",
           "description":
             "Static routing is used for the internal network.",
           "static-routes": {
             "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:ipv6": {
               "route": [
                 {
                   "destination-prefix": "::/0",
                   "next-hop": {
                     "next-hop-address": "2001:db8:0:1::2"
                   }
                 }
               ]
             }

Lhotka, et al. Standards Track [Page 74] RFC 8349 YANG Routing Management March 2018

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

Lhotka, et al. Standards Track [Page 75] RFC 8349 YANG Routing Management March 2018

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

Lhotka, et al. Standards Track [Page 76] RFC 8349 YANG Routing Management March 2018

Appendix E. NETCONF Get Data Reply Example

 This section gives an example of an XML [W3C.REC-xml-20081126] reply
 to the NETCONF <get-data> request for <operational> for a device that
 implements the example data models above.
 <rpc-reply
  xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
  message-id="101">
  <data>
    <routing
      xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"
      xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin">
      <router-id or:origin="or:intended">192.0.2.1</router-id>
      <control-plane-protocols or:origin="or:intended">
        <control-plane-protocol>
          <type>ietf-routing:static</type>
          <name>static-routing-protocol</name>
          <static-routes>
            <ietf-ipv4-unicast-routing:ipv4>
              <route>
                <destination-prefix>0.0.0.0/0</destination-prefix>
                <next-hop>
                  <next-hop-address>192.0.2.2</next-hop-address>
                </next-hop>
              </route>
            </ietf-ipv4-unicast-routing:ipv4>
            <ietf-ipv6-unicast-routing:ipv6>
              <route>
                <destination-prefix>::/0</destination-prefix>
                <next-hop>
                  <next-hop-address>2001:db8:0:1::2</next-hop-address>
                </next-hop>
              </route>
            </ietf-ipv6-unicast-routing:ipv6>
          </static-routes>
        </control-plane-protocol>
      </control-plane-protocols>
      <ribs>
        <rib or:origin="or:intended">
          <name>ipv4-master</name>
          <address-family>
            ietf-ipv4-unicast-routing:ipv4-unicast
          </address-family>
          <default-rib>true</default-rib>
          <routes>

Lhotka, et al. Standards Track [Page 77] RFC 8349 YANG Routing Management March 2018

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

Lhotka, et al. Standards Track [Page 78] RFC 8349 YANG Routing Management March 2018

              </next-hop>
              <route-preference>0</route-preference>
              <source-protocol>ietf-routing:direct</source-protocol>
              <last-updated>2015-10-24T17:11:27+02:00</last-updated>
            </route>
            <route>
              <ietf-ipv6-unicast-routing:destination-prefix>
                2001:db8:0:2::/64
              </ietf-ipv6-unicast-routing:destination-prefix>
              <next-hop>
                <outgoing-interface>eth1</outgoing-interface>
              </next-hop>
              <route-preference>0</route-preference>
              <source-protocol>ietf-routing:direct</source-protocol>
              <last-updated>2015-10-24T17:11:27+02:00</last-updated>
            </route>
            <route>
              <ietf-ipv6-unicast-routing:destination-prefix>::/0
              </ietf-ipv6-unicast-routing:destination-prefix>
              <next-hop>
                <ietf-ipv6-unicast-routing:next-hop-address>
                  2001:db8:0:1::2
                </ietf-ipv6-unicast-routing:next-hop-address>
              </next-hop>
              <route-preference>5</route-preference>
              <source-protocol>ietf-routing:static</source-protocol>
              <last-updated>2015-10-24T18:02:45+02:00</last-updated>
            </route>
          </routes>
        </rib>
      </ribs>
    </routing>
  </data>
 </rpc-reply>

Lhotka, et al. Standards Track [Page 79] RFC 8349 YANG Routing Management March 2018

Acknowledgments

 The authors wish to thank Nitin Bahadur, Martin Bjorklund, Dean
 Bogdanovic, Joe Clarke, Francis Dupont, Jeff Haas, Joel Halpern,
 Wes Hardaker, Jia He, Sriganesh Kini, Suresh Krishnan,
 David Lamparter, Xiang Li, Stephane Litkowski, Andrew McGregor,
 Jan Medved, Thomas Morin, Tom Petch, Bruno Rijsman,
 Juergen Schoenwaelder, Phil Shafer, Dave Thaler, Vladimir Vassilev,
 Rob Wilton, 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
 Huawei
 2330 Central Expressway
 Santa Clara, CA  95050
 United States of America
 Email: yingzhen.qu@huawei.com

Lhotka, et al. Standards Track [Page 80]

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