YANG Schema Item iDentifier (YANG SID)
draft-ietf-core-sid-17
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
|
|
|---|---|---|---|
| Authors | Michel Veillette , Alexander Pelov , Ivaylo Petrov , Carsten Bormann , Michael Richardson | ||
| Last updated | 2021-10-27 (Latest revision 2021-10-25) | ||
| Replaces | draft-somaraju-core-sid | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
INTDIR Telechat review
(of
-21)
by Brian Haberman
Ready w/issues
YANGDOCTORS Last Call review
(of
-15)
by Xufeng Liu
Ready w/nits
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Jaime Jimenez | ||
| Shepherd write-up | Show Last changed 2021-06-22 | ||
| IESG | IESG state | IESG Evaluation::Revised I-D Needed | |
| Consensus boilerplate | Yes | ||
| Telechat date |
(None)
Needs 2 more YES or NO OBJECTION positions to pass. |
||
| Responsible AD | Francesca Palombini | ||
| Send notices to | Carsten Bormann <cabo@tzi.org>, jaime@iki.fi | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA expert review state | Expert Reviews OK | ||
| IANA expert review comments | Expert comments: the CoAP Content-Format registration has been moved to draft-ietf-core-yang-cbor. No issues with either document. |
draft-ietf-core-sid-17
Internet Engineering Task Force M.V. Veillette, Ed.
Internet-Draft Trilliant Networks Inc.
Intended status: Standards Track A.P. Pelov, Ed.
Expires: 29 April 2022 Acklio
I. Petrov, Ed.
Google Switzerland GmbH
C. Bormann
Universität Bremen TZI
M. Richardson
Sandelman Software Works
26 October 2021
YANG Schema Item iDentifier (YANG SID)
draft-ietf-core-sid-17
Abstract
YANG Schema Item iDentifiers (YANG SID) are globally unique 63-bit
unsigned integers used to identify YANG items, as a more compact
method to identify YANG items that can be used for efficiency and in
constrained environments (RFC 7228). This document defines the
semantics, the registration, and assignment processes of YANG SIDs
for IETF managed YANG modules. To enable the implementation of these
processes, this document also defines a file format used to persist
and publish assigned YANG SIDs.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 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 at https://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 29 April 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Notation . . . . . . . . . . . . . . . . . . 4
3. ".sid" file lifecycle . . . . . . . . . . . . . . . . . . . . 5
4. ".sid" file format . . . . . . . . . . . . . . . . . . . . . 6
5. Content-Types . . . . . . . . . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
7.1. YANG Namespace Registration . . . . . . . . . . . . . . . 13
7.2. Register ".sid" File Format Module . . . . . . . . . . . 14
7.3. CoAP Content-Formats Registry . . . . . . . . . . . . . . 14
7.4. Create new IANA Registry: "YANG SID Mega-Range"
registry . . . . . . . . . . . . . . . . . . . . . . . . 14
7.4.1. Structure . . . . . . . . . . . . . . . . . . . . . . 14
7.4.2. Allocation policy . . . . . . . . . . . . . . . . . . 15
7.4.2.1. First allocation . . . . . . . . . . . . . . . . 15
7.4.2.2. Consecutive allocations . . . . . . . . . . . . . 15
7.4.3. Initial contents of the Registry . . . . . . . . . . 16
7.5. Create a new IANA Registry: IETF YANG SID Range Registry
(managed by IANA) . . . . . . . . . . . . . . . . . . . . 16
7.5.1. Structure . . . . . . . . . . . . . . . . . . . . . . 16
7.5.2. Allocation policy . . . . . . . . . . . . . . . . . . 16
7.5.3. Initial contents of the registry . . . . . . . . . . 18
7.6. Create new IANA Registry: "IETF YANG SID Registry" . . . 20
7.6.1. Structure . . . . . . . . . . . . . . . . . . . . . . 20
7.6.2. Allocation policy . . . . . . . . . . . . . . . . . . 20
7.6.3. Recursive Allocation of YANG SID Range at Document
Adoption . . . . . . . . . . . . . . . . . . . . . . 21
7.6.4. Initial contents of the registry . . . . . . . . . . 22
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.1. Normative References . . . . . . . . . . . . . . . . . . 22
8.2. Informative References . . . . . . . . . . . . . . . . . 23
Appendix A. ".sid" file example . . . . . . . . . . . . . . . . 25
Appendix B. SID auto generation . . . . . . . . . . . . . . . . 34
Appendix C. ".sid" file lifecycle . . . . . . . . . . . . . . . 36
C.1. ".sid" File Creation . . . . . . . . . . . . . . . . . . 36
C.2. ".sid" File Update . . . . . . . . . . . . . . . . . . . 37
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 38
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Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39
1. Introduction
Some of the items defined in YANG [RFC7950] require the use of a
unique identifier. In both Network Configuration Protocol (NETCONF)
[RFC6241] and RESTCONF [RFC8040], these identifiers are implemented
using names. To allow the implementation of data models defined in
YANG in constrained devices [RFC7228] and constrained networks, a
more compact method to identify YANG items is required. This compact
identifier, called YANG Schema Item iDentifier or YANG SID (or simply
SID in this document and when the context is clear), is encoded using
a 63-bit unsigned integer. The limitation to 63-bit unsigned
integers allows SIDs to be manipulated more easily on platforms that
might otherwise lack 64-bit unsigned arithmetic. The loss of a
single bit of range is not significant given the size of the
remaining space.
The following items are identified using SIDs:
* identities
* data nodes (Note: including those nodes defined by the 'yang-data'
extension.)
* remote procedure calls (RPCs) and associated input(s) and
output(s)
* actions and associated input(s) and output(s)
* notifications and associated information
* YANG modules and features
It is possible that some protocols use only a subset of the assigned
SIDs, for example, for protocols equivalent to NETCONF [RFC6241] like
[I-D.ietf-core-comi] the transportation of YANG module SIDs might be
unnecessary. Other protocols might need to be able to transport this
information, for example protocols related to discovery such as
Constrained YANG Module Library [I-D.ietf-core-yang-library].
SIDs are globally unique integers. A registration system is used in
order to guarantee their uniqueness. SIDs are registered in blocks
called "SID ranges".
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SIDs are assigned permanently. Items introduced by a new revision of
a YANG module are added to the list of SIDs already assigned.
Assignment of SIDs to YANG items SHOULD be automated. For more
details how this can be achieved, and when manual interventions may
be appropriate, see Appendix B.
Section 3 provides more details about the registration process of
YANG modules and associated SIDs. To enable the implementation of
this registry, Section 4 defines a standard file format used to store
and publish SIDs.
IETF managed YANG modules which need to allocate SIDs, MUST use the
IANA mechanism specified in this document. For YANG modules created
by other parties, the use of IANA allocation mechanisms via use of
Mega-Ranges (see Section 7.4) is RECOMMENDED. Within the Mega-Range
allocation, those other parties are free to make up their own
mechanism.
At the time of writing, a tool for automated SID file generation is
available as part of the open-source project PYANG [PYANG].
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 in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following terms are defined in [RFC7950]:
* action
* feature
* module
* notification
* RPC
* schema node
* schema tree
* submodule
The following term is defined in [RFC8040]:
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* yang-data extension
This specification also makes use of the following terminology:
* item: A schema node, an identity, a module, or a feature defined
using the YANG modeling language.
* schema-node path: A schema-node path is a string that identifies a
schema node within the schema tree. A path consists of the list
of consecutive schema node identifier(s) separated by slashes
("/"). Schema node identifier(s) are always listed from the top-
level schema node up to the targeted schema node and could contain
namespace information. (e.g. "/ietf-system:system-state/clock/
current-datetime")
* Namespace-qualified form - a schema node identifier is prefixed
with the name of the module in which the schema node is defined,
separated from the schema node identifier by the colon character
(":").
* YANG Schema Item iDentifier (YANG SID or simply SID): Unsigned
integer used to identify different YANG items.
3. ".sid" file lifecycle
YANG is a language designed to model data accessed using one of the
compatible protocols (e.g. NETCONF [RFC6241], RESTCONF [RFC8040] and
CORECONF [I-D.ietf-core-comi]). A YANG module defines hierarchies of
data, including configuration, state data, RPCs, actions and
notifications.
Many YANG modules are not created in the context of constrained
applications. YANG modules can be implemented using NETCONF
[RFC6241] or RESTCONF [RFC8040] without the need to assign SIDs.
As needed, authors of YANG modules can assign SIDs to their YANG
modules. In order to do that, they should first obtain a SID range
from a registry and use that range to assign or generate SIDs to
items of their YANG module. The assignments can then be stored in a
".sid" file. For example on how this could be achieved, please refer
to Appendix C.
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Registration of the ".sid" file associated to a YANG module is
optional but recommended to promote interoperability between devices
and to avoid duplicate allocation of SIDs to a single YANG module.
Different registries might have different requirements for the
registration and publication of the ".sid" files. For a diagram of
one of the possibilities, please refer to the activity diagram on
Figure 1 in Appendix C.
Each time a YANG module or one of its imported module(s) or included
sub-module(s) is updated, a new ".sid" file MAY be created if the new
or updated items will need SIDs. All the SIDs present in the
previous version of the ".sid" file MUST be present in the new
version as well. The creation of this new version of the ".sid" file
SHOULD be performed using an automated tool.
If a new revision requires more SIDs than initially allocated, a new
SID range MUST be added to the 'assignment-range' as defined in
Section 4. These extra SIDs are used for subsequent assignments.
For an example of this update process, see activity diagram Figure 2
in Appendix C.
4. ".sid" file format
".sid" files are used to persist and publish SIDs assigned to the
different YANG items of a specific YANG module. It has the following
structure.
module: ietf-sid-file
+-- sid-file
+-- module-name? yang:yang-identifier
+-- module-revision? revision-identifier
+-- sid-file-version? sid-file-version-identifier
+-- description? string
+-- dependency-revision* [module-name]
| +-- module-name yang:yang-identifier
| +-- module-revision revision-identifier
+-- assignment-range* [entry-point]
| +-- entry-point sid
| +-- size uint64
+-- item* [namespace identifier]
+-- namespace enumeration
+-- identifier union
+-- sid sid
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The following YANG module defines the structure of this file,
encoding is performed in JSON [RFC8259] using the rules defined in
[RFC7951]. It references ietf-yang-types defined in [RFC6991] and
ietf-restconf defined in [RFC8040].
RFC Ed.: please update the date of the module and Copyright if needed
and remove this note.
<CODE BEGINS> file "ietf-sid-file@2020-02-05.yang"
module ietf-sid-file {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-sid-file";
prefix sid;
import ietf-yang-types {
prefix yang;
reference "RFC 6991: Common YANG Data Types.";
}
import ietf-restconf {
prefix rc;
reference "RFC 8040: RESTCONF Protocol.";
}
organization
"IETF Core Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/core/>
WG List: <mailto:core@ietf.org>
Editor: Michel Veillette
<mailto:michel.veillette@trilliant.com>
Editor: Andy Bierman
<mailto:andy@yumaworks.com>
Editor: Alexander Pelov
<mailto:a@ackl.io>
Editor: Ivaylo Petrov
<mailto:ivaylopetrov@google.com>";
description
"Copyright (c) 2021 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
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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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.
This module defines the structure of the .sid files.
Each .sid file contains the mapping between each
string identifier defined by a YANG module and a
corresponding numeric value called YANG SID.";
revision 2020-02-05 {
description
"Initial revision.";
reference
"[RFC XXXX] YANG Schema Item iDentifier (YANG SID)";
}
typedef revision-identifier {
type string {
pattern '\d{4}-\d{2}-\d{2}';
}
description
"Represents a date in YYYY-MM-DD format.";
}
typedef sid-file-version-identifier {
type uint32;
description
"Represents the version of a .sid file.";
}
typedef sid {
type uint64 {
range "0..9223372036854775807";
}
description
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"YANG Schema Item iDentifier";
reference
"[RFC XXXX] YANG Schema Item iDentifier (YANG SID)";
}
typedef schema-node-path {
type string {
pattern
'/[a-zA-Z_][a-zA-Z0-9\-_.]*:[a-zA-Z_][a-zA-Z0-9\-_.]*' +
'(/[a-zA-Z_][a-zA-Z0-9\-_.]*(:[a-zA-Z_][a-zA-Z0-9\-_.]*)?)*';
}
description
"A schema-node path is an absolute YANG schema node identifier
as defined by the YANG ABNF rule absolute-schema-nodeid,
except that module names are used instead of prefixes.
This string additionally follows the following rules:
o The leftmost (top-level) data node name is always in the
namespace-qualified form.
o Any subsequent schema 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. No predicates are allowed.";
reference
"RFC 7950, The YANG 1.1 Data Modeling Language;
Section 6.5: Schema Node Identifier;";
}
rc:yang-data sid-file {
uses sid-file;
}
grouping sid-file {
description "A grouping that contains a YANG container
representing the file structure of a .sid files.";
container sid-file {
description
"A Wrapper container that together with the rc:yang-data
extension marks the YANG data structures inside as not being
intended to be implemented as part of a configuration
datastore or as an operational state within the server.";
leaf module-name {
type yang:yang-identifier;
description
"Name of the YANG module associated with this .sid file.";
}
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leaf module-revision {
type revision-identifier;
description
"Revision of the YANG module associated with this .sid
file.
This leaf is not present if no revision statement is
defined in the YANG module.";
}
leaf sid-file-version {
type sid-file-version-identifier;
default 0;
description
"Optional leaf that specifies the version number of the
.sid file. .sid files and the version sequence are
specific to a given YANG module revision. This number
starts at zero when there is a new YANG module revision and
increases monotonically. This number can distinguish
updates to the .sid file which are the result of new
processing, or the result of reported errata.";
}
leaf description {
type string;
description
"Free-form meta information about the generated file. It
might include .sid file generation tool and time among
other things.";
}
list dependency-revision {
key "module-name";
description
"Information about the used revision during the .sid file
generation of each YANG module that the module in
'module-name' imported.";
leaf module-name {
type yang:yang-identifier;
description
"Name of the YANG module, dependency of 'module-name',
for which revision information is provided.";
}
leaf module-revision {
type revision-identifier;
mandatory true;
description
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"Revision of the YANG module, dependency of
'module-name', for which revision information is
provided.";
}
}
list assignment-range {
key "entry-point";
description
"YANG SID range(s) allocated to the YANG module identified
by 'module-name' and 'module-revision'.
- The YANG SID range first available value is entry-point
and the last available value in the range is
(entry-point + size - 1).
- The YANG SID ranges specified by all assignment-rages
MUST NOT overlap.";
leaf entry-point {
type sid;
description
"Lowest YANG SID available for assignment.";
}
leaf size {
type uint64;
mandatory true;
description
"Number of YANG SIDs available for assignment.";
}
}
list item {
key "namespace identifier";
unique "sid";
description
"Each entry within this list defined the mapping between
a YANG item string identifier and a YANG SID. This list
MUST include a mapping entry for each YANG item defined by
the YANG module identified by 'module-name' and
'module-revision'.";
leaf namespace {
type enumeration {
enum module {
value 0;
description
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"All module and submodule names share the same
global module identifier namespace.";
}
enum identity {
value 1;
description
"All identity names defined in a module and its
submodules share the same identity identifier
namespace.";
}
enum feature {
value 2;
description
"All feature names defined in a module and its
submodules share the same feature identifier
namespace.";
}
enum data {
value 3;
description
"The namespace for all data nodes, as defined in
YANG.";
}
}
description
"Namespace of the YANG item for this mapping entry.";
}
leaf identifier {
type union {
type yang:yang-identifier;
type schema-node-path;
}
description
"String identifier of the YANG item for this mapping
entry.
If the corresponding 'namespace' field is 'module',
'feature', or 'identity', then this field MUST
contain a valid YANG identifier string.
If the corresponding 'namespace' field is 'data',
then this field MUST contain a valid schema node
path.";
}
leaf sid {
type sid;
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mandatory true;
description
"YANG SID assigned to the YANG item for this mapping
entry.";
}
}
}
}
}
<CODE ENDS>
5. Content-Types
The following Content-Type has been defined in
[I-D.ietf-core-yang-cbor]:
application/yang-data+cbor; id=sid: This Content-Type represents a
CBOR YANG document containing one or multiple data node values.
Each data node is identified by its associated SID.
FORMAT: CBOR map of SID, instance-value
The message payload of Content-Type 'application/yang-data+cbor'
is encoded using a CBOR map. Each entry within the CBOR map
contains the data node identifier (i.e. SID) and the associated
instance-value. Instance-values are encoded using the rules
defined in Section 4 of [I-D.ietf-core-yang-cbor].
6. Security Considerations
This document defines a new type of identifier used to encode data
that are modeled in YANG [RFC7950]. As such, this identifier does
not contribute to any new security issues in addition of those
identified for the specific protocols or contexts for which it is
used.
7. IANA Considerations
7.1. YANG Namespace Registration
This document registers the following XML namespace URN in the "IETF
XML Registry", following the format defined in [RFC3688]:
URI: please assign urn:ietf:params:xml:ns:yang:ietf-sid-file
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
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Reference: RFC XXXX
// RFC Ed.: please replace XXXX with RFC number and remove this note
7.2. Register ".sid" File Format Module
This document registers one YANG module in the "YANG Module Names"
registry [RFC6020]:
* name: ietf-sid-file
* namespace: urn:ietf:params:xml:ns:yang:ietf-sid-file
* prefix: sid
* reference: RFC XXXX
// RFC Ed.: please replace XXXX with RFC number and remove this note
7.3. CoAP Content-Formats Registry
A Content-Format for application/yang-data+cbor; id=sid has been
added to the "CoAP Content-Formats" within the "Constrained RESTful
Environments (CoRE) Parameters" registry, in
[I-D.ietf-core-yang-cbor].
7.4. Create new IANA Registry: "YANG SID Mega-Range" registry
The name of this registry is "YANG SID Mega-Range". This registry is
used to record the delegation of the management of a block of SIDs to
third parties (such as SDOs or registrars).
7.4.1. Structure
Each entry in this registry must include:
* The entry point (first SID) of the registered SID block.
* The size of the registered SID block. The size MUST be one
million (1 000 000) SIDs.
* The contact information of the requesting organization including:
- The policy of SID range allocations: Public, Private or Both.
- Organization name
- URL
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The information associated to the Organization name should not be
publicly visible in the registry, but should be available. This
information includes contact email and phone number and change
controller email and phone number.
7.4.2. Allocation policy
The IANA policy for future additions to this registry is "Expert
Review" [RFC8126].
An organization requesting to manage a YANG SID Range (and thus have
an entry in the YANG SID Mega-Range Registry), must ensure the
following capacities:
* The capacity to manage and operate a YANG SID Range Registry. A
YANG SID Range Registry MUST provide the following information for
all YANG SID Ranges allocated by the Registry:
- Entry Point of allocated YANG SID Range
- Size of allocated YANG SID Range
- Type: Public or Private
o Public Ranges MUST include at least a reference to the YANG
module and ".sid" files for that YANG SID Range.
o Private Ranges MUST be marked as "Private"
* A Policy of allocation, which clearly identifies if the YANG SID
Range allocations would be Private, Public or Both.
* Technical capacity to ensure the sustained operation of the
registry for a period of at least 5 years. If Private
Registrations are allowed, the period must be of at least 10
years.
7.4.2.1. First allocation
For a first allocation to be provided, the requesting organization
must demonstrate a functional registry infrastructure.
7.4.2.2. Consecutive allocations
On subsequent allocation request(s), the organization must
demonstrate the exhaustion of the prior range. These conditions need
to be asserted by the assigned expert(s).
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If that extra-allocation is done within 3 years from the last
allocation, the experts need to discuss this request on the CORE
working group mailing list and consensus needs to be obtained before
allocating a new Mega-Range.
7.4.3. Initial contents of the Registry
The initial entry in this registry is allocated to IANA:
+=============+=========+============+===================+==========+
| Entry Point | Size | Allocation | Organization | URL |
| | | | name | |
+=============+=========+============+===================+==========+
| 0 | 1000000 | Public | IANA | iana.org |
+-------------+---------+------------+-------------------+----------+
Table 1
7.5. Create a new IANA Registry: IETF YANG SID Range Registry (managed
by IANA)
7.5.1. Structure
Each entry in this registry must include:
* The SID range entry point.
* The SID range size.
* The YANG module name.
* Document reference.
7.5.2. Allocation policy
The first million SIDs assigned to IANA is sub-divided as follows:
* The range of 0 to 999 (size 1000) is "Reserved" as defined in
[RFC8126].
* The range of 1000 to 59,999 (size 59,000) is reserved for YANG
modules defined in RFCs.
- The IANA policy for additions to this registry is either:
o "Expert Review" [RFC8126] in case the ".sid" file comes from
a YANG module from an existing RFC, or
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o "RFC Required" [RFC8126] otherwise.
- The Expert MUST verify that the YANG module for which this
allocation is made has an RFC (existing RFC) OR is on track to
become RFC (early allocation with a request from the WG chairs
as defined by [BCP100]).
* The range of 60,000 to 99,999 (size 40,000) is reserved for
experimental YANG modules. This range MUST NOT be used in
operational deployments since these SIDs are not globally unique
which limit their interoperability. The IANA policy for this
range is "Experimental use" [RFC8126].
* The range of 100,000 to 999,999 (size 900,000) is "Reserved" as
defined in [RFC8126].
+=============+=========+===============================+
| Entry Point | Size | IANA policy |
+=============+=========+===============================+
| 0 | 1,000 | Reserved |
+-------------+---------+-------------------------------+
| 1,000 | 59,000 | Expert Review or RFC Required |
+-------------+---------+-------------------------------+
| 60,000 | 40,000 | Experimental use |
+-------------+---------+-------------------------------+
| 100,000 | 900,000 | Reserved |
+-------------+---------+-------------------------------+
Table 2
The size of the SID range allocated for a YANG module is recommended
to be a multiple of 50 and to be at least 33% above the current
number of YANG items. This headroom allows assignment within the
same range of new YANG items introduced by subsequent revisions. The
SID range size SHOULD NOT exceed 1000; a larger size may be requested
by the authors if this recommendation is considered insufficient. It
is important to note that an additional SID range can be allocated to
an existing YANG module if the initial range is exhausted; this then
just leads to slightly less efficient representation.
In case a SID range is allocated for an existing RFC through the
"Expert Review" policy, the Document reference field for the given
allocation should point to the RFC that the YANG module is defined
in.
In case a SID range is required before publishing the RFC due to
implementations needing stable SID values, early allocation as
defined in [BCP100] can be employed. As specified in Section 4.6 of
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[RFC8126], RFCs and by extension documents that are expected to
become an RFC fulfill the requirement for "Specification Required"
stated in Section 2 of [BCP100], which allows for the early
allocation process to be employed.
7.5.3. Initial contents of the registry
Initial entries in this registry are as follows:
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+=======+=====+==============+======================================+
| Entry | Size|Module name | Document reference |
| Point | | | |
+=======+=====+==============+======================================+
| 1000 | 100|ietf-coreconf | [I-D.ietf-core-comi] |
+-------+-----+--------------+--------------------------------------+
| 1100 | 50|ietf-yang- | [RFC6991] |
| | |types | |
+-------+-----+--------------+--------------------------------------+
| 1150 | 50|ietf-inet- | [RFC6991] |
| | |types | |
+-------+-----+--------------+--------------------------------------+
| 1200 | 50|iana-crypt- | [RFC7317] |
| | |hash | |
+-------+-----+--------------+--------------------------------------+
| 1250 | 50|ietf-netconf- | [RFC8341] |
| | |acm | |
+-------+-----+--------------+--------------------------------------+
| 1300 | 50|ietf-sid-file | RFCXXXX |
+-------+-----+--------------+--------------------------------------+
| 1500 | 100|ietf- | [RFC8343] |
| | |interfaces | |
+-------+-----+--------------+--------------------------------------+
| 1600 | 100|ietf-ip | [RFC8344] |
+-------+-----+--------------+--------------------------------------+
| 1700 | 100|ietf-system | [RFC7317] |
+-------+-----+--------------+--------------------------------------+
| 1800 | 400|iana-if-type | [RFC7224] |
+-------+-----+--------------+--------------------------------------+
| 2400 | 50|ietf-voucher | [RFC8366] |
+-------+-----+--------------+--------------------------------------+
| 2450 | 50|ietf- | [I-D.ietf-anima-constrained-voucher] |
| | |constrained- | |
| | |voucher | |
+-------+-----+--------------+--------------------------------------+
| 2500 | 50|ietf- | [I-D.ietf-anima-constrained-voucher] |
| | |constrained- | |
| | |voucher- | |
| | |request | |
+-------+-----+--------------+--------------------------------------+
Table 3
// RFC Ed.: replace XXXX with RFC number assigned to this draft.
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For allocation, RFC publication of the YANG module is required as per
[RFC8126]. The YANG module must be registered in the "YANG module
Name" registry according to the rules specified in Section 14 of
[RFC6020].
7.6. Create new IANA Registry: "IETF YANG SID Registry"
The name of this registry is "IETF YANG SID Registry". This registry
is used to record the allocation of SIDs for individual YANG module
items.
7.6.1. Structure
Each entry in this registry must include:
* The YANG module name. This module name must be present in the
"Name" column of the "YANG Module Names" registry.
* A link to the associated ".yang" file. This file link must be
present in the "File" column of the "YANG Module Names" registry.
* The link to the ".sid" file which defines the allocation. The
".sid" file is stored by IANA.
* The number of actually allocated SIDs in the ".sid" file.
7.6.2. Allocation policy
The allocation policy is Expert review. The Expert MUST ensure that
the following conditions are met:
* The ".sid" file has a valid structure:
- The ".sid" file MUST be a valid JSON file following the
structure of the module defined in RFCXXXX (RFC Ed: replace XXX
with RFC number assigned to this draft).
* The ".sid" file allocates individual SIDs ONLY in the YANG SID
Ranges for this YANG module (as allocated in the IETF YANG SID
Range Registry):
- All SIDs in this ".sid" file MUST be within the ranges
allocated to this YANG module in the "IETF YANG SID Range
Registry".
* If another ".sid" file has already allocated SIDs for this YANG
module (e.g. for older or newer versions of the YANG module), the
YANG items are assigned the same SIDs as in the other ".sid" file.
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* If there is an older version of the ".sid" file, all allocated
SIDs from that version are still present in the current version of
the ".sid" file.
7.6.3. Recursive Allocation of YANG SID Range at Document Adoption
Due to the difficulty in changing SID values during IETF document
processing, it is expected that most documents will ask for SID
allocations using Early Allocations [BCP100]. The details of the
Early Allocation should be included in any Working Group Adoption
call. Prior to Working Group Adoption, an internet draft authors can
use the experimental SID range (as per Section 7.5.2) for their SIDs
allocations or other values that do not create ambiguity with other
SID uses (for example they can use a range that comes from a non-IANA
managed "YANG SID Mega-Range" registry).
After Working Group Adoption, any modification of a ".sid" file is
expected to be discussed on the mailing list of the appropriate
Working Groups. Specific attention should be paid to implementers'
opinion after Working Group Last Call if a SID value is to change its
meaning. In all cases, a ".sid" file and the SIDs associated with it
are subject to change before the publication of an internet draft as
an RFC.
During the early use of SIDs, many existing, previously published
YANG modules will not have SID allocations. For an allocation to be
useful the included YANG modules may also need to have SID
allocations made.
The Expert Reviewer who performs the (Early) Allocation analysis will
need to go through the list of included YANG modules and perform SID
allocations for those modules as well.
* If the document is a published RFC, then the allocation of SIDs
for its referenced YANG modules is permanent. The Expert Reviewer
provides the generated SID file to IANA for registration. This
process may be time-consuming during a bootstrap period (there are
over 100 YANG modules to date, none of which have SID
allocations), but should quiet down once needed entries are
allocated.
* If the document is an unprocessed Internet-Draft adopted in a WG,
then an Early Allocation is performed for this document as well.
Early Allocations require approval by an IESG Area Director. An
early allocation which requires additional allocations will list
the other allocations in its description, and will be cross-posted
to the any other working group mailing lists.
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* A YANG module which references a module in a document which has
not yet been adopted by any working group will be unable to
perform an Early Allocation for that other document until it is
adopted by a working group. As described in [BCP100], an AD
Sponsored document acts as if it had a working group. The
approving AD may also exempt a document from this policy by
agreeing to AD Sponsor the document.
At the end of the IETF process all the dependencies of a given module
for which SIDs are assigned, should also have SIDs assigned. Those
dependencies' assignments should be permanent (not Early Allocation).
A previously SID-allocated YANG module which changes its references
to include a YANG module for which there is no SID allocation needs
to repeat the Early Allocation process.
Early Allocations are made with a one-year period, after which they
are expired. [BCP100] indicates that at most one renewal may be
made. For the SID allocation a far more lenient stance is desired.
1. An extension of a referencing documents Early Allocation should
update any referenced Early Allocations to expire no sooner than
the referencing document.
2. The [BCP100] mechanism allows the IESG to provide a second
renewal, and such an event may prompt some thought about how the
collection of documents are being processed.
This is driven by the very generous size of the SID space and the
often complex and deep dependencies of YANG modules. Often a core
module with many dependencies will undergo extensive review, delaying
the publication of other documents.
[BCP100] also says:
Note that if a document is submitted for review to the IESG and at
the time of submission some early allocations are valid (not
expired), these allocations should not be expired while the document
is under IESG consideration or waiting in the RFC Editor's queue
after approval by the IESG.
7.6.4. Initial contents of the registry
None.
8. References
8.1. Normative References
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[BCP100] Cotton, M., "Early IANA Allocation of Standards Track Code
Points", BCP 100, RFC 7120, January 2014.
<https://www.rfc-editor.org/info/bcp100>
[I-D.ietf-core-yang-cbor]
Veillette, M., Petrov, I., Pelov, A., and C. Bormann,
"CBOR Encoding of Data Modeled with YANG", Work in
Progress, Internet-Draft, draft-ietf-core-yang-cbor-16, 24
June 2021, <https://www.ietf.org/archive/id/draft-ietf-
core-yang-cbor-16.txt>.
[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>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[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>.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
8.2. Informative References
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[I-D.ietf-anima-constrained-voucher]
Richardson, M., Stok, P. V. D., Kampanakis, P., and E.
Dijk, "Constrained Bootstrapping Remote Secure Key
Infrastructure (BRSKI)", Work in Progress, Internet-Draft,
draft-ietf-anima-constrained-voucher-14, 25 October 2021,
<https://www.ietf.org/archive/id/draft-ietf-anima-
constrained-voucher-14.txt>.
[I-D.ietf-core-comi]
Veillette, M., Stok, P. V. D., Pelov, A., Bierman, A., and
I. Petrov, "CoAP Management Interface (CORECONF)", Work in
Progress, Internet-Draft, draft-ietf-core-comi-11, 17
January 2021, <https://www.ietf.org/archive/id/draft-ietf-
core-comi-11.txt>.
[I-D.ietf-core-yang-library]
Veillette, M. and I. Petrov, "Constrained YANG Module
Library", Work in Progress, Internet-Draft, draft-ietf-
core-yang-library-03, 11 January 2021,
<https://www.ietf.org/archive/id/draft-ietf-core-yang-
library-03.txt>.
[PYANG] Bjorklund, M., "An extensible YANG validator and converter
in python", <https://github.com/mbj4668/pyang>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[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>.
[RFC7224] Bjorklund, M., "IANA Interface Type YANG Module",
RFC 7224, DOI 10.17487/RFC7224, May 2014,
<https://www.rfc-editor.org/info/rfc7224>.
[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>.
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[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[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>.
[RFC8366] Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
"A Voucher Artifact for Bootstrapping Protocols",
RFC 8366, DOI 10.17487/RFC8366, May 2018,
<https://www.rfc-editor.org/info/rfc8366>.
Appendix A. ".sid" file example
The following ".sid" file (ietf-system@2014-08-06.sid) has been
generated using the following yang modules:
* ietf-system@2014-08-06.yang (defined in [RFC7317])
* ietf-yang-types@2013-07-15.yang (defined in [RFC6991])
* ietf-inet-types@2013-07-15.yang (defined in [RFC6991])
* ietf-netconf-acm@2018-02-14.yang (defined in [RFC8341])
* iana-crypt-hash@2014-08-06.yang (defined in [RFC7317])
For purposes of exposition, line breaks have been introduced below in
some JSON strings that represent overly long identifiers. For
reconstructing the actual JSON file from this figure, all line breaks
that occur in what would be JSON strings need to be removed,
including any following blank space (indentation) on the line after
the line break; in each such case, a single identifier without any
embedded blank space results.
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{
"ietf-sid-file:sid-file" : {
"module-name": "ietf-system",
"module-revision": "2020-02-05",
"dependency-revision": [
{
"module-name": "ietf-yang-types",
"module-revision": "2013-07-15"
},
{
"module-name": "ietf-inet-types",
"module-revision": "2013-07-15"
},
{
"module-name": "ietf-netconf-acm",
"module-revision": "2018-02-14"
},
{
"module-name": "iana-crypt-hash",
"module-revision": "2014-08-06"
}
],
"description": "Example sid file",
"assignment-range": [
{
"entry-point": 1700,
"size": 100
}
],
"item": [
{
"namespace": "module",
"identifier": "ietf-system",
"sid": 1700
},
{
"namespace": "identity",
"identifier": "authentication-method",
"sid": 1701
},
{
"namespace": "identity",
"identifier": "local-users",
"sid": 1702
},
{
"namespace": "identity",
"identifier": "radius",
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"sid": 1703
},
{
"namespace": "identity",
"identifier": "radius-authentication-type",
"sid": 1704
},
{
"namespace": "identity",
"identifier": "radius-chap",
"sid": 1705
},
{
"namespace": "identity",
"identifier": "radius-pap",
"sid": 1706
},
{
"namespace": "feature",
"identifier": "authentication",
"sid": 1707
},
{
"namespace": "feature",
"identifier": "dns-udp-tcp-port",
"sid": 1708
},
{
"namespace": "feature",
"identifier": "local-users",
"sid": 1709
},
{
"namespace": "feature",
"identifier": "ntp",
"sid": 1710
},
{
"namespace": "feature",
"identifier": "ntp-udp-port",
"sid": 1711
},
{
"namespace": "feature",
"identifier": "radius",
"sid": 1712
},
{
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"namespace": "feature",
"identifier": "radius-authentication",
"sid": 1713
},
{
"namespace": "feature",
"identifier": "timezone-name",
"sid": 1714
},
{
"namespace": "data",
"identifier": "/ietf-system:set-current-datetime",
"sid": 1715
},
{
"namespace": "data",
"identifier": "/ietf-system:set-current-datetime/
current-datetime",
"sid": 1716
},
{
"namespace": "data",
"identifier": "/ietf-system:system",
"sid": 1717
},
{
"namespace": "data",
"identifier": "/ietf-system:system-restart",
"sid": 1718
},
{
"namespace": "data",
"identifier": "/ietf-system:system-shutdown",
"sid": 1719
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state",
"sid": 1720
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/clock",
"sid": 1721
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/clock/boot-datetime",
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"sid": 1722
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/clock/
current-datetime",
"sid": 1723
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/platform",
"sid": 1724
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/platform/machine",
"sid": 1725
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/platform/os-name",
"sid": 1726
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/platform/os-release",
"sid": 1727
},
{
"namespace": "data",
"identifier": "/ietf-system:system-state/platform/os-version",
"sid": 1728
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication",
"sid": 1729
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user",
"sid": 1730
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/
user-authentication-order",
"sid": 1731
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},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user/
authorized-key",
"sid": 1732
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user/
authorized-key/algorithm",
"sid": 1733
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user/
authorized-key/key-data",
"sid": 1734
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user/
authorized-key/name",
"sid": 1735
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user/
name",
"sid": 1736
},
{
"namespace": "data",
"identifier": "/ietf-system:system/authentication/user/
password",
"sid": 1737
},
{
"namespace": "data",
"identifier": "/ietf-system:system/clock",
"sid": 1738
},
{
"namespace": "data",
"identifier": "/ietf-system:system/clock/timezone-name",
"sid": 1739
},
{
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"namespace": "data",
"identifier": "/ietf-system:system/clock/timezone-utc-offset",
"sid": 1740
},
{
"namespace": "data",
"identifier": "/ietf-system:system/contact",
"sid": 1741
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver",
"sid": 1742
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/options",
"sid": 1743
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/options/
attempts",
"sid": 1744
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/options/
timeout",
"sid": 1745
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/search",
"sid": 1746
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/server",
"sid": 1747
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/server/name",
"sid": 1748
},
{
"namespace": "data",
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"identifier": "/ietf-system:system/dns-resolver/server/
udp-and-tcp",
"sid": 1749
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/server/
udp-and-tcp/address",
"sid": 1750
},
{
"namespace": "data",
"identifier": "/ietf-system:system/dns-resolver/server/
udp-and-tcp/port",
"sid": 1751
},
{
"namespace": "data",
"identifier": "/ietf-system:system/hostname",
"sid": 1752
},
{
"namespace": "data",
"identifier": "/ietf-system:system/location",
"sid": 1753
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp",
"sid": 1754
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/enabled",
"sid": 1755
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server",
"sid": 1756
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/
association-type",
"sid": 1757
},
{
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"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/iburst",
"sid": 1758
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/name",
"sid": 1759
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/prefer",
"sid": 1760
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/udp",
"sid": 1761
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/udp/address",
"sid": 1762
},
{
"namespace": "data",
"identifier": "/ietf-system:system/ntp/server/udp/port",
"sid": 1763
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius",
"sid": 1764
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/options",
"sid": 1765
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/options/attempts",
"sid": 1766
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/options/timeout",
"sid": 1767
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},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server",
"sid": 1768
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server/
authentication-type",
"sid": 1769
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server/name",
"sid": 1770
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server/udp",
"sid": 1771
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server/udp/
address",
"sid": 1772
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server/udp/
authentication-port",
"sid": 1773
},
{
"namespace": "data",
"identifier": "/ietf-system:system/radius/server/udp/
shared-secret",
"sid": 1774
}
]
}
}
Appendix B. SID auto generation
Assignment of SIDs to YANG items SHOULD be automated. The
recommended process to assign SIDs is as follows:
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1. A tool extracts the different items defined for a specific YANG
module.
2. The list of items is sorted in alphabetical order, 'namespace' in
descending order, 'identifier' in ascending order. The
'namespace' and 'identifier' formats are described in the YANG
module 'ietf-sid-file' defined in Section 4.
3. SIDs are assigned sequentially from the entry point up to the
size of the registered SID range. This approach is recommended
to minimize the serialization overhead, especially when delta
between a reference SID and the current SID is used by protocols
aiming to reduce message size.
4. If the number of items exceeds the SID range(s) allocated to a
YANG module, an extra range is added for subsequent assignments.
5. The "dependency-revision" should reflect the revision numbers of
each YANG module that the YANG module imports at the moment of
the generation.
When updating a YANG module that is in active use, the existing SID
assignments are maintained. (In contrast, when evolving an early
draft that has not yet been adopted by a community of developers, SID
assignments are often better done from scratch after a revision.) If
the name of a schema node changes, but the data remain structurally
and semantically similar to what was previously available under an
old name, the SID that was used for the old name MAY continue to be
used for the new name. If the meaning of an item changes, a new SID
MAY be assigned to it; this is particularly useful to allow the new
SID to identify the new structure or semantics of the item. If the
YANG data type changes in a new revision of a published module, such
that the resulting CBOR encoding is changed, then implementations
will be aided significantly if a new SID is assigned. Note that
these decisions are generally at the discretion of the YANG module
author, who should decide if the benefits of a manual intervention
are worth the deviation from automatic assignment.
In case of an update to an existing ".sid" file, an additional step
is needed that increments the ".sid" file version number. If there
was no version number in the previous version of the ".sid" file, 0
is assumed as the version number of the old version of the ".sid"
file and the version number is 1 for the new ".sid" file. Apart from
that, changes of ".sid" files can also be automated using the same
method described above, only unassigned YANG items are processed at
step #3. Already existing items in the ".sid" file should not be
given new SIDs.
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Note that ".sid" file versions are specific to a YANG module
revision. For each new YANG module or each new revision of an
existing YANG module, the version number of the initial ".sid" file
should either be 0 or should not be present.
Note also that RPC or action "input" and "output" data nodes MUST
always be assigned SID even if they don't contain data nodes. The
reason for this requirement is that other modules can augment the
given module and those SIDs might be necessary.
Appendix C. ".sid" file lifecycle
Before assigning SIDs to their YANG modules, YANG module authors must
acquire a SID range from a "YANG SID Range Registry". If the YANG
module is part of an IETF draft or RFC, the SID range need to be
acquired from the "IETF YANG SID Range Registry" as defined in
Section 7.5. For the other YANG modules, the authors can acquire a
SID range from any "YANG SID Range Registry" of their choice.
Once the SID range is acquired, owners can use it to generate ".sid"
file/s for their YANG module/s. It is recommended to leave some
unallocated SIDs following the allocated range in each ".sid" file in
order to allow better evolution of the YANG module in the future.
Generation of ".sid" files should be performed using an automated
tool. Note that ".sid" files can only be generated for YANG modules
and not for submodules.
C.1. ".sid" File Creation
The following activity diagram summarizes the creation of a YANG
module and its associated ".sid" file.
+---------------+
o | Creation of a |
-+- -->| YANG module |
/ \ +------+--------+
|
v
.-------------.
/ Standardized \ yes
\ YANG module ? /------------+
'-----+-------' |
| no |
v v
.-------------. +---------------+
+--> / Constrained \ yes | SID range |
| \ application ? /---->| registration |<---------+
| '-----+-------' +------+--------+ |
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| | no | |
| v v |
| +---------------+ +---------------+ |
+----+ YANG module | | SID sub-range | |
| update | | assignment |<----------+
+---------------+ +-------+-------+ |
| |
v |
+---------------+ +------+------+
| ".sid" file | | Rework YANG |
| generation | | module |
+-------+-------+ +-------------+
| ^
v |
.----------. yes |
/ Work in \ -----------+
\ progress /
'----+-----'
| no
v
.-------------. .-------------.
/ RFC \ no / Open \ no
\ publication? /---> \ specification?/---+
'------+------' '------+------' |
yes | | yes |
| .------------' |
| / |
v v v
+---------------+ +---------------+
| IANA | | Third party |
| registration | | registration |
+-------+-------+ +---------+-----+
| |
+---------------------------------+
v
[DONE]
Figure 1: SID Lifecycle
C.2. ".sid" File Update
The following Activity diagram summarizes the update of a YANG module
and its associated ".sid" file.
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+---------------+
o | Update of the |
-+- -->| YANG module |
/ \ | or include(s) |
| or import(s) |
+------+--------+
|
v
.-------------.
/ New items \ yes
\ created ? /------+
'------+------' |
| no v
| .-------------. +----------------+
| / SID range \ yes | Extra sub-range|
| \ exhausted ? /---->| assignment |
| '------+------' +-------+--------+
| | no |
| +---------------------+
| |
| v
| +---------------+
| | ".sid" file |
| | update based |
| | on previous |
| | ".sid" file |
| +-------+-------+
| |
| v
| .-------------. +---------------+
| / Publicly \ yes | YANG module |
| \ available ? /---->| registration |
| '------+------' +-------+-------+
| | no |
+--------------+---------------------+
|
[DONE]
Figure 2: YANG and ".sid" file update
Acknowledgments
The authors would like to thank Andy Bierman, Michael Richardson,
Abhinav Somaraju, Peter van der Stok, Laurent Toutain and Randy
Turner for their help during the development of this document and
their useful comments during the review process.
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Contributors
Andy Bierman
YumaWorks
685 Cochran St.
Suite #160
Simi Valley, CA 93065
United States of America
Email: andy@yumaworks.com
Authors' Addresses
Michel Veillette (editor)
Trilliant Networks Inc.
610 Rue du Luxembourg
Granby Quebec J2J 2V2
Canada
Phone: +14503750556
Email: michel.veillette@trilliant.com
Alexander Pelov (editor)
Acklio
1137A avenue des Champs Blancs
35510 Cesson-Sevigne
France
Email: a@ackl.io
Ivaylo Petrov (editor)
Google Switzerland GmbH
Brandschenkestrasse 110
CH-8002 Zurich
Switzerland
Email: ivaylopetrov@google.com
Carsten Bormann
Universität Bremen TZI
Postfach 330440
D-28359 Bremen
Germany
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Phone: +49-421-218-63921
Email: cabo@tzi.org
Michael Richardson
Sandelman Software Works
Email: mcr+ietf@sandelman.ca
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