| Internet-Draft | Format Framework | February 2024 |
| Hoffman & Flanagan | Expires 23 August 2024 | [Page] |
In order to improve the readability of RFCs while supporting their archivability, the definitive version of the RFC Series transitioned from plain-text ASCII to XML using the RFCXML vocabulary; different publication versions are rendered from that base document. This document is the framework that provides the problem statement, lays out a road map of the documents that capture the specific requirements, and describes how RFCs are published.¶
This document obsoletes RFC 7990 and makes many significant changes to that document. It also updates the stability policy in RFC 9280.¶
This draft is part of the RFC Series Working Group (RSWG); see https://datatracker.ietf.org/edwg/rswg/documents/. There is a repository for this draft at https://github.com/paulehoffman/draft-rswg-rfc7990-updates. Issues can be raised there, but probably should be on the mailing list instead.¶
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/.¶
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This Internet-Draft will expire on 23 August 2024.¶
Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (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.¶
"RFC Series Format Requirements and Future Development" [RFC6949] discussed the need to improve the display of items such as author names and artwork in RFCs as well as the need to improve the ability of RFCs to be displayed properly on various devices. Based on the discussions with communities of interest, such as the IETF, the RFC Series Editor decided to explore a change to the format of the Series. This document serves as the framework that describes the problems that were solved and summarizes the documents created to date that capture the specific requirements for each aspect of the change in format.¶
This document is concerned with the production of RFCs, focusing on the published formats. It does not address any changes to the processes each stream uses to develop and review their submissions (specifically, how Internet-Drafts will be developed). While I-Ds have a similar set of issues and concerns, directly addressing those issues for I-Ds will be discussed within each document stream.¶
The details described in this document are expected to change based on experience gained in implementing the new publication toolsets, just as the details in [RFC7990] changed after publication. Revised documents will be published capturing those changes as the toolsets are completed. Other implementers must not expect those changes to remain backwards compatible with the details described in this document.¶
[RFC7990] defined a framework for how RFCs would be published after that document was published, including new formats and a new "canonical format" for archiving RFCs. It talked about "the XML file" as if there will only be one XML file for an RFC because this was the expectation at the time [RFC7990] was published. It also talked about "publication formats" as the versions of HTML, text, and PDF versions derived from the definitive version.¶
After extensive experience with publishing RFCs in the RFCXML format (defined in [RFC7991], it has been decided that an RFC's XML file can be updated for narrowly limited purposes. This document changes [RFC7990] in significant ways:¶
It changes the phrase "canonical format" to "definitive version" and defines the use of the definitive version in the series.¶
It changes the phrase "publication format" to "publication versions" and defines the use of the publication versions in the series.¶
It changes the phrase "xml2rfc version 3" to "RFCXML".¶
It defines a policy governing how the RFCXML format changes.¶
It updates [RFC7995] and [RFC8153] by changing the requirement from using the PDF/A-3 standard to using the PDF/A standard, and by dropping the requirement that the XML be embedded in the PDF publication version.¶
It defines a policy for when the definitive version of an RFC can be updated and older versions archived.¶
It defines a policy for when the publication versions of an RFC can be updated and older versions archived.¶
It changes the name of the body that publishes RFCs from "RFC Editor" to "RPC", based on [RFC9280]¶
It changes the use of JavaScript in HTML to be fully supported as long as it doesn't change the text¶
Historical text from [RFC7990] such as Section 2 ("Problem Statement"), Section 4 ("Overview of the Decision-Making Process"), and Section 10 ("Transition Plan") are not copied to this document.¶
Section 7.6 of "RFC Editor Model (Version 3)" [RFC9280] says "Once published, RFC Series documents are not changed." Section 2.1 and Section 3 in this document update that policy.¶
The first RFC to be published using the group of RFCs described in [RFC7990] was [RFC8650], published in November 2019. In the time since then, all published RFCs have followed the general plan from [RFC7990].¶
At the highest level, the changes that [RFC7990] made to the RFC format involved breaking away from solely ASCII ([RFC20]) plain text and moving to a definitive version that includes all the information required for rendering a document into a wide variety of publication versions. The RPC became responsible for more than just the plain-text file and the PDF-from-text format created at time of publication; the RPC now creates several different formats in order to meet the diverse requirements of the community.¶
The final XML file produced by the RPC is the definitive version for RFCs; it is the lowest common denominator that holds all the information intended for an RFC. Additonal file formats (HTML, PDF, and plain text) are also published by the RPC. The file formats are described in Section 3 and fully specified in other RFCs.¶
The definitive version produced by the RPC is the version that holds all the information intended for an RFC. The RPC may change the definitive version of an RFC over time, as described in Section 2.1. See [RFC7991] for the complete description of the XMLRFC syntax and semantics.¶
The XML may contain SVG line art, as described in [RFC7996]. That SVG will also appear in the HTML and PDF publication versions.¶
The XML may contain non-ASCII characters, as described in [RFC7997]. These characters will appear in all the publication versions.¶
The XML file will not contain any XMLRFC vocabulary elements or attributes that have been marked deprecated.¶
Authors may submit documents using the xml2rfc v2 vocabulary, but the final publication will be converted to use the XMLRFC vocabulary.¶
The published XML file must contain all information necessary to render a variety of formats; any question about what was intended in the publication will be answered from this file. It is self-contained with all the information known at publication time. For instance, all features that reference externally defined input are expanded. It does not contain src attributes for <artwork> or <sourcecode> elements. It does not contain comments or processing instructions.¶
Historically, the published version of an RFC has been immutable. This document defines a new policy that the RPC is permitted to re-issue an RFC for changes that do not affect the semantics of the RFC. Reasons for such a change include updates to the RFCXML schema, errors discovered in the XML, and changes to the tooling used to generate the publication versions of the definitive XML version of the RFC. The RPC will keep a public record of when it re-issues and RFC, and give a short description of its reasoning for each change. This policy explicitly updates the stability policy from [RFC9280] for the definitive version.¶
It is anticipated that the syntax and semantics in [RFC7991] will be updated. Updates to the RFCXML specification that are applied to existing RFCs should preserve to the greatest extent possible the semantics expressed in the original RFC. The goal of limiting changes only to syntax is to preserve the semantic meaning encoded in the RFC XML document.¶
This policy does not require that updates to RFCXML avoid all risk of introducing semantic changes to existing RFCs. Instead, it only requires that the RSWG carefully consider the potential for semantic changes, take steps to understand the risk of a semantic change (either deliberate or inadvertent), and to limit those risks.¶
Publication version files may be republished as needed. XML format errors, and better design choices, have been discovered by the community since the first RFCs were published using the RFCXML format. As the RFC XML format of a document changes, publication versions can change, even if this might not result in observable differences. Similarly, as production tools change, publication versions can be regenerated to ensure a consistent presentation across the series.¶
Publication versions and the contexts in which they are displayed can optionally provide additional details of the specific RFCXML version that they were generated from, or provide a means to discover alternative renderings.¶
This document defines a new policy that the RPC is permitted to re-issue publication versions of an RFC. This can happen if the definitive version is updated, but can also happen due to other changes, such as updates to the RPC's tooling. This policy explicitly updates the stability policy from [RFC9280] for publication versions.¶
[RFC7992] describes the semantic HTML produced by the RPC from the XMLRFC files. The HTML file is rendered from the XML file; it is not derived from the plain-text publication version. The body of the document uses a subset of HTML.¶
The documents include Cascading Style Sheets (CSS) for default visual presentation; the CSS can be overwritten by a local CSS file. The allowed CSS is described in [RFC7993].¶
JavaScript in the HTML publication version is supported. It is not be permitted to overwrite or change any text present in the rendered HTML. It may add text that provides post-publication metadata or pointers.¶
[RFC7995] describes the different versions of PDF is offered, with a recommendation of what PDF standard should apply to RFCs.¶
The PDF file is rendered from the XML file or from the HTML publication version; it is not derived from the plain-text publication version.¶
The PDF publication version conforms to the PDF standard. The RPC can decide which PDF standard will be supported after consultation with the community.¶
This document updates [RFC7995] and [RFC8153] by changing the requirement from the RPC use PDF/A-3 standard to instead using the PDF/A standard, and by dropping the requirement that the XML be embedded in the PDF publication version. Other parts of [RFC8153], particularly the need to archive metadata about RFCs, are not changed.¶
The PDF looks more like the HTML publication version than the plain-text publication version. The PDF includes a rich set of tags and metadata within the document.¶
[RFC7994] describes the details of the plain-text format; in particular, it focuses on what changed from the earlier plain-text format for publishing RFCs.¶
The plain-text format is UTF-8 encoded, and non-ASCII characters are allowed. A Byte Order Mark (BOM) is added at the start of each plain-text file.¶
The plain-text file is unpaginated. Running headers and footers are not be used in the plain-text file.¶
Authors may choose to have pointers to line art in other publication versions in place of ASCII art in the plain-text file.¶
The RPC will keep archived set of all definitive versions of RFCs as well as archived sets of the publication versions for an RFC that were published. These archived sets must be available using the same access methods as for the XML and the published publication versions. Every archived set shall record the date that a document was created or revised.¶
When the RPC archives documents, it does so in a manner that allows them to be found by people who want the historical (as compared to current) versions of those files.¶
This document does not specify how archives are maintained or how archived RFC XML might be located or identified. The methods for storage and access will be determined by the RPC in consultation with the technical community.¶
Appendix A gives some non-normative advice created by the RSWG.¶
This document has no IANA considerations.¶
Changing the format for RFCs involves modifying a great number of components to publication. Understanding those changes and the implications for the entire tool chain is critical so as to avoid unintended bugs that would allow unintended changes to text. Unintended changes to text could in turn corrupt a standard, practice, or critical piece of information about a protocol.¶
The RSWG is responsible for managing the risk of semantic changes that would affect the interpretation of existing and future RFCs. Changes to content that has security implications would have security-relevant consequences.¶
Martin Thomson wrote a great deal of the significant text here as part of draft-thomson-rswg-syntax-change.¶
This document has greatly benefitted from the input or the RSWG. In particular, Alexis Rossi, Brian Carpenter, Eliot Lear, Jay Daley, John Levine, and Pete Resnick, gave significant input on the early drafts of this document.¶
This document does not include specific guidance regarding the generation of publication versions from the RFCXML source for the definitive version of an RFC. Decisions about how to maintain publication versions are not a matter governed by policy as specified in [RFC9280]. This appendix contains advice and considerations for the process of regeneration that came out of discussions of the policy changes in this document.¶
Changes to the RFCXML for existing RFCs might result in changes to the documents rendered from that XML. At the same time, the tools used to generate renderings are under active maintenance. Making it possible for a fresh rendering to replace existing publication versions is a goal supported by the policy changes in this document.¶
This creates a risk that a rerendered documents change in unexpected ways when they are regenerated. This risk of unintentional change can be managed by implementing validation processes:¶
Tools can be continuously checked by producing renderings for existing RFCs. Any change in the rendered document can then be compared with previous outputs and validated. This will ensure that changes in tooling are deliberate and understood.¶
When a change to the XML format occurs, rendered documents can be regenerated and any change in the rendering can be validated.¶
Validation should be aided by automated tooling that is able to disregard inconsequential changes in renderings, like changes in timestamps and other annotations. Validation of tooling can be continuous, for which automation is essential.¶
The decision to make renderings available as the publication versions for an RFC is a decision that can be made on a case-by-case basis. Making fresh renderings available more often could mean a greater risk that people seeking to read RFCs will obtain a copy that contains accidental errors. However, errors in publication versions might persist if they are not replaced as tool quality and reliability improves.¶
Old copies of replaced publication versions will be retained to provide the ability to isolate changes and understand the evolution of documents.¶