Internet-Draft YANG VRRP September 2024
Lindem, et al. Expires 31 March 2025 [Page]
Workgroup:
Network Working Group
Obsoletes:
8347 (if approved)
Published:
Intended Status:
Standards Track
Expires:
Authors:
A. Lindem, Ed.
LabN Consulting, L.L.C.
X. Liu
Alef Edge
A. Kyparlis
Jabil
R. Parikh
Zoox
M. Zhang
China Tower

A YANG Data Model for the Virtual Router Redundancy Protocol (VRRP)

Abstract

This document describes a YANG data model for the Virtual Router Redundancy Protocol (VRRP). Both versions 2 and 3 of VRRP are covered.

The VRRP terminology has been updated conform to inclusive language guidelines for IETF technologies. To avoid YANG non-backward compatible change restrictions, the YANG module will have desigination ietf-vrrp-2.yang rather than ietf-vrrp.yang.

This document obsoletes RFC 8347.

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 https://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 31 March 2025.

Table of Contents

1. Introduction

This document introduces a YANG data model [RFC6020] [RFC7950] for the Virtual Router Redundancy Protocol (VRRP) [RFC3768] [RFC9568]. VRRP provides higher resiliency by specifying an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN.

The YANG module specified in this document supports both versions 2 and 3 of VRRP. VRRP version 2 (defined in [RFC3768]) supports IPv4. VRRP version 3 (defined in [RFC9568]) supports both IPv4 and IPv6.

The VRRP terminology has been updated conform to inclusive language guidelines for IETF technologies. To avoid YANG non-backward compatible change restrictions, the YANG module will have desigination ietf-vrrp-2.yang rather than ietf-vrrp.yang. The IETF has designated National Institute of Standards and Technology (NIST) "Guidance for NIST Staff on Using Inclusive Language in Documentary Standards" [NISTIR8366] for its inclusive language guidelines. This document obsoletes VRRP Version 3 [RFC8347].

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:

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]

2. Design of the Data Model

2.1. Scope of the Model

The model covers VRRP version 2 [RFC3768] and VRRP version 3 [RFC9568]. The model is designed to be implemented on a device where VRRP version 2 or 3 is implemented. With the help of a proper management protocol, the defined model can be used to:

2.2. Relationships with the Interface Model and IP Model

This model augments the interface data model "ietf-interfaces" [RFC8343] and the IP management model "ietf-ip" [RFC8344]. The augmentation relationships are shown as follows:

module: ietf-interfaces
   +--rw interfaces
      +--rw interface* [name]
            ...
         +--rw ip:ipv4!
         |  +--rw ip:address* [ip]
                  ...
         |  +--rw vrrp:vrrp
         |     +--rw vrrp:vrrp-instance* [vrid]
         |        +--rw vrrp:vrid                            uint8
         |        +--rw vrrp:virtual-ipv4-addresses
                        ...
         +--rw ip:ipv6!
            +--rw ip:address* [ip]
                  ...
            +--rw vrrp:vrrp
               +--rw vrrp:vrrp-instance* [vrid]
                  +--rw vrrp:vrid                            uint8
                  +--rw vrrp:virtual-ipv6-addresses
                        ...
Figure 1

In the above figure, a tree node without a prefix is from the model "ietf-interfaces". A tree node with prefix "ip:" is from the model "ietf-ip". A tree node with prefix "vrrp:" is from the VRRP model specified in this document.

The "vrrp" container contains a list of vrrp-instance nodes, which are instantiated under an interface for a specified address family (IPv4 or IPv6).

Each vrrp-instance node represents a VRRP router state machine, as described in Section 6.4 of [RFC9568], providing the configuration and state information for the election process of a virtual router. The IP addresses on the augmented interface are the real addresses through which the VRRP router operates. The IPv4 or IPv6 address or addresses associated with a virtual router (described in Section 1 of [RFC9568]) are modeled as a list of IPv4 or IPv6 addresses under the vrrp-instance.

2.3. Protocol Configuration

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

  augment /if:interfaces/if:interface/ip:ipv4:
    +--rw vrrp
       +--rw vrrp-instance* [vrid]
          +--rw vrid                            uint8
          |     ...
          +--rw track
          |  +--rw interfaces
          |  |  +--rw interface* [interface]
          |  |     +--rw interface             if:interface-ref
          |  |           ...
          |  +--rw networks
          |     +--rw network* [prefix]
          |        +--rw prefix                inet:ipv4-prefix
          |              ...
          +--rw virtual-ipv4-addresses
             +--rw virtual-ipv4-address* [ipv4-address]
                +--rw ipv4-address    inet:ipv4-address

  augment /if:interfaces/if:interface/ip:ipv6:
    +--rw vrrp
       +--rw vrrp-instance* [vrid]
          +--rw vrid                            uint8
          |     ...
          +--rw track
          |  +--rw interfaces
          |  |  +--rw interface* [interface]
          |  |     +--rw interface             if:interface-ref
          |  |           ...
          |  +--rw networks
          |     +--rw network* [prefix]
          |        +--rw prefix                inet:ipv6-prefix
          |              ...
          +--rw virtual-ipv6-addresses
             +--rw virtual-ipv6-address* [ipv6-address]
                +--rw ipv6-address    inet:ipv6-address
Figure 2

The model allows the following protocol entities to be configured:

2.4. Protocol States

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


module: ietf-vrrp-2
    +--ro vrrp
       |     // global operational states
       +--ro virtual-routers?   uint32
       +--ro interfaces?        uint32
       +--ro statistics                 // global statistics
          +--ro discontinuity-datetime?   yang:date-and-time
          +--ro checksum-errors?          yang:counter64
          +--ro version-errors?           yang:counter64
          +--ro vrid-errors?              yang:counter64
          +--ro ip-ttl-errors?            yang:counter64

  augment /if:interfaces/if:interface/ip:ipv4:
    +--rw vrrp
       +--rw vrrp-instance* [vrid]
          +--rw vrid                            uint8
          |     ...
          +--rw track
          |  +--rw interfaces
          |  |  +--rw interface* [interface]
          |  |     +--rw interface             if:interface-ref
          |  |           ...
          |  +--rw networks
          |     +--rw network* [prefix]
          |        +--rw prefix                inet:ipv4-prefix
          |              ...
          +--rw virtual-ipv4-addresses
          |  +--rw virtual-ipv4-address* [ipv4-address]
          |     +--rw ipv4-address    inet:ipv4-address
          |
          |     // per-instance operational states
          +--ro state?                         identityref
          +--ro is-owner?                      boolean
          +--ro effective-priority?            uint8
          +--ro last-adv-source?               inet:ip-address
          +--ro up-datetime?                   yang:date-and-time
          +--ro active-down-interval?          uint32
          +--ro skew-time?                     uint32
          +--ro last-event?                    identityref
          +--ro new-active-reason?             new-active-reason-type
          +--ro statistics                // per-instance statistics
             +--ro discontinuity-datetime?    yang:date-and-time
             +--ro active-transitions?        yang:counter32
             +--ro advertisement-rcvd?        yang:counter64
             +--ro advertisement-sent?        yang:counter64
             +--ro interval-errors?           yang:counter64
             |       {validate-interval-errors}?
             +--ro priority-zero-pkts-rcvd?   yang:counter64
             +--ro priority-zero-pkts-sent?   yang:counter64
             +--ro invalid-type-pkts-rcvd?    yang:counter64
             +--ro address-list-errors?       yang:counter64
             |       {validate-address-list-errors}?
             +--ro packet-length-errors?      yang:counter64

  augment /if:interfaces/if:interface/ip:ipv6:
    +--rw vrrp
       +--rw vrrp-instance* [vrid]
          +--rw vrid                            uint8
          +     ...
          +--rw track
          |  +--rw interfaces
          |  |  +--rw interface* [interface]
          |  |     +--rw interface             if:interface-ref
          |  |           ...
          |  +--rw networks
          |     +--rw network* [prefix]
          |        +--rw prefix                inet:ipv6-prefix
          |              ...
          +--rw virtual-ipv6-addresses
          |  +--rw virtual-ipv6-address* [ipv6-address]
          |     +--rw ipv6-address    inet:ipv6-address
          |
          |     // per-instance operational states
          +--ro state?                         identityref
          +--ro is-owner?                      boolean
          +--ro effective-priority?            uint8
          +--ro last-adv-source?               inet:ip-address
          +--ro up-datetime?                   yang:date-and-time
          +--ro active-down-interval?          uint32
          +--ro skew-time?                     uint32
          +--ro last-event?                    identityref
          +--ro new-active-reason?             new-active-reason-type
          +--ro statistics                // per-instance statistics
             +--ro discontinuity-datetime?    yang:date-and-time
             +--ro active-transitions?        yang:counter32
             +--ro advertisement-rcvd?        yang:counter64
             +--ro advertisement-sent?        yang:counter64
             +--ro interval-errors?           yang:counter64
             |       {validate-interval-errors}?
             +--ro priority-zero-pkts-rcvd?   yang:counter64
             +--ro priority-zero-pkts-sent?   yang:counter64
             +--ro invalid-type-pkts-rcvd?    yang:counter64
             +--ro address-list-errors?       yang:counter64
             |       {validate-address-list-errors}?
             +--ro packet-length-errors?      yang:counter64
Figure 3

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:

2.5. Notifications

This model defines the following VRRP-specific notifications:

notifications:
   +---n vrrp-new-active-event
   |  +--ro active-ip-address    inet:ip-address
   |  +--ro new-active-reason    new-active-reason-type
   +---n vrrp-protocol-error-event
   |  +--ro protocol-error-reason    identityref
   +---n vrrp-virtual-router-error-event
      +--ro interface                      if:interface-ref
      +--ro (ip-version)
      |  +--:(ipv4)
      |  |  +--ro ipv4
      |  |     +--ro vrid    leafref
      |  +--:(ipv6)
      |     +--ro ipv6
      |        +--ro vrid    leafref
      +--ro virtual-router-error-reason    identityref
Figure 4

Each notification type is used to indicate a type of VRRP state change or error occurrence:

vrrp-new-active-event

VRRP new active event, indicating that a new active virtual router has been elected.

vrrp-protocol-error-event

VRRP protocol error event for a message that fails to reach a VRRP instance to be processed.

vrrp-virtual-router-error-event

VRRP virtual router error event for a message processed on a VRRP instance.

In addition to the notifications specified above, the mechanisms defined in [RFC8639] and [RFC8641] can be used for other general notifications. These mechanisms currently allow the user to:

3. Tree Structure

The VRRP-2 YANG data model defined in this document has the following tree structure:

module: ietf-vrrp-2
    +--ro vrrp
       +--ro virtual-routers?   uint32
       +--ro interfaces?        uint32
       +--ro statistics
          +--ro discontinuity-datetime?   yang:date-and-time
          +--ro checksum-errors?          yang:counter64
          +--ro version-errors?           yang:counter64
          +--ro vrid-errors?              yang:counter64
          +--ro ip-ttl-errors?            yang:counter64
  augment /if:interfaces/if:interface/ip:ipv4:
    +--rw vrrp
       +--rw vrrp-instance* [vrid]
          +--rw vrid                            uint8
          +--rw version                         identityref
          +--rw log-state-change?               boolean
          +--rw preempt
          |  +--rw enabled?     boolean
          |  +--rw hold-time?   uint16
          +--rw priority?                       uint8
          +--rw accept-mode?                    boolean
          +--rw (advertise-interval-choice)?
          |  +--:(v2)
          |  |  +--rw advertise-interval-sec?         uint8
          |  +--:(v3)
          |     +--rw advertise-interval-centi-sec?   uint16
          +--rw track
          |  +--rw interfaces
          |  |  +--rw interface* [interface]
          |  |     +--rw interface             if:interface-ref
          |  |     +--rw priority-decrement?   uint8
          |  +--rw networks
          |     +--rw network* [prefix]
          |        +--rw prefix                inet:ipv4-prefix
          |        +--rw priority-decrement?   uint8
          +--rw virtual-ipv4-addresses
          |  +--rw virtual-ipv4-address* [ipv4-address]
          |     +--rw ipv4-address    inet:ipv4-address
          +--ro state?                          identityref
          +--ro is-owner?                       boolean
          +--ro effective-priority?             uint8
          +--ro last-adv-source?                inet:ip-address
          +--ro up-datetime?                    yang:date-and-time
          +--ro active-down-interval?           uint32
          +--ro skew-time?                      uint32
          +--ro last-event?                     identityref
          +--ro new-active-reason?
 new-active-reason-type
          +--ro statistics
             +--ro discontinuity-datetime?    yang:date-and-time
             +--ro active-transitions?        yang:counter32
             +--ro advertisement-rcvd?        yang:counter64
             +--ro advertisement-sent?        yang:counter64
             +--ro interval-errors?           yang:counter64
             |       {validate-interval-errors}?
             +--ro priority-zero-pkts-rcvd?   yang:counter64
             +--ro priority-zero-pkts-sent?   yang:counter64
             +--ro invalid-type-pkts-rcvd?    yang:counter64
             +--ro address-list-errors?       yang:counter64
             |       {validate-address-list-errors}?
             +--ro packet-length-errors?      yang:counter64
  augment /if:interfaces/if:interface/ip:ipv6:
    +--rw vrrp
       +--rw vrrp-instance* [vrid]
          +--rw vrid                            uint8
          +--rw version                         identityref
          +--rw log-state-change?               boolean
          +--rw preempt
          |  +--rw enabled?     boolean
          |  +--rw hold-time?   uint16
          +--rw priority?                       uint8
          +--rw accept-mode?                    boolean
          +--rw advertise-interval-centi-sec?   uint16
          +--rw track
          |  +--rw interfaces
          |  |  +--rw interface* [interface]
          |  |     +--rw interface             if:interface-ref
          |  |     +--rw priority-decrement?   uint8
          |  +--rw networks
          |     +--rw network* [prefix]
          |        +--rw prefix                inet:ipv6-prefix
          |        +--rw priority-decrement?   uint8
          +--rw virtual-ipv6-addresses
          |  +--rw virtual-ipv6-address* [ipv6-address]
          |     +--rw ipv6-address    inet:ipv6-address
          +--ro state?                          identityref
          +--ro is-owner?                       boolean
          +--ro effective-priority?             uint8
          +--ro last-adv-source?                inet:ip-address
          +--ro up-datetime?                    yang:date-and-time
          +--ro active-down-interval?           uint32
          +--ro skew-time?                      uint32
          +--ro last-event?                     identityref
          +--ro new-active-reason?
 new-active-reason-type
          +--ro statistics
             +--ro discontinuity-datetime?    yang:date-and-time
             +--ro active-transitions?        yang:counter32
             +--ro advertisement-rcvd?        yang:counter64
             +--ro advertisement-sent?        yang:counter64
             +--ro interval-errors?           yang:counter64
             |       {validate-interval-errors}?
             +--ro priority-zero-pkts-rcvd?   yang:counter64
             +--ro priority-zero-pkts-sent?   yang:counter64
             +--ro invalid-type-pkts-rcvd?    yang:counter64
             +--ro address-list-errors?       yang:counter64
             |       {validate-address-list-errors}?
             +--ro packet-length-errors?      yang:counter64

  notifications:
    +---n vrrp-new-active-event
    |  +--ro active-ip-address    inet:ip-address
    |  +--ro new-active-reason    new-active-reason-type
    +---n vrrp-protocol-error-event
    |  +--ro protocol-error-reason    identityref
    +---n vrrp-virtual-router-error-event
       +--ro interface                      if:interface-ref
       +--ro (ip-version)
       |  +--:(ipv4)
       |  |  +--ro ipv4
       |  |     +--ro vrid    leafref
       |  +--:(ipv6)
       |     +--ro ipv6
       |        +--ro vrid    leafref
       +--ro virtual-router-error-reason    identityref
Figure 5

4. YANG Module

This module references [RFC2787], [RFC3768], [RFC9568], and [RFC6527].

<CODE BEGINS> file "ietf-vrrp-2@2024-09-17.yang"
module ietf-vrrp-2 {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-vrrp-2";
  prefix vrrp;

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

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

     Editor:   Acee Lindem
               <mailto:acee.ietf@gmail.com>

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

     Editor:   Athanasios Kyparlis
               <mailto:Athanasios_Kyparlis@jabil.com>

     Editor:   Ravi Parikh
               <mailto:parikhr@vmware.com>

     Editor:   Mingui Zhang
               <mailto:zhangmingui@huawei.com>";
  description
    "This YANG module defines a model for managing Virtual Router
     Redundancy Protocol (VRRP) versions 2 and 3.

     Copyright (c) 2024 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 Revised BSD License set
     forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
     for full legal notices.

     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 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.";

  revision 2024-09-17 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for the Virtual Router Redundancy
                 Protocol (VRRP)
       RFC 2787: Definitions of Managed Objects for the Virtual
                 Router Redundancy Protocol
       RFC 3768: Virtual Router Redundancy Protocol (VRRP)
       RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                 Version 3 for IPv4 and IPv6
       RFC 6527: Definitions of Managed Objects for the Virtual
                 Router Redundancy Protocol Version 3 (VRRPv3)";
  }

  /*
   * Features
   */

  feature validate-interval-errors {
    description
      "This feature indicates that the system validates that the
       advertisement interval from advertisement packets received
       is the same as the interval configured for the local
       VRRP router.";
  }

  feature validate-address-list-errors {
    description
      "This feature indicates that the system validates that
       the address list from received packets matches the
       locally configured list for the VRRP router.";
  }

  /*
   * Typedefs
   */

  typedef new-active-reason-type {
    type enumeration {
      enum not-active {
        description
          "The virtual router has never transitioned to active
           state.";
      }
      enum priority {
        description
          "Priority was higher.";
      }
      enum preempted {
        description
          "The active virtual router was preempted.";
      }
      enum no-response {
        description
          "Previous active virutal router did not respond.";
      }
    }
    description
      "Indicates why the virtual router has transitioned to
       active state.";
  } // new-active-reason-type

  /*
   * Identities
   */
  /* vrrp-event-type identity and its derivatives. */

  identity vrrp-event-type {
    description
      "Indicates the type of a VRRP protocol event.";
  }

  identity vrrp-event-none {
    base vrrp-event-type;
    description
      "Indicates a non-meaningful event.";
  }

  identity vrrp-event-startup {
    base vrrp-event-type;
    description
      "Indicates that a VRRP router has initiated the protocol.";
  }

  identity vrrp-event-shutdown {
    base vrrp-event-type;
    description
      "Indicates that a VRRP router has closed down the protocol.";
  }

  identity vrrp-event-higher-priority-backup {
    base vrrp-event-type;
    description
      "Indicates that a backup router has a higher priority than
       the current active.";
  }

  identity vrrp-event-active-timeout {
    base vrrp-event-type;
    description
      "Indicates that the current active virtual router has not sent
       an advertisement within the limit of active-down-interval.";
  }

  identity vrrp-event-interface-up {
    base vrrp-event-type;
    description
      "Indicates that the VRRP-enabled interface has become
       'operational up'.";
  }

  identity vrrp-event-interface-down {
    base vrrp-event-type;
    description
      "Indicates that the VRRP-enabled interface has become
       'operational down'.";
  }

  identity vrrp-event-no-primary-ip-address {
    base vrrp-event-type;
    description
      "Indicates that the primary IP address on the VRRP-enabled
       interface has become unavailable.";
  }

  identity vrrp-event-primary-ip-address {
    base vrrp-event-type;
    description
      "Indicates that the primary IP address on the VRRP-enabled
       interface has become available.";
  }

  identity vrrp-event-no-virtual-ip-addresses {
    base vrrp-event-type;
    description
      "Indicates that there are no virtual IP addresses on the
       virtual router.";
  }

  identity vrrp-event-virtual-ip-addresses {
    base vrrp-event-type;
    description
      "Indicates that there are virtual IP addresses on the
       virtual router.";
  }

  identity vrrp-event-preempt-hold-timeout {
    base vrrp-event-type;
    description
      "Indicates that the configured preemption hold time has
       passed.";
  }

  identity vrrp-event-lower-priority-active {
    base vrrp-event-type;
    description
      "Indicates that there is a lower-priority VRRP active router.";
  }

  identity vrrp-event-owner-preempt {
    base vrrp-event-type;
    description
      "Indicates that the owner has preempted another virtual router
       to become the active virtual router.";
  }

  /* vrrp-error-global identity and its derivatives. */

  identity vrrp-error-global {
    description
      "Indicates the type of a VRRP error that occurred
       for a packet before it reaches a VRRP router.";
  }

  identity checksum-error {
    base vrrp-error-global;
    description
      "A packet has been received with an invalid VRRP checksum
       value.";
  }

  identity ip-ttl-error {
    base vrrp-error-global;
    description
      "A packet has been received with IP TTL (Time-To-Live)
       not equal to 255.";
  }

  identity version-error {
    base vrrp-error-global;
    description
      "A packet has been received with an unknown or unsupported
       version number.";
  }

  identity vrid-error {
    base vrrp-error-global;
    description
      "A packet has been received with a Virtual Router Identifier
       (VRID) that is not valid for any virtual router on this
       router.";
  }

  /* vrrp-error-virtual-router identity and its derivatives. */

  identity vrrp-error-virtual-router {
    description
      "Indicates the type of a VRRP error that occurred
       after a packet reaches a VRRP router.";
  }

  identity address-list-error {
    base vrrp-error-virtual-router;
    description
      "A packet has been received with an address list that
       does not match the locally configured address list for
       the virtual router.";
  }

  identity interval-error {
    base vrrp-error-virtual-router;
    description
      "A packet has been received with an advertisement interval
       different than the interval configured for the local
       virtual router.";
  }

  identity packet-length-error {
    base vrrp-error-virtual-router;
    description
      "A packet has been received with a packet length less
       than the length of the VRRP header.";
  }

  /* vrrp-state-type identity and its derivatives. */

  identity vrrp-state-type {
    description
      "Indicates the state of a virtual router.";
  }

  identity initialize {
    base vrrp-state-type;
    description
      "Indicates that the virtual router is waiting
       for a startup event.";
  }

  identity backup {
    base vrrp-state-type;
    description
      "Indicates that the virtual router is monitoring the
       availability of the active virtual router.";
  }

  identity active {
    base vrrp-state-type;
    description
      "Indicates that the virtual router is forwarding
       packets for IP addresses that are associated with
       this virtual router.";
  }

  /* vrrp-version identity and its derivatives. */

  identity vrrp-version {
    description
      "The version of VRRP.";
  }

  identity vrrp-v2 {
    base vrrp-version;
    description
      "Indicates version 2 of VRRP.";
  }

  identity vrrp-v3 {
    base vrrp-version;
    description
      "Indicates version 3 of VRRP.";
  }

  /*
   * Groupings
   */

  grouping vrrp-common-attributes {
    description
      "Group of VRRP attributes common to versions 2 and 3.";
    leaf vrid {
      type uint8 {
        range "1..255";
      }
      description
        "Virtual Router ID (i.e., VRID).";
    }
    leaf version {
      type identityref {
        base vrrp:vrrp-version;
      }
      mandatory true;
      description
        "Version 2 or 3 of VRRP.";
    }
    leaf log-state-change {
      type boolean;
      default "false";
      description
        "Generates VRRP state change messages each time the
         VRRP instance changes state (from 'up' to 'down'
         or 'down' to 'up').";
    }
    container preempt {
      description
        "Enables a higher-priority VRRP backup router to preempt a
         lower-priority VRRP active router.";
      leaf enabled {
        type boolean;
        default "true";
        description
          "'true' if preemption is enabled.";
      }
      leaf hold-time {
        type uint16;
        units "seconds";
        default "0";
        description
          "Hold time, in seconds, for which a higher-priority VRRP
           backup router must wait before preempting a lower-priority
           VRRP active router.";
      }
    }
    leaf priority {
      type uint8 {
        range "1..254";
      }
      default "100";
      description
        "Configures the VRRP election priority for the backup
         virtual router.";
    }
    leaf accept-mode {
      when "derived-from-or-self(current()/../version, 'vrrp-v3')" {
        description
          "Applicable only to version 3.";
      }
      type boolean;
      default "false";
      description
        "Controls whether a virtual router in active state will
         accept packets addressed to the address owner's IPvX address
         as its own if it is not the IPvX address owner.  The default
         is 'false'.  Deployments that rely on, for example, pinging
         the address owner's IPvX address may wish to configure
         accept-mode to 'true'.

         Note: IPv6 Neighbor Solicitations and Neighbor
         Advertisements MUST NOT be dropped when accept-mode
         is 'false'.";
    }
  } // vrrp-common-attributes

  grouping vrrp-ipv4-attributes {
    description
      "Group of VRRP attributes for IPv4.";
    uses vrrp-common-attributes;
    choice advertise-interval-choice {
      description
        "The options for the advertisement interval at which VRRPv2
         or VRRPv3 advertisements are sent from the specified
         interface.";
      case v2 {
        when "derived-from-or-self(version, 'vrrp-v2')" {
          description
            "Applicable only to version 2.";
        }
        leaf advertise-interval-sec {
          type uint8 {
            range "1..254";
          }
          units "seconds";
          default "1";
          description
            "Configures the interval that VRRPv2 advertisements
             are sent from the specified interface.";
        }
      }
      case v3 {
        when "derived-from-or-self(version, 'vrrp-v3')" {
          description
            "Applicable only to version 3.";
        }
        leaf advertise-interval-centi-sec {
          type uint16 {
            range "1..4095";
          }
          units "centiseconds";
          default "100";
          description
            "Configures the interval that VRRPv3 advertisements
             are sent from the specified interface.";
        }
      }
    } // advertise-interval-choice
    container track {
      description
        "Enables the specified VRRP instance to track interfaces
         or networks.";
      container interfaces {
        description
          "Enables the specified VRRPv2 or VRRPv3 instance to track
           interfaces.  Interface tracking prevents traffic loss by
           detecting the availability of interfaces.  The operational
           states of other interfaces are associated with the
           priority of a VRRP router.  When a tracked interface
           becomes unavailable (or 'operational down'), the priority
           of the VRRP router decrements.  When an unavailable
           interface becomes available again, the priority of the
           VRRP router is incremented by the same amount.";
        list interface {
          key "interface";
          description
            "Interface to track.";
          leaf interface {
            type if:interface-ref;
            must '/if:interfaces/if:interface[if:name=current()]/'
               + 'ip:ipv4' {
              description
                "Interface is IPv4.";
            }
            description
              "Interface to track.";
          }
          leaf priority-decrement {
            type uint8 {
              range "1..254";
            }
            default "10";
            description
              "Specifies how much to decrement the priority of the
               VRRP instance if the interface goes down.";
          }
        } // interface
      } // interfaces
      container networks {
        description
          "Enables the VRRPv2 or VRRPv3 router instance to track the
           specified networks through their IPv4 network prefixes.
           Network tracking prevents traffic loss by detecting
           network connectivity failure.  The states of
           connectivity to some networks are associated with the
           priority of a VRRP router.  When connectivity to a
           tracked network represented by its prefix is lost, the
           priority of the VRRP router decrements.  When an
           unavailable network is again reachable, the priority of
           the VRRP router is incremented by the same amount.";
        list network {
          key "prefix";
          description
            "Enables the specified VRRPv2 or VRRPv3 instance to
             track an IPv4 network by specifying the prefix of the
             IPv4 network.";
          leaf prefix {
            type inet:ipv4-prefix;
            description
              "The IPv4 prefix of the network to track.";
          }
          leaf priority-decrement {
            type uint8 {
              range "1..254";
            }
            default "10";
            description
              "Specifies how much to decrement the priority of the
               VRRP router if there is a failure in the IPv4
               network.";
          }
        } // network
      } // networks
    } // track
    container virtual-ipv4-addresses {
      description
        "Configures the virtual IPv4 address for the
         VRRP interface.";
      list virtual-ipv4-address {
        key "ipv4-address";
        max-elements 16;
        description
          "Virtual IPv4 addresses for a single VRRP instance.  For a
           VRRP owner router, the virtual address must match one
           of the IPv4 addresses configured on the interface
           corresponding to the virtual router.";
        leaf ipv4-address {
          type inet:ipv4-address;
          description
            "An IPv4 address associated with a virtual router.";
          reference
            "RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                       Version 3 for IPv4 and IPv6.  Section 1.2";
        }
      } // virtual-ipv4-address
    } // virtual-ipv4-addresses
  } // vrrp-ipv4-attributes

  grouping vrrp-ipv6-attributes {
    description
      "Group of VRRP attributes for IPv6.";
    uses vrrp-common-attributes;
    leaf advertise-interval-centi-sec {
      type uint16 {
        range "1..4095";
      }
      units "centiseconds";
      default "100";
      description
        "Configures the interval that VRRPv3 advertisements
         are sent from the specified interface.";
    }
    container track {
      description
        "Enables the specified VRRP instance to track interfaces
         or networks.";
      container interfaces {
        description
          "Enables the specified VRRPv2 or VRRPv3 instance to track
           interfaces.  Interface tracking prevents traffic loss by
           detecting the availability of interfaces.  The operational
           states of other interfaces are associated with the
           priority of a VRRP router.  When a tracked interface
           becomes unavailable (or 'operational down'), the priority
           of the VRRP router decrements.  When an unavailable
           interface becomes available again, the priority of the
           VRRP router is incremented by the same amount.";
        list interface {
          key "interface";
          description
            "Interface to track.";
          leaf interface {
            type if:interface-ref;
            must '/if:interfaces/if:interface[if:name=current()]/'
               + 'ip:ipv6' {
              description
                "Interface is IPv6.";
            }
            description
              "Interface to track.";
          }
          leaf priority-decrement {
            type uint8 {
              range "1..254";
            }
            default "10";
            description
              "Specifies how much to decrement the priority of the
               VRRP instance if the interface goes down.";
          }
        } // interface
      } // interfaces
      container networks {
        description
          "Enables the VRRPv2 or VRRPv3 router instance to track the
           specified networks through their IPv6 network prefixes.
           Network tracking prevents traffic loss by detecting
           network connectivity failure.  The states of
           connectivity to some networks are associated with the
           priority of a VRRP router.  When connectivity to a
           tracked network represented by its prefix is lost, the
           priority of the VRRP router decrements.  When an
           unavailable network is again reachable, the priority of
           the VRRP router is incremented by the same amount.";
        list network {
          key "prefix";
          description
            "Enables the specified VRRPv2 or VRRPv3 instance to
             track an IPv6 network by specifying the prefix of the
             IPv6 network.";
          leaf prefix {
            type inet:ipv6-prefix;
            description
              "The IPv6 prefix of the network to track.";
          }
          leaf priority-decrement {
            type uint8 {
              range "1..254";
            }
            default "10";
            description
              "Specifies how much to decrement the priority of the
               VRRP router if there is a failure in the IPv6
               network.";
          }
        } // network
      } // networks
    } // track
    container virtual-ipv6-addresses {
      description
        "Configures the virtual IPv6 address for the
         VRRP interface.";
      list virtual-ipv6-address {
        key "ipv6-address";
        max-elements 2;
        description
          "Two IPv6 addresses are allowed.  The first address must
           be a link-local address.  The second address can be a
           link-local or global address.";
        leaf ipv6-address {
          type inet:ipv6-address;
          description
            "An IPv6 address associated with a virtual router.";
          reference
            "RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                       Version 3 for IPv4 and IPv6.  Section 1.3";
        }
      } // virtual-ipv6-address
    } // virtual-ipv6-addresses
  } // vrrp-ipv6-attributes

  grouping vrrp-state-attributes {
    description
      "Group of VRRP state attributes.";
    leaf state {
      type identityref {
        base vrrp:vrrp-state-type;
      }
      config false;
      description
        "Operational state.";
    }
    leaf is-owner {
      type boolean;
      config false;
      description
        "Set to 'true' if this virtual router is the owner.";
    }
    leaf effective-priority {
      type uint8 {
        range "1..255";
      }
      config false;
      description
        "The effect priority of the virtual router taking account
         address ownership and any modifications due to
         local policy.";
    }
    leaf last-adv-source {
      type inet:ip-address;
      config false;
      description
        "Last advertised IPv4/IPv6 source address.";
    }
    leaf up-datetime {
      type yang:date-and-time;
      config false;
      description
        "The date and time when this virtual router
         transitioned out of 'init' state.";
    }
    leaf active-down-interval {
      type uint32;
      units "centiseconds";
      config false;
      description
        "Time interval for the backup virtual router to declare
         'active down'.";
    }
    leaf skew-time {
      type uint32;
      units "microseconds";
      config false;
      description
        "Calculated based on the priority and advertisement
         interval configuration command parameters.  See RFC 3768.";
    }
    leaf last-event {
      type identityref {
        base vrrp:vrrp-event-type;
      }
      config false;
      description
        "Last reported event.";
    }
    leaf new-active-reason {
      type new-active-reason-type;
      config false;
      description
        "Indicates why the virtual router has transitioned to
         active state.";
    }
    container statistics {
      config false;
      description
        "VRRP statistics.";
      leaf discontinuity-datetime {
        type yang:date-and-time;
        description
          "The time on the most recent occasion at which any one or
           more of the VRRP 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 that the
           local management subsystem re-initialized itself.";
      }
      leaf active-transitions {
        type yang:counter32;
        description
          "The total number of times that this virtual router's
           state has transitioned to 'Active'.";
      }
      leaf advertisement-rcvd {
        type yang:counter64;
        description
          "The total number of VRRP advertisements received by
           this virtual router.";
      }
      leaf advertisement-sent {
        type yang:counter64;
        description
          "The total number of VRRP advertisements sent by
           this virtual router.";
      }
      leaf interval-errors {
        if-feature "validate-interval-errors";
        type yang:counter64;
        description
          "The total number of VRRP advertisement packets received
           with an advertisement interval different than the
           interval configured for the local virtual router.";
      }
      leaf priority-zero-pkts-rcvd {
        type yang:counter64;
        description
          "The total number of VRRP packets received by the
           virtual router with a priority of 0.";
      }
      leaf priority-zero-pkts-sent {
        type yang:counter64;
        description
          "The total number of VRRP packets sent by the
           virtual router with a priority of 0.";
      }
      leaf invalid-type-pkts-rcvd {
        type yang:counter64;
        description
          "The number of VRRP packets received by the virtual
           router with an invalid value in the 'type' field.";
      }
      leaf address-list-errors {
        if-feature "validate-address-list-errors";
        type yang:counter64;
        description
          "The total number of packets received with an
           address list that does not match the locally
           configured address list for the virtual router.";
      }
      leaf packet-length-errors {
        type yang:counter64;
        description
          "The total number of packets received with a packet
           length less than the length of the VRRP header.";
      }
    } // statistics
  } // vrrp-state-attributes

  grouping vrrp-global-state-attributes {
    description
      "Group of VRRP global state attributes.";
    leaf virtual-routers {
      type uint32;
      description
        "Number of configured virtual routers.";
    }
    leaf interfaces {
      type uint32;
      description
        "Number of interfaces with VRRP configured.";
    }
    container statistics {
      description
        "VRRP global statistics.";
      leaf discontinuity-datetime {
        type yang:date-and-time;
        description
          "The time on the most recent occasion at which any
           one or more of checksum-errors, version-errors,
           vrid-errors, or ip-ttl-errors 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 that the local management
           subsystem re-initialized itself.";
      }
      leaf checksum-errors {
        type yang:counter64;
        description
          "The total number of VRRP packets received with an invalid
           VRRP checksum value.";
        reference
          "RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6.  Section 5.2.8";
      }
      leaf version-errors {
        type yang:counter64;
        description
          "The total number of VRRP packets received with an unknown
           or unsupported version number.";
        reference
          "RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6.  Section 5.2.1";
      }
      leaf vrid-errors {
        type yang:counter64;
        description
          "The total number of VRRP packets received with a VRID that
           is not valid for any virtual router on this router.";
        reference
          "RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6.  Section 5.2.3";
      }
      leaf ip-ttl-errors {
        type yang:counter64;
        description
          "The total number of VRRP packets received by the
           virtual router with IP TTL (IPv4) or Hop Limit (IPv6)
           not equal to 255.";
        reference
          "RFC 9568: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6.
                     Sections 5.1.1.3 and 5.1.2.3";
      }
    } // statistics
  } // vrrp-global-state-attributes

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

  augment "/if:interfaces/if:interface/ip:ipv4" {
    description
      "Augments IPv4 interface.";
    container vrrp {
      description
        "Configures VRRP version 2 or 3 for IPv4.";
      list vrrp-instance {
        key "vrid";
        description
          "Defines a virtual router, identified by a VRID, within the
           IPv4 address space.";
        uses vrrp-ipv4-attributes;
        uses vrrp-state-attributes;
      }
    }
  } // augments ipv4

  augment "/if:interfaces/if:interface/ip:ipv6" {
    description
      "Augments IPv6 interface.";
    container vrrp {
      description
        "Configures VRRP version 3 for IPv6.";
      list vrrp-instance {
        must "derived-from-or-self(version, 'vrrp-v3')" {
          description
            "IPv6 is only supported by version 3.";
        }
        key "vrid";
        description
          "Defines a virtual router, identified by a VRID, within the
           IPv6 address space.";
        uses vrrp-ipv6-attributes;
        uses vrrp-state-attributes;
      }
    }
  } // augments ipv6

  container vrrp {
    config false;
    description
      "VRRP data at the global level.";
    uses vrrp-global-state-attributes;
  }

  /*
   * Notifications
   */

  notification vrrp-new-active-event {
    description
      "Notification event for the election of a new VRRP
       active router.";
    leaf active-ip-address {
      type inet:ip-address;
      mandatory true;
      description
        "IPv4 or IPv6 address of the new VRRP active router.";
    }
    leaf new-active-reason {
      type new-active-reason-type;
      mandatory true;
      description
        "Indicates why the virtual router has transitioned to
         active state.";
    }
  }

  notification vrrp-protocol-error-event {
    description
      "Notification event for a VRRP protocol error.";
    leaf protocol-error-reason {
      type identityref {
        base vrrp:vrrp-error-global;
      }
      mandatory true;
      description
        "Indicates the reason for the protocol error.";
    }
  }

  notification vrrp-virtual-router-error-event {
    description
      "Notification event for an error that happened on a
       virtual router.";
    leaf interface {
      type if:interface-ref;
      mandatory true;
      description
        "Indicates the interface on which the event has occurred.";
    }
    choice ip-version {
      mandatory true;
      description
        "The error may have happened on either an IPv4 virtual
         router or an IPv6 virtual router.  The information
         related to a specific IP version is provided by one of
         the following cases.";
      case ipv4 {
        description
          "IPv4.";
        container ipv4 {
          description
            "Error information for IPv4.";
          leaf vrid {
            type leafref {
              path "/if:interfaces/if:interface"
                 + "[if:name = current()/../../vrrp:interface]/"
                 + "ip:ipv4/vrrp:vrrp/vrrp:vrrp-instance/vrrp:vrid";
            }
            mandatory true;
            description
              "Indicates the virtual router on which the event has
               occurred.";
          }
        }
      }
      case ipv6 {
        description
          "IPv6.";
        container ipv6 {
          description
            "Error information for IPv6.";
          leaf vrid {
            type leafref {
              path "/if:interfaces/if:interface"
                 + "[if:name = current()/../../vrrp:interface]/"
                 + "ip:ipv6/vrrp:vrrp/vrrp:vrrp-instance/vrrp:vrid";
            }
            mandatory true;
            description
              "Indicates the virtual router on which the event has
               occurred.";
          }
        }
      }
    }
    leaf virtual-router-error-reason {
      type identityref {
        base vrrp:vrrp-error-virtual-router;
      }
      mandatory true;
      description
        "Indicates the reason for the virtual router error.";
    }
  }
}
<CODE ENDS>
Figure 6

5. IANA Considerations

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

--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-vrrp-2
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
--------------------------------------------------------------------
Figure 7

This document registers the following YANG module in the "YANG Module Names" registry [RFC7950]:

--------------------------------------------------------------------
name:         ietf-vrrp-2
namespace:    urn:ietf:params:xml:ns:yang:ietf-vrrp-2
prefix:       vrrp
reference:    RFC 8347
--------------------------------------------------------------------
Figure 8

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 [RFC5246].

The NETCONF access control model [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.

There are a number of data nodes defined in 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:

/if:interfaces/if:interface/ip:ipv4/vrrp:vrrp/vrrp:vrrp-instance

/if:interfaces/if:interface/ip:ipv6/vrrp:vrrp/vrrp:vrrp-instance

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:

/ietf-vrrp-2:vrrp

/if:interfaces/if:interface/ip:ipv4/vrrp:vrrp/vrrp:vrrp-instance

/if:interfaces/if:interface/ip:ipv6/vrrp:vrrp/vrrp:vrrp-instance

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

7. Acknowledgments

Thanks to Nicola Serafini for his suggestion to add effective-priority to the virtual router operational state.

8. Normative References

[NISTIR8366]
"Guidance for NIST Staff on Using Inclusive Language in Documentary Standards, National Institute of Standards and Technology (NIST) Interagency or Internal Report 8366", NISTIR 8366, , <https://doi.org/10.6028/NIST.IR.8366>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC2787]
Jewell, B. and D. Chuang, "Definitions of Managed Objects for the Virtual Router Redundancy Protocol", RFC 2787, DOI 10.17487/RFC2787, , <https://www.rfc-editor.org/info/rfc2787>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
[RFC5246]
Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, , <https://www.rfc-editor.org/info/rfc5246>.
[RFC6020]
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <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, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC6527]
Tata, K., "Definitions of Managed Objects for Virtual Router Redundancy Protocol Version 3 (VRRPv3)", RFC 6527, DOI 10.17487/RFC6527, , <https://www.rfc-editor.org/info/rfc6527>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <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, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <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, , <https://www.rfc-editor.org/info/rfc8342>.
[RFC8343]
Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, , <https://www.rfc-editor.org/info/rfc8343>.
[RFC8344]
Bjorklund, M., "A YANG Data Model for IP Management", RFC 8344, DOI 10.17487/RFC8344, , <https://www.rfc-editor.org/info/rfc8344>.
[RFC8347]
Liu, X., Ed., Kyparlis, A., Parikh, R., Lindem, A., and M. Zhang, "A YANG Data Model for the Virtual Router Redundancy Protocol (VRRP)", RFC 8347, DOI 10.17487/RFC8347, , <https://www.rfc-editor.org/info/rfc8347>.
[RFC9568]
Lindem, A. and A. Dogra, "Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6", RFC 9568, DOI 10.17487/RFC9568, , <https://www.rfc-editor.org/info/rfc9568>.

9. Informative References

[RFC3768]
Hinden, R., Ed., "Virtual Router Redundancy Protocol (VRRP)", RFC 3768, DOI 10.17487/RFC3768, , <https://www.rfc-editor.org/info/rfc3768>.
[RFC7224]
Bjorklund, M., "IANA Interface Type YANG Module", RFC 7224, DOI 10.17487/RFC7224, , <https://www.rfc-editor.org/info/rfc7224>.
[RFC7951]
Lhotka, L., "JSON Encoding of Data Modeled with YANG", RFC 7951, DOI 10.17487/RFC7951, , <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, , <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, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8641>.

Appendix A. Data Tree Example

This section contains an example of an instance data tree in JSON encoding [RFC7951], containing both configuration and state data. (This example includes "iana-if-type", which is defined in [RFC7224].)

              Virtual router IP address: fe80::1
           +-----------------+        +-----------------+
           |                 |        |                 |
           |    Router 1     |        |    Router 2     |
           |                 |        |                 |
           +--------+--------+        +--------+--------+
                    |eth1                      |eth1
                    |fe80::11                  |fe80::12
             -------+--------------------------+-------
                    |                          |
                    |fe80::51                  |fe80::52
           +--------+--------+        +--------+--------+
           |     Host 1      |        |     Host 2      |
           | Default gateway:|        | Default gateway:|
           |     fe80::1     |        |     fe80::1     |
           +-----------------+        +-----------------+
Figure 9

The configuration instance data for Router 1 in the above figure could be as follows:

{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "eth1",
        "description": "An interface with VRRP enabled.",
        "type": "iana-if-type:ethernetCsmacd",
        "ietf-ip:ipv6": {
          "address": [
            {
              "ip": "2001:db8:0:1::1",
              "prefix-length": 64
            },
            {
              "ip": "fe80::11",
              "prefix-length": 64
            }
          ],
          "forwarding": true,
          "ietf-vrrp-2:vrrp": {
            "vrrp-instance": [
              {
                "vrid": 1,
                "version": "vrrp-v3",
                "priority": 200,
                "advertise-interval-centi-sec": 50,
                "virtual-ipv6-addresses": {
                  "virtual-ipv6-address": [
                    "ipv6-address": "fe80::1"
                  ]
                }
              }
            ]
          }
        }
      }
    ]
  }
}
Figure 10

The corresponding operational state data for Router 1 could be as follows:

{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "eth1",
        "description": "An interface with VRRP 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::11",
              "prefix-length": 64,
              "origin": "static",
              "status": "preferred"
            }
          ]
          "ietf-vrrp-2:vrrp": {
            "vrrp-instance": [
              {
                "vrid": 1,
                "version": "vrrp-v3",
                "log-state-change": false,
                "preempt": {
                  "enabled": true,
                  "hold-time": 0
                }
                "priority": 200,
                "accept-mode": false,
                "advertise-interval-centi-sec": 50,
                "virtual-ipv6-addresses": {
                  "virtual-ipv6-address": [
                    "ipv6-address": "fe80::1"
                  ]
                },
                "state": "active",
                "is-owner": false,
                "effective-priority": 200,
                "last-adv-source": "fe80::11",
                "up-datetime": "2016-10-24T17:11:27+02:00",
                "active-down-interval": 161,
                "skew-time": 11,
                "last-event": "vrrp-event-interface-up",
                "new-active-reason": "priority",
                "statistics": {
                  "discontinuity-datetime":
                    "2016-10-24T17:11:27+02:00",
                  "active-transitions": 2,
                  "advertisement-rcvd": 20,
                  "advertisement-sent": 12,
                  "interval-errors": 0,
                  "priority-zero-pkts-rcvd": 0,
                  "priority-zero-pkts-sent": 0,
                  "invalid-type-pkts-rcvd": 0,
                  "address-list-errors": 0,
                  "packet-length-errors": 1
                }
              }
            ]
          }
        }
      }
    ]
  }
}

{
  "ietf-vrrp-2:vrrp": {
    "virtual-routers": 3,
    "interfaces": 2,
    "statistics": {
      "discontinuity-datetime": "2016-10-24T17:11:27+02:00",
      "checksum-errors": 2,
      "version-errors": 0,
      "vrid-errors": 0,
      "ip-ttl-errors": 1
    }
  }
}
Figure 11

Authors' Addresses

Acee Lindem (editor)
LabN Consulting, L.L.C.
301 Midenhall Way
Cary, NC 27513
United States of America
Xufeng Liu
Alef Edge
United States of America
Athanasios Kyparlis
Jabil
8281 Greensboro Drive, Suite 200
McLean, VA 22102
United States of America
Ravi Parikh
Zoox
United States of America
Mingui Zhang
China Tower
9 Dongranbeijie Haidian District
Beijing
China