Internet Engineering Task Force M. Veillette, Ed.Internet-Draft Trilliant Networks Inc.Intended status: Standards Track I. Petrov, Ed.Expires: September 10, 2020 A. Pelov Acklio March 09, 2020CBOR Encoding of Data Modeled with YANGdraft-ietf-core-yang-cbor-12Abstract This document defines encoding rules for serializing configuration data, state data, RPC input and RPC output, Action input, Action output, notifications and yang data template defined within YANG modules using the Concise Binary Object Representation (CBOR) [RFC7049].Status of This Memo This Internet-Draft is submitted in full conformance with the provisions ofBCP 78 andBCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is athttps://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 10, 2020.Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject toBCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described inSection 4.e ofVeillette, et al. Expires September 10, 2020 [Page 1]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.Table of Contents1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .32. Terminology and Notation . . . . . . . . . . . . . . . . . .33. Properties of the CBOR Encoding . . . . . . . . . . . . . . .53.1. CBOR diagnostic notation . . . . . . . . . . . . . . . .53.2. YANG Schema Item iDentifier (SID) . . . . . . . . . . . .63.3. Name . . . . . . . . . . . . . . . . . . . . . . . . . .74. Encoding of YANG Schema Node Instances . . . . . . . . . . .94.1. The 'leaf' . . . . . . . . . . . . . . . . . . . . . . .94.1.1. Using SIDs in keys . . . . . . . . . . . . . . . . .94.1.2. Using names in keys . . . . . . . . . . . . . . . . .94.2. The 'container' and other collections . . . . . . . . . .104.2.1. Using SIDs in keys . . . . . . . . . . . . . . . . .114.2.2. Using names in keys . . . . . . . . . . . . . . . . .124.3. The 'leaf-list' . . . . . . . . . . . . . . . . . . . . .134.3.1. Using SIDs in keys . . . . . . . . . . . . . . . . .144.3.2. Using names in keys . . . . . . . . . . . . . . . . .144.4. The 'list' and 'list' instance(s) . . . . . . . . . . . .154.4.1. Using SIDs in keys . . . . . . . . . . . . . . . . .164.4.2. Using names in keys . . . . . . . . . . . . . . . . .184.5. The 'anydata' . . . . . . . . . . . . . . . . . . . . . .204.5.1. Using SIDs in keys . . . . . . . . . . . . . . . . .214.5.2. Using names in keys . . . . . . . . . . . . . . . . .224.6. The 'anyxml' . . . . . . . . . . . . . . . . . . . . . .234.6.1. Using SIDs in keys . . . . . . . . . . . . . . . . .234.6.2. Using names in keys . . . . . . . . . . . . . . . . .245. Encoding of YANG data templates . . . . . . . . . . . . . . .245.1. Using SIDs in keys . . . . . . . . . . . . . . . . . . .255.2. Using names in keys . . . . . . . . . . . . . . . . . . .266. Representing YANG Data Types in CBOR . . . . . . . . . . . .276.1. The unsigned integer Types . . . . . . . . . . . . . . .276.2. The integer Types . . . . . . . . . . . . . . . . . . . .286.3. The 'decimal64' Type . . . . . . . . . . . . . . . . . .286.4. The 'string' Type . . . . . . . . . . . . . . . . . . . .296.5. The 'boolean' Type . . . . . . . . . . . . . . . . . . .296.6. The 'enumeration' Type . . . . . . . . . . . . . . . . .296.7. The 'bits' Type . . . . . . . . . . . . . . . . . . . . .306.8. The 'binary' Type . . . . . . . . . . . . . . . . . . . .326.9. The 'leafref' Type . . . . . . . . . . . . . . . . . . .326.10. The 'identityref' Type . . . . . . . . . . . . . . . . .336.10.1. SIDs as identityref . . . . . . . . . . . . . . . .336.10.2. Name as identityref . . . . . . . . . . . . . . . .346.11. The 'empty' Type . . . . . . . . . . . . . . . . . . . .346.12. The 'union' Type . . . . . . . . . . . . . . . . . . . .35Veillette, et al. Expires September 10, 2020 [Page 2]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 20206.13. The 'instance-identifier' Type . . . . . . . . . . . . .366.13.1. SIDs as instance-identifier . . . . . . . . . . . .366.13.2. Names as instance-identifier . . . . . . . . . . . .397. Security Considerations . . . . . . . . . . . . . . . . . . .418. IANA Considerations . . . . . . . . . . . . . . . . . . . . .418.1. CBOR Tags Registry . . . . . . . . . . . . . . . . . . .419. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .4110. References . . . . . . . . . . . . . . . . . . . . . . . . .4210.1. Normative References . . . . . . . . . . . . . . . . . .4210.2. Informative References . . . . . . . . . . . . . . . . .42 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .431. Introduction The specification of the YANG 1.1 data modeling language [RFC7950] defines an XML encoding for data instances, i.e. contents of configuration datastores, state data, RPC inputs and outputs, action inputs and outputs, and event notifications. A new set of encoding rules has been defined to allow the use of the same data models in environments based on the JavaScript Object Notation (JSON) Data Interchange Format [RFC8259]. This is accomplished in the JSON Encoding of Data Modeled with YANG specification [RFC7951]. The aim of this document is to define a set of encoding rules for the Concise Binary Object Representation (CBOR) [RFC7049]. The resulting encoding is more compact compared to XML and JSON and more suitable for Constrained Nodes and/or Constrained Networks as defined by [RFC7228].2. Terminology and Notation 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 inBCP14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. The following terms are defined in [RFC7950]: o action o anydata o anyxml o data nodeVeillette, et al. Expires September 10, 2020 [Page 3]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 o data tree o datastore o feature o identity o module o notification o RPC o schema node o schema tree o submodule The following terms are defined in [RFC8040]: o yang-data (YANG extension) o YANG data template This specification also makes use of the following terminology: o child: A schema node defined within a collection such as a container, a list, a case, a notification, an RPC input, an RPC output, an action input, an action output. o delta: Difference between the current SID and a reference SID. A reference SID is defined for each context for which deltas are used. o item: A schema node, an identity, a module, a submodule or a feature defined using the YANG modeling language. o parent: The collection in which a schema node is defined. o YANG Schema Item iDentifier (SID): Unsigned integer used to identify different YANG items.Veillette, et al. Expires September 10, 2020 [Page 4]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 20203. Properties of the CBOR Encoding This document defines CBOR encoding rules for YANG schema trees and their subtrees. A collection such as container, list instance, notification, RPC input, RPC output, action input and action output is serialized using a CBOR map in which each child schema node is encoded using a key and a value. This specification supports two type of CBOR keys; YANG Schema Item iDentifier (SID) as defined inSection 3.2 and names as defined inSection 3.3. Each of these key types is encoded using a specific CBOR type which allows their interpretation during the deserialization process. Protocols or mechanisms implementing this specification can mandate the use of a specific key type. In order to minimize the size of the encoded data, the proposed mapping avoids any unnecessary meta-information beyond those natively supported by CBOR. For instance, CBOR tags are used solely in the case of SID not encoded as delta, anyxml schema nodes and the union datatype to distinguish explicitly the use of different YANG datatypes encoded using the same CBOR major type. Unless specified otherwise by the protocol or mechanism implementing this specification, the indefinite lengths encoding as defined in[RFC7049] section 2.2 SHALL be supported by CBOR decoders. Data nodes implemented using a CBOR array, map, byte string, and text string can be instantiated but empty. In this case, they are encoded with a length of zero. Application payloads carrying a value serialized using the rules defined by this specification (e.g. CoAP Content-Format) SHOULD include the identifier (e.g. SID, namespace qualified name, instance-identifier) of this value. When SIDs are used as identifiers, the reference SID SHALL be included in the payload to allow stateless conversion of delta values to SIDs. Examples in sectionSection 4 include a root CBOR map with a single entry having a key set to either a namespace qualified name or a SID. This root CBOR map is provided only as a typical usage example and is not part of the present encoding rules. Only the value within this CBOR map is compulsory.3.1. CBOR diagnostic notation Within this document, CBOR binary contents are represented using an equivalent textual form called CBOR diagnostic notation as defined in[RFC7049] section 6. This notation is used strictly forVeillette, et al. Expires September 10, 2020 [Page 5]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 documentation purposes and is never used in the data serialization. Table 1 below provides a summary of this notation. +----------+------+--------------------------+-----------+----------+ | CBOR | CBOR | Diagnostic notation | Example | CBOR | | content | type | | | encoding | +----------+------+--------------------------+-----------+----------+ | Unsigned | 0 | Decimal digits | 123 | 18 7B | | integer | | | | | | Negative | 1 | Decimal digits prefixed | -123 | 38 7A | | integer | | by a minus sign | | | | Byte | 2 | Hexadecimal value | h'F15C' | 42 f15C | | string | | enclosed between single | | | | | | quotes and prefixed by | | | | | | an 'h' | | | | Text | 3 | String of Unicode | "txt" | 63 | | string | | characters enclosed | | 747874 | | | | between double quotes | | | | Array | 4 | Comma-separated list of | [ 1, 2 ] | 82 01 02 | | | | values within square | | | | | | brackets | | | | Map | 5 | Comma-separated list of | { 1: 123, | a2 | | | | key : value pairs within | 2: 456 } | 01187B | | | | curly braces | | 021901C8 | | Boolean | 7/20 | false | false | F4 | | | 7/21 | true | true | F5 | | Null | 7/22 | null | null | F6 | | Not | 7/23 | undefined | undefined | F7 | | assigned | | | | | +----------+------+--------------------------+-----------+----------+ Table 1: CBOR diagnostic notation summary Note: CBOR binary contents shown in this specification are annotated with comments. These comments are delimited by slashes ("/") as defined in[RFC8610] Appendix G.6.3.2. YANG Schema Item iDentifier (SID) Some of the items defined in YANG [RFC7950] require the use of a unique identifier. In both NETCONF [RFC6241] and RESTCONF [RFC8040], these identifiers are implemented using strings. To allow the implementation of data models defined in YANG in constrained devices and constrained networks, a more compact method to identify YANG items is required. This compact identifier, called YANG Schema Item iDentifier (SID), is an unsigned integer. The following items are identified using SIDs:Veillette, et al. Expires September 10, 2020 [Page 6]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 o identities o data nodes o RPCs and associated input(s) and output(s) o actions and associated input(s) and output(s) o notifications and associated information o YANG modules, submodules and features To minimize their size, SIDs used as keys in inner CBOR maps are typically encoded using deltas. Conversion from SIDs to deltas and back to SIDs are stateless processes solely based on the data serialized or deserialized. These SIDs may also be encoded as absolute number when enclosed by CBOR tag 47. Mechanisms and processes used to assign SIDs to YANG items and to guarantee their uniqueness are outside the scope of the present specification. If SIDs are to be used, the present specification is used in conjunction with a specification defining this management. One example for such a specification is [I-D.ietf-core-sid].3.3. Name This specification also supports the encoding of YANG item identifiers as string, similar as those used by the JSON Encoding of Data Modeled with YANG [RFC7951]. This approach can be used to avoid the management overhead associated to SIDs allocation. The main drawback is the significant increase in size of the encoded data. YANG item identifiers implemented using names MUST be in one of the following forms: o simple - the identifier of the YANG item (i.e. schema node or identity). o namespace qualified - the identifier of the YANG item is prefixed with the name of the module in which this item is defined, separated by the colon character (":"). The name of a module determines the namespace of all YANG items defined in that module. If an item is defined in a submodule, then the namespace qualified name uses the name of the main module to which the submodule belongs.Veillette, et al. Expires September 10, 2020 [Page 7]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 ABNF syntax [RFC5234] of a name is shown in Figure 1, where the production for "identifier" is defined inSection 14 of [RFC7950]. name = [identifier ":"] identifier Figure 1: ABNF Production for a simple or namespace qualified name A namespace qualified name MUST be used for all members of a top- level CBOR map and then also whenever the namespaces of the data node and its parent node are different. In all other cases, the simple form of the name SHOULD be used. Definition example: module example-foomod { container top { leaf foo { type uint8; } } } module example-barmod { import example-foomod { prefix "foomod"; } augment "/foomod:top" { leaf bar { type boolean; } } } A valid CBOR encoding of the 'top' container is as follow. CBOR diagnostic notation: { "example-foomod:top": { "foo": 54, "example-barmod:bar": true } } Both the 'top' container and the 'bar' leaf defined in a different YANG module as its parent container are encoded as namespace qualified names. The 'foo' leaf defined in the same YANG module as its parent container is encoded as simple name.Veillette, et al. Expires September 10, 2020 [Page 8]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 20204. Encoding of YANG Schema Node Instances Schema node instances defined using the YANG modeling language are encoded using CBOR [RFC7049] based on the rules defined in this section. We assume that the reader is already familiar with both YANG [RFC7950] and CBOR [RFC7049].4.1. The 'leaf' A 'leaf' MUST be encoded accordingly to its datatype using one of the encoding rules specified inSection 6. The following examples shows the encoding of a 'hostname' leaf using a SID or a name. Definition example from [RFC7317]: leaf hostname { type inet:domain-name; }4.1.1. Using SIDs in keys CBOR diagnostic notation: { 1752 : "myhost.example.com" / hostname (SID 1752) / } CBOR encoding: A1 # map(1) 19 06D8 # unsigned(1752) 72 # text(18) 6D79686F73742E6578616D706C652E636F6D # "myhost.example.com"4.1.2. Using names in keys CBOR diagnostic notation: { "ietf-system:hostname" : "myhost.example.com" } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 9]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 74 # text(20) 696574662D73797374656D3A686F73746E616D65 72 # text(18) 6D79686F73742E6578616D706C652E636F6D4.2. The 'container' and other collections Collections such as containers, list instances, notification contents, rpc inputs, rpc outputs, action inputs and action outputs MUST be encoded using a CBOR map data item (major type 5). A map is comprised of pairs of data items, with each data item consisting of a key and a value. Each key within the CBOR map is set to a schema node identifier, each value is set to the value of this schema node instance according to the instance datatype. This specification supports two type of CBOR keys; SID as defined inSection 3.2 and names as defined inSection 3.3. The following examples shows the encoding of a 'system-state' container instance using SIDs or names. Definition example from [RFC7317]: 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})'; } } container system-state { container clock { leaf current-datetime { type date-and-time; } leaf boot-datetime { type date-and-time; } } }Veillette, et al. Expires September 10, 2020 [Page 10]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 20204.2.1. Using SIDs in keys In the context of containers and other collections, CBOR map keys within inner CBOR maps can be encoded using deltas or SIDs. In the case of deltas, they MUST be encoded using a CBOR unsigned integer (major type 0) or CBOR negative integer (major type 1), depending on the actual delta value. In the case of SID, they are encoded using the SID value enclosed by CBOR tag 47 as defined inSection 8.1. Delta values are computed as follows: o In the case of a 'container', deltas are equal to the SID of the current schema node minus the SID of the parent 'container'. o In the case of a 'list', deltas are equal to the SID of the current schema node minus the SID of the parent 'list'. o In the case of an 'rpc input' or 'rcp output', deltas are equal to the SID of the current schema node minus the SID of the 'rpc'. o In the case of an 'action input' or 'action output', deltas are equal to the SID of the current schema node minus the SID of the 'action'. o In the case of an 'notification content', deltas are equal to the SID of the current schema node minus the SID of the 'notification'. CBOR diagnostic notation: { 1720 : { / system-state (SID 1720) / 1 : { / clock (SID 1721) / 2 : "2015-10-02T14:47:24Z-05:00", / current-datetime(SID 1723)/ 1 : "2015-09-15T09:12:58Z-05:00" / boot-datetime (SID 1722) / } } } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 11]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 19 06B8 # unsigned(1720) A1 # map(1) 01 # unsigned(1) A2 # map(2) 02 # unsigned(2) 78 1A # text(26) 323031352D31302D30325431343A34373A32345A2D30353A3030 01 # unsigned(1) 78 1A # text(26) 323031352D30392D31355430393A31323A35385A2D30353A3030 Figure 2: System state clock encoding4.2.2. Using names in keys CBOR map keys implemented using names MUST be encoded using a CBOR text string data item (major type 3). A namespace-qualified name MUST be used each time the namespace of a schema node and its parent differ. In all other cases, the simple form of the name MUST be used. Names and namespaces are defined in[RFC7951] section 4. The following example shows the encoding of a 'system' container instance using names. Definition example from [RFC7317]: 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})'; } } container system-state { container clock { leaf current-datetime { type date-and-time; } leaf boot-datetime { type date-and-time; } } } CBOR diagnostic notation:Veillette, et al. Expires September 10, 2020 [Page 12]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 { "ietf-system:system-state" : { "clock" : { "current-datetime" : "2015-10-02T14:47:24Z-05:00", "boot-datetime" : "2015-09-15T09:12:58Z-05:00" } } } CBOR encoding: A1 # map(1) 78 18 # text(24) 696574662D73797374656D3A73797374656D2D7374617465 A1 # map(1) 65 # text(5) 636C6F636B # "clock" A2 # map(2) 70 # text(16) 63757272656E742D6461746574696D65 78 1A # text(26) 323031352D31302D30325431343A34373A32345A2D30353A3030 6D # text(13) 626F6F742D6461746574696D65 78 1A # text(26) 323031352D30392D31355430393A31323A35385A2D30353A30304.3. The 'leaf-list' A leaf-list MUST be encoded using a CBOR array data item (major type 4). Each entry of this array MUST be encoded accordingly to its datatype using one of the encoding rules specified inSection 6. The following example shows the encoding of the 'search' leaf-list instance containing two entries, "ietf.org" and "ieee.org". Definition example [RFC7317]:Veillette, et al. Expires September 10, 2020 [Page 13]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 typedef domain-name { type string { length "1..253"; pattern '((([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9].) *([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.? )|\.'; } } leaf-list search { type domain-name; ordered-by user; }4.3.1. Using SIDs in keys CBOR diagnostic notation: { 1746 : [ "ietf.org", "ieee.org" ] / search (SID 1746) / } CBOR encoding: A1 # map(1) 19 06D2 # unsigned(1746) 82 # array(2) 68 # text(8) 696574662E6F7267 # "ietf.org" 68 # text(8) 696565652E6F7267 # "ieee.org"4.3.2. Using names in keys CBOR diagnostic notation: { "ietf-system:search" : [ "ietf.org", "ieee.org" ] } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 14]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 72 # text(18) 696574662D73797374656D3A736561726368 # "ietf-system:search" 82 # array(2) 68 # text(8) 696574662E6F7267 # "ietf.org" 68 # text(8) 696565652E6F7267 # "ieee.org"4.4. The 'list' and 'list' instance(s) A list or a subset of a list MUST be encoded using a CBOR array data item (major type 4). Each list instance within this CBOR array is encoded using a CBOR map data item (major type 5) based on the encoding rules of a collection as defined inSection 4.2. It is important to note that this encoding rule also apply to a single 'list' instance. The following examples show the encoding of a 'server' list using SIDs or names. Definition example from [RFC7317]:Veillette, et al. Expires September 10, 2020 [Page 15]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 list server { key name; leaf name { type string; } choice transport { case udp { container udp { leaf address { type host; mandatory true; } leaf port { type port-number; } } } } leaf association-type { type enumeration { enum server; enum peer; enum pool; } default server; } leaf iburst { type boolean; default false; } leaf prefer { type boolean; default false; } }4.4.1. Using SIDs in keys The encoding rules of each 'list' instance are defined inSection 4.2.1. Deltas of list members are equal to the SID of the current schema node minus the SID of the 'list'. CBOR diagnostic notation:Veillette, et al. Expires September 10, 2020 [Page 16]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 { 1756 : [ / server (SID 1756) / { 3 : "NRC TIC server", / name (SID 1759) / 5 : { / udp (SID 1761) / 1 : "tic.nrc.ca", / address (SID 1762) / 2 : 123 / port (SID 1763) / }, 1 : 0, / association-type (SID 1757) / 2 : false, / iburst (SID 1758) / 4 : true / prefer (SID 1760) / }, { 3 : "NRC TAC server", / name (SID 1759) / 5 : { / udp (SID 1761) / 1 : "tac.nrc.ca" / address (SID 1762) / } } ] } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 17]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 19 06DC # unsigned(1756) 82 # array(2) A5 # map(5) 03 # unsigned(3) 6E # text(14) 4E52432054494320736572766572 # "NRC TIC server" 05 # unsigned(5) A2 # map(2) 01 # unsigned(1) 6A # text(10) 7469632E6E72632E6361 # "tic.nrc.ca" 02 # unsigned(2) 18 7B # unsigned(123) 01 # unsigned(1) 00 # unsigned(0) 02 # unsigned(2) F4 # primitive(20) 04 # unsigned(4) F5 # primitive(21) A2 # map(2) 03 # unsigned(3) 6E # text(14) 4E52432054414320736572766572 # "NRC TAC server" 05 # unsigned(5) A1 # map(1) 01 # unsigned(1) 6A # text(10) 7461632E6E72632E6361 # "tac.nrc.ca"4.4.2. Using names in keys The encoding rules of each 'list' instance are defined inSection 4.2.2. CBOR diagnostic notation:Veillette, et al. Expires September 10, 2020 [Page 18]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 { "ietf-system:server" : [ { "name" : "NRC TIC server", "udp" : { "address" : "tic.nrc.ca", "port" : 123 }, "association-type" : 0, "iburst" : false, "prefer" : true }, { "name" : "NRC TAC server", "udp" : { "address" : "tac.nrc.ca" } } ] } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 19]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 72 # text(18) 696574662D73797374656D3A736572766572 82 # array(2) A5 # map(5) 64 # text(4) 6E616D65 # "name" 6E # text(14) 4E52432054494320736572766572 63 # text(3) 756470 # "udp" A2 # map(2) 67 # text(7) 61646472657373 # "address" 6A # text(10) 7469632E6E72632E6361 # "tic.nrc.ca" 64 # text(4) 706F7274 # "port" 18 7B # unsigned(123) 70 # text(16) 6173736F63696174696F6E2D74797065 00 # unsigned(0) 66 # text(6) 696275727374 # "iburst" F4 # primitive(20) 66 # text(6) 707265666572 # "prefer" F5 # primitive(21) A2 # map(2) 64 # text(4) 6E616D65 # "name" 6E # text(14) 4E52432054414320736572766572 63 # text(3) 756470 # "udp" A1 # map(1) 67 # text(7) 61646472657373 # "address" 6A # text(10) 7461632E6E72632E6361 # "tac.nrc.ca"4.5. The 'anydata' An anydata serves as a container for an arbitrary set of schema nodes that otherwise appear as normal YANG-modeled data. An anydata instance is encoded using the same rules as a container, i.e., CBOR map. The requirement that anydata content can be modeled by YANG implies the following:Veillette, et al. Expires September 10, 2020 [Page 20]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 o CBOR map keys of any inner schema nodes MUST be set to valid deltas or names. o The CBOR array MUST contain either unique scalar values (as a leaf-list, seeSection 4.3), or maps (as a list, seeSection 4.4). o CBOR map values MUST follow the encoding rules of one of the datatypes listed inSection 4. The following example shows a possible use of an anydata. In this example, an anydata is used to define a schema node containing a notification event, this schema node can be part of a YANG list to create an event logger. Definition example: module event-log { ... anydata last-event; # SID 60123 This example also assumes the assistance of the following notification. module example-port { ... notification example-port-fault { # SID 60200 leaf port-name { # SID 60201 type string; } leaf port-fault { # SID 60202 type string; } } }4.5.1. Using SIDs in keys CBOR diagnostic notation: { 60123 : { / last-event (SID 60123) / 77 : { / event (SID 60200) / 1 : "0/4/21", / port-name (SID 60201) / 2 : "Open pin 2" / port-fault (SID 60202) / } } }Veillette, et al. Expires September 10, 2020 [Page 21]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 CBOR encoding: A1 # map(1) 19 EADB # unsigned(60123) A1 # map(1) 18 4D # unsigned(77) A2 # map(2) 18 4E # unsigned(78) 66 # text(6) 302F342F3231 # "0/4/21" 18 4F # unsigned(79) 6A # text(10) 4F70656E2070696E2032 # "Open pin 2" In some implementations, it might be simpler to use the absolute SID tag encoding for the anydata root element. The resulting encoding is as follow: { 60123 : { / last-event (SID 60123) / 47(60200) : { / event (SID 60123) / 1 : "0/4/21", / port-name (SID 60201) / 2 : "Open pin 2" / port-fault (SID 60202) / } } }4.5.2. Using names in keys CBOR diagnostic notation: { "event-log:last-event" : { "example-port: example-port-fault" : { "port-name" : "0/4/21", "port-fault" : "Open pin 2" } } } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 22]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 74 # text(20) 6576656E742D6C6F673A6C6173742D6576656E74 A1 # map(1) 78 20 # text(32) 6578616D706C652D706F72743A206578616D7 06C652D706F72742D6661756C74 A2 # map(2) 69 # text(9) 706F72742D6E616D65 # "port-name" 66 # text(6) 302F342F3231 # "0/4/21" 6A # text(10) 706F72742D6661756C74 # "port-fault" 6A # text(10) 4F70656E2070696E2032 # "Open pin 2"4.6. The 'anyxml' An anyxml schema node is used to serialize an arbitrary CBOR content, i.e., its value can be any CBOR binary object. anyxml value MAY contain CBOR data items tagged with one of the tag listed inSection 8.1, these tags shall be supported. The following example shows a valid CBOR encoded instance consisting of a CBOR array containing the CBOR simple values 'true', 'null' and 'true'. Definition example from [RFC7951]: module bar-module { ... anyxml bar;4.6.1. Using SIDs in keys CBOR diagnostic notation: { 60000 : [true, null, true] / bar (SID 60000) / } CBOR encoding:Veillette, et al. Expires September 10, 2020 [Page 23]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 A1 # map(1) 19 EA60 # unsigned(60000) 83 # array(3) F5 # primitive(21) F6 # primitive(22) F5 # primitive(21)4.6.2. Using names in keys CBOR diagnostic notation: { "bar-module:bar" : [true, null, true] / bar (SID 60000) / } CBOR encoding: A1 # map(1) 6E # text(14) 6261722D6D6F64756C653A626172 # "bar-module:bar" 83 # array(3) F5 # primitive(21) F6 # primitive(22) F5 # primitive(21)5. Encoding of YANG data templates YANG data templates are data structures defined in YANG but not intended to be implemented as part of a datastore. YANG data templates are defined using the 'yang-data' extension as described by [RFC8040]. YANG data templates MUST be encoded using the encoding rules of a collection as defined inSection 4.2. Just like YANG containers, YANG data templates can be encoded using either SIDs or names. Definition example from [I-D.ietf-core-comi]:Veillette, et al. Expires September 10, 2020 [Page 24]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 import ietf-restconf { prefix rc; } rc:yang-data yang-errors { container error { leaf error-tag { type identityref { base error-tag; } } leaf error-app-tag { type identityref { base error-app-tag; } } leaf error-data-node { type instance-identifier; } leaf error-message { type string; } } }5.1. Using SIDs in keys YANG template encoded using SIDs are carried in a CBOR map containing a single item pair. The key of this item is set to the SID assigned to the YANG template container, the value is set the CBOR encoding of this container as defined inSection 4.2. This example shows a serialization example of the yang-errors template as defined in [I-D.ietf-core-comi] using SIDs as defined inSection 3.2. CBOR diagnostic notation:Veillette, et al. Expires September 10, 2020 [Page 25]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 { 1024 : { / error (SID 1024) / 4 : 1011, / error-tag (SID 1028) / / = invalid-value (SID 1011) / 1 : 1018, / error-app-tag (SID 1025) / / = not-in-range (SID 1018) / 2 : 1740, / error-data-node (SID 1026) / / = timezone-utc-offset (SID 1740) / 3 : "Maximum exceeded" / error-message (SID 1027) / } } CBOR encoding: A1 # map(1) 19 0400 # unsigned(1024) A4 # map(4) 04 # unsigned(4) 19 03F3 # unsigned(1011) 01 # unsigned(1) 19 03FA # unsigned(1018) 02 # unsigned(2) 19 06CC # unsigned(1740) 03 # unsigned(3) 70 # text(16) 4D6178696D756D2065786365656465645.2. Using names in keys YANG template encoded using names are carried in a CBOR map containing a single item pair. The key of this item is set to the namespace qualified name of the YANG template container, the value is set the CBOR encoding of this container as defined inSection 3.3. This example shows a serialization example of the yang-errors template as defined in [I-D.ietf-core-comi] using names as definedSection 3.3. CBOR diagnostic notation: { "ietf-comi:error" : { "error-tag" : "invalid-value", "error-app-tag" : "not-in-range", "error-data-node" : "timezone-utc-offset", "error-message" : "Maximum exceeded" } }Veillette, et al. Expires September 10, 2020 [Page 26]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 CBOR encoding: A1 # map(1) 6F # text(15) 696574662D636F6D693A6572726F72 # "ietf-comi:error" A4 # map(4) 69 # text(9) 6572726F722D746167 # "error-tag" 6D # text(13) 696E76616C69642D76616C7565 # "invalid-value" 6D # text(13) 6572726F722D6170702D746167 # "error-app-tag" 6C # text(12) 6E6F742D696E2D72616E6765 # "not-in-range" 6F # text(15) 6572726F722D646174612D6E6F6465 # "error-data-node" 73 # text(19) 74696D657A6F6E652D7574632D6F6666736574 # "timezone-utc-offset" 6D # text(13) 6572726F722D6D657373616765 # "error-message" 70 # text(16) 4D6178696D756D2065786365656465646. Representing YANG Data Types in CBOR The CBOR encoding of an instance of a leaf or leaf-list schema node depends on the built-in type of that schema node. The following sub- section defined the CBOR encoding of each built-in type supported by YANG as listed in[RFC7950] section 4.2.4. Each subsection shows an example value assigned to a schema node instance of the discussed built-in type.6.1. The unsigned integer Types Leafs of type uint8, uint16, uint32 and uint64 MUST be encoded using a CBOR unsigned integer data item (major type 0). The following example shows the encoding of a 'mtu' leaf instance set to 1280 bytes. Definition example from [RFC8344]: leaf mtu { type uint16 { range "68..max"; } }Veillette, et al. Expires September 10, 2020 [Page 27]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 CBOR diagnostic notation: 1280 CBOR encoding: 19 05006.2. The integer Types Leafs of type int8, int16, int32 and int64 MUST be encoded using either CBOR unsigned integer (major type 0) or CBOR negative integer (major type 1), depending on the actual value. The following example shows the encoding of a 'timezone-utc-offset' leaf instance set to -300 minutes. Definition example from [RFC7317]: leaf timezone-utc-offset { type int16 { range "-1500 .. 1500"; } } CBOR diagnostic notation: -300 CBOR encoding: 39 012B6.3. The 'decimal64' Type Leafs of type decimal64 MUST be encoded using a decimal fraction as defined in[RFC7049] section 2.4.3. The following example shows the encoding of a 'my-decimal' leaf instance set to 2.57. Definition example from [RFC7317]: leaf my-decimal { type decimal64 { fraction-digits 2; range "1 .. 3.14 | 10 | 20..max"; } } CBOR diagnostic notation: 4([-2, 257]) CBOR encoding: C4 82 21 19 0101Veillette, et al. Expires September 10, 2020 [Page 28]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 20206.4. The 'string' Type Leafs of type string MUST be encoded using a CBOR text string data item (major type 3). The following example shows the encoding of a 'name' leaf instance set to "eth0". Definition example from [RFC8343]: leaf name { type string; } CBOR diagnostic notation: "eth0" CBOR encoding: 64 657468306.5. The 'boolean' Type Leafs of type boolean MUST be encoded using a CBOR simple value 'true' (major type 7, additional information 21) or 'false' (major type 7, additional information 20). The following example shows the encoding of an 'enabled' leaf instance set to 'true'. Definition example from [RFC7317]: leaf enabled { type boolean; } CBOR diagnostic notation: true CBOR encoding: F56.6. The 'enumeration' Type Leafs of type enumeration MUST be encoded using a CBOR unsigned integer (major type 0) or CBOR negative integer (major type 1), depending on the actual value. Enumeration values are either explicitly assigned using the YANG statement 'value' or automatically assigned based on the algorithm defined in[RFC7950] section 9.6.4.2. The following example shows the encoding of an 'oper-status' leaf instance set to 'testing'.Veillette, et al. Expires September 10, 2020 [Page 29]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 Definition example from [RFC7317]: leaf oper-status { type enumeration { enum up { value 1; } enum down { value 2; } enum testing { value 3; } enum unknown { value 4; } enum dormant { value 5; } enum not-present { value 6; } enum lower-layer-down { value 7; } } } CBOR diagnostic notation: 3 CBOR encoding: 03 To avoid overlap of 'value' defined in different 'enumeration' statements, 'enumeration' defined in a Leafs of type 'union' MUST be encoded using a CBOR text string data item (major type 3) and MUST contain one of the names assigned by 'enum' statements in YANG. The encoding MUST be enclosed by the enumeration CBOR tag as specified inSection 8.1. Definition example from [RFC7950]: type union { type int32; type enumeration { enum "unbounded"; } } CBOR diagnostic notation: 44("unbounded") CBOR encoding: D8 2C 69 756E626F756E6465646.7. The 'bits' Type Leafs of type bits MUST be encoded using a CBOR byte string data item (major type 2). Bits position are either explicitly assigned using the YANG statement 'position' or automatically assigned based on the algorithm defined in[RFC7950] section 9.7.4.2. Bits position 0 to 7 are assigned to the first byte within the byte string, bits 8 to 15 to the second byte, and subsequent bytes areVeillette, et al. Expires September 10, 2020 [Page 30]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 assigned similarly. Within each byte, bits are assigned from least to most significant. The following example shows the encoding of an 'alarm-state' leaf instance with the 'under-repair' and 'critical' flags set. Definition example from [RFC8348]: typedef alarm-state { type bits { bit unknown; bit under-repair; bit critical; bit major; bit minor; bit warning; bit indeterminate; } } leaf alarm-state { type alarm-state; } CBOR diagnostic notation: h'06' CBOR encoding: 41 06 To avoid overlap of 'bit' defined in different 'bits' statements, 'bits' defined in a Leafs of type 'union' MUST be encoded using a CBOR text string data item (major type 3) and MUST contain a space- separated sequence of names of 'bit' that are set. The encoding MUST be enclosed by the bits CBOR tag as specified inSection 8.1. The following example shows the encoding of an 'alarm-state' leaf instance defined using a union type with the 'under-repair' and 'critical' flags set. Definition example: leaf alarm-state-2 { type union { type alarm-state; type bits { bit extra-flag; } } }Veillette, et al. Expires September 10, 2020 [Page 31]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 CBOR diagnostic notation: 43("under-repair critical") CBOR encoding: D8 2B 75 756E6465722D72657061697220637269746963616C6.8. The 'binary' Type Leafs of type binary MUST be encoded using a CBOR byte string data item (major type 2). The following example shows the encoding of an 'aes128-key' leaf instance set to 0x1f1ce6a3f42660d888d92a4d8030476e. Definition example: leaf aes128-key { type binary { length 16; } } CBOR diagnostic notation: h'1F1CE6A3F42660D888D92A4D8030476E' CBOR encoding: 50 1F1CE6A3F42660D888D92A4D8030476E6.9. The 'leafref' Type Leafs of type leafref MUST be encoded using the rules of the schema node referenced by the 'path' YANG statement. The following example shows the encoding of an 'interface-state-ref' leaf instance set to "eth1". Definition example from [RFC8343]:Veillette, et al. Expires September 10, 2020 [Page 32]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 typedef interface-state-ref { type leafref { path "/interfaces-state/interface/name"; } } container interfaces-state { list interface { key "name"; leaf name { type string; } leaf-list higher-layer-if { type interface-state-ref; } } } CBOR diagnostic notation: "eth1" CBOR encoding: 64 657468316.10. The 'identityref' Type This specification supports two approaches for encoding identityref, a YANG Schema Item iDentifier (SID) as defined inSection 3.2 or a name as defined in[RFC7951] section 6.8.6.10.1. SIDs as identityref When schema nodes of type identityref are implemented using SIDs, they MUST be encoded using a CBOR unsigned integer data item (major type 0). (Note that no delta mechanism is employed for SIDs as identityref.) The following example shows the encoding of a 'type' leaf instance set to the value 'iana-if-type:ethernetCsmacd' (SID 1880). Definition example from [RFC7317]:Veillette, et al. Expires September 10, 2020 [Page 33]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 identity interface-type { } identity iana-interface-type { base interface-type; } identity ethernetCsmacd { base iana-interface-type; } leaf type { type identityref { base interface-type; } } CBOR diagnostic notation: 1880 CBOR encoding: 19 07586.10.2. Name as identityref Alternatively, an identityref MAY be encoded using a name as defined inSection 3.3. When names are used, identityref MUST be encoded using a CBOR text string data item (major type 3). If the identity is defined in different module than the leaf node containing the identityref data node, the namespace qualified form MUST be used. Otherwise, both the simple and namespace qualified forms are permitted. Names and namespaces are defined inSection 3.3. The following example shows the encoding of the identity 'iana-if- type:ethernetCsmacd' using its namespace qualified name. This example is described inSection 6.10.1. CBOR diagnostic notation: "iana-if-type:ethernetCsmacd" CBOR encoding: 78 1b 69616E612D69662D747970653A65746865726E657443736D6163646.11. The 'empty' Type Leafs of type empty MUST be encoded using the CBOR null value (major type 7, additional information 22). The following example shows the encoding of a 'is-router' leaf instance when present.Veillette, et al. Expires September 10, 2020 [Page 34]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 Definition example from [RFC8344]: leaf is-router { type empty; } CBOR diagnostic notation: null CBOR encoding: F66.12. The 'union' Type Leafs of type union MUST be encoded using the rules associated with one of the types listed. When used in a union, the following YANG datatypes are enclosed by a CBOR tag to avoid confusion between different YANG datatypes encoded using the same CBOR major type. o bits o enumeration o identityref o instance-identifier SeeSection 8.1 for the assigned value of these CBOR tags. As mentioned inSection 6.6 and inSection 6.7, 'enumeration' and 'bits' are encoded as CBOR text string data item (major type 3) when defined within a 'union' type. The following example shows the encoding of an 'ip-address' leaf instance when set to "2001:db8:a0b:12f0::1". Definition example from [RFC7317]:Veillette, et al. Expires September 10, 2020 [Page 35]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 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}]+)?'; } } 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}(([^:]+:[^:]+)|(.*\..*)))|((([^:]+:)*[^:]+) ?::(([^:]+:)*[^:]+)?)(%.+)?'; } } typedef ip-address { type union { type ipv4-address; type ipv6-address; } } leaf address { type inet:ip-address; } CBOR diagnostic notation: "2001:db8:a0b:12f0::1" CBOR encoding: 74 323030313A6462383A6130623A313266303A3A316.13. The 'instance-identifier' Type This specification supports two approaches for encoding an instance- identifier, one based on YANG Schema Item iDentifier (SID) as defined inSection 3.2 and one based on names as defined inSection 3.3.6.13.1. SIDs as instance-identifier SIDs uniquely identify a schema node. In the case of a single instance schema node, i.e. a schema node defined at the root of a YANG module or submodule or schema nodes defined within a container, the SID is sufficient to identify this instance.Veillette, et al. Expires September 10, 2020 [Page 36]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 In the case of a schema node member of a YANG list, a SID is combined with the list key(s) to identify each instance within the YANG list(s). Single instance schema nodes MUST be encoded using a CBOR unsigned integer data item (major type 0) and set to the targeted schema node SID. Schema nodes member of a YANG list MUST be encoded using a CBOR array data item (major type 4) containing the following entries: o The first entry MUST be encoded as a CBOR unsigned integer data item (major type 0) and set to the targeted schema node SID. o The following entries MUST contain the value of each key required to identify the instance of the targeted schema node. These keys MUST be ordered as defined in the 'key' YANG statement, starting from top level list, and follow by each of the subordinate list(s). Examples within this section assume the definition of a schema node of type 'instance-identifier': Definition example from [RFC7950]: container system { ... leaf reporting-entity { type instance-identifier; } leaf contact { type string; } leaf hostname { type inet:domain-name; } } ~~~~ *First example:* The following example shows the encoding of the 'reporting-entity' value referencing data node instance "/system/contact" (SID 1741). Definition example from [RFC7317]:Veillette, et al. Expires September 10, 2020 [Page 37]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 container system { leaf contact { type string; } leaf hostname { type inet:domain-name; } } CBOR diagnostic notation: 1741 CBOR encoding: 19 06CD *Second example:* The following example shows the encoding of the 'reporting-entity' value referencing list instance "/system/authentication/user/ authorized-key/key-data" (SID 1734) for user name "bob" and authorized-key "admin". Definition example from [RFC7317]: list user { key name; leaf name { type string; } leaf password { type ianach:crypt-hash; } list authorized-key { key name; leaf name { type string; } leaf algorithm { type string; } leaf key-data { type binary; } }Veillette, et al. Expires September 10, 2020 [Page 38]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 CBOR diagnostic notation: [1734, "bob", "admin"] CBOR encoding: 83 # array(3) 19 06C6 # unsigned(1734) 63 # text(3) 626F62 # "bob" 65 # text(5) 61646D696E # "admin" *Third example:* The following example shows the encoding of the 'reporting-entity' value referencing the list instance "/system/authentication/user" (SID 1730) corresponding to user name "jack". CBOR diagnostic notation: [1730, "jack"] CBOR encoding: 82 # array(2) 19 06C2 # unsigned(1730) 64 # text(4) 6A61636B # "jack"6.13.2. Names as instance-identifier An "instance-identifier" value is encoded as a string that is analogical to the lexical representation in XML encoding; seeSection 9.13.2 in [RFC7950]. However, the encoding of namespaces in instance-identifier values follows the rules stated inSection 3.3, namely: o The leftmost (top-level) data node name is always in the namespace qualified form. o Any subsequent data node name is in the namespace qualified form if the node is defined in a module other than its parent node, and the simple form is used otherwise. This rule also holds for node names appearing in predicates. For example, /ietf-interfaces:interfaces/interface[name='eth0']/ietf-ip:ipv4/ipVeillette, et al. Expires September 10, 2020 [Page 39]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 is a valid instance-identifier value because the data nodes "interfaces", "interface", and "name" are defined in the module "ietf-interfaces", whereas "ipv4" and "ip" are defined in "ietf-ip". The resulting xpath MUST be encoded using a CBOR text string data item (major type 3). *First example:* This example is described inSection 6.13.1. CBOR diagnostic notation: "/ietf-system:system/contact" CBOR encoding: 78 1c 2F696574662D73797374656D3A73797374656D2F636F6E74616374 *Second example:* This example is described inSection 6.13.1. CBOR diagnostic notation: "/ietf-system:system/authentication/user[name='bob']/authorized-key [name='admin']/key-data" CBOR encoding: 78 59 2F696574662D73797374656D3A73797374656D2F61757468656E74696361 74696F6E2F757365725B6E616D653D27626F62275D2F617574686F72697A 65642D6B65790D0A5B6E616D653D2761646D696E275D2F6B65792D64617461 *Third example:* This example is described inSection 6.13.1. CBOR diagnostic notation: "/ietf-system:system/authentication/user[name='bob']" CBOR encoding: 78 33 2F696574662D73797374656D3A73797374656D2F61757468656E74696361 74696F6E2F757365725B6E616D653D27626F62275DVeillette, et al. Expires September 10, 2020 [Page 40]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 20207. Security Considerations The security considerations of [RFC7049] and [RFC7950] apply. This document defines an alternative encoding for data modeled in the YANG data modeling language. As such, this encoding does not contribute any new security issues in addition of those identified for the specific protocol or context for which it is used. To minimize security risks, software on the receiving side SHOULD reject all messages that do not comply to the rules of this document and reply with an appropriate error message to the sender.8. IANA Considerations8.1. CBOR Tags Registry This specification requires the assignment of CBOR tags for the following YANG datatypes. These tags are added to the CBOR Tags Registry as defined insection 7.2 of [RFC7049]. +-----+------------------+-----------------------------+-----------+ | Tag | Data Item | Semantics | Reference | +-----+------------------+-----------------------------+-----------+ | 43 | byte string | YANG bits datatype | [this] | | | | ; seeSection 6.7. | | | 44 | unsigned integer | YANG enumeration datatype | [this] | | | | ;seeSection 6.6. | | | 45 | unsigned integer | YANG identityref datatype | [this] | | | or text string | ; seeSection 6.10. | | | 46 | unsigned integer | YANG instance-identifier | [this] | | | or text string | datatype; seeSection 6.13. | [this] | | | or array | | | | 47 | unsigned integer | YANG Schema Item iDentifier | | | | | ; seeSection 3.2. | [this] | +-----+------------------+-----------------------------+-----------+ // RFC Ed.: replace [this] with RFC number and remove this note9. Acknowledgments This document has been largely inspired by the extensive works done by Andy Bierman and Peter van der Stok on [I-D.ietf-core-comi]. [RFC7951] has also been a critical input to this work. The authors would like to thank the authors and contributors to these two drafts. The authors would also like to acknowledge the review, feedback, and comments from Ladislav Lhotka and Juergen Schoenwaelder.Veillette, et al. Expires September 10, 2020 [Page 41]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 202010. References10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels",BCP 14,RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>. [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68,RFC 5234, DOI 10.17487/RFC5234, January 2008, <https://www.rfc-editor.org/info/rfc5234>. [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)",RFC 6241, DOI 10.17487/RFC6241, June 2011, <https://www.rfc-editor.org/info/rfc6241>. [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)",RFC 7049, DOI 10.17487/RFC7049, October 2013, <https://www.rfc-editor.org/info/rfc7049>. [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",RFC 7950, DOI 10.17487/RFC7950, August 2016, <https://www.rfc-editor.org/info/rfc7950>. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase inRFC2119 Key Words",BCP 14,RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>. [RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures",RFC 8610, DOI 10.17487/RFC8610, June 2019, <https://www.rfc-editor.org/info/rfc8610>.10.2. Informative References [I-D.ietf-core-comi] Veillette, M., Stok, P., Pelov, A., Bierman, A., and I. Petrov, "CoAP Management Interface",draft-ietf-core-comi-08 (work in progress), September 2019. [I-D.ietf-core-sid] Veillette, M., Pelov, A., and I. Petrov, "YANG Schema Item iDentifier (SID)",draft-ietf-core-sid-11 (work in progress), March 2020.Veillette, et al. Expires September 10, 2020 [Page 42]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 [RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for Constrained-Node Networks",RFC 7228, DOI 10.17487/RFC7228, May 2014, <https://www.rfc-editor.org/info/rfc7228>. [RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for System Management",RFC 7317, DOI 10.17487/RFC7317, August 2014, <https://www.rfc-editor.org/info/rfc7317>. [RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",RFC 7951, DOI 10.17487/RFC7951, August 2016, <https://www.rfc-editor.org/info/rfc7951>. [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol",RFC 8040, DOI 10.17487/RFC8040, January 2017, <https://www.rfc-editor.org/info/rfc8040>. [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90,RFC 8259, DOI 10.17487/RFC8259, December 2017, <https://www.rfc-editor.org/info/rfc8259>. [RFC8343] Bjorklund, M., "A YANG Data Model for Interface Management",RFC 8343, DOI 10.17487/RFC8343, March 2018, <https://www.rfc-editor.org/info/rfc8343>. [RFC8344] Bjorklund, M., "A YANG Data Model for IP Management",RFC 8344, DOI 10.17487/RFC8344, March 2018, <https://www.rfc-editor.org/info/rfc8344>. [RFC8348] Bierman, A., Bjorklund, M., Dong, J., and D. Romascanu, "A YANG Data Model for Hardware Management",RFC 8348, DOI 10.17487/RFC8348, March 2018, <https://www.rfc-editor.org/info/rfc8348>.Authors' Addresses Michel Veillette (editor) Trilliant Networks Inc. 610 Rue du Luxembourg Granby, Quebec J2J 2V2 Canada Email: michel.veillette@trilliantinc.comVeillette, et al. Expires September 10, 2020 [Page 43]
Internet-Draft CBOR Encoding of Data Modeled with YANG March 2020 Ivaylo Petrov (editor) Acklio 1137A avenue des Champs Blancs Cesson-Sevigne, Bretagne 35510 France Email: ivaylo@ackl.io Alexander Pelov Acklio 1137A avenue des Champs Blancs Cesson-Sevigne, Bretagne 35510 France Email: a@ackl.ioVeillette, et al. Expires September 10, 2020 [Page 44]Datatracker
draft-ietf-core-yang-cbor-12
This is an older version of an Internet-Draft that was ultimately published asRFC 9254.
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| Authors | Michel Veillette,Ivaylo Petrov,Alexander Pelov | ||
| Replaces | draft-veillette-core-yang-cbor-mapping | ||
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| Additional resources | Mailing list discussion |