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]