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draft-ietf-quic-invariants.html
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draft-ietf-quic-invariants.html
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<!DOCTYPE html>
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<title>Version-Independent Properties of QUIC</title>
<meta content="Martin Thomson" name="author">
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This document defines the properties of the QUIC transport protocol that are
expected to remain unchanged over time as new versions of the protocol are
developed.
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<body>
<table class="ears">
<thead><tr>
<td class="left">Internet-Draft</td>
<td class="center">QUIC Invariants</td>
<td class="right">June 2020</td>
</tr></thead>
<tfoot><tr>
<td class="left">Thomson</td>
<td class="center">Expires 10 December 2020</td>
<td class="right">[Page]</td>
</tr></tfoot>
</table>
<div id="external-metadata" class="document-information"></div>
<div id="internal-metadata" class="document-information">
<dl id="identifiers">
<dt class="label-workgroup">Workgroup:</dt>
<dd class="workgroup">QUIC</dd>
<dt class="label-internet-draft">Internet-Draft:</dt>
<dd class="internet-draft">draft-ietf-quic-invariants-latest</dd>
<dt class="label-published">Published:</dt>
<dd class="published">
<time datetime="2020-06-08" class="published">8 June 2020</time>
</dd>
<dt class="label-intended-status">Intended Status:</dt>
<dd class="intended-status">Standards Track</dd>
<dt class="label-expires">Expires:</dt>
<dd class="expires"><time datetime="2020-12-10">10 December 2020</time></dd>
<dt class="label-authors">Author:</dt>
<dd class="authors">
<div class="author">
<div class="author-name">M. Thomson</div>
<div class="org">Mozilla</div>
</div>
</dd>
</dl>
</div>
<h1 id="title">Version-Independent Properties of QUIC</h1>
<section id="section-abstract">
<h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document defines the properties of the QUIC transport protocol that are
expected to remain unchanged over time as new versions of the protocol are
developed.<a href="#section-abstract-1" class="pilcrow">¶</a></p>
</section>
<section class="note" id="section-note.1">
<h2 id="name-note-to-readers">
<a href="#name-note-to-readers" class="section-name selfRef">Note to Readers</a>
</h2>
<p id="section-note.1-1">Discussion of this draft takes place on the QUIC working group mailing list
(<a href="mailto:quic@ietf.org">quic@ietf.org</a>), which is archived at
<span><a href="https://mailarchive.ietf.org/arch/search/?email_list=quic">https://mailarchive.ietf.org/arch/search/?email_list=quic</a></span>.<a href="#section-note.1-1" class="pilcrow">¶</a></p>
<p id="section-note.1-2">Working Group information can be found at <span><a href="https://github.com/quicwg">https://github.com/quicwg</a></span>; source
code and issues list for this draft can be found at
<span><a href="https://github.com/quicwg/base-drafts/labels/-invariants">https://github.com/quicwg/base-drafts/labels/-invariants</a></span>.<a href="#section-note.1-2" class="pilcrow">¶</a></p>
</section>
<div id="status-of-memo">
<section id="section-boilerplate.1">
<h2 id="name-status-of-this-memo">
<a href="#name-status-of-this-memo" class="section-name selfRef">Status of This Memo</a>
</h2>
<p id="section-boilerplate.1-1">
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.<a href="#section-boilerplate.1-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-2">
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 <span><a href="https://datatracker.ietf.org/drafts/current/">https://datatracker.ietf.org/drafts/current/</a></span>.<a href="#section-boilerplate.1-2" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-3">
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."<a href="#section-boilerplate.1-3" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-4">
This Internet-Draft will expire on 10 December 2020.<a href="#section-boilerplate.1-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="copyright">
<section id="section-boilerplate.2">
<h2 id="name-copyright-notice">
<a href="#name-copyright-notice" class="section-name selfRef">Copyright Notice</a>
</h2>
<p id="section-boilerplate.2-1">
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.<a href="#section-boilerplate.2-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.2-2">
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<span><a href="https://trustee.ietf.org/license-info">https://trustee.ietf.org/license-info</a></span>) 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.<a href="#section-boilerplate.2-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="toc">
<section id="section-toc.1">
<a href="#" onclick="scroll(0,0)" class="toplink">▲</a><h2 id="name-table-of-contents">
<a href="#name-table-of-contents" class="section-name selfRef">Table of Contents</a>
</h2>
<nav class="toc"><ul class="toc compact ulEmpty">
<li class="toc compact ulEmpty" id="section-toc.1-1.1">
<p id="section-toc.1-1.1.1" class="keepWithNext"><a href="#section-1" class="xref">1</a>. <a href="#name-introduction" class="xref">Introduction</a><a href="#section-toc.1-1.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.2">
<p id="section-toc.1-1.2.1" class="keepWithNext"><a href="#section-2" class="xref">2</a>. <a href="#name-conventions-and-definitions" class="xref">Conventions and Definitions</a><a href="#section-toc.1-1.2.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.3">
<p id="section-toc.1-1.3.1" class="keepWithNext"><a href="#section-3" class="xref">3</a>. <a href="#name-an-extremely-abstract-descr" class="xref">An Extremely Abstract Description of QUIC</a><a href="#section-toc.1-1.3.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.4">
<p id="section-toc.1-1.4.1"><a href="#section-4" class="xref">4</a>. <a href="#name-notational-conventions" class="xref">Notational Conventions</a><a href="#section-toc.1-1.4.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.5">
<p id="section-toc.1-1.5.1"><a href="#section-5" class="xref">5</a>. <a href="#name-quic-packet-headers" class="xref">QUIC Packet Headers</a><a href="#section-toc.1-1.5.1" class="pilcrow">¶</a></p>
<ul class="toc compact ulEmpty">
<li class="toc compact ulEmpty" id="section-toc.1-1.5.2.1">
<p id="section-toc.1-1.5.2.1.1"><a href="#section-5.1" class="xref">5.1</a>. <a href="#name-long-header" class="xref">Long Header</a><a href="#section-toc.1-1.5.2.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.5.2.2">
<p id="section-toc.1-1.5.2.2.1"><a href="#section-5.2" class="xref">5.2</a>. <a href="#name-short-header" class="xref">Short Header</a><a href="#section-toc.1-1.5.2.2.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.5.2.3">
<p id="section-toc.1-1.5.2.3.1"><a href="#section-5.3" class="xref">5.3</a>. <a href="#name-connection-id" class="xref">Connection ID</a><a href="#section-toc.1-1.5.2.3.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.5.2.4">
<p id="section-toc.1-1.5.2.4.1"><a href="#section-5.4" class="xref">5.4</a>. <a href="#name-version" class="xref">Version</a><a href="#section-toc.1-1.5.2.4.1" class="pilcrow">¶</a></p>
</li>
</ul>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.6">
<p id="section-toc.1-1.6.1"><a href="#section-6" class="xref">6</a>. <a href="#name-version-negotiation" class="xref">Version Negotiation</a><a href="#section-toc.1-1.6.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.7">
<p id="section-toc.1-1.7.1"><a href="#section-7" class="xref">7</a>. <a href="#name-security-and-privacy-consid" class="xref">Security and Privacy Considerations</a><a href="#section-toc.1-1.7.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.8">
<p id="section-toc.1-1.8.1"><a href="#section-8" class="xref">8</a>. <a href="#name-iana-considerations" class="xref">IANA Considerations</a><a href="#section-toc.1-1.8.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.9">
<p id="section-toc.1-1.9.1"><a href="#section-9" class="xref">9</a>. <a href="#name-references" class="xref">References</a><a href="#section-toc.1-1.9.1" class="pilcrow">¶</a></p>
<ul class="toc compact ulEmpty">
<li class="toc compact ulEmpty" id="section-toc.1-1.9.2.1">
<p id="section-toc.1-1.9.2.1.1"><a href="#section-9.1" class="xref">9.1</a>. <a href="#name-normative-references" class="xref">Normative References</a><a href="#section-toc.1-1.9.2.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.9.2.2">
<p id="section-toc.1-1.9.2.2.1"><a href="#section-9.2" class="xref">9.2</a>. <a href="#name-informative-references" class="xref">Informative References</a><a href="#section-toc.1-1.9.2.2.1" class="pilcrow">¶</a></p>
</li>
</ul>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.10">
<p id="section-toc.1-1.10.1"><a href="#section-appendix.a" class="xref">Appendix A</a>. <a href="#name-incorrect-assumptions" class="xref">Incorrect Assumptions</a><a href="#section-toc.1-1.10.1" class="pilcrow">¶</a></p>
</li>
<li class="toc compact ulEmpty" id="section-toc.1-1.11">
<p id="section-toc.1-1.11.1"><a href="#section-appendix.b" class="xref"></a><a href="#name-authors-address" class="xref">Author's Address</a><a href="#section-toc.1-1.11.1" class="pilcrow">¶</a></p>
</li>
</ul>
</nav>
</section>
</div>
<div id="introduction">
<section id="section-1">
<h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
</h2>
<p id="section-1-1">In addition to providing secure, multiplexed transport, QUIC <span>[<a href="#QUIC-TRANSPORT" class="xref">QUIC-TRANSPORT</a>]</span>
includes the ability to negotiate a version. This allows the protocol to change
over time in response to new requirements. Many characteristics of the protocol
will change between versions.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2">This document describes the subset of QUIC that is intended to remain stable as
new versions are developed and deployed. All of these invariants are
IP-version-independent.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3">The primary goal of this document is to ensure that it is possible to deploy new
versions of QUIC. By documenting the properties that can't change, this
document aims to preserve the ability to change any other aspect of the
protocol. Thus, unless specifically described in this document, any aspect of
the protocol can change between different versions.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4"><a href="#bad-assumptions" class="xref">Appendix A</a> is a non-exhaustive list of some incorrect assumptions that
might be made based on knowledge of QUIC version 1; these do not apply to every
version of QUIC.<a href="#section-1-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="conventions-and-definitions">
<section id="section-2">
<h2 id="name-conventions-and-definitions">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-conventions-and-definitions" class="section-name selfRef">Conventions and Definitions</a>
</h2>
<p id="section-2-1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",