Internet Engineering Task Force (IETF) J. Schoenwaelder, Ed.
Request for Comments: 6991 Jacobs University
Obsoletes: 6021 July 2013
Category: Standards Track
ISSN: 2070-1721
Common YANG Data Types
Abstract
This document introduces a collection of common data types to be used
with the YANG data modeling language. This document obsoletes RFC
6021.
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 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6991.
Copyright Notice
Copyright (c) 2013 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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
Schoenwaelder Standards Track [Page 1]RFC 6991 Common YANG Data Types July 2013
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
1. Introduction ....................................................2
2. Overview ........................................................3
3. Core YANG Derived Types .........................................4
4. Internet-Specific Derived Types ................................14
5. IANA Considerations ............................................24
6. Security Considerations ........................................25
7. Contributors ...................................................25
8. Acknowledgments ................................................25
9. References .....................................................26
9.1. Normative References ......................................26
9.2. Informative References ....................................26
Appendix A. Changes from RFC 6021 ................................30
1. Introduction
YANG [RFC6020] is a data modeling language used to model
configuration and state data manipulated by the Network Configuration
Protocol (NETCONF) [RFC6241]. The YANG language supports a small set
of built-in data types and provides mechanisms to derive other types
from the built-in types.
This document introduces a collection of common data types derived
from the built-in YANG data types. The derived types are designed to
be applicable for modeling all areas of management information. The
definitions are organized in several YANG modules. The
"ietf-yang-types" module contains generally useful data types. The
"ietf-inet-types" module contains definitions that are relevant for
the Internet protocol suite.
This document adds new type definitions to the YANG modules and
obsoletes [RFC6021]. For further details, see the revision
statements of the YANG modules in Sections 3 and 4 or the summary in
Appendix A.
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].
Schoenwaelder Standards Track [Page 2]RFC 6991 Common YANG Data Types July 2013
2. Overview
This section provides a short overview of the types defined in
subsequent sections and their equivalent Structure of Management
Information Version 2 (SMIv2) [RFC2578][RFC2579] data types. 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 1 lists the types defined in the ietf-yang-types YANG module
and the corresponding SMIv2 types (- indicates there is no
corresponding SMIv2 type).
+-----------------------+--------------------------------+
| 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 | - |
| object-identifier-128 | OBJECT IDENTIFIER |
| yang-identifier | - |
| date-and-time | - |
| timeticks | TimeTicks (SNMPv2-SMI) |
| timestamp | TimeStamp (SNMPv2-TC) |
| phys-address | PhysAddress (SNMPv2-TC) |
| mac-address | MacAddress (SNMPv2-TC) |
| xpath1.0 | - |
| hex-string | - |
| uuid | - |
| dotted-quad | - |
+-----------------------+--------------------------------+
Table 1: ietf-yang-types
Schoenwaelder Standards Track [Page 3]RFC 6991 Common YANG Data Types July 2013
Table 2 lists the types defined in the ietf-inet-types YANG module
and the corresponding SMIv2 types (if any).
+----------------------+--------------------------------------------+
| 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) |
| ip-address | - |
| ipv4-address | - |
| ipv6-address | - |
| ip-address-no-zone | - |
| ipv4-address-no-zone | - |
| ipv6-address-no-zone | - |
| ip-prefix | - |
| ipv4-prefix | - |
| ipv6-prefix | - |
| domain-name | - |
| host | - |
| uri | Uri (URI-TC-MIB) |
+----------------------+--------------------------------------------+
Table 2: ietf-inet-types
3. Core YANG Derived Types
The ietf-yang-types YANG module references [IEEE802], [ISO9834-1],
[RFC2578], [RFC2579], [RFC2856], [RFC3339], [RFC4122], [RFC4502],
[RFC6020], [XPATH], and [XSD-TYPES].
<CODE BEGINS> file "ietf-yang-types@2013-07-15.yang"
module ietf-yang-types {
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>
Schoenwaelder Standards Track [Page 4]RFC 6991 Common YANG Data Types July 2013
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";
}
/*** collection of counter and gauge types ***/
typedef counter32 {
type uint32;
Schoenwaelder Standards Track [Page 5]RFC 6991 Common YANG Data Types July 2013
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 yang: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.
Schoenwaelder Standards Track [Page 6]RFC 6991 Common YANG Data Types July 2013
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 yang:counter64;
default "0";
description
"The zero-based-counter64 type represents a counter64 that
has the defined 'initial' value zero.
Schoenwaelder Standards Track [Page 7]RFC 6991 Common YANG Data Types July 2013
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
Schoenwaelder Standards Track [Page 8]RFC 6991 Common YANG Data Types July 2013
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]\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.
Schoenwaelder Standards Track [Page 9]RFC 6991 Common YANG Data Types July 2013
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)";
}
Schoenwaelder Standards Track [Page 10]RFC 6991 Common YANG Data Types July 2013
/*** collection of types related to date and time***/
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";
}
Schoenwaelder Standards Track [Page 11]RFC 6991 Common YANG Data Types July 2013
typedef timeticks {
type uint32;
description
"The timeticks type represents a non-negative integer that
represents the time, modulo 2^32 (4294967296 decimal), in
hundredths of a second between two epochs. When a schema
node is defined that uses this type, the description of
the schema node identifies both of the reference epochs.
In the value set and its semantics, this type is equivalent
to the TimeTicks type of the SMIv2.";
reference
"RFC 2578: Structure of Management Information Version 2
(SMIv2)";
}
typedef timestamp {
type yang:timeticks;
description
"The timestamp type represents the value of an associated
timeticks schema node 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";
}
/*** collection of generic address types ***/
typedef phys-address {
type string {
pattern '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
}
Schoenwaelder Standards Track [Page 12]RFC 6991 Common YANG Data Types July 2013
description
"Represents media- or physical-level addresses represented
as a sequence octets, each octet represented by two hexadecimal
numbers. Octets are separated by colons. The canonical
representation uses lowercase characters.
In the value set and its semantics, this type is equivalent
to the PhysAddress textual convention of the SMIv2.";
reference
"RFC 2579: Textual Conventions for SMIv2";
}
typedef mac-address {
type string {
pattern '[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){5}';
}
description
"The mac-address type represents an IEEE 802 MAC address.
The canonical representation uses lowercase characters.
In the value set and its semantics, this type is equivalent
to the MacAddress textual convention of the SMIv2.";
reference
"IEEE 802: IEEE Standard for Local and Metropolitan Area
Networks: Overview and Architecture
RFC 2579: Textual Conventions for SMIv2";
}
/*** collection of XML-specific types ***/
typedef xpath1.0 {
type string;
description
"This type represents an XPATH 1.0 expression.
When a schema node is defined that uses this type, the
description of the schema node MUST specify the XPath
context in which the XPath expression is evaluated.";
reference
"XPATH: XML Path Language (XPath) Version 1.0";
}
/*** collection of string types ***/
typedef hex-string {
type string {
pattern '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
}
Schoenwaelder Standards Track [Page 13]RFC 6991 Common YANG Data Types July 2013
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.";
}
}
<CODE ENDS>
4. Internet-Specific Derived Types
The ietf-inet-types YANG module references [RFC0768], [RFC0791],
[RFC0793], [RFC0952], [RFC1034], [RFC1123], [RFC1930], [RFC2460],
[RFC2474], [RFC2780], [RFC2782], [RFC3289], [RFC3305], [RFC3595],
[RFC3986], [RFC4001], [RFC4007], [RFC4271], [RFC4291], [RFC4340],
[RFC4960], [RFC5017], [RFC5890], [RFC5952], and [RFC6793].
Schoenwaelder Standards Track [Page 14]RFC 6991 Common YANG Data Types July 2013
<CODE BEGINS> file "ietf-inet-types@2013-07-15.yang"
module ietf-inet-types {
namespace "urn:ietf:params:xml:ns:yang:ietf-inet-types";
prefix "inet";
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 for Internet addresses and related things.
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:
- ip-address-no-zone
- ipv4-address-no-zone
- ipv6-address-no-zone";
reference
"RFC 6991: Common YANG Data Types";
Schoenwaelder Standards Track [Page 15]RFC 6991 Common YANG Data Types July 2013
}
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 2460.";
}
}
description
"This value represents the version of the IP protocol.
In the value set and its semantics, this type is equivalent
to the InetVersion textual convention of the SMIv2.";
reference
"RFC 791: Internet Protocol
RFC 2460: 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.
Schoenwaelder Standards Track [Page 16]RFC 6991 Common YANG Data Types July 2013
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 2460: 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. A current list of
all assignments is available from <http://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 793: Transmission Control Protocol
RFC 4960: Stream Control Transmission Protocol
RFC 4340: Datagram Congestion Control Protocol (DCCP)
RFC 4001: Textual Conventions for Internet Network Addresses";
Schoenwaelder Standards Track [Page 17]RFC 6991 Common YANG Data Types July 2013
}
/*** collection of types related to autonomous systems ***/
typedef as-number {
type uint32;
description
"The as-number type represents autonomous system numbers
which identify an Autonomous System (AS). An AS is a set
of routers under a single technical administration, using
an interior gateway protocol and common metrics to route
packets within the AS, and using an exterior gateway
protocol to route packets to other ASes. IANA maintains
the AS number space and has delegated large parts to the
regional registries.
Autonomous system numbers were originally limited to 16
bits. BGP extensions have enlarged the autonomous system
number space to 32 bits. This type therefore uses an uint32
base type without a range restriction in order to support
a larger autonomous system number space.
In the value set and its semantics, this type is equivalent
to the InetAutonomousSystemNumber textual convention of
the SMIv2.";
reference
"RFC 1930: Guidelines for creation, selection, and registration
of an Autonomous System (AS)
RFC 4271: A Border Gateway Protocol 4 (BGP-4)
RFC 4001: Textual Conventions for Internet Network Addresses
RFC 6793: BGP Support for Four-Octet Autonomous System (AS)
Number Space";
}
/*** collection of types related to IP addresses and hostnames ***/
typedef ip-address {
type union {
type inet:ipv4-address;
type inet:ipv6-address;
}
description
"The ip-address type represents an IP address and is IP
version neutral. The format of the textual representation
implies the IP version. This type supports scoped addresses
by allowing zone identifiers in the address format.";
reference
"RFC 4007: IPv6 Scoped Address Architecture";
Schoenwaelder Standards Track [Page 18]RFC 6991 Common YANG Data Types July 2013
}
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])'
+ '(%[\p{N}\p{L}]+)?';
}
description
"The ipv4-address type represents an IPv4 address in
dotted-quad notation. The IPv4 address may include a zone
index, separated by a % sign.
The zone index is used to disambiguate identical address
values. For link-local addresses, the zone index will
typically be the interface index number or the name of an
interface. If the zone index is not present, the default
zone of the device will be used.
The canonical format for the zone index is the numerical
format";
}
typedef ipv6-address {
type string {
pattern '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}'
+ '((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|'
+ '(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}'
+ '(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))'
+ '(%[\p{N}\p{L}]+)?';
pattern '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|'
+ '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)'
+ '(%.+)?';
}
description
"The ipv6-address type represents an IPv6 address in full,
mixed, shortened, and shortened-mixed notation. The IPv6
address may include a zone index, separated by a % sign.
The zone index is used to disambiguate identical address
values. For link-local addresses, the zone index will
typically be the interface index number or the name of an
interface. If the zone index is not present, the default
zone of the device will be used.
Schoenwaelder Standards Track [Page 19]RFC 6991 Common YANG Data Types July 2013
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 inet:ipv4-address-no-zone;
type inet:ipv6-address-no-zone;
}
description
"The ip-address-no-zone type represents an IP address and is
IP version neutral. The format of the textual representation
implies the IP version. This type does not support scoped
addresses since it does not allow zone identifiers in the
address format.";
reference
"RFC 4007: IPv6 Scoped Address Architecture";
}
typedef ipv4-address-no-zone {
type inet:ipv4-address {
pattern '[0-9\.]*';
}
description
"An IPv4 address without a zone index. This type, derived from
ipv4-address, may be used in situations where the zone is
known from the context and hence no zone index is needed.";
}
typedef ipv6-address-no-zone {
type inet:ipv6-address {
pattern '[0-9a-fA-F:\.]*';
}
description
"An IPv6 address without a zone index. This type, derived from
ipv6-address, may be used in situations where the zone is
known from the context and hence no zone index is needed.";
reference
"RFC 4291: IP Version 6 Addressing Architecture
RFC 4007: IPv6 Scoped Address Architecture
RFC 5952: A Recommendation for IPv6 Address Text
Schoenwaelder Standards Track [Page 20]RFC 6991 Common YANG Data Types July 2013
Representation";
}
typedef ip-prefix {
type union {
type inet:ipv4-prefix;
type inet:ipv6-prefix;
}
description
"The ip-prefix type represents an IP prefix and is IP
version neutral. The format of the textual representations
implies the IP version.";
}
typedef ipv4-prefix {
type string {
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 address 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.";
}
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}(([^:]+:[^:]+)|(.*\..*)))|'
+ '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)'
+ '(/.+)';
}
Schoenwaelder Standards Track [Page 21]RFC 6991 Common YANG Data Types July 2013
description
"The ipv6-prefix type represents an IPv6 address 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 IPv6 address should have all bits that do not belong
to the prefix set to zero.
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.";
reference
"RFC 5952: A Recommendation for IPv6 Address Text
Representation";
}
/*** collection of domain name and URI types ***/
typedef domain-name {
type string {
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]\.?)'
+ '|\.';
length "1..253";
}
description
"The domain-name type represents a DNS domain name. The
name SHOULD be fully qualified whenever possible.
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. It is designed to hold various types of
domain names, including names used for A or AAAA records
(host names) and other records, such as SRV records. Note
that Internet host names have a stricter syntax (described
in RFC 952) than the DNS recommendations in RFCs 1034 and
1123, and that systems that want to store host names in
schema nodes using the domain-name type are recommended to
adhere to this stricter standard to ensure interoperability.
Schoenwaelder Standards Track [Page 22]RFC 6991 Common YANG Data Types July 2013
The encoding of DNS names in the DNS protocol is limited
to 255 characters. Since the encoding consists of labels
prefixed by a length bytes and there is a trailing NULL
byte, only 253 characters can appear in the textual dotted
notation.
The description clause of schema nodes using the domain-name
type MUST describe when and how these names are resolved to
IP addresses. Note that the resolution of a domain-name value
may require to query multiple DNS records (e.g., A for IPv4
and AAAA for IPv6). The order of the resolution process and
which DNS record takes precedence can either be defined
explicitly or may depend on the configuration of the
resolver.
Domain-name values use the US-ASCII encoding. Their canonical
format uses lowercase US-ASCII characters. Internationalized
domain names MUST be A-labels as per RFC 5890.";
reference
"RFC 952: DoD Internet Host Table Specification
RFC 1034: Domain Names - Concepts and Facilities
RFC 1123: Requirements for Internet Hosts -- Application
and Support
RFC 2782: A DNS RR for specifying the location of services
(DNS SRV)
RFC 5890: Internationalized Domain Names in Applications
(IDNA): Definitions and Document Framework";
}
typedef host {
type union {
type inet:ip-address;
type inet:domain-name;
}
description
"The host type represents either an IP address or a DNS
domain name.";
}
typedef uri {
type string;
description
"The uri type represents a Uniform Resource Identifier
(URI) as defined by STD 66.
Objects using the uri type MUST be in US-ASCII encoding,
and MUST be normalized as described by RFC 3986 Sections
6.2.1, 6.2.2.1, and 6.2.2.2. All unnecessary
Schoenwaelder Standards Track [Page 23]RFC 6991 Common YANG Data Types July 2013
percent-encoding is removed, and all case-insensitive
characters are set to lowercase except for hexadecimal
digits, which are normalized to uppercase as described in
Section 6.2.2.1.
The purpose of this normalization is to help provide
unique URIs. Note that this normalization is not
sufficient to provide uniqueness. Two URIs that are
textually distinct after this normalization may still be
equivalent.
Objects using the uri type may restrict the schemes that
they permit. For example, 'data:' and 'urn:' schemes
might not be appropriate.
A zero-length URI is not a valid URI. This can be used to
express 'URI absent' where required.
In the value set and its semantics, this type is equivalent
to the Uri SMIv2 textual convention defined in RFC 5017.";
reference
"RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
RFC 3305: Report from the Joint W3C/IETF URI Planning Interest
Group: Uniform Resource Identifiers (URIs), URLs,
and Uniform Resource Names (URNs): Clarifications
and Recommendations
RFC 5017: MIB Textual Conventions for Uniform Resource
Identifiers (URIs)";
}
}
<CODE ENDS>
5. IANA Considerations
This document registers two URIs in the IETF XML registry [RFC3688].
Following the format in RFC 3688, the following registrations have
been made.
URI: urn:ietf:params:xml:ns:yang:ietf-yang-types
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-inet-types
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
Schoenwaelder Standards Track [Page 24]RFC 6991 Common YANG Data Types July 2013
This document registers two YANG modules in the YANG Module Names
registry [RFC6020].
name: ietf-yang-types
namespace: urn:ietf:params:xml:ns:yang:ietf-yang-types
prefix: yang
reference: RFC 6991
name: ietf-inet-types
namespace: urn:ietf:params:xml:ns:yang:ietf-inet-types
prefix: inet
reference: RFC 6991
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 [RFC6020] apply for this document as well.
7. Contributors
The following people contributed significantly to the initial version
of this document:
- Andy Bierman (Brocade)
- Martin Bjorklund (Tail-f Systems)
- Balazs Lengyel (Ericsson)
- David Partain (Ericsson)
- Phil Shafer (Juniper Networks)
8. Acknowledgments
The editor wishes to thank the following individuals for providing
helpful comments on various versions of this document: Andy Bierman,
Martin Bjorklund, Benoit Claise, Joel M. Halpern, Ladislav Lhotka,
Lars-Johan Liman, and Dan Romascanu.
Juergen Schoenwaelder was partly funded by Flamingo, a Network of
Excellence project (ICT-318488) supported by the European Commission
under its Seventh Framework Programme.
Schoenwaelder Standards Track [Page 25]RFC 6991 Common YANG Data Types July 2013
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and
B. Zill, "IPv6 Scoped Address Architecture", RFC 4007,
March 2005.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
July 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath)
Version 1.0", World Wide Web Consortium
Recommendation REC-xpath-19991116, November 1999,
<http://www.w3.org/TR/1999/REC-xpath-19991116>.
9.2. Informative References
[IEEE802] IEEE, "IEEE Standard for Local and Metropolitan Area
Networks: Overview and Architecture", IEEE Std. 802-
2001, 2001.
[ISO9834-1] ISO/IEC, "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", ISO/
IEC 9834-1:2008, 2008.
Schoenwaelder Standards Track [Page 26]RFC 6991 Common YANG Data Types July 2013
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981.
[RFC0952] Harrenstien, K., Stahl, M., and E. Feinler, "DoD
Internet host table specification", RFC 952,
October 1985.
[RFC1034] Mockapetris, P., "Domain names - concepts and
facilities", STD 13, RFC 1034, November 1987.
[RFC1123] Braden, R., "Requirements for Internet Hosts -
Application and Support", STD 3, RFC 1123, October 1989.
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System
(AS)", BCP 6, RFC 1930, March 1996.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[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,
December 1998.
[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
[RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Textual Conventions for SMIv2",
STD 58, RFC 2579, April 1999.
[RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines
For Values In the Internet Protocol and Related
Headers", BCP 37, RFC 2780, March 2000.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)",
RFC 2782, February 2000.
Schoenwaelder Standards Track [Page 27]RFC 6991 Common YANG Data Types July 2013
[RFC2856] Bierman, A., McCloghrie, K., and R. Presuhn, "Textual
Conventions for Additional High Capacity Data Types",
RFC 2856, June 2000.
[RFC3289] Baker, F., Chan, K., and A. Smith, "Management
Information Base for the Differentiated Services
Architecture", RFC 3289, May 2002.
[RFC3305] Mealling, M. and R. Denenberg, "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,
August 2002.
[RFC3595] Wijnen, B., "Textual Conventions for IPv6 Flow Label",
RFC 3595, September 2003.
[RFC4001] Daniele, M., Haberman, B., Routhier, S., and J.
Schoenwaelder, "Textual Conventions for Internet Network
Addresses", RFC 4001, February 2005.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
Congestion Control Protocol (DCCP)", RFC 4340,
March 2006.
[RFC4502] Waldbusser, S., "Remote Network Monitoring Management
Information Base Version 2", RFC 4502, May 2006.
[RFC4960] Stewart, R., "Stream Control Transmission Protocol",
RFC 4960, September 2007.
[RFC5017] McWalter, D., "MIB Textual Conventions for Uniform
Resource Identifiers (URIs)", RFC 5017, September 2007.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document
Framework", RFC 5890, August 2010.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for
IPv6 Address Text Representation", RFC 5952,
August 2010.
[RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
October 2010.
Schoenwaelder Standards Track [Page 28]RFC 6991 Common YANG Data Types July 2013
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J.,
Ed., and A. Bierman, Ed., "Network Configuration
Protocol (NETCONF)", RFC 6241, June 2011.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
December 2012.
[XSD-TYPES] Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
Second Edition", World Wide Web Consortium
Recommendation REC-xmlschema-2-20041028, October 2004,
<http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.
Schoenwaelder Standards Track [Page 29]RFC 6991 Common YANG Data Types July 2013
Appendix A. Changes from RFC 6021
This version adds new type definitions to the YANG modules. The
following new data types have been added to the ietf-yang-types
module:
o yang-identifier
o hex-string
o uuid
o dotted-quad
The following new data types have been added to the ietf-inet-types
module:
o ip-address-no-zone
o ipv4-address-no-zone
o ipv6-address-no-zone
Author's Address
Juergen Schoenwaelder (editor)
Jacobs University
EMail: j.schoenwaelder@jacobs-university.de
Schoenwaelder Standards Track [Page 30]
