Internet DRAFT - draft-kuehlewind-update-tag
draft-kuehlewind-update-tag
Network Working Group M. Kuehlewind
Internet-Draft Ericsson
Intended status: Best Current Practice S. Krishnan
Expires: 13 January 2022 Kaloom
12 July 2021
Definition of new tags for relations between RFCs
draft-kuehlewind-update-tag-04
Abstract
An RFC can include a tag called "Updates" which can be used to link a
new RFC to an existing RFC. On publication of such an RFC, the
existing RFC will include an additional metadata tag called "Updated
by" which provides a link to the new RFC. However, this tag pair is
not well-defined and therefore it is currently used for multiple
different purposes, which leads to confusion about the actual meaning
of this tag and inconsistency in its use.
This document recommends the discontinuation of the use of the
updates/updated by tag pair, and instead proposes three new tag pairs
that have well-defined meanings and use cases.
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
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This Internet-Draft will expire on 13 January 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. New Definitions . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Cross-stream use and maturity levels . . . . . . . . . . 5
4. Additional Recommendations . . . . . . . . . . . . . . . . . 5
4.1. Discontinuation of the Use of Updates/Updated by . . . . 5
4.2. Formatting Style of Amendments . . . . . . . . . . . . . 6
4.3. Indication of Linkage in the Abstract and Introduction . 6
5. Future work . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Alternative Approaches . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
An RFC can include a tag called "Updates" which can be used to link a
new RFC to an existing RFC. On publication of such an RFC, the
existing RFC will include an additional metadata tag called "Updated
by" which provides a link to the new RFC. However, this tag pair is
not well-defined and therefore it is currently used for multiple
different purposes, which leads to confusion about the actual meaning
of this tag and inconsistency in its use.
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The "Updates/Updates by" tag pair is currently used consistently as
different working groups or areas tend to apply different meanings to
it. Opinions also differ greatly about the obligations on
implementors for the updated RFC. While updating an RFC never makes
the updated RFC invalid, updates can contain bug fixes or critical
changes. Some groups apply the update tag only to these kind of
changes with the expectation that new implementations are also
obliged to implement the new updating RFC. Some other groups use the
update tag to define optional extensions or new uses of extension
points in the current protocol. This disconnect leads to a situation
where it is desirable to add a "mandatory-to-implement" indication to
an existing RFC.
Groups or individuals that apply such restrictive conditions to the
Updates tag, consequently usually do not use the update tag for any
extensions or addition to a protocol. However, as there is no other
way in the current metadata scheme to link a new RFC to an existing
RFC, not using the Updates tag makes it harder to find these new
RFCs. While implementors might well benefit from some extensions or
additions, they might not be aware of them and either not use them
or, in the worst case, implement an alternate mechanism instead.
Currently the Updates/Updated by tag pair mainly provides a way to
link two documents. The cases mentioned above clearly benefit from
such a linkage which the expectation that readers of updated RFC as
least look or also read the updating RFC. Additionally, there are
more cases where such a linkage could be useful to improve awareness
of some newer related technology without providing any indication on
the importance of the linked document. As the conditions for the use
of the Updates tag are not clear, often it is not used in such cases.
This document recommends the discontinuation of the use of the
Updates/Updated by tag pair, and instead proposes three new tag pairs
that have well-defined meanings and use cases.
2. Requirements Language
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.
3. New Definitions
Based on the problems identified above this document defines three
new tag pairs with the following meanings:
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Amends/Amended by: This tag pair is used with an amending RFC that
changes the amended RFC. This could include bug fixes, behavior
changes etc. This is intended to specify mandatory changes to the
protocol. The goal of this tag pair is to signal to anyone looking
to implement the amended RFC that they MUST also implement the
amending RFC.
Extends/Extended by: This tag pair is used with an extending RFC that
defines an optional addition to the extended RFC. This can be used
by documents that use existing extension points or clarifications
that do not change existing protocol behavior. This signals to
implementers and protocol designers that there are changes to the
extended RFC that they need to consider but not necessarily
implement.
See Also/See Also: This is intended as a catch-all tag where two
documents are related loosely but do not fit either of the above
categories. The main intention of this tag is to provide a forward
reference from the existing RFC to the RFCs that may be of interest
to read. However, it is not recommenced to use this tag extensively.
These three tags MUST only be used for the defined meanings, mostly
with respect to the implication on implementation requirements. This
document does not mandate the use of these tags if one of the
described use cases apply. Tags are optional metadata that are
useful to understand the context of RFCs and navigate the RFC series.
All three tags can only be used to reference other RFCs (and not as
reference to external sources).
If a new RFC amends an old RFC while also defining an extension,
usually it is sufficient to use the "Amends" tag. However, both tags
could be used as well. In any case, it is more important to explain
clearly in the abstract what is amended/extended by the new RFC (see
section Section 4.3).
As today with "updates", none of the new tags makes the extended/
amended RFC invalid. An implementation that conforms to the amended
RFC still conforms to that RFC, even when an amendment is published.
However, an implementation can, and hopefully should, of course be
updated to also conform to the new RFC with the amendment. If only
conformance to the new RFC is desired, obsoleting the respective RFC
with a new full (bis) specification may be more appropriate and
should be consider instead.
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3.1. Cross-stream use and maturity levels
This document does not impose any restrictions on the status or
maturity level of the RFC that uses these new tags in relation the
RFC that gets amended/extended. Further, no restrictions are made on
the use of these tags across RFC streams.
However, it is expected that some cases are less likely, e.g. an
IETF-stream RFC gets amended by an RFC from another stream. For
amendments that effectively change the originally RFC is is expected
that the same consensus process is applied. This document does not
specify any detailed process requirements on how this is achieved.
Examples exist where non IETF-stream documents update IETF-stream
documents. However, these updates usually utilise an existing
extension point and therefore the use of "Extends" would be expected
in future, e.g. RFC 3579 (RADIUS Support For EAP) which is a
document in the Independent Submission Stream updates RFC 2869
(RADIUS Extensions), an IETF stream document. In fact, this new,
more clear definition of tags could even lead to an increase in cross
stream usage of the "Extends" tag (if adopted by other streams, which
is still open for discussion and may be reflected in future versions
of this document).
4. Additional Recommendations
4.1. Discontinuation of the Use of Updates/Updated by
[NOTE: This is open for discussion and we would like opinions on
whether the use of Updates needs to be discontinued for all future
documents or not. This requires further discussion with the RFC
Editor and the other stream managers to see if we can have a unified
policy for all streams]
This document makes the updates tag obsolete for future use: it MUST
NOT be used in new IETF stream documents. The new tags are to be
used instead, beginning with the publication of this document as an
RFC.
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However, the Updates/Updated by tag pair will remain in existing
documents and there is no plans to change these metadata in order to
apply the new tags instead. While it would be possible to change the
"Updated by" tag in the metadata without republishing the updating
RFC, the mapping to either "Amended by", "Extended by", or "See also"
is not always straight forward and as such would require building
consensus for each RFC separately. Further, simply replacing the tag
would in any way not be sufficient, as also RFCs that currently do
not have an updates tag would probably qualify to have one of the new
tags defined in this document.
4.2. Formatting Style of Amendments
This document does not impose any requirements on the form of the
amendment made. Some RFCs use and OLD/NEW style to highlight actual
text changes others simply describe the changes in text. Both can
make sense in certain situation. However, this document does
recommend to use the OLD/NEW rather for smaller and a limited number
of changes, while if larger or many changes are needed, a new
document revision that obsoletes the old RFC should be considered.
4.3. Indication of Linkage in the Abstract and Introduction
The RFC style guide [RFC7322] recommends to indicate updates in the
abstract and introduction. Note that both is needed as the abstract
is meant to function in a stand-alone fashion. This document will
keep this practice for the new Amends/Amended by and Extends/Extended
by tag pairs as well. It is further recommended to provide
additional information about the extension in the abstract or
introduction for the Extends/Extended by tag pair in order to provide
the reader some assistance whether he or she also needs to read the
rest of extending RFC.
For the See Also/See Also tag pair, additional information of the
linked RFC may be added in the introduction but there is no
expectation to name these RFC in the abstract.
5. Future work
There will be a need to update the RFC Style Guide [RFC7322] (and
specifically Section 4.1.4.) in order to discuss the new tags if and
when this document is published.
Further, the "updates" attribute is part of the "xml2rfc" Version 3
Vocabulary [RFC7991]. Therefore an extension to [RFC7991] is need as
well. This may be done by a future version of this draft or in a
separate draft, e.g. with other extension or amendments to [RFC7991].
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6. Alternative Approaches
This document proposes three new meta data tag pairs to address the
problem that the use of the "Updates" tag is currently undefined
which causes confusion due to various different practices applied in
different group and after all a waste of time in recurring discussion
about using or not using the tag.
Alternatively, in order to solely solve the problem of avoiding
unnecessary discussion time, it would also be possible to document
that the "Updates" tag is undefined and as such there are no strict
rules about applying it or any implications of using it. This was
proposed by the IESG providing an IESG statement for community
discussion and lead to community feedback indicating that this
solution is not preferred.
However, rather than defining three new tags, one could also just
clearly define the meaning of the existing update tag. Still, this
could also be confusing as it would not apply to RFCs that are
already published. So re-naming and defining one tags, instead of
three, would be an alternative. This one tag could either cover all
three usages that are described in this draft or only one (probably
the one as defined by the proposed "Amends" tag, as this is usually
seen as the most important one).
This draft proposes three tags as those tags are considered to cover
most of the usages that we see today for the "Updates" tag, assuming
that these cases are benefiting from a forward reference of an
already published RFC to a new RFC. Especially separating changes to
an existing RFC, as often done by use of the OLD/NEW notation, from
extension/additions to an RFC is one of the main confusion and
discussion points and therefore this draft proposes different tags
for it. However, if it is observed that not all proposed tags are
actively used in future, or their usage is still not sufficiently
clear, it should be considered to deprecate the unused tags and
therefore restrict forward references to only some of the identified
usages.
7. Security Considerations
The changes in this document do not have directly impact the security
of any protocol or mechanism specified in the RFC series. However,
amendments or extensions can help to improve security or discuss
security-related issues. Therefore, the use of the proposed tags and
their clear definition can also support such RFCs in their intended
goals regarding security.
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If a document is amended, it is expected that the same consensus
process is used as for the original document as an amended can be see
as an actual change of the original document. For extension points
usually the originally specification also defines requirement for an
extension mechanism to be used, e.g. in form of policy for IANA
registries. Of course, the requirement must be considered when
extending a protocol.
There is a risk that this experiment fails by either not seeing
adoption from the community or not addressing the discussed problems
sufficiently (ambiguity of use, implications for implementations).
However, it is not expected that the proposed tags will make these
problem worse. In the worst case, if the experiment is decided to be
reverted in future and the Updates tag should be used instead again,
this will likely not make the situation worse or more confusing than
it already is either. Maybe this effort is than seen as a waste of
time but the same recurring discussions about using or not using the
Updates tag (especially during IESG review but also before that in
the working group discussion) are a waste of time as well.
8. Acknowledgments
The authors would like to thank Alexey Melnikov, Alvaro Retana, Barry
Leiba, Eric Vyncke, Heather Flanagan, Martin Vigoureux, Brian
Carpenter and Sandy Ginoza for their reviews and comments that
improved this document.
9. References
9.1. 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>.
[RFC7322] Flanagan, H. and S. Ginoza, "RFC Style Guide", RFC 7322,
DOI 10.17487/RFC7322, September 2014,
<https://www.rfc-editor.org/info/rfc7322>.
[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>.
9.2. Informative References
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[RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",
RFC 7991, DOI 10.17487/RFC7991, December 2016,
<https://www.rfc-editor.org/info/rfc7991>.
Authors' Addresses
Mirja Kuehlewind
Ericsson
Email: mirja.kuehlewind@ericsson.com
Suresh Krishnan
Kaloom
Email: Suresh@kaloom.com
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