NETMOD Working Group L. Lhotka
Internet-Draft CZ.NIC
Intended status: Standards Track A. Lindem
Expires: February 19, 2017 Cisco Systems
August 18, 2016

A YANG Data Model for Routing Management
draft-ietf-netmod-routing-cfg-23

Abstract

This document contains a specification of three YANG modules and one submodule. Together they form the core routing data model which 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 (RIB), and control plane protocols.

Status of This Memo

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

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

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

This Internet-Draft will expire on February 19, 2017.

Copyright Notice

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

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


Table of Contents

1. Introduction

This document contains a specification of the following YANG modules:

These modules together define the so-called core routing data model, which is intended as a basis for future data model development covering more sophisticated routing systems. While these three modules can be directly used for simple IP devices with static routing (see Appendix 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 other IETF working groups.

2. Terminology and Notation

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

The following terms are defined in [RFC6241]:

The following terms are defined in [I-D.ietf-netmod-rfc6020bis]:

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

2.2. Tree Diagrams

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

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.

Prefixes and corresponding YANG modules
Prefix YANG module Reference
if ietf-interfaces [RFC7223]
ip ietf-ip [RFC7277]
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]

3. Objectives

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

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. Module "ietf-ipv6-unicast-routing" has a submodule, "ietf-ipv6-router-advertisements", that augments the "ietf-interfaces" [RFC7223] and "ietf-ip" [RFC7277] modules with configuration variables for IPv6 router advertisements as required by [RFC4861]. Figures 1 and 2 show abridged views of the configuration and state data hierarchies. See Appendix A for the complete data trees.

+--rw routing
   +--rw router-id?
   +--rw control-plane-protocols
   |  +--rw control-plane-protocol* [type name]
   |     +--rw type
   |     +--rw name
   |     +--rw description?
   |     +--rw static-routes
   |        +--rw v6ur:ipv6
   |        |     ...
   |        +--rw v4ur:ipv4
   |              ...
   +--rw ribs
      +--rw rib* [name]
         +--rw name
         +--rw address-family?
         +--rw description?

Figure 1: Configuration data hierarchy.

+--ro routing-state
   +--ro router-id?
   +--ro interfaces
   |  +--ro interface*
   +--ro control-plane-protocols
   |  +--ro control-plane-protocol* [type name]
   |     +--ro type
   |     +--ro name
   +--ro ribs
      +--ro rib* [name]
         +--ro name
         +--ro address-family
         +--ro default-rib?
         +--ro routes
         |  +--ro route*
         |        ...

Figure 2: State data hierarchy.

As can be seen from Figures 1 and 2, the core routing data model introduces several generic components of a routing framework: routes, RIBs containing lists of routes, and control plane protocols. Section 5 describes these components in more detail.

4.1. System-Controlled and User-Controlled List Entries

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

In such a list, the server creates the required item as a so-called system-controlled entry in state data, i.e., inside the "routing-state" container.

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

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

Corresponding entries in both versions of the list (in state data and configuration) have the same value of the list key.

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

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

5. Basic Building Blocks

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

5.1. Route

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

  • "destination-prefix": address prefix specifying the set of destination addresses for which the route may be used. This attribute is mandatory.
  • "route-preference": an integer value (also known as administrative distance) that is used for selecting a preferred route among routes with the same destination prefix. A lower value means a more preferred route.
  • "next-hop": determines the outgoing interface and/or next-hop address(es), other operation to be performed with a packet.

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

5.2. Routing Information Base (RIB)

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

In the core routing data model, RIBs are state data represented as entries of the list "/routing-state/ribs/rib". The contents of RIBs are controlled and manipulated by control plane protocol operations which may result in route additions, removals and modifications. This also includes manipulations via the "static" and/or "direct" pseudo-protocols, see Section 5.3.1.

For every supported address family, exactly one RIB MUST be marked as the so-called default RIB. Its role is explained in Section 5.3.

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

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

The following action (see Section 7.15 of [I-D.ietf-netmod-rfc6020bis]) is defined for the "rib" list:

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

5.3. Control Plane Protocol

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

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

5.3.1. Routing Pseudo-Protocols

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

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

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

5.3.2. Defining New Control Plane Protocols

    /rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route
              
    /rt:routing-state/rt:ribs/rt:rib/rt:output/rt:route,
              

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

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

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

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

The above steps are implemented by the example YANG module for the RIP routing protocol in Appendix C.

5.4. Parameters of IPv6 Router Advertisements

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

  • send-advertisements,
  • max-rtr-adv-interval,
  • min-rtr-adv-interval,
  • managed-flag,
  • other-config-flag,
  • link-mtu,
  • reachable-time,
  • retrans-timer,
  • cur-hop-limit,
  • default-lifetime,
  • prefix-list: a list of prefixes to be advertised.

    The following parameters are associated with each prefix in the list:
    • valid-lifetime,
    • on-link-flag,
    • preferred-lifetime,
    • autonomous-flag.

NOTES:

  1. The "IsRouter" flag, which is also required by [RFC4861], is implemented in the "ietf-ip" module [RFC7277] (leaf "ip:forwarding").
  2. The original specification [RFC4861] allows the implementations to decide whether the "valid-lifetime" and "preferred-lifetime" parameters remain the same in consecutive advertisements, or decrement in real time. However, the latter behavior seems problematic because the values might be reset again to the (higher) configured values after a configuration is reloaded. Moreover, no implementation is known to use the decrementing behavior. The "ietf-ipv6-router-advertisements" submodule therefore stipulates the former behavior with constant values.

6. Interactions with Other YANG Modules

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

6.1. Module "ietf-interfaces"

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

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


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

6.2. Module "ietf-ip"

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

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


If this switch is set to "false" for a network layer interface, then all IPv4 routing and forwarding functions MUST be disabled on that 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 that interface.
/if:interfaces/if:interface/ip:ipv6/ip:forwarding


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

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

7. Routing Management YANG Module

RFC Editor: In this section, replace all occurrences of 'XXXX' with the actual RFC number and all occurrences of the revision date below with the date of RFC publication (and remove this note).

<CODE BEGINS> file "ietf-routing@2016-08-18.yang"

module ietf-routing {

  yang-version "1.1";

  namespace "urn:ietf:params:xml:ns:yang:ietf-routing";

  prefix "rt";

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

  import ietf-interfaces {
    prefix "if";
  }

  organization
    "IETF NETMOD (NETCONF Data Modeling Language) Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

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

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

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

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

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

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

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

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
     'OPTIONAL' in the module text are to be interpreted as described
     in RFC 2119 (http://tools.ietf.org/html/rfc2119).

     This version of this YANG module is part of RFC XXXX
     (http://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

  revision 2016-08-18 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for Routing Management";
  }

  /* Features */

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

       Servers that do not advertise this feature SHOULD provide
       exactly one system-controlled RIB per supported address family
       and make them also the default RIBs. These RIBs then appear as
       entries of the list /routing-state/ribs/rib.";
  }

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

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

  /* Identities */

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

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

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

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

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

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

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

  /* Type Definitions */

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

  /* Groupings */

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

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

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

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

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

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

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

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

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

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

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

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

  /* State data */

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

         It may be either configured or assigned algorithmically by
         the implementation.";
    }
    container interfaces {
      description
        "Network layer interfaces used for routing.";
      leaf-list interface {
        type if:interface-state-ref;
        description
          "Each entry is a reference to the name of a configured
           network layer interface.";
      }
    }
    container control-plane-protocols {
      description
        "Container for the list of routing protocol instances.";
      list control-plane-protocol {
        key "type name";
        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;
          }
          description
            "Type of the control plane protocol.";
        }
        leaf name {
          type string;
          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 {
      description
        "Container for RIBs.";
      list rib {
        key "name";
        min-elements "1";
        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;
          description
            "The name of the RIB.";
        }
        uses address-family;
        leaf default-rib {
          if-feature "multiple-ribs";
          type boolean;
          default "true";
          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 {
          description
            "Current content of the RIB.";
          list route {
            description
              "A RIB route entry. This data node MUST be augmented
               with information specific for routes of each address
               family.";
            leaf route-preference {
              type route-preference;
              description
                "This route attribute, also known as administrative
                 distance, allows for selecting the preferred route
                 among routes with the same destination prefix. A
                 smaller value means a more preferred route.";
            }
            container next-hop {
              description
                "Route's next-hop attribute.";
              uses next-hop-state-content;
            }
            uses route-metadata;
          }
        }
        action active-route {
          description
            "Return the active RIB route that is used for the
             destination address.

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

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

                 Address family specific modules MUST augment this
                 container with appropriate route contents.";
              container next-hop {
                description
                  "Route's next-hop attribute.";
                uses next-hop-state-content;
              }
              uses route-metadata;
            }
          }
        }
      }
    }
  }

  /* Configuration Data */

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

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

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

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

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

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

<CODE ENDS>

8. IPv4 Unicast Routing Management YANG Module

RFC Editor: In this section, replace all occurrences of 'XXXX' with the actual RFC number and all occurrences of the revision date below with the date of RFC publication (and remove this note).

<CODE BEGINS> file "ietf-ipv4-unicast-routing@2016-08-18.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";
  }

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

  organization
    "IETF NETMOD (NETCONF Data Modeling Language) Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

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

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

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

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

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

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

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

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
     'OPTIONAL' in the module text are to be interpreted as described
     in RFC 2119 (http://tools.ietf.org/html/rfc2119).

     This version of this YANG module is part of RFC XXXX
     (http://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

  revision 2016-08-18 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for Routing Management";
  }

  /* Identities */

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

  /* State data */

  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.";
    }
    description
      "This leaf augments an IPv4 unicast route.";
    leaf destination-prefix {
      type inet:ipv4-prefix;
      description
        "IPv4 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, "
       + "'v4ur:ipv4-unicast')" {
      description
        "This augment is valid only for IPv4 unicast.";
    }
    description
      "Augment '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-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.";
    }
    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
    "/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.";
    }
    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-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.";
    }
    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-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.";
    }
    description
      "Augment '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.";
    }
  }

  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, "
       + "'v4ur:ipv4-unicast')" {
      description
        "This augment is valid only for IPv4 unicast.";
    }
    description
      "Augment '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.";
    }
  }

  /* Configuration data */

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

<CODE ENDS>

9. IPv6 Unicast Routing Management YANG Module

RFC Editor: In this section, replace all occurrences of 'XXXX' with the actual RFC number and all occurrences of the revision date below with the date of RFC publication (and remove this note).

<CODE BEGINS> file "ietf-ipv6-unicast-routing@2016-08-18.yang"

module ietf-ipv6-unicast-routing {

  yang-version "1.1";

  namespace "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing";

  prefix "v6ur";

  import ietf-routing {
    prefix "rt";
  }

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

  include ietf-ipv6-router-advertisements {
    revision-date 2016-08-18;
  }

  organization
    "IETF NETMOD (NETCONF Data Modeling Language) Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

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

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

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

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

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

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

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

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
     'OPTIONAL' in the module text are to be interpreted as described
     in RFC 2119 (http://tools.ietf.org/html/rfc2119).

     This version of this YANG module is part of RFC XXXX
     (http://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

  revision 2016-08-18 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for Routing Management";
  }

  /* Identities */

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

  /* State data */

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

  augment
    "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/rt:input" {
    when "derived-from-or-self(../../rt:address-family, "
       + "'v6ur:ipv6-unicast')" {
      description
        "This augment is valid only for IPv6 unicast RIBs.";
    }
    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-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.";
    }
    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-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.";
    }
    description
      "Augment '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-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.";
    }
    description
      "Augment '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.";
    }
  }

  /* Configuration data */

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

<CODE ENDS>

9.1. IPv6 Router Advertisements Submodule

RFC Editor: In this section, replace all occurrences of 'XXXX' with the actual RFC number and all occurrences of the revision date below with the date of RFC publication (and remove this note).

<CODE BEGINS> file "ietf-ipv6-router-advertisements@2016-08-18.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";
  }

  import ietf-ip {
    prefix "ip";
  }

  organization
    "IETF NETMOD (NETCONF Data Modeling Language) Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

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

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

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

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

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

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

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

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and
     'OPTIONAL' in the module text are to be interpreted as described
     in RFC 2119 (http://tools.ietf.org/html/rfc2119).

     This version of this YANG module is part of RFC XXXX
     (http://tools.ietf.org/html/rfcXXXX); see the RFC itself for
     full legal notices.";

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

  revision 2016-08-18 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for Routing Management";
  }

  /* State data */

  augment "/if:interfaces-state/if:interface/ip:ipv6" {
    description
      "Augment interface state data with parameters of IPv6 router
       advertisements.";
    container ipv6-router-advertisements {
      description
        "Parameters of IPv6 Router Advertisements.";
      leaf send-advertisements {
        type boolean;
        description
          "A flag indicating whether or not the router sends periodic
           Router Advertisements and responds to Router
           Solicitations.";
      }
      leaf max-rtr-adv-interval {
        type uint16 {
          range "4..1800";
        }
        units "seconds";
        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";
        description
          "The minimum time allowed between sending unsolicited
           multicast Router Advertisements from the interface.";
      }
      leaf managed-flag {
        type boolean;
        description
          "The value that is placed in the 'Managed address
           configuration' flag field in the Router Advertisement.";
      }
      leaf other-config-flag {
        type boolean;
        description
          "The value that is placed in the 'Other configuration' flag
           field in the Router Advertisement.";
      }
      leaf link-mtu {
        type uint32;
        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";
        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";
        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;
        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";
        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 {
        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";
          description
            "Advertised prefix entry and its parameters.";
          leaf prefix-spec {
            type inet:ipv6-prefix;
            description
              "IPv6 address prefix.";
          }
          leaf valid-lifetime {
            type uint32;
            units "seconds";
            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;
            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";
            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;
            description
              "The value that is placed in the Autonomous Flag field
               in the Prefix Information option.";
          }
        }
      }
    }
  }

  /* Configuration data */

  augment "/if:interfaces/if:interface/ip:ipv6" {
    description
      "Augment interface configuration with parameters of IPv6 router
       advertisements.";
    container ipv6-router-advertisements {
      description
        "Configuration of 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..1800";
        }
        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";
        }
        units "seconds";
        must ". <= 0.75 * ../max-rtr-adv-interval" {
          description
            "The value MUST NOT be greater than 75 % of
             'max-rtr-adv-interval'.";
        }
        description
          "The minimum time allowed between sending unsolicited
           multicast Router Advertisements from the interface.

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

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

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

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

           IANA: IP Parameters,
           http://www.iana.org/assignments/ip-parameters";
      }
      leaf default-lifetime {
        type uint16 {
          range "0..9000";
        }
        units "seconds";
        description
          "The value to be placed in the Router Lifetime field of
           Router Advertisements sent from the interface, in seconds.
           It MUST be either zero or between max-rtr-adv-interval and
           9000 seconds. A value of zero 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
          "Configuration of prefixes to be placed in Prefix
           Information options in Router Advertisement messages sent
           from the interface.

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

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

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

<CODE ENDS>

10. IANA Considerations

RFC Ed.: In this section, replace all occurrences of 'XXXX' with the actual RFC number (and remove this note).

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

--------------------------------------------------------------------
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.
--------------------------------------------------------------------
        

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

--------------------------------------------------------------------
name:         ietf-routing
namespace:    urn:ietf:params:xml:ns:yang:ietf-routing
prefix:       rt
reference:    RFC XXXX
--------------------------------------------------------------------
        
--------------------------------------------------------------------
name:         ietf-ipv4-unicast-routing
namespace:    urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing
prefix:       v4ur
reference:    RFC XXXX
--------------------------------------------------------------------
        
--------------------------------------------------------------------
name:         ietf-ipv6-unicast-routing
namespace:    urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing
prefix:       v6ur
reference:    RFC XXXX
--------------------------------------------------------------------
        

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

--------------------------------------------------------------------
name:         ietf-ipv6-router-advertisements
parent:       ietf-ipv6-unicast-routing
reference:    RFC XXXX
--------------------------------------------------------------------
        

11. Security Considerations

Configuration and state data conforming to the core routing data model (defined in this document) are designed to be accessed via a management protocol with secure transport layer, such as NETCONF [RFC6241]. The NETCONF access control model [RFC6536] provides the means to restrict access for particular NETCONF users to a pre-configured subset of all available NETCONF protocol operations and content.

A number of configuration data nodes defined in the YANG modules belonging to the core routing data model are writable/creatable/deletable (i.e., "config true" in YANG terms, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations to these data nodes, such as "edit-config" in NETCONF, can have negative effects on the network if the protocol operations are not properly protected.

The vulnerable "config true" parameters and subtrees are the following:

/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.

Unauthorised access to any of these lists can adversely affect the routing subsystem of both the local device and the network. This may lead to network malfunctions, delivery of packets to inappropriate destinations and other problems.

12. Acknowledgments

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

13. References

13.1. Normative References

[I-D.ietf-netmod-rfc6020bis] Bjorklund, M., "The YANG 1.1 Data Modeling Language", Internet-Draft draft-ietf-netmod-rfc6020bis-14, June 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004.
[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.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011.
[RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013.
[RFC7223] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 7223, DOI 10.17487/RFC7223, May 2014.
[RFC7277] Bjorklund, M., "A YANG Data Model for IP Management", RFC 7277, DOI 10.17487/RFC7277, June 2014.

13.2. Informative References

[I-D.ietf-netmod-yang-json] Lhotka, L., "JSON Encoding of Data Modeled with YANG", Internet-Draft draft-ietf-netmod-yang-json-10, March 2016.
[RFC6087] Bierman, A., "Guidelines for Authors and Reviewers of YANG Data Model Documents", RFC 6087, DOI 10.17487/RFC6087, January 2011.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012.
[RFC7895] Bierman, A., Bjorklund, M. and K. Watsen, "YANG Module Library", RFC 7895, DOI 10.17487/RFC7895, June 2016.

Appendix A. The Complete Data Trees

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

A.1. Configuration Data

+--rw routing
   +--rw router-id?                 yang:dotted-quad
   +--rw control-plane-protocols
   |  +--rw control-plane-protocol* [type name]
   |     +--rw type             identityref
   |     +--rw name             string
   |     +--rw description?     string
   |     +--rw static-routes
   |        +--rw v6ur:ipv6
   |        |  +--rw v6ur:route* [destination-prefix]
   |        |     +--rw v6ur:destination-prefix    inet:ipv6-prefix
   |        |     +--rw v6ur:description?          string
   |        |     +--rw v6ur:next-hop
   |        |        +--rw (v6ur:next-hop-options)
   |        |           +--:(v6ur:simple-next-hop)
   |        |           |  +--rw v6ur:outgoing-interface?
   |        |           |  +--rw v6ur:next-hop-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?
   |        |                    +--rw v6ur:next-hop-address?
   |        +--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?
   |                    |  +--rw v4ur:next-hop-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?
   |                             +--rw v4ur:next-hop-address?
   +--rw ribs
      +--rw rib* [name]
         +--rw name              string
         +--rw address-family?   identityref
         +--rw description?      string

A.2. State Data

   +--ro routing-state
   |  +--ro router-id?                 yang:dotted-quad
   |  +--ro interfaces
   |  |  +--ro interface*   if:interface-state-ref
   |  +--ro control-plane-protocols
   |  |  +--ro control-plane-protocol* [type name]
   |  |     +--ro type    identityref
   |  |     +--ro name    string
   |  +--ro ribs
   |     +--ro rib* [name]
   |        +--ro name              string
   |        +--ro 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?
   |        |     |     |  +--ro v6ur:next-hop-address?
   |        |     |     |  +--ro v4ur:next-hop-address?
   |        |     |     +--:(special-next-hop)
   |        |     |     |  +--ro special-next-hop?        enumeration
   |        |     |     +--:(next-hop-list)
   |        |     |        +--ro next-hop-list
   |        |     |           +--ro next-hop*
   |        |     |              +--ro outgoing-interface?
   |        |     |              +--ro v6ur:address?
   |        |     |              +--ro v4ur:address?
   |        |     +--ro source-protocol            identityref
   |        |     +--ro active?                    empty
   |        |     +--ro last-updated?              yang:date-and-time
   |        |     +--ro v6ur:destination-prefix?   inet:ipv6-prefix
   |        |     +--ro v4ur:destination-prefix?   inet:ipv4-prefix
   |        +---x active-route
   |           +---w input
   |           |  +---w v6ur:destination-address?   inet:ipv6-address
   |           |  +---w v4ur:destination-address?   inet:ipv4-address
   |           +--ro output
   |              +--ro route
   |                 +--ro next-hop
   |                 |  +--ro (next-hop-options)
   |                 |     +--:(simple-next-hop)
   |                 |     |  +--ro outgoing-interface?
   |                 |     |  +--ro v6ur:next-hop-address?
   |                 |     |  +--ro v4ur:next-hop-address?
   |                 |     +--:(special-next-hop)
   |                 |     |  +--ro special-next-hop?     enumeration
   |                 |     +--:(next-hop-list)
   |                 |        +--ro next-hop-list
   |                 |           +--ro next-hop*
   |                 |              +--ro outgoing-interface?
   |                 |              +--ro v6ur:next-hop-address?
   |                 |              +--ro v4ur:next-hop-address?
   |                 +--ro source-protocol            identityref
   |                 +--ro active?                    empty
   |                 +--ro last-updated?           yang:date-and-time
   |                 +--ro v6ur:destination-prefix?  inet:ipv6-prefix
   |                 +--ro v4ur:destination-prefix?  inet:ipv4-prefix

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 feature "multiple-ribs". This means that a single system-controlled RIB is available for each supported address family - IPv4, IPv6 or both. These RIBs are also the default RIBs. No user-controlled RIBs are allowed.

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

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 RIP routing protocol. For the sake of brevity, this module does not obey all the guidelines specified in [RFC6087]. See also Section 5.3.2.

module example-rip {

  yang-version "1.1";

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

  prefix "rip";

  import ietf-interfaces {
    prefix "if";
  }

  import ietf-routing {
    prefix "rt";
  }

  identity rip {
    base rt:routing-protocol;
    description
      "Identity for the RIP routing protocol.";
  }

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

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

  augment "/rt:routing-state/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 routes whose source
         protocol is RIP.";
    }
    description
      "RIP-specific route attributes.";
    uses route-content;
  }

  augment "/rt:routing-state/rt:ribs/rt:rib/rt:active-route/"
        + "rt:output/rt:route" {
    description
      "RIP-specific route attributes in the output of 'active-route'
       RPC.";
    uses route-content;
  }

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

Appendix D. Data Tree Example

{
  "ietf-yang-library:modules-state": {
    "module-set-id": "3e9be92f252db56fe912cd61a6f516ecf2f46315",
    "module": [
      {
        "name": "ietf-routing",
        "revision": "2016-08-18",
        "feature": [
          "multiple-ribs",
          "router-id"
        ],
        "namespace": "urn:ietf:params:xml:ns:yang:ietf-routing",
        "conformance-type": "implement"
      },
      {
        "name": "ietf-ipv4-unicast-routing",
        "revision": "2016-08-18",
        "namespace":
          "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing",
        "conformance-type": "implement"
      },
      {
        "name": "ietf-ipv6-unicast-routing",
        "revision": "2016-08-18",
        "namespace":
          "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing",
        "conformance-type": "implement",
        "submodule": [
          {
            "name": "ietf-ipv6-router-advertisements",
            "revision": "2016-08-18"
          }
        ]
      },
      {
        "name": "ietf-interfaces",
        "revision": "2014-05-08",
        "namespace": "urn:ietf:params:xml:ns:yang:ietf-interfaces",
        "conformance-type": "implement"
      },
      {
        "name": "iana-if-type",
        "namespace": "urn:ietf:params:xml:ns:yang:iana-if-type",
        "revision": "",
        "conformance-type": "implement"
      },
      {
        "name": "ietf-inet-types",
        "revision": "2013-07-15",
        "namespace": "urn:ietf:params:xml:ns:yang:ietf-inet-types",
        "conformance-type": "import"
      },
      {
        "name": "ietf-yang-types",
        "revision": "2013-07-15",
        "namespace": "urn:ietf:params:xml:ns:yang:ietf-yang-types",
        "conformance-type": "import"
      },
      {
        "name": "ietf-ip",
        "revision": "2014-06-16",
        "namespace": "urn:ietf:params:xml:ns:yang:ietf-ip",
        "conformance-type": "implement"
      }
    ]
  }
}

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

A simple network set-up as shown in Figure 3 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 3: Example network configuration

The instance data tree could then be as follows:

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

Appendix E. Change Log

RFC Editor: Remove this section upon publication as an RFC.

E.1. Changes Between Versions -22 and -23

  • Removed "route-tag" feature.
  • Removed next-hop classifiers.
  • Fixed invalid when expressions in augments.
  • In simple-next-hop, an address, outgoing interface or both can be specified.
  • RPC "fib-route" changed into RIB action "active-route".
  • The requirement that direct routes be always placed in default RIBs.

E.2. Changes Between Versions -21 and -22

  • Added "next-hop-list" as a new case of the "next-hop-options" choice.
  • Renamed "routing protocol" to "control plane protocol" in both the YANG modules and I-D text.

E.3. Changes Between Versions -20 and -21

  • Routing instances were removed.
  • IPv6 RA parameters were moved to the "ietf-ipv6-router-advertisements".

E.4. Changes Between Versions -19 and -20

  • Assignment of L3 interfaces to routing instances is now part of interface configuration.
  • Next-hop options in configuration were aligned with state data.
  • It is recommended to enclose protocol-specific configuration in a presence container.

E.5. Changes Between Versions -18 and -19

  • The leaf "route-preference" was removed from the "routing-protocol" container in both "routing" and "routing-state".
  • The "vrf-routing-instance" identity was added in support of a common routing-instance type in addition to the "default-routing-instance".
  • Removed "enabled" switch from "routing-protocol".

E.6. Changes Between Versions -17 and -18

  • The container "ribs" was moved under "routing-instance" (in both "routing" and "routing-state").
  • Typedefs "rib-ref" and "rib-state-ref" were removed.
  • Removed "recipient-ribs" (both state and configuration).
  • Removed "connected-ribs" from "routing-protocol" (both state and configuration).
  • Configuration and state data for IPv6 RA were moved under "if:interface" and "if:interface-state".
  • Assignment of interfaces to routing instances now use leaf-list rather than list (both config and state). The opposite reference from "if:interface" to "rt:routing-instance" was changed to a single leaf (an interface cannot belong to multiple routing instances).
  • Specification of a default RIB is now a simple flag under "rib" (both config and state).
  • Default RIBs are marked by a flag in state data.

E.7. Changes Between Versions -16 and -17

  • Added Acee as a co-author.
  • Removed all traces of route filters.
  • Removed numeric IDs of list entries in state data.
  • Removed all next-hop cases except "simple-next-hop" and "special-next-hop".
  • Removed feature "multipath-routes".
  • Augmented "ietf-interfaces" module with a leaf-list of leafrefs pointing form state data of an interface entry to the routing instance(s) to which the interface is assigned.

E.8. Changes Between Versions -15 and -16

  • Added 'type' as the second key component of 'routing-protocol', both in configuration and state data.
  • The restriction of no more than one connected RIB per address family was removed.
  • Removed the 'id' key of routes in RIBs. This list has no keys anymore.
  • Remove the 'id' key from static routes and make 'destination-prefix' the only key.
  • Added 'route-preference' as a new attribute of routes in RIB.
  • Added 'active' as a new attribute of routes in RIBs.
  • Renamed RPC operation 'active-route' to 'fib-route'.
  • Added 'route-preference' as a new parameter of routing protocol instances, both in configuration and state data.
  • Renamed identity 'rt:standard-routing-instance' to 'rt:default-routing-instance'.
  • Added next-hop lists to state data.
  • Added two cases for specifying next-hops indirectly - via a new RIB or a recursive list of next-hops.
  • Reorganized next-hop in static routes.
  • Removed all 'if-feature' statements from state data.

E.9. Changes Between Versions -14 and -15

  • Removed all defaults from state data.
  • Removed default from 'cur-hop-limit' in config.

E.10. Changes Between Versions -13 and -14

  • Removed dependency of 'connected-ribs' on the 'multiple-ribs' feature.
  • Removed default value of 'cur-hop-limit' in state data.
  • Moved parts of descriptions and all references on IPv6 RA parameters from state data to configuration.
  • Added reference to RFC 6536 in the Security section.

E.11. Changes Between Versions -12 and -13

  • Wrote appendix about minimum implementation.
  • Remove "when" statement for IPv6 router interface state data - it was dependent on a config value that may not be present.
  • Extra container for the next-hop list.
  • Names rather than numeric ids are used for referring to list entries in state data.
  • Numeric ids are always declared as mandatory and unique. Their description states that they are ephemeral.
  • Descriptions of "name" keys in state data lists are required to be persistent.
  • Removed "if-feature multiple-ribs;" from connected-ribs.
  • "rib-name" instead of "name" is used as the name of leafref nodes.
  • "next-hop" instead of "nexthop" or "gateway" used throughout, both in node names and text.

E.12. Changes Between Versions -11 and -12

  • Removed feature "advanced-router" and introduced two features instead: "multiple-ribs" and "multipath-routes".
  • Unified the keys of config and state versions of "routing-instance" and "rib" lists.
  • Numerical identifiers of state list entries are not keys anymore, but they are constrained using the "unique" statement.
  • Updated acknowledgements.

E.13. Changes Between Versions -10 and -11

  • Migrated address families from IANA enumerations to identities.
  • Terminology and node names aligned with the I2RS RIB model: router -> routing instance, routing table -> RIB.
  • Introduced uint64 keys for state lists: routing-instance, rib, route, nexthop.
  • Described the relationship between system-controlled and user-controlled list entries.
  • Feature "user-defined-routing-tables" changed into "advanced-router".
  • Made nexthop into a choice in order to allow for nexthop-list (I2RS requirement).
  • Added nexthop-list with entries having priorities (backup) and weights (load balancing).
  • Updated bibliography references.

E.14. Changes Between Versions -09 and -10

  • Added subtree for state data ("/routing-state").
  • Terms "system-controlled entry" and "user-controlled entry" defined and used.
  • New feature "user-defined-routing-tables". Nodes that are useful only with user-defined routing tables are now conditional.
  • Added grouping "router-id".
  • In routing tables, "source-protocol" attribute of routes now reports only protocol type, and its datatype is "identityref".
  • Renamed "main-routing-table" to "default-routing-table".

E.15. Changes Between Versions -08 and -09

  • Fixed "must" expression for "connected-routing-table".
  • Simplified "must" expression for "main-routing-table".
  • Moved per-interface configuration of a new routing protocol under 'routing-protocol'. This also affects the 'example-rip' module.

E.16. Changes Between Versions -07 and -08

  • Changed reference from RFC6021 to RFC6021bis.

E.17. Changes Between Versions -06 and -07

  • The contents of <get-reply> in Appendix D was updated: "eth[01]" is used as the value of "location", and "forwarding" is on for both interfaces and both IPv4 and IPv6.
  • The "must" expression for "main-routing-table" was modified to avoid redundant error messages reporting address family mismatch when "name" points to a non-existent routing table.
  • The default behavior for IPv6 RA prefix advertisements was clarified.
  • Changed type of "rt:router-id" to "ip:dotted-quad".
  • Type of "rt:router-id" changed to "yang:dotted-quad".
  • Fixed missing prefixes in XPath expressions.

E.18. Changes Between Versions -05 and -06

  • Document title changed: "Configuration" was replaced by "Management".
  • New typedefs "routing-table-ref" and "route-filter-ref".
  • Double slashes "//" were removed from XPath expressions and replaced with the single "/".
  • Removed uniqueness requirement for "router-id".
  • Complete data tree is now in Appendix A.
  • Changed type of "source-protocol" from "leafref" to "string".
  • Clarified the relationship between routing protocol instances and connected routing tables.
  • Added a must constraint saying that a routing table connected to the direct pseudo-protocol must not be a main routing table.

E.19. Changes Between Versions -04 and -05

  • Routing tables are now global, i.e., "routing-tables" is a child of "routing" rather than "router".
  • "must" statement for "static-routes" changed to "when".
  • Added "main-routing-tables" containing references to main routing tables for each address family.
  • Removed the defaults for "address-family" and "safi" and made them mandatory.
  • Removed the default for route-filter/type and made this leaf mandatory.
  • If there is no active route for a given destination, the "active-route" RPC returns no output.
  • Added "enabled" switch under "routing-protocol".
  • Added "router-type" identity and "type" leaf under "router".
  • Route attribute "age" changed to "last-updated", its type is "yang:date-and-time".
  • The "direct" pseudo-protocol is always connected to main routing tables.
  • Entries in the list of connected routing tables renamed from "routing-table" to "connected-routing-table".
  • Added "must" constraint saying that a routing table must not be its own recipient.

E.20. Changes Between Versions -03 and -04

  • Changed "error-tag" for both RPC operations from "missing element" to "data-missing".
  • Removed the decrementing behavior for advertised IPv6 prefix parameters "valid-lifetime" and "preferred-lifetime".
  • Changed the key of the static route lists from "seqno" to "id" because the routes needn't be sorted.
  • Added 'must' constraint saying that "preferred-lifetime" must not be greater than "valid-lifetime".

E.21. Changes Between Versions -02 and -03

  • Module "iana-afn-safi" moved to I-D "iana-if-type".
  • Removed forwarding table.
  • RPC "get-route" changed to "active-route". Its output is a list of routes (for multi-path routing).
  • New RPC "route-count".
  • For both RPCs, specification of negative responses was added.
  • Relaxed separation of router instances.
  • Assignment of interfaces to router instances needn't be disjoint.
  • Route filters are now global.
  • Added "allow-all-route-filter" for symmetry.
  • Added Section 6 about interactions with "ietf-interfaces" and "ietf-ip".
  • Added "router-id" leaf.
  • Specified the names for IPv4/IPv6 unicast main routing tables.
  • Route parameter "last-modified" changed to "age".
  • Added container "recipient-routing-tables".

E.22. Changes Between Versions -01 and -02

  • Added module "ietf-ipv6-unicast-routing".
  • The example in Appendix D now uses IP addresses from blocks reserved for documentation.
  • Direct routes appear by default in the forwarding table.
  • Network layer interfaces must be assigned to a router instance. Additional interface configuration may be present.
  • The "when" statement is only used with "augment", "must" is used elsewhere.
  • Additional "must" statements were added.
  • The "route-content" grouping for IPv4 and IPv6 unicast now includes the material from the "ietf-routing" version via "uses rt:route-content".
  • Explanation of symbols in the tree representation of data model hierarchy.

E.23. Changes Between Versions -00 and -01

  • AFN/SAFI-independent stuff was moved to the "ietf-routing" module.
  • Typedefs for AFN and SAFI were placed in a separate "iana-afn-safi" module.
  • Names of some data nodes were changed, in particular "routing-process" is now "router".
  • The restriction of a single AFN/SAFI per router was lifted.
  • RPC operation "delete-route" was removed.
  • Illegal XPath references from "get-route" to the datastore were fixed.
  • Section "Security Considerations" was written.

Authors' Addresses

Ladislav Lhotka CZ.NIC EMail: lhotka@nic.cz
Acee Lindem Cisco Systems EMail: acee@cisco.com