RFC 8695 | A YANG Data Model for RIP | February 2020
Liu, et al. | Standards Track | [Page]

Stream:
  Internet Engineering Task Force (IETF)
RFC:
  8695
Category:
  Standards Track
Published:
  February 2020
ISSN:
  2070-1721
Authors:
  X. Liu
  Volta Networks
  P. Sarda
  Ericsson
  V. Choudhary
  Individual

# RFC 8695

# A YANG Data Model for the Routing Information Protocol (RIP)

## Abstract

This document describes a data model for the management of the Routing Information Protocol (RIP). Both RIP version 2 and RIPng are covered. The data model includes definitions for configuration, operational state, and Remote Procedure Calls (RPCs).¶

The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA).¶

## Status of This Memo

This is an Internet Standards Track document.¶

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8695.¶

## Copyright Notice

Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.¶

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

## 1. Introduction

This document introduces a YANG [RFC7950] data model for the Routing Information Protocol (RIP) [RFC2453][RFC2080]. RIP was designed to work as an Interior Gateway Protocol (IGP) in moderate-size Autonomous Systems (AS).¶

This YANG data model supports both RIP version 2 and RIPng. RIP version 2 (defined in [RFC2453]) supports IPv4. RIPng (defined in [RFC2080]) supports IPv6.¶

### 1.1. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

The following terms are defined in [RFC7950] and are not redefined here:¶

- augment¶
- data model¶
- data node¶

### 1.2. Tree Diagrams

A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams is defined in [RFC8340].¶

### 1.3. 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.¶

Table 1: Prefixes and Corresponding YANG Modules
Prefix | YANG module | Reference
--- | --- | ---
yang | ietf-yang-types | [RFC6991]
inet | ietf-inet-types | [RFC6991]
if | ietf-interfaces | [RFC8343]
ip | ietf-ip | [RFC8344]
rt | ietf-routing | [RFC8349]
bfd-types | ietf-bfd-types | [YANG-BFD]
isis | ietf-isis | [YANG-ISIS]
key-chain | ietf-key-chain | [RFC8177]
ospf | ietf-ospf | [YANG-OSPF]

## 2. Design of the Data Model

### 2.1. Scope of the Data Model

The data model covers RIP version 2 [RFC2453] and RIPng [RFC2080] protocols. The model is designed to be implemented on a device where RIP version 2 or RIPng is implemented, and can be used to:¶

- Configure the RIP version 2 or RIPng protocol.¶
- Manage the protocol operational behaviors.¶
- Retrieve the protocol operational status.¶

The capabilities described in [RFC1724] are covered.¶

### 2.2. Relation to the Core Routing Framework

This data model augments the core routing data model "ietf-routing" specified in [RFC8349].¶

      +--rw routing
         +--rw router-id?
         +--rw control-plane-protocols
         |  +--rw control-plane-protocol* [type name]
         |     +--rw type
         |     +--rw name
         |     +--rw rip     <= Augmented by this Model
                     ...

¶

The "rip" container instantiates a RIP entity that supports RIP version 2 or RIPng. Depending on the implementation of "ietf-routing", a RIP instance MAY belong to a logical router or network instance.¶

### 2.3. Protocol Configuration

The data model structure for the protocol configuration is as shown below:¶

      augment /rt:routing/rt:control-plane-protocols/
      rt:control-plane-protocol:
        +--rw rip
           +--rw <per instance configuration>
           +--rw interface* [interface]
              +--rw interface                  if:interface-ref
              +--rw <per interface configuration>
              +--rw neighbors {explicit-neighbors}?
              |  +--rw neighbor* [address]
              |     +--rw address    inet:ip-address
              |     +--rw <per neighbor configuration>

¶

The data model allows the configuration of the following protocol entities:¶

- Protocol instance (RIP version 2 or RIPng)¶
- Interface¶
- Neighbor¶

### 2.4. Protocol States

The data model structure for the protocol states is as shown below:¶

      augment /rt:routing/rt:control-plane-protocols/
      rt:control-plane-protocol:
        +--rw rip
           +--ro <per instance operational states>
           +--rw interface* [interface]
           |  +--rw interface                  if:interface-ref
           |  +--ro <per instance operational states>
           |  +--ro statistics {interface-statistics}?
           |     +--ro <per instance statistics>
           +--ro ipv4
           |  +--ro neighbors
           |  |  +--ro neighbor* [ipv4-address]
           |  |     +--ro <per neighbor IPv4 operational states>
           |  +--ro routes
           |     +--ro route* [ipv4-prefix]
           |        +--ro <IPv4 RIP route states>
           +--ro ipv6
           |  +--ro neighbors
           |  |  +--ro neighbor* [ipv6-address]
           |  |     +--ro <per neighbor IPv6 operational states>
           |  +--ro routes
           |     +--ro route* [ipv6-prefix]
           |        +--ro ipv6-prefix                    inet:ipv6-prefix
           |        +--ro <IPv4 RIP route states>
           +--ro statistics {global-statistics}?
              +--ro <per instance statistics>

¶

This model conforms to the Network Management Datastore Architecture (NMDA) [RFC8342]. The operational state data is combined with the associated configuration data in the same hierarchy [RFC8407]. When protocol states are retrieved from the NMDA operational state datastore, the returned states cover all "config true" (rw) and "config false" (ro) nodes defined in the schema.¶

The model allows the retrieval of protocol states at the following levels:¶

- Protocol instance (RIP version 2 or RIPng)¶
- Interface¶
- Neighbor¶
- Route¶

### 2.5. RPC Operations

This model defines one RPC "clear-rip-route" that can be used to clear RIP routes from the routing table.¶

### 2.6. Notifications

This model does not define RIP-specific notifications. To enable notifications, the mechanisms defined in [RFC8639] and [RFC8641] can be used. This mechanism currently allows the user to do the following:¶

- Subscribe to notifications on a per-client basis.¶
- Specify subtree filters or XML Path Language (XPath) filters so that only interested contents will be sent.¶
- Specify either periodic or on-demand notifications.¶

### 2.7. Optional Features

This model defines several features that are beyond the basic RIP configuration, and it is the responsibility of each vendor to decide whether to support a given feature on a device.¶

## 3. Tree Structure

This document defines the YANG module "ietf-rip", which has the following tree structure:¶

    module: ietf-rip
      augment /rt:routing/rt:control-plane-protocols
    /rt:control-plane-protocol:
        +--rw rip
           +--rw originate-default-route
           |  +--rw enabled?        boolean
           |  +--rw route-policy?   route-policy-ref
           +--rw default-metric?               uint8
           +--rw distance?                     uint8
           +--rw triggered-update-threshold?   uint8
           +--rw maximum-paths?                uint8
           +--rw output-delay?                 uint8
           +--rw distribute-list* [prefix-set-name direction]
           |  +--rw prefix-set-name    prefix-set-ref
           |  +--rw direction          enumeration
           |  +--rw if-name?           if:interface-ref
           +--rw redistribute
           |  +--rw bgp* [asn]
           |  |  +--rw asn             inet:as-number
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw cg-nat!
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw connected!
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw ipsec!
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw isis* [instance]
           |  |  +--rw instance
           |  |  |       -> ../../../../../rt:control-plane-protocol/name
           |  |  +--rw level?          enumeration
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw nat!
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw ospfv2* [instance]
           |  |  +--rw instance
           |  |  |       -> ../../../../../rt:control-plane-protocol/name
           |  |  +--rw route-type?     ospf:route-type
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw ospfv3* [instance]
           |  |  +--rw instance
           |  |  |       -> ../../../../../rt:control-plane-protocol/name
           |  |  +--rw route-type?     ospf:route-type
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw ripv2* [instance]
           |  |  +--rw instance
           |  |  |       -> ../../../../../rt:control-plane-protocol/name
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw ripng* [instance]
           |  |  +--rw instance
           |  |  |       -> ../../../../../rt:control-plane-protocol/name
           |  |  +--rw metric?         uint8
           |  |  +--rw route-policy?   route-policy-ref
           |  +--rw static!
           |     +--rw metric?         uint8
           |     +--rw route-policy?   route-policy-ref
           +--rw timers
           |  +--rw update-interval?     uint16
           |  +--rw invalid-interval?    uint16
           |  +--rw holddown-interval?   uint16
           |  +--rw flush-interval?      uint16
           +--rw interfaces
           |  +--rw interface* [interface]
           |     +--rw interface                  if:interface-ref
           |     +--rw authentication
           |     |  +--rw (auth-type-selection)?
           |     |     +--:(auth-key-chain)
           |     |     |  +--rw key-chain?
     key-chain:key-chain-ref
           |     |     +--:(auth-key)
           |     |        +--rw key?                string
           |     |        +--rw crypto-algorithm?   identityref
           |     +--rw bfd {bfd}?
           |     |  +--rw enable?                     boolean
           |     |  +--rw local-multiplier?           multiplier
           |     |  +--rw (interval-config-type)?
           |     |     +--:(tx-rx-intervals)
           |     |     |  +--rw desired-min-tx-interval?    uint32
           |     |     |  +--rw required-min-rx-interval?   uint32
           |     |     +--:(single-interval)
           |     |        +--rw min-interval?               uint32
           |     +--rw cost?                      uint8
           |     +--rw neighbors {explicit-neighbors}?
           |     |  +--rw neighbor* [address]
           |     |     +--rw address    inet:ip-address
           |     +--rw no-listen?                 empty
           |     +--rw originate-default-route
           |     |  +--rw enabled?        boolean
           |     |  +--rw route-policy?   route-policy-ref
           |     +--rw passive?                   empty
           |     +--rw split-horizon?             enumeration
           |     +--rw summary-address
           |     |  +--rw address?   inet:ip-prefix
           |     |  +--rw metric?    uint8
           |     +--rw timers
           |     |  +--rw update-interval?     uint16
           |     |  +--rw invalid-interval?    uint16
           |     |  +--rw holddown-interval?   uint16
           |     |  +--rw flush-interval?      uint16
           |     +--ro oper-status?               enumeration
           |     +--ro next-full-update?          uint32
           |     +--ro valid-address?             boolean
           |     +--ro statistics {interface-statistics}?
           |        +--ro discontinuity-time?   yang:date-and-time
           |        +--ro bad-packets-rcvd?     yang:counter32
           |        +--ro bad-routes-rcvd?      yang:counter32
           |        +--ro updates-sent?         yang:counter32
           +--ro next-triggered-update?        uint32
           +--ro num-of-routes?                uint32
           +--ro ipv4
           |  +--ro neighbors
           |  |  +--ro neighbor* [ipv4-address]
           |  |     +--ro ipv4-address        inet:ipv4-address
           |  |     +--ro last-update?        yang:date-and-time
           |  |     +--ro bad-packets-rcvd?   yang:counter32
           |  |     +--ro bad-routes-rcvd?    yang:counter32
           |  +--ro routes
           |     +--ro route* [ipv4-prefix]
           |        +--ro ipv4-prefix
     inet:ipv4-prefix
           |        +--ro next-hop?
     inet:ipv4-address
           |        +--ro interface?
     if:interface-ref
           |        +--ro redistributed?                  boolean
           |        +--ro route-type?                     enumeration
           |        +--ro metric?                         uint8
           |        +--ro expire-time?                    uint16
           |        +--ro deleted?                        boolean
           |        +--ro holddown?                       boolean
           |        +--ro need-triggered-update?          boolean
           |        +--ro inactive?                       boolean
           |        +--ro flush-expire-before-holddown?   boolean
           +--ro ipv6
           |  +--ro neighbors
           |  |  +--ro neighbor* [ipv6-address]
           |  |     +--ro ipv6-address        inet:ipv6-address
           |  |     +--ro last-update?        yang:date-and-time
           |  |     +--ro bad-packets-rcvd?   yang:counter32
           |  |     +--ro bad-routes-rcvd?    yang:counter32
           |  +--ro routes
           |     +--ro route* [ipv6-prefix]
           |        +--ro ipv6-prefix
     inet:ipv6-prefix
           |        +--ro next-hop?
     inet:ipv6-address
           |        +--ro interface?
     if:interface-ref
           |        +--ro redistributed?                  boolean
           |        +--ro route-type?                     enumeration
           |        +--ro metric?                         uint8
           |        +--ro expire-time?                    uint16
           |        +--ro deleted?                        boolean
           |        +--ro holddown?                       boolean
           |        +--ro need-triggered-update?          boolean
           |        +--ro inactive?                       boolean
           |        +--ro flush-expire-before-holddown?   boolean
           +--ro statistics {global-statistics}?
              +--ro discontinuity-time?   yang:date-and-time
              +--ro requests-rcvd?        yang:counter32
              +--ro requests-sent?        yang:counter32
              +--ro responses-rcvd?       yang:counter32
              +--ro responses-sent?       yang:counter32

      rpcs:
        +---x clear-rip-route
           +---w input
              +---w rip-instance?   leafref

¶

## 4. YANG Module

    <CODE BEGINS> file "ietf-rip@2020-02-20.yang"

    module ietf-rip {
      yang-version 1.1;
      namespace "urn:ietf:params:xml:ns:yang:ietf-rip";
      prefix rip;

      import ietf-inet-types {
        prefix inet;
      }
      import ietf-yang-types {
        prefix yang;
      }
      import ietf-interfaces {
        prefix if;
      }
      import ietf-ip {
        prefix ip;
      }
      import ietf-routing {
        prefix rt;
      }
      import ietf-key-chain {
        prefix key-chain;
      }
      import ietf-bfd-types {
        prefix bfd-types;
      }
      import ietf-ospf {
        prefix ospf;
      }
      import ietf-isis {
        prefix isis;
      }

      organization
        "IETF Routing Area Working Group (rtgwg)";
      contact
        "WG Web:   <https://datatracker.ietf.org/wg/rtgwg/>
         WG List:  <mailto:rgtwg@ietf.org>

         Editor:   Xufeng Liu
                   <mailto:xufeng.liu.ietf@gmail.com>

         Editor:   Prateek Sarda
                   <mailto:prateek.sarda@ericsson.com>

         Editor:   Vikram Choudhary
                   <mailto:vikschw@gmail.com>";
      description
        "This YANG module defines a model for managing Routing
         Information Protocol (RIP), including RIP version 2 and RIPng.

         Copyright (c) 2020 IETF Trust and the persons identified as
         authors of the code.  All rights reserved.

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

         This version of this YANG module is part of RFC 8695; see the
         RFC itself for full legal notices.";

      revision 2020-02-20 {
        description
          "Initial revision.";
        reference
          "RFC 8695: A YANG Data Model for Routing Information Protocol
           (RIP).
           RFC 2453: RIP Version 2.
           RFC 2080: RIPng for IPv6.
           RFC 1724: RIP Version 2 MIB Extension.";
      }

      /*
       * Features
       */

      feature bfd {
        description
          "This feature indicates that the RIP implementation on the
           system supports BFD (Bidirectional Forwarding Detection).";
      }

      feature explicit-neighbors {
        description
          "This feature indicates that the system supports explicit
           neighbor configuration on a RIP interface.";
      }

      feature global-statistics {
        description
          "This feature indicates that the system supports collecting
           global statistics data related to RIP.";
      }

      feature interface-statistics {
        description
          "This feature indicates that the system supports collecting
           per-interface statistics data related to RIP.";
      }

      /*
       * Typedefs
       */

      typedef prefix-set-ref {
        type string;
        description
          "A type for a reference to a prefix set.
           The string value is the name identifier for uniquely
           identifying the referenced prefix set, which contains a list
           of prefixes that a routing policy can applied.  The definition
           of such a prefix set is outside the scope of this document.";
      }

      typedef route-policy-ref {
        type string;
        description
          "A type for a reference to a route policy.
           The string value is the name identifier for uniquely
           identifying the referenced routing policy, which contains one
           or more policy rules that can be used for a routing decision.
           The definition of such a routing policy is outside the scope
           of this document.";
      }

      /*
       * Identities
       */

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

      identity ripv2 {
        base rip:rip;
        description
          "Identity for RIPv2 (RIP version 2).";
      }

      identity ripng {
        base rip:rip;
        description
          "Identity for RIPng.";
      }

      /*
       * Groupings
       */

      grouping originate-default-route-container {
        description
          "Container for settings on whether to originate the default
           route in RIP routing instance.";
        container originate-default-route {
          description
            "Injects the default route into the RIP (RIPv2 or RIPng)
             routing instance.";
          leaf enabled {
            type boolean;
            default "false";
            description
              "'true' if originating default route is enabled.";
          }
          leaf route-policy {
            type route-policy-ref;
            description
              "The conditions of the route policy are applied to the
               default route.";
          }
        }
      }

      grouping redistribute-container {
        description
          "Container of redistribute attributes.";
        container redistribute {
          description
            "Redistributes routes learned from other routing protocols
             into the RIP routing instance.";
          list bgp {
            key "asn";
            description
              "Redistributes routes from the specified BGP (Border
               Gateway Protocol) autonomous system (AS) into the RIP
               routing instance.";
            leaf asn {
              type inet:as-number;
              description
                "BGP autonomous system (AS) number.";
            }
            uses redistribute-route-policy-attributes;
          }
          container cg-nat {
            presence "Present if Carrier-Grade Network Address
                      Translation (CGNAT) routes are redistributed.";
            description
              "Carrier-Grade Network Address Translation (CGNAT)
               routes.";
            uses redistribute-route-policy-attributes;
          }
          container connected {
            presence "Present if directly attached network routes are
                      redistributed.";
            description
              "Redistributes directly attached networks into the RIP
               routing instance.";
            uses redistribute-route-policy-attributes;
          }
          container ipsec {
            presence "Present if IP security routing instance routes
                      are redistributed.";
            description
              "Redistributes routes from the IP security routing
               instance into the RIP routing instance.";
            uses redistribute-route-policy-attributes;
          }
          list isis {
            key "instance";
            description
              "Redistributes IS-IS routes.";
            leaf instance {
              type leafref {
                path "../../../../../rt:control-plane-protocol/rt:name";
              }
              must "derived-from-or-self("
                 + "../../../../../rt:control-plane-protocol"
                 + "[rt:name = current()]/rt:type, 'isis:isis')" {
                description
                  "The type of the routing protocol must be 'isis'.";
              }
              description
                "Redistributes routes from the specified IS-IS routing
                 instance into the RIP routing instance.";
            }
            leaf level {
              type enumeration {
                enum 1 {
                  description
                    "IS-IS level 1 routes.";
                }
                enum 2 {
                  description
                    "IS-IS level 2 routes.";
                }
                enum 1-2 {
                  description
                    "IS-IS level 1-2 routes.";
                }
              }
              description
                "IS-IS level.";
            }
            uses redistribute-route-policy-attributes;
          }
          container nat {
            presence "Present if Network Address Translation (NAT) routes
                      are redistributed.";
            description
              "Redistributes Network Address Translation (NAT)
               routes into the RIP routing instance.";
            uses redistribute-route-policy-attributes;
          }
          list ospfv2 {
            when "derived-from-or-self(../../../rt:type, 'rip:ripv2')" {
              description
                "Applicable to RIPv2.";
            }
            key "instance";
            description
              "Redistributes routes from the specified OSPFv2 routing
               instance into the RIPv2 routing instance.";
            leaf instance {
              type leafref {
                path "../../../../../rt:control-plane-protocol/rt:name";
              }
              must "derived-from-or-self("
                 + "../../../../../rt:control-plane-protocol"
                 + "[rt:name = current()]/rt:type, 'ospf:ospfv2')" {
                description
                  "The type of the routing protocol must be 'ospfv2'.";
              }
              description
                "OSPFv2 instance ID. Redistributes routes from the
                 specified OSPFv2 routing instance into the RIPv2 routing
                 instance.";
            }
            leaf route-type {
              type ospf:route-type;
              description
                "Redistributes only those OSPFv2 routes matching the
                 specified route type into the RIPv2 routing instance.";
            }
            uses redistribute-route-policy-attributes;
          }
          list ospfv3 {
            when "derived-from-or-self(../../../rt:type, 'rip:ripng')" {
              description
                "Applicable to RIPng.";
            }
            key "instance";
            description
              "Redistributes routes from the specified OSPFv3 routing
               instance into the RIPng routing instance.";
            leaf instance {
              type leafref {
                path "../../../../../rt:control-plane-protocol/rt:name";
              }
              must "derived-from-or-self("
                 + "../../../../../rt:control-plane-protocol"
                 + "[rt:name = current()]/rt:type, 'ospf:ospfv3')" {
                description
                  "The type of the routing protocol must be 'ospfv3'.";
              }
              description
                "OSPFv3 instance ID. Redistributes routes from the
                 specified OSPFv3 routing instance into the RIPng routing
                 instance.";
            }
            leaf route-type {
              type ospf:route-type;
              description
                "Redistributes only those OSPFv3 routes matching the
                 specified route type into the RIPng routing instance.";
            }
            uses redistribute-route-policy-attributes;
          }
          list ripv2 {
            when "derived-from-or-self(../../../rt:type, 'rip:ripv2')" {
              description
                "Applicable to RIPv2.";
            }
            key "instance";
            description
              "Redistributes routes from another RIPv2 routing instance
               into the current RIPv2 routing instance.";
            leaf instance {
              type leafref {
                path "../../../../../rt:control-plane-protocol/rt:name";
              }
              must "derived-from-or-self("
                 + "../../../../../rt:control-plane-protocol"
                 + "[rt:name = current()]/rt:type, 'rip:ripv2')" {
                description
                  "The type of the routing protocol must be 'ripv2'.";
              }
              description
                "Redistributes routes from the specified RIPv2 routing
                 instance into the RIPv2 routing instance.";
            }
            uses redistribute-route-policy-attributes;
          }
          list ripng {
            when "derived-from-or-self(../../../rt:type, 'rip:ripng')" {
              description
                "Applicable to RIPng.";
            }
            key "instance";
            description
              "Redistributes routes from another RIPng routing instance
               into the current RIPng routing instance.";
            leaf instance {
              type leafref {
                path "../../../../../rt:control-plane-protocol/rt:name";
              }
              must "derived-from-or-self("
                 + "../../../../../rt:control-plane-protocol"
                 + "[rt:name = current()]/rt:type, 'rip:ripng')" {
                description
                  "The type of the routing protocol must be 'ripng'.";
              }
              description
                "Redistributes routes from the specified RIPng routing
                 instance into the RIPng routing instance.";
            }
            uses redistribute-route-policy-attributes;
          }
          container static {
            presence "Present if redistributing static routes.";
            description
              "Redistributes static routes into the RIP routing
               instance.";
            uses redistribute-route-policy-attributes;
          }
        }
        // redistribute
      }
      // redistribute-container

      grouping redistribute-route-policy-attributes {
        description
          "Attributes for redistributing a route policy.";
        leaf metric {
          type uint8 {
            range "0..16";
          }
          description
            "Metric used for the redistributed route. If a metric is
             not specified, the metric configured with the
             default-metric attribute in RIP router configuration is
             used.  If the default-metric attribute has not been
             configured, the default metric for redistributed routes
             is 1.";
        }
        leaf route-policy {
          type route-policy-ref;
          description
            "Applies the conditions of the specified route policy to
             routes that are redistributed into the RIP routing
             instance.";
        }
      }
      // redistribute-route-policy-attributes

      grouping timers-container {
        description
          "Container for settings of basic timers";
        container timers {
          must 'invalid-interval >= (update-interval * 3)' {
            description
              "invalid-interval must be at least three times the value
               for the update-interval argument.";
          }
          must 'flush-interval > invalid-interval' {
            description
              "flush-interval must be larger than the value for the
               invalid-interval argument.";
          }
          description
            "Timers for the specified RIPv2 or RIPng instance or
             interface.";
          leaf update-interval {
            type uint16 {
              range "1..32767";
            }
            units "seconds";
            default "30";
            description
              "Interval at which RIPv2 or RIPng updates are sent.";
          }
          leaf invalid-interval {
            type uint16 {
              range "1..32767";
            }
            units "seconds";
            default "180";
            description
              "Interval before a route is declared invalid after no
               updates are received.  This value is at least three times
               the value for the update-interval argument.";
          }
          leaf holddown-interval {
            type uint16 {
              range "1..32767";
            }
            units "seconds";
            default "180";
            description
              "Interval before better routes are released.";
          }
          leaf flush-interval {
            type uint16 {
              range "1..32767";
            }
            units "seconds";
            default "240";
            description
              "Interval before a route is flushed from the routing
               table. This value must be larger than the value for the
               invalid-interval argument.";
          }
        }
        // timers
      }
      // timers-container

      grouping global-attributes {
        description
          "Global configuration and state attributes.";
        uses originate-default-route-container;
        leaf default-metric {
          type uint8 {
            range "0..16";
          }
          default "1";
          description
            "Set the default metric.";
        }
        leaf distance {
          type uint8 {
            range "1..255";
          }
          default "120";
          description
            "The administrative distance of the RIPv2 or RIPng for the
             current RIPv2 or RIPng instance.";
        }
        leaf triggered-update-threshold {
          type uint8 {
            range "1..30";
          }
          units "seconds";
          default "5";
          description
            "This attribute is used to suppress triggered updates.
             When the arrival of a regularly scheduled update matches the
             number of seconds or is less than the number seconds
             configured with this attribute, the triggered update is
             suppressed.";
        }
        leaf maximum-paths {
          type uint8 {
            range "1..16";
          }
          default "8";
          description
            "The number of multiple equal-cost RIPv2 or RIPng routes
             that can be used as the best paths for balancing the load
             of outgoing traffic packets.";
        }
        leaf output-delay {
          type uint8 {
            range "1..50";
          }
          units "milliseconds";
          description
            "A delay time between packets sent in multipacket
             RIPv2 or RIPng updates.";
        }
      }
      // global-attributes

      grouping distribute-lists {
        description
          "Grouping for distribute lists.";
        list distribute-list {
          key "prefix-set-name direction";
          description
            "List of distribute-lists, which are used to filter incoming
             or outgoing routing updates.";
          leaf prefix-set-name {
            type prefix-set-ref;
            description
              "Reference to a prefix list to be applied to RIPv2 or
               RIPng packets.";
          }
          leaf direction {
            type enumeration {
              enum in {
                description
                  "Apply the distribute-list to incoming routes.";
              }
              enum out {
                description
                  "Apply the distribute-list to outgoing routes.";
              }
            }
            description
              "Direction of the routing updates.";
          }
          leaf if-name {
            type if:interface-ref;
            description
              "Reference to an interface to which the prefix list is
               applied.";
          }
        }
        // distribute-list
      }
      // distribute-lists

      grouping route-attributes {
        description
          "Grouping for route attributes.";
        leaf redistributed {
          type boolean;
          description
            "Redistributed routes.";
        }
        leaf route-type {
          type enumeration {
            enum connected {
              description
                "Connected route.";
            }
            enum external {
              description
                "External route.";
            }
            enum external-backup {
              description
                "External backup route.";
            }
            enum rip {
              description
                "RIP route.";
            }
          }
          description
            "Route type.";
        }
        leaf metric {
          type uint8 {
            range "0..16";
          }
          description
            "Route metric.";
        }
        leaf expire-time {
          type uint16;
          description
            "Expiration time.";
        }
        leaf deleted {
          type boolean;
          description
            "Deleted route.";
        }
        leaf holddown {
          type boolean;
          description
            "Holddown route.";
        }
        leaf need-triggered-update {
          type boolean;
          description
            "The route needs triggered update.";
        }
        leaf inactive {
          type boolean;
          description
            "The route is inactive.";
        }
        leaf flush-expire-before-holddown {
          type boolean;
          description
            "The flush timer expired before holddown time.";
        }
      }
      // route-attributes

      /*
       * Configuration data and operational state data nodes
       */

      augment "/rt:routing/rt:control-plane-protocols/"
            + "rt:control-plane-protocol" {
        when "derived-from(rt:type, 'rip:rip')" {
          description
            "This augment is only valid for a routing protocol instance
             of RIP (type 'ripv2' or 'ripng').";
        }
        description
          "RIP augmentation.";
        container rip {
          description
            "RIP data.";
          uses global-attributes;
          uses distribute-lists;
          uses redistribute-container;
          uses timers-container;
          container interfaces {
            description
              "Containing a list of RIP interfaces.";
            list interface {
              key "interface";
              description
                "List of RIP interfaces.";
              leaf interface {
                type if:interface-ref;
                must "(derived-from-or-self("
                   + "../../../../rt:type, 'rip:ripv2') and "
                   + "/if:interfaces/if:interface[if:name=current()]/"
                   + "ip:ipv4) or "
                   + "(derived-from-or-self("
                   + "../../../../rt:type, 'rip:ripng') and "
                   + "/if:interfaces/if:interface[if:name=current()]/"
                   + "ip:ipv6)" {
                  error-message "Invalid interface type.";
                  description
                    "RIPv2 can be enabled on IPv4 interface, and
                     RIPng can be enabled on IPv6 interface.";
                }
                description
                  "Enable RIP on this interface.";
              }
              container authentication {
                when "derived-from-or-self("
                   + "../../../../rt:type, 'rip:ripv2')" {
                  description
                    "Only applicable to RIPv2.";
                }
                description
                  "Enables authentication and specifies the
                   authentication scheme for the RIP interface.";
                choice auth-type-selection {
                  description
                    "Specify the authentication scheme.";
                  reference
                    "RFC8177: YANG Data Model for Key Chains.";
                  case auth-key-chain {
                    leaf key-chain {
                      type key-chain:key-chain-ref;
                      description
                        "key-chain name.";
                    }
                  }
                  case auth-key {
                    leaf key {
                      type string;
                      description
                        "Key string in ASCII format.";
                    }
                    leaf crypto-algorithm {
                      type identityref {
                        base key-chain:crypto-algorithm;
                      }
                      description
                        "Cryptographic algorithm associated with the
                         key.";
                    }
                  }
                }
              }
              container bfd {
                if-feature "bfd";
                description
                  "BFD configuration.";
                uses bfd-types:client-cfg-parms;
              }
              leaf cost {
                type uint8 {
                  range "1..16";
                }
                default "1";
                description
                  "Interface cost.";
              }
              container neighbors {
                if-feature "explicit-neighbors";
                description
                  "Specifies the RIP neighbors.  Useful for a
                   non-broadcast multiple access (NBMA) network.";
                list neighbor {
                  key "address";
                  description
                    "Specify a RIP neighbor on a non-broadcast network.";
                  leaf address {
                    type inet:ip-address;
                    description
                      "Neighbor IP address.";
                  }
                }
              }
              leaf no-listen {
                type empty;
                description
                  "Disables listening to, and processing of, RIPv2 or
                   RIPng packets on the specified interface.";
              }
              uses originate-default-route-container;
              leaf passive {
                type empty;
                description
                  "Disables sending of RIPv2 or RIPng packets on the
                   specified interface.";
              }
              leaf split-horizon {
                type enumeration {
                  enum disabled {
                    description
                      "Disables split-horizon processing.";
                  }
                  enum simple {
                    description
                      "Enables simple split-horizon processing.";
                  }
                  enum poison-reverse {
                    description
                      "Enables split-horizon processing with poison
                       reverse.";
                  }
                }
                default "simple";
                description
                  "Controls RIPv2 or RIPng split-horizon processing on
                   the specified interface.";
              }
              container summary-address {
                description
                  "Summarizes information about RIPv2 or RIPng routes
                   sent over the specified interface in RIPv2 or RIPng
                   update packets.";
                leaf address {
                  type inet:ip-prefix;
                  description
                    "Specifies the IP address and the prefix length that
                     identify the routes to be summarized.  The IP
                     address can be specified in either IPv4 or IPv6
                     format, as specified in RFC6991.";
                }
                leaf metric {
                  type uint8 {
                    range "0..16";
                  }
                  description
                    "Metric used for the route.  If this attribute is not
                     used, the value set through the default-metric
                     attribute in RIPv2 or RIPng router configuration is
                     used for the route.";
                }
              }
              uses timers-container;

              /* Operational state */
              leaf oper-status {
                type enumeration {
                  enum up {
                    description
                      "RIPv2 or RIPng is operational on this interface.";
                  }
                  enum down {
                    description
                      "RIPv2 or RIPng is not operational on this
                       interface.";
                  }
                }
                config false;
                description
                  "Operational state.";
              }
              leaf next-full-update {
                type uint32;
                config false;
                description
                  "Next full update time.";
              }
              leaf valid-address {
                type boolean;
                config false;
                description
                  "The interface has a valid address.";
              }
              container statistics {
                if-feature "interface-statistics";
                config false;
                description
                  "Interface statistics counters.";
                leaf discontinuity-time {
                  type yang:date-and-time;
                  description
                    "The time on the most recent occasion at which any
                     one or more of the statistics counters suffered a
                     discontinuity.  If no such discontinuities have
                     occurred since the last re-initialization of the
                     local management subsystem, then this node contains
                     the time the local management subsystem
                     re-initialized itself.";
                }
                leaf bad-packets-rcvd {
                  type yang:counter32;
                  description
                    "The number of RIP invalid packets received by
                     the RIP process that were subsequently discarded
                     for any reason (e.g., a version 0 packet, or an
                     unknown command type).";
                }
                leaf bad-routes-rcvd {
                  type yang:counter32;
                  description
                    "The number of routes, in valid RIP packets,
                     which were ignored for any reason (e.g., unknown
                     address family, or invalid metric).";
                }
                leaf updates-sent {
                  type yang:counter32;
                  description
                    "The number of triggered RIP updates actually
                     sent on this interface.  This explicitly does
                     NOT include full updates sent containing new
                     information.";
                }
              }
            }
            // interface
          }
          // interfaces

          /* Operational state */
          leaf next-triggered-update {
            type uint32;
            config false;
            description
              "Next triggered update.";
          }
          leaf num-of-routes {
            type uint32;
            config false;
            description
              "The number of routes.";
          }
          container ipv4 {
            when "derived-from-or-self(../../rt:type, 'rip:ripv2')" {
              description
                "IPv4 address family is supported by RIPv2.";
            }
            config false;
            description
              "IPv4 address family information.";
            container neighbors {
              description
                "IPv4 neighbor information.";
              list neighbor {
                key "ipv4-address";
                description
                  "A RIPv2 neighbor.";
                leaf ipv4-address {
                  type inet:ipv4-address;
                  description
                    "IP address that a RIP neighbor is using as its
                     source address.";
                }
                leaf last-update {
                  type yang:date-and-time;
                  description
                    "The time when the most recent RIP update was
                     received from this neighbor.";
                }
                leaf bad-packets-rcvd {
                  type yang:counter32;
                  description
                    "The number of RIP invalid packets received from
                     this neighbor that were subsequently discarded
                     for any reason (e.g., a version 0 packet, or an
                     unknown command type).";
                }
                leaf bad-routes-rcvd {
                  type yang:counter32;
                  description
                    "The number of routes received from this neighbor,
                     in valid RIP packets that were ignored for any
                     reason (e.g., unknown address family, or invalid
                     metric).";
                }
              }
              // neighbor
            }
            // neighbors

            container routes {
              description
                "IPv4 route information.";
              list route {
                key "ipv4-prefix";
                description
                  "A RIPv2 IPv4 route.";
                leaf ipv4-prefix {
                  type inet:ipv4-prefix;
                  description
                    "IPv4 address and prefix length, in the format
                     specified in RFC6991.";
                }
                leaf next-hop {
                  type inet:ipv4-address;
                  description
                    "Next hop IPv4 address.";
                }
                leaf interface {
                  type if:interface-ref;
                  description
                    "The interface that the route uses.";
                }
                uses route-attributes;
              }
              // route
            }
            // routes
          }
          // ipv4

          container ipv6 {
            when "derived-from-or-self(../../rt:type, 'rip:ripng')" {
              description
                "IPv6 address family is supported by RIPng.";
            }
            config false;
            description
              "IPv6 address family information.";
            container neighbors {
              description
                "IPv6 neighbor information.";
              list neighbor {
                key "ipv6-address";
                description
                  "A RIPng neighbor.";
                leaf ipv6-address {
                  type inet:ipv6-address;
                  description
                    "IP address that a RIP neighbor is using as its
                     source address.";
                }
                leaf last-update {
                  type yang:date-and-time;
                  description
                    "The time when the most recent RIP update was
                     received from this neighbor.";
                }
                leaf bad-packets-rcvd {
                  type yang:counter32;
                  description
                    "The number of RIP invalid packets received from
                     this neighbor that were subsequently discarded
                     for any reason (e.g., a version 0 packet, or an
                     unknown command type).";
                }
                leaf bad-routes-rcvd {
                  type yang:counter32;
                  description
                    "The number of routes received from this neighbor,
                     in valid RIP packets that were ignored for any
                     reason (e.g., unknown address family, or invalid
                     metric).";
                }
              }
              // neighbor
            }
            // neighbors

            container routes {
              description
                "IPv6 route information.";
              list route {
                key "ipv6-prefix";
                description
                  "A RIPng IPv6 route.";
                leaf ipv6-prefix {
                  type inet:ipv6-prefix;
                  description
                    "IPv6 address and prefix length, in the format
                     specified in RFC6991.";
                }
                leaf next-hop {
                  type inet:ipv6-address;
                  description
                    "Next hop IPv6 address.";
                }
                leaf interface {
                  type if:interface-ref;
                  description
                    "The interface that the route uses.";
                }
                uses route-attributes;
              }
              // route
            }
            // routes
          }
          // ipv6

          container statistics {
            if-feature "global-statistics";
            config false;
            description
              "Global statistics counters.";
            leaf discontinuity-time {
              type yang:date-and-time;
              description
                "The time on the most recent occasion at which any one
                 or more of the statistics counters suffered a
                 discontinuity.  If no such discontinuities have occurred
                 since the last re-initialization of the local
                 management subsystem, then this node contains the time
                 the local management subsystem re-initialized itself.";
            }
            leaf requests-rcvd {
              type yang:counter32;
              description
                "The number of requests received by RIP.";
            }
            leaf requests-sent {
              type yang:counter32;
              description
                "The number of requests sent by RIP.";
            }
            leaf responses-rcvd {
              type yang:counter32;
              description
                "The number of responses received by RIP.";
            }
            leaf responses-sent {
              type yang:counter32;
              description
                "The number of responses sent by RIP.";
            }
          }
          // statistics
        }
        // rip
      }

      /*
       * RPCs
       */

      rpc clear-rip-route {
        description
          "Clears RIP routes from the IP routing table and routes
           redistributed into RIP for the specified RIP instance
           or for all RIP instances in the current context.";
        input {
          leaf rip-instance {
            type leafref {
              path "/rt:routing/rt:control-plane-protocols/"
                 + "rt:control-plane-protocol/rt:name";
            }
            description
              "Instance name identifying a specific RIP instance.
               This leaf is optional for the RPC.
               If it is specified, the RPC will clear all routes in the
               specified RIP instance;
               if it is not specified, the RPC will clear all routes in
               all RIP instances.";
          }
        }
      }
      // clear-rip-route

    }

    <CODE ENDS>

¶

## 5. IANA Considerations

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

URI:
  urn:ietf:params:xml:ns:yang:ietf-rip¶
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-rip¶
Namespace:
  urn:ietf:params:xml:ns:yang:ietf-rip¶
Prefix:
  rip¶
Reference:
  RFC 8695¶

## 6. Security Considerations

The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].¶

The NETCONF Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.¶

There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:¶

       /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/
       rip:rip

¶

Unauthorized access to any data node of these subtrees 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.¶

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

       /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/
       rip:rip

¶

Unauthorized access to any data node of these subtrees can disclose the operational state information of RIP on this device.¶

Some of the RPC operations in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control access to these operations. These are the operations and their sensitivity/vulnerability:¶

RPC clear-rip-route:¶

Unauthorized access to the RPC above 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.¶

## 7. References

### 7.1. Normative References

[RFC1724]
  Malkin, G. and F. Baker, "RIP Version 2 MIB Extension", RFC 1724, DOI 10.17487/RFC1724, November 1994, <https://www.rfc-editor.org/info/rfc1724>.
[RFC2119]
  Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[RFC2453]
  Malkin, G., "RIP Version 2", STD 56, RFC 2453, DOI 10.17487/RFC2453, November 1998, <https://www.rfc-editor.org/info/rfc2453>.
[RFC2080]
  Malkin, G. and R. Minnear, "RIPng for IPv6", RFC 2080, DOI 10.17487/RFC2080, January 1997, <https://www.rfc-editor.org/info/rfc2080>.
[RFC3688]
  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, <https://www.rfc-editor.org/info/rfc3688>.
[RFC6020]
  Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, <https://www.rfc-editor.org/info/rfc6020>.
[RFC6241]
  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
  Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, <https://www.rfc-editor.org/info/rfc6242>.
[RFC6991]
  Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, <https://www.rfc-editor.org/info/rfc6991>.
[RFC7950]
  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, <https://www.rfc-editor.org/info/rfc8040>.
[RFC8174]
  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8177]
  Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J. Zhang, "YANG Data Model for Key Chains", RFC 8177, DOI 10.17487/RFC8177, June 2017, <https://www.rfc-editor.org/info/rfc8177>.
[RFC8341]
  Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, <https://www.rfc-editor.org/info/rfc8341>.
[RFC8342]
  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, <https://www.rfc-editor.org/info/rfc8342>.
[RFC8343]
  Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, March 2018, <https://www.rfc-editor.org/info/rfc8343>.
[RFC8344]
  Bjorklund, M., "A YANG Data Model for IP Management", RFC 8344, DOI 10.17487/RFC8344, March 2018, <https://www.rfc-editor.org/info/rfc8344>.
[RFC8349]
  Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for Routing Management (NMDA Version)", RFC 8349, DOI 10.17487/RFC8349, March 2018, <https://www.rfc-editor.org/info/rfc8349>.
[RFC8446]
  Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, <https://www.rfc-editor.org/info/rfc8446>.

### 7.2. Informative References

[RFC7951]
  Lhotka, L., "JSON Encoding of Data Modeled with YANG", RFC 7951, DOI 10.17487/RFC7951, August 2016, <https://www.rfc-editor.org/info/rfc7951>.
[RFC8340]
  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, <https://www.rfc-editor.org/info/rfc8340>.
[RFC8407]
  Bierman, A., "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", BCP 216, RFC 8407, DOI 10.17487/RFC8407, October 2018, <https://www.rfc-editor.org/info/rfc8407>.
[RFC8639]
  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard, E., and A. Tripathy, "Subscription to YANG Notifications", RFC 8639, DOI 10.17487/RFC8639, September 2019, <https://www.rfc-editor.org/info/rfc8639>.
[RFC8641]
  Clemm, A. and E. Voit, "Subscription to YANG Notifications for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641, September 2019, <https://www.rfc-editor.org/info/rfc8641>.
[YANG-BFD]
  Rahman, R., Zheng, L., Jethanandani, M., Pallagatti, S., and G. Mirsky, "YANG Data Model for Bidirectional Forwarding Detection (BFD)", Work in Progress, Internet-Draft, draft-ietf-bfd-yang-17, 2 August 2018, <https://tools.ietf.org/html/draft-ietf-bfd-yang-17>.
[YANG-ISIS]
  Litkowski, S., Yeung, D., Lindem, A., Zhang, Z., and L. Lhotka, "YANG Data Model for IS-IS Protocol", Work in Progress, Internet-Draft, draft-ietf-isis-yang-isis-cfg-42, 15 October 2019, <https://tools.ietf.org/html/draft-ietf-isis-yang-isis-cfg-42>.
[YANG-OSPF]
  Yeung, D., Qu, Y., Zhang, Z., Chen, I., and A. Lindem, "YANG Data Model for OSPF Protocol", Work in Progress, Internet-Draft, draft-ietf-ospf-yang-29, 17 October 2019, <https://tools.ietf.org/html/draft-ietf-ospf-yang-29>.

## Appendix A. Data Tree Example

This section contains an example of an instance data tree in the JSON encoding [RFC7951], containing both configuration and state data.¶

                      +---------------------+
                      |                     |
                      | Router 203.0.113.1  |
                      |                     |
                      +----------+----------+
                                 |eth1
                                 |2001:db8:0:1::1/64
                                 |
                                 |
                                 |2001:db8:0:1::2/64
                      +----------+----------+
                      |                     |         |
                      |   Another Router    +---------| 2001:db8:0:2::/64
                      |                     |         |
                      +---------------------+

Figure 1: RIPng Example

The configuration instance data tree for Router 203.0.113.1 in Figure 1 could be as follows:¶

    {
      "ietf-interfaces:interfaces": {
        "interface": [
          {
            "name": "eth1",
            "description": "An interface with RIPng enabled.",
            "type": "iana-if-type:ethernetCsmacd",
            "ietf-ip:ipv6": {
              "address": [
                {
                  "ip": "2001:db8:0:1::1",
                  "prefix-length": 64
                }
              ],
              "forwarding": true
            }
          }
        ]
      },
      "ietf-routing:routing": {
        "router-id": "203.0.113.1",
        "control-plane-protocols": {
          "control-plane-protocol": [
            {
              "type": "ietf-rip:ripng",
              "name": "ripng-1",
              "description": "RIPng instance ripng-1.",
              "ietf-rip:rip": {
                "redistribute": {
                  "connected": {
                  }
                },
                "interfaces": {
                  "interface": [
                    {
                      "interface": "eth1",
                      "split-horizon": "poison-reverse"
                    }
                  ]
                }
              }
            }
          ]
        }
      }
    }

¶

The corresponding operational state data for Router 203.0.113.1 could be as follows:¶

    {
      "ietf-interfaces:interfaces": {
        "interface": [
          {
            "name": "eth1",
            "description": "An interface with RIPng enabled.",
            "type": "iana-if-type:ethernetCsmacd",
            "phys-address": "00:00:5e:00:53:01",
            "oper-status": "up",
            "statistics": {
              "discontinuity-time": "2016-10-24T17:11:27+02:00"
            },
            "ietf-ip:ipv6": {
              "forwarding": true,
              "mtu": 1500,
              "address": [
                {
                  "ip": "2001:db8:0:1::1",
                  "prefix-length": 64,
                  "origin": "static",
                  "status": "preferred"
                },
                {
                  "ip": "fe80::200:5eff:fe00:5301",
                  "prefix-length": 64,
                  "origin": "link-layer",
                  "status": "preferred"
                }
              ],
              "neighbor": [
                {
                  "ip": "2001:db8:0:1::2",
                  "link-layer-address": "00:00:5e:00:53:02",
                  "origin": "dynamic",
                  "is-router": [null],
                  "state": "reachable"
                },
                {
                  "ip": "fe80::200:5eff:fe00:5302",
                  "link-layer-address": "00:00:5e:00:53:02",
                  "origin": "dynamic",
                  "is-router": [null],
                  "state": "reachable"
                }
              ]
            }
          }
        ]
      },
      "ietf-routing:routing": {
        "router-id": "203.0.113.1",
        "interfaces": {
          "interface": [
            "eth1"
          ]
        },
        "control-plane-protocols": {
          "control-plane-protocol": [
            {
              "type": "ietf-rip:ripng",
              "name": "ripng-1",
              "description": "RIPng instance ripng-1.",
              "ietf-rip:rip": {
                "default-metric": 1,
                "next-triggered-update": 5,
                "interfaces": {
                  "interface": [
                    {
                      "interface": "eth1",
                      "oper-status": "up",
                      "cost": 1,
                      "split-horizon": "poison-reverse",
                      "valid-address": true
                    }
                  ]
                },
                "ipv6": {
                  "neighbors": {
                    "neighbor": [
                      {
                        "ipv6-address": "fe80::200:5eff:fe00:5302",
                        "last-update": "2017-01-02T10:34:55+02:00"
                      }
                    ]
                  },
                  "routes": {
                    "route": [
                      {
                        "ipv6-prefix": "2001:db8:0:1::/64",
                        "interface": "eth1",
                        "redistributed": true,
                        "route-type": "connected",
                        "metric": 1,
                        "expire-time": 22
                      },
                      {
                        "ipv6-prefix": "2001:db8:0:2::/64",
                        "next-hop": "fe80::200:5eff:fe00:5302",
                        "interface": "eth1",
                        "redistributed": false,
                        "route-type": "rip",
                        "metric": 2,
                        "expire-time": 82
                      }
                    ]
                  }
                },
                "statistics": {
                  "discontinuity-time": "2016-10-24T17:11:27+02:00",
                  "requests-rcvd": 523,
                  "requests-sent": 262,
                  "responses-rcvd": 261,
                  "responses-sent": 523
                }
              }
            }
          ]
        }
      }
    }

¶

## Authors' Addresses