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Common YANG Data Types
draft-ietf-netmod-rfc6991-bis-15

Document Type Active Internet-Draft (netmod WG)
Author Jürgen Schönwälder
Last updated 2023-03-22 (Latest revision 2023-01-23)
Replaces draft-schoenw-netmod-rfc6991-bis
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
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Additional resources Yang catalog entry for ietf-inet-types@2020-07-06.yang
Yang catalog entry for ietf-yang-types@2020-07-06.yang
Yang impact analysis for draft-ietf-netmod-rfc6991-bis
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Stream WG state Submitted to IESG for Publication
Document shepherd Kent Watsen
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draft-ietf-netmod-rfc6991-bis-15
Network Working Group                                J. Schönwälder, Ed.
Internet-Draft                                    Constructor University
Obsoletes: 6991 (if approved)                            23 January 2023
Intended status: Standards Track                                        
Expires: 27 July 2023

                         Common YANG Data Types
                    draft-ietf-netmod-rfc6991-bis-15

Abstract

   This document defines a collection of common data types to be used
   with the YANG data modeling language.  This version of the document
   adds several new type definitions and obsoletes RFC 6991.

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 27 July 2023.

Copyright Notice

   Copyright (c) 2023 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Core YANG Types . . . . . . . . . . . . . . . . . . . . . . .   7
   4.  Internet Protocol Suite Types . . . . . . . . . . . . . . . .  23
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  36
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  37
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  37
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .  37
   9.  Informative References  . . . . . . . . . . . . . . . . . . .  39
   Appendix A.  Changes from RFC 6991  . . . . . . . . . . . . . . .  42
   Appendix B.  Changes from RFC 6021  . . . . . . . . . . . . . . .  43
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  43

1.  Introduction

   YANG [RFC7950] is a data modeling language used to model
   configuration and state data manipulated by the Network Configuration
   Protocol (NETCONF) [RFC6241].  The YANG language supports a small set
   of built-in data types and provides mechanisms to derive other types
   from the built-in types.

   This document introduces a collection of common data types derived
   from the built-in YANG data types.  The derived types are designed to
   be applicable for modeling all areas of management information.  The
   definitions are organized in two YANG modules.  The "ietf-yang-types"
   module contains generally useful data types.  The "ietf-inet-types"
   module contains definitions that are relevant for the Internet
   protocol suite.

   This document adds new type definitions to these YANG modules and
   obsoletes [RFC6991].  For further details, see the revision
   statements of the YANG modules in Section 3 and Section 4 and the
   brief summary in Appendix A.

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   This document uses the YANG terminology defined in Section 3 of
   [RFC7950].

   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.

2.  Overview

   Table 1 and Table 2 list the types defined in the YANG modules "ietf-
   yang-types" and "ietf-inet-types".  For each type, the name of the
   type, the base type it was derived from, and the RFC introducing the
   type is listed.

        +=======================+===================+============+
        | Type                  | Base Type         | Introduced |
        +=======================+===================+============+
        | counter32             | uint32            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | zero-based-counter32  | uint32            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | counter64             | uint64            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | zero-based-counter64  | uint64            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | gauge32               | uint32            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | gauge64               | uint64            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | object-identifier     | string            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | object-identifier-128 | object-identifier | RFC 6021   |
        +-----------------------+-------------------+------------+
        | date-and-time         | string            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | date-with-zone-offset | string            | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | date-no-zone          | string            | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | time-with-zone-offset | string            | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | time-no-zone          | string            | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | hours32               | int32             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | minutes32             | int32             | RFC XXXX   |

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        +-----------------------+-------------------+------------+
        | seconds32             | int32             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | centiseconds32        | int32             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | milliseconds32        | int32             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | microseconds32        | int32             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | microseconds64        | int64             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | nanoseconds32         | int32             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | nanoseconds64         | int64             | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | timeticks             | int32             | RFC 6021   |
        +-----------------------+-------------------+------------+
        | timestamp             | timeticks         | RFC 6021   |
        +-----------------------+-------------------+------------+
        | phys-address          | string            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | mac-address           | string            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | xpath1.0              | string            | RFC 6021   |
        +-----------------------+-------------------+------------+
        | hex-string            | string            | RFC 6991   |
        +-----------------------+-------------------+------------+
        | uuid                  | string            | RFC 6991   |
        +-----------------------+-------------------+------------+
        | dotted-quad           | string            | RFC 6991   |
        +-----------------------+-------------------+------------+
        | language-tag          | string            | RFC XXXX   |
        +-----------------------+-------------------+------------+
        | yang-identifier       | string            | RFC 6991   |
        +-----------------------+-------------------+------------+

                Table 1: Types defined in ietf-yang-types

          +=========================+==============+============+
          | Type                    | Base Type    | Introduced |
          +=========================+==============+============+
          | ip-version              | enum         | RFC 6021   |
          +-------------------------+--------------+------------+
          | dscp                    | uint8        | RFC 6021   |
          +-------------------------+--------------+------------+
          | ipv6-flow-label         | uint32       | RFC 6021   |
          +-------------------------+--------------+------------+
          | port-number             | uint16       | RFC 6021   |

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          +-------------------------+--------------+------------+
          | protocol-number         | uint8        | RFC XXXX   |
          +-------------------------+--------------+------------+
          | as-number               | uint32       | RFC 6021   |
          +-------------------------+--------------+------------+
          | ip-address              | union        | RFC 6021   |
          +-------------------------+--------------+------------+
          | ipv4-address            | string       | RFC 6021   |
          +-------------------------+--------------+------------+
          | ipv6-address            | string       | RFC 6021   |
          +-------------------------+--------------+------------+
          | ip-address-no-zone      | union        | RFC 6991   |
          +-------------------------+--------------+------------+
          | ipv4-address-no-zone    | ipv4-address | RFC 6991   |
          +-------------------------+--------------+------------+
          | ipv6-address-no-zone    | ipv6-address | RFC 6991   |
          +-------------------------+--------------+------------+
          | ip-address-link-local   | union        | RFC XXXX   |
          +-------------------------+--------------+------------+
          | ipv4-address-link-local | ipv4-address | RFC XXXX   |
          +-------------------------+--------------+------------+
          | ipv6-address-link-local | ipv6-address | RFC XXXX   |
          +-------------------------+--------------+------------+
          | ip-prefix               | union        | RFC 6021   |
          +-------------------------+--------------+------------+
          | ipv4-prefix             | string       | RFC 6021   |
          +-------------------------+--------------+------------+
          | ipv6-prefix             | string       | RFC 6021   |
          +-------------------------+--------------+------------+
          | ip-address-and-prefix   | union        | RFC XXXX   |
          +-------------------------+--------------+------------+
          | ipv4-address-and-prefix | string       | RFC XXXX   |
          +-------------------------+--------------+------------+
          | ipv6-address-and-prefix | string       | RFC XXXX   |
          +-------------------------+--------------+------------+
          | domain-name             | string       | RFC 6021   |
          +-------------------------+--------------+------------+
          | host-name               | domain-name  | RFC XXXX   |
          +-------------------------+--------------+------------+
          | host                    | union        | RFC 6021   |
          +-------------------------+--------------+------------+
          | uri                     | string       | RFC 6021   |
          +-------------------------+--------------+------------+
          | email-address           | string       | RFC XXXX   |
          +-------------------------+--------------+------------+

                 Table 2: Types defined in ietf-inet-types

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   Some types have an equivalent Structure of Management Information
   Version 2 (SMIv2) [RFC2578] [RFC2579] data type.  A YANG data type is
   equivalent to an SMIv2 data type if the data types have the same set
   of values and the semantics of the values are equivalent.

   Table 3 lists the types defined in the "ietf-yang-types" YANG module
   with their corresponding SMIv2 types and Table 4 lists the types
   defined in the "ietf-inet-types" module with their corresponding
   SMIv2 types.

        +=======================+================================+
        | YANG type             | Equivalent SMIv2 type (module) |
        +=======================+================================+
        | counter32             | Counter32 (SNMPv2-SMI)         |
        +-----------------------+--------------------------------+
        | zero-based-counter32  | ZeroBasedCounter32 (RMON2-MIB) |
        +-----------------------+--------------------------------+
        | counter64             | Counter64 (SNMPv2-SMI)         |
        +-----------------------+--------------------------------+
        | zero-based-counter64  | ZeroBasedCounter64 (HCNUM-TC)  |
        +-----------------------+--------------------------------+
        | gauge32               | Gauge32 (SNMPv2-SMI)           |
        +-----------------------+--------------------------------+
        | gauge64               | CounterBasedGauge64 (HCNUM-TC) |
        +-----------------------+--------------------------------+
        | object-identifier-128 | OBJECT IDENTIFIER              |
        +-----------------------+--------------------------------+
        | centiseconds32        | TimeInterval (SNMPv2-TC)       |
        +-----------------------+--------------------------------+
        | timeticks             | TimeTicks (SNMPv2-SMI)         |
        +-----------------------+--------------------------------+
        | timestamp             | TimeStamp (SNMPv2-TC)          |
        +-----------------------+--------------------------------+
        | phys-address          | PhysAddress (SNMPv2-TC)        |
        +-----------------------+--------------------------------+
        | mac-address           | MacAddress (SNMPv2-TC)         |
        +-----------------------+--------------------------------+
        | language-tag          | LangTag (LANGTAG-TC-MIB)       |
        +-----------------------+--------------------------------+

           Table 3: Equivalent SMIv2 types for ietf-yang-types

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    +=================+===============================================+
    | YANG type       | Equivalent SMIv2 type (module)                |
    +=================+===============================================+
    | ip-version      | InetVersion (INET-ADDRESS-MIB)                |
    +-----------------+-----------------------------------------------+
    | dscp            | Dscp (DIFFSERV-DSCP-TC)                       |
    +-----------------+-----------------------------------------------+
    | ipv6-flow-label | IPv6FlowLabel (IPV6-FLOW-LABEL-MIB)           |
    +-----------------+-----------------------------------------------+
    | port-number     | InetPortNumber (INET-ADDRESS-MIB)             |
    +-----------------+-----------------------------------------------+
    | as-number       | InetAutonomousSystemNumber (INET-ADDRESS-MIB) |
    +-----------------+-----------------------------------------------+
    | uri             | Uri (URI-TC-MIB)                              |
    +-----------------+-----------------------------------------------+

            Table 4: Equivalent SMIv2 types for ietf-inet-types

3.  Core YANG Types

   The ietf-yang-types YANG module references [IEEE-802-2001],
   [ISO-9834-1], [RFC2578], [RFC2579], [RFC2856], [RFC3339], [RFC4122],
   [RFC4502], [RFC5131], [RFC5646], [RFC7950], [RFC8294], [W3C.xpath],
   and [W3C.xmlschema11-2].

   <CODE BEGINS> file "ietf-yang-types@2023-01-23.yang"
   module ietf-yang-types {

     namespace "urn:ietf:params:xml:ns:yang:ietf-yang-types";
     prefix "yang";

     organization
      "IETF Network Modeling (NETMOD) Working Group";

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

       Editor:   Juergen Schoenwaelder
                 <mailto:jschoenwaelder@constructor.university>";

     description
      "This module contains a collection of generally useful derived
       YANG data types.

       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

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       described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
       they appear in all capitals, as shown here.

       Copyright (c) 2022 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;
       see the RFC itself for full legal notices.";

     revision 2023-01-23 {
       description
        "This revision adds the following new data types:
         - yang:date-with-zone-offset
         - yang:date-no-zone
         - yang:time-with-zone-offset
         - yang:time-no-zone
         - yang:hours32
         - yang:minutes32
         - yang:seconds32
         - yang:centiseconds32
         - yang:milliseconds32
         - yang:microseconds32
         - yang:microseconds64
         - yang:nanoseconds32
         - yang:nanoseconds64
         - yang:language-tag
         The yang-identifier definition has been aligned with YANG 1.1.
         Several pattern statements have been improved.";
       reference
        "RFC XXXX: Common YANG Data Types";
     }

     revision 2013-07-15 {
       description
        "This revision adds the following new data types:
         - yang:yang-identifier
         - yang:hex-string
         - yang:uuid
         - yang:dotted-quad";
       reference
        "RFC 6991: Common YANG Data Types";

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     }

     revision 2010-09-24 {
       description
        "Initial revision.";
       reference
        "RFC 6021: Common YANG Data Types";
     }

     /*** collection of counter and gauge types ***/

     typedef counter32 {
       type uint32;
       description
        "The counter32 type represents a non-negative integer
         that monotonically increases until it reaches a
         maximum value of 2^32-1 (4294967295 decimal), when it
         wraps around and starts increasing again from zero.

         Counters have no defined 'initial' value, and thus, a
         single value of a counter has (in general) no information
         content.  Discontinuities in the monotonically increasing
         value normally occur at re-initialization of the
         management system, and at other times as specified in the
         description of a schema node using this type.  If such
         other times can occur, for example, the instantiation of
         a schema node of type counter32 at times other than
         re-initialization, then a corresponding schema node
         should be defined, with an appropriate type, to indicate
         the last discontinuity.

         The counter32 type should not be used for configuration
         schema nodes.  A default statement SHOULD NOT be used in
         combination with the type counter32.

         In the value set and its semantics, this type is equivalent
         to the Counter32 type of the SMIv2.";
       reference
        "RFC 2578: Structure of Management Information Version 2
                   (SMIv2)";
     }

     typedef zero-based-counter32 {
       type yang:counter32;
       default "0";
       description
        "The zero-based-counter32 type represents a counter32
         that has the defined 'initial' value zero.

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         A schema node instance of this type will be set to zero (0)
         on creation and will thereafter increase monotonically until
         it reaches a maximum value of 2^32-1 (4294967295 decimal),
         when it wraps around and starts increasing again from zero.

         Provided that an application discovers a new schema node
         instance of this type within the minimum time to wrap, it
         can use the 'initial' value as a delta.  It is important for
         a management station to be aware of this minimum time and the
         actual time between polls, and to discard data if the actual
         time is too long or there is no defined minimum time.

         In the value set and its semantics, this type is equivalent
         to the ZeroBasedCounter32 textual convention of the SMIv2.";
       reference
         "RFC 4502: Remote Network Monitoring Management Information
                    Base Version 2";
     }

     typedef counter64 {
       type uint64;
       description
        "The counter64 type represents a non-negative integer
         that monotonically increases until it reaches a
         maximum value of 2^64-1 (18446744073709551615 decimal),
         when it wraps around and starts increasing again from zero.

         Counters have no defined 'initial' value, and thus, a
         single value of a counter has (in general) no information
         content.  Discontinuities in the monotonically increasing
         value normally occur at re-initialization of the
         management system, and at other times as specified in the
         description of a schema node using this type.  If such
         other times can occur, for example, the instantiation of
         a schema node of type counter64 at times other than
         re-initialization, then a corresponding schema node
         should be defined, with an appropriate type, to indicate
         the last discontinuity.

         The counter64 type should not be used for configuration
         schema nodes.  A default statement SHOULD NOT be used in
         combination with the type counter64.

         In the value set and its semantics, this type is equivalent
         to the Counter64 type of the SMIv2.";
       reference
        "RFC 2578: Structure of Management Information Version 2
                   (SMIv2)";

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     }

     typedef zero-based-counter64 {
       type yang:counter64;
       default "0";
       description
        "The zero-based-counter64 type represents a counter64 that
         has the defined 'initial' value zero.

         A schema node instance of this type will be set to zero (0)
         on creation and will thereafter increase monotonically until
         it reaches a maximum value of 2^64-1 (18446744073709551615
         decimal), when it wraps around and starts increasing again
         from zero.

         Provided that an application discovers a new schema node
         instance of this type within the minimum time to wrap, it
         can use the 'initial' value as a delta.  It is important for
         a management station to be aware of this minimum time and the
         actual time between polls, and to discard data if the actual
         time is too long or there is no defined minimum time.

         In the value set and its semantics, this type is equivalent
         to the ZeroBasedCounter64 textual convention of the SMIv2.";
       reference
        "RFC 2856: Textual Conventions for Additional High Capacity
                   Data Types";
     }

     typedef gauge32 {
       type uint32;
       description
        "The gauge32 type represents a non-negative integer, which
         may increase or decrease, but shall never exceed a maximum
         value, nor fall below a minimum value.  The maximum value
         cannot be greater than 2^32-1 (4294967295 decimal), and
         the minimum value cannot be smaller than 0.  The value of
         a gauge32 has its maximum value whenever the information
         being modeled is greater than or equal to its maximum
         value, and has its minimum value whenever the information
         being modeled is smaller than or equal to its minimum value.
         If the information being modeled subsequently decreases
         below (increases above) the maximum (minimum) value, the
         gauge32 also decreases (increases).

         In the value set and its semantics, this type is equivalent
         to the Gauge32 type of the SMIv2.";
       reference

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        "RFC 2578: Structure of Management Information Version 2
                   (SMIv2)";
     }

     typedef gauge64 {
       type uint64;
       description
        "The gauge64 type represents a non-negative integer, which
         may increase or decrease, but shall never exceed a maximum
         value, nor fall below a minimum value.  The maximum value
         cannot be greater than 2^64-1 (18446744073709551615), and
         the minimum value cannot be smaller than 0.  The value of
         a gauge64 has its maximum value whenever the information
         being modeled is greater than or equal to its maximum
         value, and has its minimum value whenever the information
         being modeled is smaller than or equal to its minimum value.
         If the information being modeled subsequently decreases
         below (increases above) the maximum (minimum) value, the
         gauge64 also decreases (increases).

         In the value set and its semantics, this type is equivalent
         to the CounterBasedGauge64 SMIv2 textual convention defined
         in RFC 2856";
       reference
        "RFC 2856: Textual Conventions for Additional High Capacity
                   Data Types";
     }

     /*** collection of identifier-related types ***/

     typedef object-identifier {
       type string {
         pattern '(([0-1](\.[1-3]?[0-9]))|(2\.(0|([1-9][0-9]*))))'
               + '(\.(0|([1-9][0-9]*)))*';
       }
       description
        "The object-identifier type represents administratively
         assigned names in a registration-hierarchical-name tree.

         Values of this type are denoted as a sequence of numerical
         non-negative sub-identifier values.  Each sub-identifier
         value MUST NOT exceed 2^32-1 (4294967295).  Sub-identifiers
         are separated by single dots and without any intermediate
         whitespace.

         The ASN.1 standard restricts the value space of the first
         sub-identifier to 0, 1, or 2.  Furthermore, the value space
         of the second sub-identifier is restricted to the range

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         0 to 39 if the first sub-identifier is 0 or 1.  Finally,
         the ASN.1 standard requires that an object identifier
         has always at least two sub-identifiers.  The pattern
         captures these restrictions.

         Although the number of sub-identifiers is not limited,
         module designers should realize that there may be
         implementations that stick with the SMIv2 limit of 128
         sub-identifiers.

         This type is a superset of the SMIv2 OBJECT IDENTIFIER type
         since it is not restricted to 128 sub-identifiers.  Hence,
         this type SHOULD NOT be used to represent the SMIv2 OBJECT
         IDENTIFIER type; the object-identifier-128 type SHOULD be
         used instead.";
       reference
        "ISO9834-1: Information technology -- Open Systems
         Interconnection -- Procedures for the operation of OSI
         Registration Authorities: General procedures and top
         arcs of the ASN.1 Object Identifier tree";
     }

     typedef object-identifier-128 {
       type object-identifier {
         pattern '[0-9]*(\.[0-9]*){1,127}';
       }
       description
        "This type represents object-identifiers restricted to 128
         sub-identifiers.

         In the value set and its semantics, this type is equivalent
         to the OBJECT IDENTIFIER type of the SMIv2.";
       reference
        "RFC 2578: Structure of Management Information Version 2
                   (SMIv2)";
     }

     /*** collection of types related to date and time ***/

     typedef date-and-time {
       type string {
         pattern '[0-9]{4}-(1[0-2]|0[1-9])-(0[1-9]|[1-2][0-9]|3[0-1])'
               + 'T(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9](\.[0-9]+)?'
               + '(Z|[\+\-]((1[0-3]|0[0-9]):([0-5][0-9])|14:00))?';
       }
       description
        "The date-and-time type is a profile of the ISO 8601
         standard for representation of dates and times using the

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         Gregorian calendar.  The profile is defined by the
         date-time production in Section 5.6 of RFC 3339.

         The date-and-time type is compatible with the dateTime XML
         schema dateTime type with the following notable exceptions:

         (a) The date-and-time type does not allow negative years.

         (b) The time-offset -00:00 indicates that the date-and-time
             value is reported in UTC and that the local time zone
             reference point is unknown. The time-offsets +00:00 and Z
             both indicate that the date-and-time value is reported in
             UTC and that the local time reference point is UTC (see RFC
             3339 section 4.3).

         This type is not equivalent to the DateAndTime textual
         convention of the SMIv2 since RFC 3339 uses a different
         separator between full-date and full-time and provides
         higher resolution of time-secfrac.

         The canonical format for date-and-time values with a known time
         zone uses a numeric time zone offset that is calculated using
         the device's configured known offset to UTC time.  A change of
         the device's offset to UTC time will cause date-and-time values
         to change accordingly.  Such changes might happen periodically
         in case a server follows automatically daylight saving time
         (DST) time zone offset changes.  The canonical format for
         date-and-time values with an unknown time zone (usually
         referring to the notion of local time) uses the time-offset
         -00:00, i.e., date-and-time values must be reported in UTC.";
       reference
        "RFC 3339: Date and Time on the Internet: Timestamps
         RFC 2579: Textual Conventions for SMIv2
         XSD-TYPES: XML Schema Definition Language (XSD) 1.1
                    Part 2: Datatypes";
     }

     typedef date-with-zone-offset {
       type string {
         pattern '[0-9]{4}-(1[0-2]|0[1-9])-(0[1-9]|[1-2][0-9]|3[0-1])'
               + '(Z|[\+\-]((1[0-3]|0[0-9]):([0-5][0-9])|14:00))?';
       }
       description
        "The date type represents a time-interval of the length
         of a day, i.e., 24 hours.

         The date type is compatible with the XML schema date
         type with the following notable exceptions:

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         (a) The date type does not allow negative years.

         (b) The time-offset -00:00 indicates that the date value is
             reported in UTC and that the local time zone reference point
             is unknown. The time-offsets +00:00 and Z both indicate that
             the date value is reported in UTC and that the local time
             reference point is UTC (see RFC 3339 section 4.3).

         The canonical format for date values with a known time
         zone uses a numeric time zone offset that is calculated using
         the device's configured known offset to UTC time.  A change of
         the device's offset to UTC time will cause date values
         to change accordingly.  Such changes might happen periodically
         in case a server follows automatically daylight saving time
         (DST) time zone offset changes.  The canonical format for
         date values with an unknown time zone (usually referring
         to the notion of local time) uses the time-offset -00:00,
         i.e., date values must be reported in UTC.";
       reference
        "RFC 3339: Date and Time on the Internet: Timestamps
         XSD-TYPES: XML Schema Definition Language (XSD) 1.1
                    Part 2: Datatypes";
     }

     typedef date-no-zone {
       type date-with-zone-offset {
         pattern '[0-9]{4}-(1[0-2]|0[1-9])-(0[1-9]|[1-2][0-9]|3[0-1])';
       }
       description
        "The date-no-zone type represents a date without the optional
         time zone offset information.";
     }

     typedef time-with-zone-offset {
       type string {
         pattern '(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9](\.[0-9]+)?'
               + '(Z|[\+\-]((1[0-3]|0[0-9]):([0-5][0-9])|14:00))?';
       }
       description
        "The time type represents an instance of time of zero-duration
         that recurs every day.

         The time type is compatible with the XML schema time
         type with the following notable exception:

         (a) The time-offset -00:00 indicates that the time value is
             reported in UTC and that the local time zone reference point
             is unknown. The time-offsets +00:00 and Z both indicate that

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             the time value is reported in UTC and that the local time
             reference point is UTC (see RFC 3339 section 4.3).

         The canonical format for time values with a known time
         zone uses a numeric time zone offset that is calculated using
         the device's configured known offset to UTC time.  A change of
         the device's offset to UTC time will cause time values
         to change accordingly.  Such changes might happen periodically
         in case a server follows automatically daylight saving time
         (DST) time zone offset changes.  The canonical format for
         time values with an unknown time zone (usually referring
         to the notion of local time) uses the time-offset -00:00,
         i.e., time values must be reported in UTC.";
       reference
        "RFC 3339: Date and Time on the Internet: Timestamps
         XSD-TYPES: XML Schema Definition Language (XSD) 1.1
                    Part 2: Datatypes";
     }

     typedef time-no-zone {
       type time-with-zone-offset {
         pattern '(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9](\.[0-9]+)?';
       }
       description
        "The time-no-zone type represents a time without the optional
         time zone offset information.";
     }

     typedef hours32 {
       type int32;
       units "hours";
       description
        "A period of time, measured in units of hours.

         The maximum time period that can be expressed is in the
         range [-89478485 days 08:00:00 to 89478485 days 07:00:00].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef minutes32 {
       type int32;
       units "minutes";
       description
        "A period of time, measured in units of minutes.

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         The maximum time period that can be expressed is in the
         range [-1491308 days 2:08:00 to 1491308 days 2:07:00].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef seconds32 {
       type int32;
       units "seconds";
       description
        "A period of time, measured in units of seconds.

         The maximum time period that can be expressed is in the
         range [-24855 days 03:14:08 to 24855 days 03:14:07].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef centiseconds32 {
       type int32;
       units "centiseconds";
       description
        "A period of time, measured in units of 10^-2 seconds.

         The maximum time period that can be expressed is in the
         range [-248 days 13:13:56 to 248 days 13:13:56].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef milliseconds32 {
       type int32;
       units "milliseconds";
       description
        "A period of time, measured in units of 10^-3 seconds.

         The maximum time period that can be expressed is in the
         range [-24 days 20:31:23 to 24 days 20:31:23].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";

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     }

     typedef microseconds32 {
       type int32;
       units "microseconds";
       description
        "A period of time, measured in units of 10^-6 seconds.

         The maximum time period that can be expressed is in the
         range [-00:35:47 to 00:35:47].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef microseconds64 {
       type int64;
       units "microseconds";
       description
        "A period of time, measured in units of 10^-6 seconds.

         The maximum time period that can be expressed is in the
         range [-106751991 days 04:00:54 to 106751991 days 04:00:54].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef nanoseconds32 {
       type int32;
       units "nanoseconds";
       description
        "A period of time, measured in units of 10^-9 seconds.

         The maximum time period that can be expressed is in the
         range [-00:00:02 to 00:00:02].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef nanoseconds64 {
       type int64;
       units "nanoseconds";
       description

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        "A period of time, measured in units of 10^-9 seconds.

         The maximum time period that can be expressed is in the
         range [-106753 days 23:12:44 to 106752 days 0:47:16].

         This type should be range restricted in situations
         where only non-negative time periods are desirable,
         (i.e., range '0..max').";
     }

     typedef timeticks {
       type uint32;
       description
        "The timeticks type represents a non-negative integer that
         represents the time, modulo 2^32 (4294967296 decimal), in
         hundredths of a second between two epochs.  When a schema
         node is defined that uses this type, the description of
         the schema node identifies both of the reference epochs.

         In the value set and its semantics, this type is equivalent
         to the TimeTicks type of the SMIv2.";
       reference
        "RFC 2578: Structure of Management Information Version 2
                   (SMIv2)";
     }

     typedef timestamp {
       type yang:timeticks;
       description
        "The timestamp type represents the value of an associated
         timeticks schema node instance at which a specific occurrence
         happened.  The specific occurrence must be defined in the
         description of any schema node defined using this type.  When
         the specific occurrence occurred prior to the last time the
         associated timeticks schema node instance was zero, then the
         timestamp value is zero.

         Note that this requires all timestamp values to be reset to
         zero when the value of the associated timeticks schema node
         instance reaches 497+ days and wraps around to zero.

         The associated timeticks schema node must be specified
         in the description of any schema node using this type.

         In the value set and its semantics, this type is equivalent
         to the TimeStamp textual convention of the SMIv2.";
       reference
        "RFC 2579: Textual Conventions for SMIv2";

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     }

     /*** collection of generic address types ***/

     typedef phys-address {
       type string {
         pattern '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
       }
       description
        "Represents media- or physical-level addresses represented
         as a sequence octets, each octet represented by two hexadecimal
         numbers.  Octets are separated by colons.  The canonical
         representation uses lowercase characters.

         In the value set and its semantics, this type is equivalent
         to the PhysAddress textual convention of the SMIv2.";
       reference
        "RFC 2579: Textual Conventions for SMIv2";
     }

     typedef mac-address {
       type string {
         pattern '[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){5}';
       }
       description
        "The mac-address type represents an IEEE 802 MAC address.
         The canonical representation uses lowercase characters.

         In the value set and its semantics, this type is equivalent
         to the MacAddress textual convention of the SMIv2.";
       reference
        "IEEE 802: IEEE Standard for Local and Metropolitan Area
                   Networks: Overview and Architecture
         RFC 2579: Textual Conventions for SMIv2";
     }

     /*** collection of XML-specific types ***/

     typedef xpath1.0 {
       type string;
       description
        "This type represents an XPATH 1.0 expression.

         When a schema node is defined that uses this type, the
         description of the schema node MUST specify the XPath
         context in which the XPath expression is evaluated.";
       reference
        "XPATH: XML Path Language (XPath) Version 1.0";

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     }

     /*** collection of string types ***/

     typedef hex-string {
       type string {
         pattern '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
       }
       description
        "A hexadecimal string with octets represented as hex digits
         separated by colons.  The canonical representation uses
         lowercase characters.";
     }

     typedef uuid {
       type string {
         pattern '[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-'
               + '[0-9a-fA-F]{4}-[0-9a-fA-F]{12}';
       }
       description
        "A Universally Unique IDentifier in the string representation
         defined in RFC 4122.  The canonical representation uses
         lowercase characters.

         The following is an example of a UUID in string representation:
         f81d4fae-7dec-11d0-a765-00a0c91e6bf6
         ";
       reference
        "RFC 4122: A Universally Unique IDentifier (UUID) URN
                   Namespace";
     }

     typedef dotted-quad {
       type string {
         pattern
           '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}'
         + '([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])';
       }
       description
         "An unsigned 32-bit number expressed in the dotted-quad
          notation, i.e., four octets written as decimal numbers
          and separated with the '.' (full stop) character.";
     }

     typedef language-tag {
       type string;
       description
          "A language tag according to RFC 5646 (BCP 47). The

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           canonical representation uses lowercase characters.

           Values of this type must be well-formed language tags,
           in conformance with the definition of well-formed tags
           in BCP 47. Implementations MAY further limit the values
           they accept to those permitted by a 'validating'
           processor, as defined in BCP 47.

           The canonical representation of values of this type is
           aligned with the SMIv2 LangTag textual convention for
           language tags fitting the length constraints imposed
           by the LangTag textual convention.";
       reference
          "RFC 5646: Tags for Identifying Languages
           RFC 5131: A MIB Textual Convention for Language Tags";
     }

     /*** collection of YANG specific types ***/

     typedef yang-identifier {
       type string {
         length "1..max";
         pattern '[a-zA-Z_][a-zA-Z0-9\-_.]*';
       }
       description
         "A YANG identifier string as defined by the 'identifier'
          rule in Section 14 of RFC 7950. An identifier must
          start with an alphabetic character or an underscore
          followed by an arbitrary sequence of alphabetic or
          numeric characters, underscores, hyphens, or dots.

          This definition conforms to YANG 1.1 defined in RFC
          7950. An earlier version of this definition did exclude
          all identifiers starting with any possible combination
          of the lowercase or uppercase character sequence 'xml',
          as required by YANG 1 defined in RFC 6020. If this type
          is used in a YANG 1 context, then this restriction still
          applies.";
       reference
         "RFC 7950: The YANG 1.1 Data Modeling Language
          RFC 6020: YANG - A Data Modeling Language for the
                    Network Configuration Protocol (NETCONF)";
     }

   }

   <CODE ENDS>

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4.  Internet Protocol Suite Types

   The ietf-inet-types YANG module references [RFC0768], [RFC0791],
   [RFC0952], [RFC1034], [RFC1123], [RFC1930], [RFC2317], [RFC2474],
   [RFC2780], [RFC2782], [RFC3289], [RFC3305], [RFC3595], [RFC3927],
   [RFC3986], [RFC4001], [RFC4007], [RFC4271], [RFC4291], [RFC4340],
   [RFC4592], [RFC5017], [RFC5322], [RFC5890], [RFC5952], [RFC6793],
   [RFC8200], [RFC9260], and [RFC9293].

   <CODE BEGINS> file "ietf-inet-types@2023-01-23.yang"
   module ietf-inet-types {

     namespace "urn:ietf:params:xml:ns:yang:ietf-inet-types";
     prefix "inet";

     organization
      "IETF Network Modeling (NETMOD) Working Group";

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

       Editor:   Juergen Schoenwaelder
                 <mailto:jschoenwaelder@constructor.university>";

     description
      "This module contains a collection of generally useful derived
       YANG data types for Internet addresses and related things.

       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.

       Copyright (c) 2022 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;
       see the RFC itself for full legal notices.";

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     revision 2023-01-23 {
       description
        "This revision adds the following new data types:
         - inet:ip-address-and-prefix
         - inet:ipv4-address-and-prefix
         - inet:ipv6-address-and-prefix
         - inet:protocol-number
         - inet:host-name
         - inet:email-address
         - inet:ip-address-link-local
         - inet:ipv4-address-link-local
         - inet:ipv6-address-link-local
         The inet:host union was changed to use inet:host-name instead
         of inet:domain-name. Several pattern statements have been
         improved.";
       reference
        "RFC XXXX: Common YANG Data Types";
     }

     revision 2013-07-15 {
       description
        "This revision adds the following new data types:
         - inet:ip-address-no-zone
         - inet:ipv4-address-no-zone
         - inet:ipv6-address-no-zone";
       reference
        "RFC 6991: Common YANG Data Types";
     }

     revision 2010-09-24 {
       description
        "Initial revision.";
       reference
        "RFC 6021: Common YANG Data Types";
     }

     /*** collection of types related to protocol fields ***/

     typedef ip-version {
       type enumeration {
         enum unknown {
           value "0";
           description
            "An unknown or unspecified version of the Internet
             protocol.";
         }
         enum ipv4 {
           value "1";

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           description
            "The IPv4 protocol as defined in RFC 791.";
         }
         enum ipv6 {
           value "2";
           description
            "The IPv6 protocol as defined in RFC 8200.";
         }
       }
       description
        "This value represents the version of the IP protocol.

         In the value set and its semantics, this type is equivalent
         to the InetVersion textual convention of the SMIv2.";
       reference
        "RFC  791: Internet Protocol
         RFC 8200: Internet Protocol, Version 6 (IPv6) Specification
         RFC 4001: Textual Conventions for Internet Network Addresses";
     }

     typedef dscp {
       type uint8 {
         range "0..63";
       }
       description
        "The dscp type represents a Differentiated Services Code Point
         that may be used for marking packets in a traffic stream.

         In the value set and its semantics, this type is equivalent
         to the Dscp textual convention of the SMIv2.";
       reference
        "RFC 3289: Management Information Base for the Differentiated
                   Services Architecture
         RFC 2474: Definition of the Differentiated Services Field
                   (DS Field) in the IPv4 and IPv6 Headers
         RFC 2780: IANA Allocation Guidelines For Values In
                   the Internet Protocol and Related Headers";
     }

     typedef ipv6-flow-label {
       type uint32 {
         range "0..1048575";
       }
       description
        "The ipv6-flow-label type represents the flow identifier or
         Flow Label in an IPv6 packet header that may be used to
         discriminate traffic flows.

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         In the value set and its semantics, this type is equivalent
         to the IPv6FlowLabel textual convention of the SMIv2.";
       reference
        "RFC 3595: Textual Conventions for IPv6 Flow Label
         RFC 8200: Internet Protocol, Version 6 (IPv6) Specification";
     }

     typedef port-number {
       type uint16 {
         range "0..65535";
       }
       description
        "The port-number type represents a 16-bit port number of an
         Internet transport-layer protocol such as UDP, TCP, DCCP, or
         SCTP.

         Port numbers are assigned by IANA.  The current list of
         all assignments is available from <https://www.iana.org/>.

         Note that the port number value zero is reserved by IANA.  In
         situations where the value zero does not make sense, it can
         be excluded by subtyping the port-number type.

         In the value set and its semantics, this type is equivalent
         to the InetPortNumber textual convention of the SMIv2.";
       reference
        "RFC  768: User Datagram Protocol
         RFC 9293: Transmission Control Protocol (TCP)
         RFC 9260: Stream Control Transmission Protocol
         RFC 4340: Datagram Congestion Control Protocol (DCCP)
         RFC 4001: Textual Conventions for Internet Network Addresses";
     }

     typedef protocol-number {
       type uint8;
       description
        "The protocol-number type represents an 8-bit Internet
         protocol number, carried in the 'protocol' field of the
         IPv4 header or in the 'next header' field of the IPv6
         header. If IPv6 extension headers are present, then the
         protocol number type represents the upper layer protocol
         number, i.e., the number of the last next header' field
         of the IPv6 extension headers.

         Protocol numbers are assigned by IANA. The current list of
         all assignments is available from <https://www.iana.org/>.";
       reference
        "RFC  791: Internet Protocol

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         RFC 8200: Internet Protocol, Version 6 (IPv6) Specification";
     }

     /*** collection of types related to autonomous systems ***/

     typedef as-number {
       type uint32;
       description
        "The as-number type represents autonomous system numbers
         which identify an Autonomous System (AS).  An AS is a set
         of routers under a single technical administration, using
         an interior gateway protocol and common metrics to route
         packets within the AS, and using an exterior gateway
         protocol to route packets to other ASes.  IANA maintains
         the AS number space and has delegated large parts to the
         regional registries.

         Autonomous system numbers were originally limited to 16
         bits.  BGP extensions have enlarged the autonomous system
         number space to 32 bits.  This type therefore uses an uint32
         base type without a range restriction in order to support
         a larger autonomous system number space.

         In the value set and its semantics, this type is equivalent
         to the InetAutonomousSystemNumber textual convention of
         the SMIv2.";
       reference
        "RFC 1930: Guidelines for creation, selection, and registration
                   of an Autonomous System (AS)
         RFC 4271: A Border Gateway Protocol 4 (BGP-4)
         RFC 4001: Textual Conventions for Internet Network Addresses
         RFC 6793: BGP Support for Four-Octet Autonomous System (AS)
                   Number Space";
     }

     /*** collection of types related to IP addresses and hostnames ***/

     typedef ip-address {
       type union {
         type inet:ipv4-address;
         type inet:ipv6-address;
       }
       description
        "The ip-address type represents an IP address and is IP
         version neutral.  The format of the textual representation
         implies the IP version.  This type supports scoped addresses
         by allowing zone identifiers in the address format.";
       reference

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        "RFC 4007: IPv6 Scoped Address Architecture";
     }

     typedef ipv4-address {
       type string {
         pattern
           '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}'
         +  '([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])'
         + '(%[A-Za-z0-9][A-Za-z0-9\-\._~/]*)?';
       }
       description
         "The ipv4-address type represents an IPv4 address in
          dotted-quad notation.  The IPv4 address may include a zone
          index, separated by a % sign.

          The zone index is used to disambiguate identical address
          values.  For link-local addresses, the zone index will
          typically be the interface index number or the name of an
          interface.  If the zone index is not present, the default
          zone of the device will be used.

          The canonical format for the zone index is the numerical
          format";
     }

     typedef ipv6-address {
       type string {
         pattern '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}'
               + '((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|'
               + '(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}'
               + '(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))'
               + '(%[A-Za-z0-9][A-Za-z0-9\-\._~/]*)?';
         pattern '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|'
               + '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)'
               + '(%.+)?';
       }
       description
        "The ipv6-address type represents an IPv6 address in full,
         mixed, shortened, and shortened-mixed notation.  The IPv6
         address may include a zone index, separated by a % sign.

         The zone index is used to disambiguate identical address
         values.  For link-local addresses, the zone index will
         typically be the interface index number or the name of an
         interface.  If the zone index is not present, the default
         zone of the device will be used.

         The canonical format of IPv6 addresses uses the textual

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         representation defined in Section 4 of RFC 5952.  The
         canonical format for the zone index is the numerical
         format as described in Section 11.2 of RFC 4007.";
       reference
        "RFC 4291: IP Version 6 Addressing Architecture
         RFC 4007: IPv6 Scoped Address Architecture
         RFC 5952: A Recommendation for IPv6 Address Text
                   Representation";
     }

     typedef ip-address-no-zone {
       type union {
         type inet:ipv4-address-no-zone;
         type inet:ipv6-address-no-zone;
       }
       description
        "The ip-address-no-zone type represents an IP address and is
         IP version neutral.  The format of the textual representation
         implies the IP version.  This type does not support scoped
         addresses since it does not allow zone identifiers in the
         address format.";
       reference
        "RFC 4007: IPv6 Scoped Address Architecture";
     }

     typedef ipv4-address-no-zone {
       type inet:ipv4-address {
         pattern '[0-9\.]*';
       }
       description
         "An IPv4 address without a zone index.  This type, derived from
          ipv4-address, may be used in situations where the zone is known
          from the context and hence no zone index is needed.";
     }

     typedef ipv6-address-no-zone {
       type inet:ipv6-address {
         pattern '[0-9a-fA-F:\.]*';
       }
       description
         "An IPv6 address without a zone index.  This type, derived from
          ipv6-address, may be used in situations where the zone is known
          from the context and hence no zone index is needed.";
       reference
        "RFC 4291: IP Version 6 Addressing Architecture
         RFC 4007: IPv6 Scoped Address Architecture
         RFC 5952: A Recommendation for IPv6 Address Text
                   Representation";

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     }

     typedef ip-address-link-local {
       type union {
         type inet:ipv4-address-link-local;
         type inet:ipv6-address-link-local;
       }
       description
        "The ip-address-link-local type represents a link-local IP
         address and is IP version neutral. The format of the textual
         representation implies the IP version.";
     }

     typedef ipv4-address-link-local {
       type ipv4-address {
         pattern '169\.254\..*';
       }
       description
         "A link-local IPv4 address in the prefix 169.254.0.0/16 as
          defined in section 2.1. of RFC 3927.";
       reference
         "RFC 3927: Dynamic Configuration of IPv4 Link-Local Addresses";
     }

     typedef ipv6-address-link-local {
       type ipv6-address {
         pattern '[fF][eE]80:.*';
       }
       description
         "A link-local IPv6 address in the prefix fe80::/10 as defined
          in section 2.5.6. of RFC 4291.";
       reference
         "RFC 4291: IP Version 6 Addressing Architecture";
     }

     typedef ip-prefix {
       type union {
         type inet:ipv4-prefix;
         type inet:ipv6-prefix;
       }
       description
        "The ip-prefix type represents an IP prefix and is IP
         version neutral.  The format of the textual representations
         implies the IP version.";
     }

     typedef ipv4-prefix {
       type string {

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         pattern
            '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}'
          +  '([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])'
          + '/(([0-9])|([1-2][0-9])|(3[0-2]))';
       }
       description
        "The ipv4-prefix type represents an IPv4 prefix.
         The prefix length is given by the number following the
         slash character and must be less than or equal to 32.

         A prefix length value of n corresponds to an IP address
         mask that has n contiguous 1-bits from the most
         significant bit (MSB) and all other bits set to 0.

         The canonical format of an IPv4 prefix has all bits of
         the IPv4 address set to zero that are not part of the
         IPv4 prefix.

         The definition of ipv4-prefix does not require that bits,
         which are not part of the prefix, are set to zero. However,
         implementations have to return values in canonical format,
         which requires non-prefix bits to be set to zero. This means
         that 192.0.2.1/24 must be accepted as a valid value but it
         will be converted into the canonical format 192.0.2.0/24.";
     }

     typedef ipv6-prefix {
       type string {
         pattern '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}'
               + '((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|'
               + '(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}'
               + '(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))'
               + '(/(([0-9])|([0-9]{2})|(1[0-1][0-9])|(12[0-8])))';
         pattern '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|'
               + '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)'
               + '(/.+)';
       }
       description
        "The ipv6-prefix type represents an IPv6 prefix.
         The prefix length is given by the number following the
         slash character and must be less than or equal to 128.

         A prefix length value of n corresponds to an IP address
         mask that has n contiguous 1-bits from the most
         significant bit (MSB) and all other bits set to 0.

         The canonical format of an IPv6 prefix has all bits of
         the IPv6 address set to zero that are not part of the

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         IPv6 prefix.  Furthermore, the IPv6 address is represented
         as defined in Section 4 of RFC 5952.

         The definition of ipv6-prefix does not require that bits,
         which are not part of the prefix, are set to zero. However,
         implementations have to return values in canonical format,
         which requires non-prefix bits to be set to zero. This means
         that 2001:db8::1/64 must be accepted as a valid value but it
         will be converted into the canonical format 2001:db8::/64.";
       reference
        "RFC 5952: A Recommendation for IPv6 Address Text
                   Representation";
     }

     typedef ip-address-and-prefix {
       type union {
         type inet:ipv4-address-and-prefix;
         type inet:ipv6-address-and-prefix;
       }
       description
        "The ip-address-and-prefix type represents an IP address and
         prefix and is IP version neutral.  The format of the textual
         representations implies the IP version.";
     }

     typedef ipv4-address-and-prefix {
       type string {
         pattern
            '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}'
          +  '([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])'
          + '/(([0-9])|([1-2][0-9])|(3[0-2]))';
       }
       description
        "The ipv4-address-and-prefix type represents an IPv4
         address and an associated ipv4 prefix.
         The prefix length is given by the number following the
         slash character and must be less than or equal to 32.

         A prefix length value of n corresponds to an IP address
         mask that has n contiguous 1-bits from the most
         significant bit (MSB) and all other bits set to 0.";
     }

     typedef ipv6-address-and-prefix {
       type string {
         pattern '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}'
               + '((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|'
               + '(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}'

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               + '(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))'
               + '(/(([0-9])|([0-9]{2})|(1[0-1][0-9])|(12[0-8])))';
         pattern '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|'
               + '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)'
               + '(/.+)';
       }
       description
        "The ipv6-address-and-prefix type represents an IPv6
         address and an associated ipv4 prefix.
         The prefix length is given by the number following the
         slash character and must be less than or equal to 128.

         A prefix length value of n corresponds to an IP address
         mask that has n contiguous 1-bits from the most
         significant bit (MSB) and all other bits set to 0.

         The canonical format requires that the IPv6 address is
         represented as defined in Section 4 of RFC 5952.";
       reference
        "RFC 5952: A Recommendation for IPv6 Address Text
                   Representation";
     }

     /*** collection of domain name and URI types ***/

     typedef domain-name {
       type string {
         length "1..253";
         pattern
           '((([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.)*'
         + '([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.?)'
         + '|\.';
       }
       description
        "The domain-name type represents a DNS domain name.  The
         name SHOULD be fully qualified whenever possible. This
         type does not support wildcards (see RFC 4592) or
         classless in-addr.arpa delegations (see RFC 2317).

         Internet domain names are only loosely specified.  Section
         3.5 of RFC 1034 recommends a syntax (modified in Section
         2.1 of RFC 1123).  The pattern above is intended to allow
         for current practice in domain name use, and some possible
         future expansion.  Note that Internet host names have a
         stricter syntax (described in RFC 952) than the DNS
         recommendations in RFCs 1034 and 1123. Schema nodes
         representing host names should use the host-name type
         instead of the domain-type.

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         The encoding of DNS names in the DNS protocol is limited
         to 255 characters.  Since the encoding consists of labels
         prefixed by a length bytes and there is a trailing NULL
         byte, only 253 characters can appear in the textual dotted
         notation.

         The description clause of schema nodes using the domain-name
         type MUST describe when and how these names are resolved to
         IP addresses.  Note that the resolution of a domain-name value
         may require to query multiple DNS records (e.g., A for IPv4
         and AAAA for IPv6).  The order of the resolution process and
         which DNS record takes precedence can either be defined
         explicitly or may depend on the configuration of the
         resolver.

         Domain-name values use the US-ASCII encoding.  Their canonical
         format uses lowercase US-ASCII characters.  Internationalized
         domain names MUST be A-labels as per RFC 5890.";
       reference
        "RFC  952: DoD Internet Host Table Specification
         RFC 1034: Domain Names - Concepts and Facilities
         RFC 1123: Requirements for Internet Hosts -- Application
                   and Support
         RFC 2317: Classless IN-ADDR.ARPA delegation
         RFC 2782: A DNS RR for specifying the location of services
                   (DNS SRV)
         RFC 4592: The Role of Wildcards in the Domain Name System
         RFC 5890: Internationalized Domain Names in Applications
                   (IDNA): Definitions and Document Framework";
     }

     typedef host-name {
       type domain-name {
         length "2..max";
         pattern '[a-zA-Z0-9\-\.]+';
       }
       description
        "The host-name type represents (fully qualified) host names.
         Host names must be at least two characters long (see RFC 952)
         and they are restricted to labels consisting of letters, digits
         and hyphens separated by dots (see RFC1123 and RFC 952).";
       reference
        "RFC  952: DoD Internet Host Table Specification
         RFC 1123: Requirements for Internet Hosts -- Application
                   and Support";
     }

     typedef host {

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       type union {
         type inet:ip-address;
         type inet:host-name;
       }
       description
        "The host type represents either an IP address or a (fully
         qualified) host name.";
     }

     typedef uri {
       type string {
         pattern '[a-z][a-z0-9+.-]*:.*';
       }
       description
        "The uri type represents a Uniform Resource Identifier
         (URI) as defined by the rule 'URI' in RFC 3986.

         Objects using the uri type MUST be in US-ASCII encoding,
         and MUST be normalized as described by RFC 3986 Sections
         6.2.1, 6.2.2.1, and 6.2.2.2.  All unnecessary
         percent-encoding is removed, and all case-insensitive
         characters are set to lowercase except for hexadecimal
         digits, which are normalized to uppercase as described in
         Section 6.2.2.1.

         The purpose of this normalization is to help provide
         unique URIs.  Note that this normalization is not
         sufficient to provide uniqueness.  Two URIs that are
         textually distinct after this normalization may still be
         equivalent.

         Objects using the uri type may restrict the schemes that
         they permit.  For example, 'data:' and 'urn:' schemes
         might not be appropriate.

         A zero-length URI is not a valid URI.  This can be used to
         express 'URI absent' where required.

         In the value set and its semantics, this type is equivalent
         to the Uri SMIv2 textual convention defined in RFC 5017.";
       reference
        "RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
         RFC 3305: Report from the Joint W3C/IETF URI Planning Interest
                   Group: Uniform Resource Identifiers (URIs), URLs,
                   and Uniform Resource Names (URNs): Clarifications
                   and Recommendations
         RFC 5017: MIB Textual Conventions for Uniform Resource
                   Identifiers (URIs)";

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     }

     typedef email-address {
       type string {
         pattern '(([a-zA-Z0-9!#$%&'+"'"+'*+/=?\^_`{|}~-]+'
               + '(\.[a-zA-Z0-9!#$%&'+"'"+'*+/=?\^_`{|}~-]+)*)|'
               + '("[a-zA-Z0-9!#$%&'+"'"+'()*+,./\[\]\^_`{|}~-]*"))'
               + '@'
               + '(([a-zA-Z0-9!#$%&'+"'"+'*+/=?\^_`{|}~-]+'
               + '(\.[a-zA-Z0-9!#$%&'+"'"+'*+/=?\^_`{|}~-]+)*)|'
               + '\[[a-zA-Z0-9!"#$%&'+"'"+'()*+,./:;<=>?@\^_`{|}~-]+\])';
       }
       description
         "The email-address type represents an email address as
          defined as addr-spec in RFC 5322 section 3.4.1 except
          that obs-local-part, obs-domain and obs-qtext of the
          quoted-string are not supported.

          The email-address type uses US-ASCII characters. The
          canonical format of the domain part of an email-address
          uses lowercase US-ASCII characters.";
       reference
         "RFC 5322: Internet Message Format";
     }

   }
   <CODE ENDS>

5.  IANA Considerations

   This document registers two URIs in the IETF XML registry [RFC3688].
   Following the format in RFC 3688, the following registrations have
   been made.

     URI: urn:ietf:params:xml:ns:yang:ietf-yang-types
     Registrant Contact: The NETMOD WG of the IETF.
     XML: N/A, the requested URI is an XML namespace.

     URI: urn:ietf:params:xml:ns:yang:ietf-inet-types
     Registrant Contact: The NETMOD WG of the IETF.
     XML: N/A, the requested URI is an XML namespace.

   This document registers two YANG modules in the YANG Module Names
   registry [RFC6020].

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     name:         ietf-yang-types
     namespace:    urn:ietf:params:xml:ns:yang:ietf-yang-types
     prefix:       yang
     reference:    RFC XXXX

     name:         ietf-inet-types
     namespace:    urn:ietf:params:xml:ns:yang:ietf-inet-types
     prefix:       inet
     reference:    RFC XXXX

6.  Security Considerations

   This document defines common data types using the YANG data modeling
   language.  The definitions themselves have no security impact on the
   Internet, but the usage of these definitions in concrete YANG modules
   might have.  The security considerations spelled out in the YANG
   specification [RFC7950] apply for this document as well.

7.  Acknowledgments

   The following people contributed significantly to the original
   version of this document published as [RFC6020]: Andy Bierman, Martin
   Bjorklund, Balazs Lengyel, David Partain and Phil Shafer.

   Helpful comments on various versions of this document were provided
   by the following individuals: Andy Bierman, Martin Bjorklund, Benoit
   Claise, Joel M.  Halpern, Ladislav Lhotka, Lars-Johan Liman, and Dan
   Romascanu.

   Juergen Schoenwaelder was partly funded by the European Union's
   Seventh Framework Programme under Grant Agreement ICT-318488 and the
   European Union’s Horizon 2020 research and innovation programme under
   Grant Agreement No. 830927.

8.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <https://www.rfc-editor.org/info/rfc3339>.

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

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   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC4007]  Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and
              B. Zill, "IPv6 Scoped Address Architecture", RFC 4007,
              DOI 10.17487/RFC4007, March 2005,
              <https://www.rfc-editor.org/info/rfc4007>.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,
              DOI 10.17487/RFC4122, July 2005,
              <https://www.rfc-editor.org/info/rfc4122>.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, DOI 10.17487/RFC4291, February
              2006, <https://www.rfc-editor.org/info/rfc4291>.

   [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>.

   [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>.

   [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>.

   [RFC8294]  Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger,
              "Common YANG Data Types for the Routing Area", RFC 8294,
              DOI 10.17487/RFC8294, December 2017,
              <https://www.rfc-editor.org/info/rfc8294>.

   [W3C.xpath]
              Clark, J. and S. DeRose, "XML Path Language (XPath)
              Version 1.0", W3C REC xpath, W3C Recommendation xpath,
              W3C xpath, 16 November 1999,
              <https://www.w3.org/TR/xpath/>.

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   [W3C.xmlschema11-2]
              "W3C XML Schema Definition Language (XSD) 1.1 Part 2:
              Datatypes", W3C REC xmlschema11-2, W3C xmlschema11-2,
              <https://www.w3.org/TR/xmlschema11-2/>.

9.  Informative References

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              DOI 10.17487/RFC0768, August 1980,
              <https://www.rfc-editor.org/info/rfc768>.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              DOI 10.17487/RFC0791, September 1981,
              <https://www.rfc-editor.org/info/rfc791>.

   [RFC0952]  Harrenstien, K., Stahl, M., and E. Feinler, "DoD Internet
              host table specification", RFC 952, DOI 10.17487/RFC0952,
              October 1985, <https://www.rfc-editor.org/info/rfc952>.

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC1123]  Braden, R., Ed., "Requirements for Internet Hosts -
              Application and Support", STD 3, RFC 1123,
              DOI 10.17487/RFC1123, October 1989,
              <https://www.rfc-editor.org/info/rfc1123>.

   [RFC1930]  Hawkinson, J. and T. Bates, "Guidelines for creation,
              selection, and registration of an Autonomous System (AS)",
              BCP 6, RFC 1930, DOI 10.17487/RFC1930, March 1996,
              <https://www.rfc-editor.org/info/rfc1930>.

   [RFC2317]  Eidnes, H., de Groot, G., and P. Vixie, "Classless IN-
              ADDR.ARPA delegation", BCP 20, RFC 2317,
              DOI 10.17487/RFC2317, March 1998,
              <https://www.rfc-editor.org/info/rfc2317>.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              DOI 10.17487/RFC2474, December 1998,
              <https://www.rfc-editor.org/info/rfc2474>.

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   [RFC2578]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Structure of Management Information
              Version 2 (SMIv2)", STD 58, RFC 2578,
              DOI 10.17487/RFC2578, April 1999,
              <https://www.rfc-editor.org/info/rfc2578>.

   [RFC2579]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Textual Conventions for SMIv2",
              STD 58, RFC 2579, DOI 10.17487/RFC2579, April 1999,
              <https://www.rfc-editor.org/info/rfc2579>.

   [RFC2780]  Bradner, S. and V. Paxson, "IANA Allocation Guidelines For
              Values In the Internet Protocol and Related Headers",
              BCP 37, RFC 2780, DOI 10.17487/RFC2780, March 2000,
              <https://www.rfc-editor.org/info/rfc2780>.

   [RFC2782]  Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
              specifying the location of services (DNS SRV)", RFC 2782,
              DOI 10.17487/RFC2782, February 2000,
              <https://www.rfc-editor.org/info/rfc2782>.

   [RFC2856]  Bierman, A., McCloghrie, K., and R. Presuhn, "Textual
              Conventions for Additional High Capacity Data Types",
              RFC 2856, DOI 10.17487/RFC2856, June 2000,
              <https://www.rfc-editor.org/info/rfc2856>.

   [RFC3289]  Baker, F., Chan, K., and A. Smith, "Management Information
              Base for the Differentiated Services Architecture",
              RFC 3289, DOI 10.17487/RFC3289, May 2002,
              <https://www.rfc-editor.org/info/rfc3289>.

   [RFC3305]  Mealling, M., Ed. and R. Denenberg, Ed., "Report from the
              Joint W3C/IETF URI Planning Interest Group: Uniform
              Resource Identifiers (URIs), URLs, and Uniform Resource
              Names (URNs): Clarifications and Recommendations",
              RFC 3305, DOI 10.17487/RFC3305, August 2002,
              <https://www.rfc-editor.org/info/rfc3305>.

   [RFC3595]  Wijnen, B., "Textual Conventions for IPv6 Flow Label",
              RFC 3595, DOI 10.17487/RFC3595, September 2003,
              <https://www.rfc-editor.org/info/rfc3595>.

   [RFC3927]  Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
              Configuration of IPv4 Link-Local Addresses", RFC 3927,
              DOI 10.17487/RFC3927, May 2005,
              <https://www.rfc-editor.org/info/rfc3927>.

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   [RFC4001]  Daniele, M., Haberman, B., Routhier, S., and J.
              Schoenwaelder, "Textual Conventions for Internet Network
              Addresses", RFC 4001, DOI 10.17487/RFC4001, February 2005,
              <https://www.rfc-editor.org/info/rfc4001>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4340]  Kohler, E., Handley, M., and S. Floyd, "Datagram
              Congestion Control Protocol (DCCP)", RFC 4340,
              DOI 10.17487/RFC4340, March 2006,
              <https://www.rfc-editor.org/info/rfc4340>.

   [RFC4502]  Waldbusser, S., "Remote Network Monitoring Management
              Information Base Version 2", RFC 4502,
              DOI 10.17487/RFC4502, May 2006,
              <https://www.rfc-editor.org/info/rfc4502>.

   [RFC4592]  Lewis, E., "The Role of Wildcards in the Domain Name
              System", RFC 4592, DOI 10.17487/RFC4592, July 2006,
              <https://www.rfc-editor.org/info/rfc4592>.

   [RFC5017]  McWalter, D., Ed., "MIB Textual Conventions for Uniform
              Resource Identifiers (URIs)", RFC 5017,
              DOI 10.17487/RFC5017, September 2007,
              <https://www.rfc-editor.org/info/rfc5017>.

   [RFC5131]  McWalter, D., Ed., "A MIB Textual Convention for Language
              Tags", RFC 5131, DOI 10.17487/RFC5131, December 2007,
              <https://www.rfc-editor.org/info/rfc5131>.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <https://www.rfc-editor.org/info/rfc5322>.

   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
              Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
              September 2009, <https://www.rfc-editor.org/info/rfc5646>.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, DOI 10.17487/RFC5890, August 2010,
              <https://www.rfc-editor.org/info/rfc5890>.

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   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", RFC 5952,
              DOI 10.17487/RFC5952, August 2010,
              <https://www.rfc-editor.org/info/rfc5952>.

   [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>.

   [RFC6793]  Vohra, Q. and E. Chen, "BGP Support for Four-Octet
              Autonomous System (AS) Number Space", RFC 6793,
              DOI 10.17487/RFC6793, December 2012,
              <https://www.rfc-editor.org/info/rfc6793>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC9260]  Stewart, R., Tüxen, M., and K. Nielsen, "Stream Control
              Transmission Protocol", RFC 9260, DOI 10.17487/RFC9260,
              June 2022, <https://www.rfc-editor.org/info/rfc9260>.

   [RFC9293]  Eddy, W., Ed., "Transmission Control Protocol (TCP)",
              STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
              <https://www.rfc-editor.org/info/rfc9293>.

   [ISO-9834-1]
              ISO/IEC 9834-1:2008, "Information technology -- Open
              Systems Interconnection -- Procedures for the operation of
              OSI Registration Authorities: General procedures and top
              arcs of the ASN.1 Object Identifier tree", 2008.

   [IEEE-802-2001]
              IEEE Std 802-2001, "IEEE Standard for Local and
              Metropolitan Area Networks: Overview and Architecture",
              June 2001.

Appendix A.  Changes from RFC 6991

   This version adds new type definitions to the YANG modules.  For an
   overview, see the revision statements in the YANG modules defined in
   Section 3 and Section 4.

   The yang-identifier definition has been aligned with YANG 1.1.  Some
   pattern statements have been rewritten to make them tighter.
   Finally, this version addresses errata 4076 and 5105 of RFC 6991.

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Appendix B.  Changes from RFC 6021

   This version adds new type definitions to the YANG modules.  For an
   overview, see the revision statements in the YANG modules defined in
   Section 3 and Section 4.

Author's Address

   Jürgen Schönwälder (editor)
   Constructor University
   Email: jschoenwaelder@constructor.university

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