  module ietf-yang-types {

    yang-version 1;

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

    prefix yang;

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

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

    WG Chair: David Kessens
              <mailto:david.kessens@nsn.com>

    WG Chair: Juergen Schoenwaelder
              <mailto:j.schoenwaelder@jacobs-university.de>

    Editor:   Juergen Schoenwaelder
              <mailto:j.schoenwaelder@jacobs-university.de>";

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

    Copyright (c) 2013 IETF Trust and the persons identified as
    authors of the code.  All rights reserved.

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

    This version of this YANG module is part of RFC 6991; see
    the RFC itself for full legal notices.";

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

    }

    revision "2010-09-24" {
      description "Initial revision.";
      reference
        "RFC 6021: Common YANG Data 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 creation 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 counter32;
      default "0";
      description
        "The zero-based-counter32 type represents a counter32
      that has the defined 'initial' value zero.

      A schema node 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
      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 creation 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)";

    }

    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 schema node 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
      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
        "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";

    }

    typedef object-identifier {
      type string {
        pattern
          '(([0-1](\.[1-3]?[0-9]))|(2\.(0|([1-9]\d*))))(\.(0|([1-9]\d*)))*';
      }
      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
        "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 '\d*(\.\d*){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)";

    }

    typedef yang-identifier {
      type string {
        length "1..max";
        pattern '[a-zA-Z_][a-zA-Z0-9\-_.]*';
        pattern
          '.|..|[^xX].*|.[^mM].*|..[^lL].*';
      }
      description
        "A YANG identifier string as defined by the 'identifier'
       rule in Section 12 of RFC 6020.  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.

       A YANG identifier MUST NOT start with any possible
       combination of the lowercase or uppercase character
       sequence 'xml'.";
      reference
        "RFC 6020: YANG - A Data Modeling Language for the Network
        	  Configuration Protocol (NETCONF)";

    }

    typedef date-and-time {
      type string {
        pattern
          '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d+)?(Z|[\+\-]\d{2}:\d{2})';
      }
      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.

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

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

      (b) The date-and-time time-offset -00:00 indicates an unknown
          time zone (see RFC 3339) while -00:00 and +00:00 and Z
          all represent the same time zone in dateTime.

      (c) The canonical format (see below) of data-and-time values
          differs from the canonical format used by the dateTime XML
          schema type, which requires all times to be in UTC using
          the time-offset 'Z'.

      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.";
      reference
        "RFC 3339: Date and Time on the Internet: Timestamps
         RFC 2579: Textual Conventions for SMIv2
        XSD-TYPES: XML Schema Part 2: Datatypes Second Edition";

    }

    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 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 attribute 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
      attribute 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";

    }

    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";

    }

    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";

    }

    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.";
    }
  }  // module ietf-yang-types