RFC 9911 | Common YANG Data Types | December 2025
Schönwälder | Standards Track | [Page]

Stream:
  Internet Engineering Task Force (IETF)
RFC:
  9911
Obsoletes:
  6991
Category:
  Standards Track
Published:
  December 2025
ISSN:
  2070-1721
Author:
  J. Schönwälder, Ed.
  Constructor University

# RFC 9911

# Common YANG Data Types

## Abstract

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

## Status of This Memo

This is an Internet Standards Track document.¶

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

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9911.¶

## Copyright Notice

Copyright (c) 2025 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.¶

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.¶

## 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 defines a collection of common data types. The definitions are organized into two YANG modules:¶

- The "ietf-yang-types" module defines generally useful data types such as types for counters and gauges, types related to date and time, and types for common string values (e.g., UUIDs, dotted-quad notation, and language tags).¶

- The "ietf-inet-types" module defines data types relevant for the Internet Protocol suite such as types related to IP addresses, types for domain name, host name, URI, and email, and types for values in common protocol fields (e.g., port numbers).¶

The initial version of these YANG modules was published as [RFC6021]. The first revision of [RFC6021], published as [RFC6991], added several type definitions to the YANG modules. This second revision adds further new type definitions and addresses Erratum IDs 4076 [Err4076] and 5105 [Err5105]. Furthermore, the yang-identifier definition has been aligned with YANG 1.1 [RFC7950], and some pattern statements have been improved. For further details, see the revision statements of the YANG modules in Sections 3 and 4. A brief overview of all types and when they were introduced can be found in Section 2. Additional type definitions may be added in the future by submitting proposals to the NETMOD Working Group.¶

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

Tables 1 and 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.¶

Table 1: Types Defined in the "ietf-yang-types" Module
Type | Base Type | Introduced in
--- | --- | ---
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 | string | RFC 9911
date-no-zone | string | RFC 9911
time | string | RFC 9911
time-no-zone | string | RFC 9911
hours32 | int32 | RFC 9911
minutes32 | int32 | RFC 9911
seconds32 | int32 | RFC 9911
centiseconds32 | int32 | RFC 9911
milliseconds32 | int32 | RFC 9911
microseconds32 | int32 | RFC 9911
microseconds64 | int64 | RFC 9911
nanoseconds32 | int32 | RFC 9911
nanoseconds64 | int64 | RFC 9911
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 9911
yang-identifier | string | RFC 6991

Table 2: Types Defined in the "ietf-inet-types" Module
Type | Base Type | Introduced in
--- | --- | ---
ip-version | enum | RFC 6021
dscp | uint8 | RFC 6021
ipv6-flow-label | uint32 | RFC 6021
port-number | uint16 | RFC 6021
protocol-number | uint8 | RFC 9911
upper-layer-protocol-number | protocol-number | RFC 9911
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 9911
ipv4-address-link-local | ipv4-address | RFC 9911
ipv6-address-link-local | ipv6-address | RFC 9911
ip-prefix | union | RFC 6021
ipv4-prefix | string | RFC 6021
ipv6-prefix | string | RFC 6021
ip-address-and-prefix | union | RFC 9911
ipv4-address-and-prefix | string | RFC 9911
ipv6-address-and-prefix | string | RFC 9911
domain-name | string | RFC 6021
host-name | domain-name | RFC 9911
host | union | RFC 6021
uri | string | RFC 6021
email-address | string | RFC 9911

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.¶

Table 3: Equivalent SMIv2 Types for the "ietf-yang-types" Module
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 4: Equivalent SMIv2 Types for the "ietf-inet-types" Module
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)

## 3. Core YANG Types

The "ietf-yang-types" YANG module references [IEEE-802-2024], [ISO-8601], [ISO-9834-1], [RFC2578], [RFC2579], [RFC2856], [RFC3339], [RFC4502], [RFC5131], [RFC5646], [RFC7950], [RFC9557], [RFC9562], [XPATH], and [XSD-TYPES].¶

    <CODE BEGINS> file "ietf-yang-types@2025-12-22.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:   Jürgen Schönwälder
                   <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
         described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
         they appear in all capitals, as shown here.

         Copyright (c) 2025 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 9911;
         see the RFC itself for full legal notices.";

      revision 2025-12-22 {
        description
          "This revision adds the following new data types:
           - yang:date
           - yang:date-no-zone
           - yang:time
           - 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, and types representing time support the representation
           of leap seconds.  The representation of time zone offsets
           has been aligned with RFC 9557.  Several description and
           pattern statements have been improved.";
        reference
          "RFC 9911: 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";
      }
      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
           discontinuities occur at times other than re-initialization
           (for example, at the instantiation of a schema node of type
           counter32), 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 counter32;
        default "0";
        description
          "The zero-based-counter32 type represents a counter32
           that has the defined 'initial' value zero.

           A data tree node using 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 data tree node
           using 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
           discontinuities occur at times other than re-initialization
           (for example, at the instantiation of a schema node of type
           counter64), 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)";
      }

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

           A data tree node using 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 data tree node
           using 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
           the maximum value, the gauge32 also decreases; likewise, if
           the information increases above the minimum value, the
           gauge32 also increases.

           In the value set and its semantics, this type is equivalent
           to the Gauge32 type of the SMIv2.";
        reference
          "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
           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
          "ISO 9834-1: Information technology -- Procedures for the
           operation of object identifier registration authorities --
           Part 1: General procedures and top arcs of the international
           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]|60)'
          + '(\.[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
           Gregorian calendar.  The profile is defined by the
           date-time production in Section 5.6 of RFC 3339 and the
           update defined in Section 2 of RFC 9557.  The value of
           60 for seconds is allowed only in the case of leap seconds.

           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 Z indicates that the date-and-time
               value is reported in UTC and that the local time zone
               reference point is unknown.  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 UTC
               (see Section 2 of RFC 9557).

           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 if a server automatically follows
           daylight saving time (DST) time zone offset changes.  The
           canonical format for date-and-time values reported in UTC
           with an unknown local time zone offset SHOULD use the
           time-offset Z and MAY use -00:00 for backwards
           compatibility.";
        reference
          "ISO 8601: Data elements and interchange formats -- Information
                     interchange -- Representation of dates and times
           RFC 3339: Date and Time on the Internet: Timestamps
           RFC 9557: Date and Time on the Internet: Timestamps
                     with Additional Information
           RFC 2579: Textual Conventions for SMIv2
           XSD-TYPES: XML Schema Definition Language (XSD) 1.1
                      Part 2: Datatypes";
      }

      typedef date {
        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.  It includes an optional time
           zone offset.

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

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

           (b) The time-offset Z indicates that the date value is
               reported in UTC and that the local time zone reference
               point is unknown.  The time-offset +00:00 indicates that
               the date value is reported in UTC and that the local
               time zone reference point is UTC (see Section 2 of
               RFC 9557).

           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
           if a server automatically follows daylight saving time
           (DST) time zone offset changes.  The canonical format for
           date values reported in UTC with an unknown local time zone
           offset uses the time-offset Z.";
        reference
          "RFC 3339: Date and Time on the Internet: Timestamps
           RFC 9557: Date and Time on the Internet: Timestamps
                     with Additional Information
           XSD-TYPES: XML Schema Definition Language (XSD) 1.1
                      Part 2: Datatypes";
      }

      typedef date-no-zone {
        type date {
          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 {
        type string {
          pattern
            '(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:([0-5][0-9]|60)'
          + '(\.[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.  It includes an optional time zone
           offset.  The value of 60 for seconds is allowed only in the
           case of leap seconds.

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

           (a) The time-offset Z indicates that the time value is
               reported in UTC and that the local time zone reference
               point is unknown.  The time-offset +00:00 indicates that
               the time value is reported in UTC and that the local
               time zone reference point is UTC (see Section 2 of
               RFC 9557).

           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
           if a server automatically follows daylight saving time
           (DST) time zone offset changes.  The canonical format for
           time values reported in UTC with an unknown local time zone
           offset uses the time-offset Z.";
        reference
          "RFC 3339: Date and Time on the Internet: Timestamps
           RFC 9557: Date and Time on the Internet: Timestamps
                     with Additional Information
           XSD-TYPES: XML Schema Definition Language (XSD) 1.1
                      Part 2: Datatypes";
      }

      typedef time-no-zone {
        type time {
          pattern
            '(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:([0-5][0-9]|60)'
          + '(\.[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.

           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').";
      }

      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
          "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 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";
      }

      /*** 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 of 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 a 48-bit IEEE 802 Media
           Access Control (MAC) address.  The canonical representation
           uses lowercase characters.  Note that there are IEEE 802 MAC
           addresses with a different length that this type cannot
           represent.  The phys-address type may be used to represent
           physical addresses of varying length.

           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";
      }

      /*** 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 9562.  The canonical representation uses
           lowercase characters.

           The following is an example of a UUID in string
           representation:
           f81d4fae-7dec-11d0-a765-00a0c91e6bf6.
          ";
        reference
          "RFC 9562: Universally Unique IDentifiers (UUIDs)";
      }

      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
           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.  In RFC 6991, this definition excluded
           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 6991: Common YANG Data Types
           RFC 6020: YANG - A Data Modeling Language for the
                     Network Configuration Protocol (NETCONF)";
      }
    }

    <CODE ENDS>

¶

## 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], [RFC6532], [RFC6793], [RFC8200], [RFC9260], [RFC9293], and [RFC9499].¶

    <CODE BEGINS> file "ietf-inet-types@2025-12-22.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:   Jürgen Schönwälder
                   <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) 2025 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 9911;
         see the RFC itself for full legal notices.";

      revision 2025-12-22 {
        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:upper-layer-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 9911: 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;
            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 Internet 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.

           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.

           Protocol numbers are assigned by IANA.  The current list of
           all assignments is available from <https://www.iana.org/>.";
        reference
          "RFC  791: Internet Protocol
           RFC 8200: Internet Protocol, Version 6 (IPv6) Specification";
      }

      typedef upper-layer-protocol-number {
        type protocol-number;
        description
          "The upper-layer-protocol-number represents the upper-layer
           protocol number carried in an IP packet.  For IPv6 packets
           with extension headers, this is the protocol number carried
           in the last 'next header' field of the chain of IPv6 extension
           headers.";
        reference
          "RFC  791: Internet Protocol
           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
           that 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 autonomous system 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 ipv4-address;
          type 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
          "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])'
          + '(%.+)?';
        }
        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.  If a system uses zone names
           that are not represented in UTF-8, then an implementation
           needs to use some mechanism to transform the local name
           into UTF-8.  The definition of such a mechanism is outside
           the scope of this document.

           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.
           If a system uses zone names that are not represented in
           UTF-8, then an implementation needs to use some mechanism
           to transform the local name into UTF-8.  The definition of
           such a mechanism is outside the scope of this document.

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

      typedef ipv6-address-no-zone {
        type ipv6-address {
          pattern '[0-9a-fA-F:\.]*';
        }
        description
          "An IPv6 address without a zone index.  This type, derived
           from the type ipv6-address, may be used in situations where
           the zone is known from the context and 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";
      }

      typedef ip-address-link-local {
        type union {
          type ipv4-address-link-local;
          type 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
          "The ipv4-address-link-local type represents 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][89aAbB][0-9a-fA-F]:.*';
        }
        description
          "The ipv6-address-link-local type represents a link-local IPv6
           address in the prefix fe80::/10 as defined in Section 2.4 of
           RFC 4291.";
        reference
          "RFC 4291: IP Version 6 Addressing Architecture";
      }

      typedef ip-prefix {
        type union {
          type ipv4-prefix;
          type 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 {
          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
           that are not part of the prefix be 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
           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
           that are not part of the prefix be 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 ipv4-address-and-prefix;
          type 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}'
                + '(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 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 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.

           The encoding of DNS names in the DNS protocol is limited
           to 255 characters.  Since the encoding consists of labels
           prefixed by a length byte and there is a trailing NUL
           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 depend on the configuration of the
           resolver.

           Domain-name values use the ASCII encoding.  Their canonical
           format uses lowercase 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
           RFC 9499: DNS Terminology";
      }

      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 RFCs 1123 and
           952).";
        reference
          "RFC  952: DoD Internet Host Table Specification
           RFC 1123: Requirements for Internet Hosts -- Application
                     and Support";
      }

      typedef host {
        type union {
          type ip-address;
          type 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 ASCII encoding
           and MUST be normalized as described in Sections 6.2.1,
           6.2.2.1, and 6.2.2.2 of RFC 3986.  Characters that can be
           represented without using percent-encoding are represented
           as characters (without percent-encoding), and all
           case-insensitive characters are set to lowercase except
           for hexadecimal digits within a percent-encoded triplet,
           which are normalized to uppercase as described in
           Section 6.2.2.1 of RFC 3986.

           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)";
      }

      typedef email-address {
        type string {
          pattern '.+@.+';
        }
        description
          "The email-address type represents an internationalized
           email address.

           The email address format is defined by the addr-spec
           ABNF rule in Section 3.4.1 of RFC 5322.  This format has
           been extended by RFC 6532 to support internationalized
           email addresses.  Implementations MUST support the
           internationalization extensions of RFC 6532.  Support
           for the obsolete obs-local-part, obs-domain, and
           obs-qtext in RFC 5322 is not required.

           The domain part may use both A-labels and U-labels
           (see RFC 5890).  The canonical format of the domain part
           uses lowercase characters and U-labels (RFC 5890) where
           applicable.";
        reference
          "RFC 5322: Internet Message Format
           RFC 5890: Internationalized Domain Names in Applications
                     (IDNA): Definitions and Document Framework
           RFC 6532: Internationalized Email Headers";
      }
    }

    <CODE ENDS>

¶

## 5. IANA Considerations

This document reuses the URIs for "ietf-yang-types" and "ietf-inet-types" in the "IETF XML Registry" [RFC3688].¶

Per this document, IANA has updated the "YANG Module Names" registry to reference this RFC instead of [RFC6991] for the "ietf-yang-types" and "ietf-inet-types" modules. Following the format in [RFC6020], these registrations have been made.¶

Name:
  ietf-yang-types¶
Namespace:
  urn:ietf:params:xml:ns:yang:ietf-yang-types¶
Prefix:
  yang¶
Reference:
  RFC 9911¶

Name:
  ietf-inet-types¶
Namespace:
  urn:ietf:params:xml:ns:yang:ietf-inet-types¶
Prefix:
  inet¶
Reference:
  RFC 9911¶

## 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. References

### 7.1. Normative References

[RFC2119]
  Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[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>.
[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>.
[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>.
[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>.
[RFC9499]
  Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219, RFC 9499, DOI 10.17487/RFC9499, March 2024, <https://www.rfc-editor.org/info/rfc9499>.
[RFC9557]
  Sharma, U. and C. Bormann, "Date and Time on the Internet: Timestamps with Additional Information", RFC 9557, DOI 10.17487/RFC9557, April 2024, <https://www.rfc-editor.org/info/rfc9557>.
[RFC9562]
  Davis, K., Peabody, B., and P. Leach, "Universally Unique IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May 2024, <https://www.rfc-editor.org/info/rfc9562>.
[XPATH]
  Clark, J., Ed. and S. DeRose, Ed., "XML Path Language (XPath) Version 1.0", W3C Recommendation, 16 November 1999, <http://www.w3.org/TR/xpath-10>.
[XSD-TYPES]
  Peterson, D., Ed., Gao, S., Ed., Malhotra, A., Ed., Sperberg-McQueen, C., Ed., and H. S. Thompson, Ed., "W3C XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes", W3C Recommendation, 5 April 2012, <https://www.w3.org/TR/xmlschema11-2/>.

### 7.2. 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>.
[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>.
[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>.
[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>.
[RFC6021]
  Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6021, DOI 10.17487/RFC6021, October 2010, <https://www.rfc-editor.org/info/rfc6021>.
[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>.
[RFC6532]
  Yang, A., Steele, S., and N. Freed, "Internationalized Email Headers", RFC 6532, DOI 10.17487/RFC6532, February 2012, <https://www.rfc-editor.org/info/rfc6532>.
[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>.
[RFC6991]
  Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, <https://www.rfc-editor.org/info/rfc6991>.
[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-8601]
  ISO/IEC, "Data elements and interchange formats -- Information interchange -- Representation of dates and times", ISO/IEC 8601:2000, December 2008, <https://www.iso.org/standard/26780.html>.
[ISO-9834-1]
  ISO/IEC, "Information technology -- Procedures for the operation of object identifier registration authorities -- Part 1: General procedures and top arcs of the international object identifier tree", ISO/IEC 9834-1:2012, 2012, <https://www.iso.org/standard/58055.html>.
[IEEE-802-2024]
  IEEE, "IEEE Standard for Local and Metropolitan Area Networks: Overview and Architecture", IEEE Std 802-2024, DOI 10.1109/IEEESTD.2025.10935844, March 2025, <https://doi.org/10.1109/IEEESTD.2025.10935844>.
[Err4076]
  RFC Errata, Erratum ID 4076, RFC 6991, <https://www.rfc-editor.org/errata/eid4076>.
[Err5105]
  RFC Errata, Erratum ID 5105, RFC 6991, <https://www.rfc-editor.org/errata/eid5105>.

## Acknowledgments

The following people contributed significantly to the original version of this document, which was published as [RFC6021]: Andy Bierman, Martin Björklund, Balazs Lengyel, David Partain, and Phil Shafer.¶

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

## Author's Address