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draft-ietf-quic-transport.html
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<title>QUIC: A UDP-Based Multiplexed and Secure Transport</title>
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<meta name="viewport" content="initial-scale=1.0">
<link href="#rfc.toc" rel="Contents">
<link href="#rfc.section.1" rel="Chapter" title="1 Introduction">
<link href="#rfc.section.1.1" rel="Chapter" title="1.1 Document Structure">
<link href="#rfc.section.1.2" rel="Chapter" title="1.2 Terms and Definitions">
<link href="#rfc.section.1.3" rel="Chapter" title="1.3 Notational Conventions">
<link href="#rfc.section.2" rel="Chapter" title="2 Streams">
<link href="#rfc.section.2.1" rel="Chapter" title="2.1 Stream Types and Identifiers">
<link href="#rfc.section.2.2" rel="Chapter" title="2.2 Sending and Receiving Data">
<link href="#rfc.section.2.3" rel="Chapter" title="2.3 Stream Prioritization">
<link href="#rfc.section.3" rel="Chapter" title="3 Stream States">
<link href="#rfc.section.3.1" rel="Chapter" title="3.1 Sending Stream States">
<link href="#rfc.section.3.2" rel="Chapter" title="3.2 Receiving Stream States">
<link href="#rfc.section.3.3" rel="Chapter" title="3.3 Permitted Frame Types">
<link href="#rfc.section.3.4" rel="Chapter" title="3.4 Bidirectional Stream States">
<link href="#rfc.section.3.5" rel="Chapter" title="3.5 Solicited State Transitions">
<link href="#rfc.section.4" rel="Chapter" title="4 Flow Control">
<link href="#rfc.section.4.1" rel="Chapter" title="4.1 Data Flow Control">
<link href="#rfc.section.4.2" rel="Chapter" title="4.2 Flow Credit Increments">
<link href="#rfc.section.4.3" rel="Chapter" title="4.3 Handling Stream Cancellation">
<link href="#rfc.section.4.4" rel="Chapter" title="4.4 Stream Final Size">
<link href="#rfc.section.4.5" rel="Chapter" title="4.5 Controlling Concurrency">
<link href="#rfc.section.5" rel="Chapter" title="5 Connections">
<link href="#rfc.section.5.1" rel="Chapter" title="5.1 Connection ID">
<link href="#rfc.section.5.1.1" rel="Chapter" title="5.1.1 Issuing Connection IDs">
<link href="#rfc.section.5.1.2" rel="Chapter" title="5.1.2 Consuming and Retiring Connection IDs">
<link href="#rfc.section.5.2" rel="Chapter" title="5.2 Matching Packets to Connections">
<link href="#rfc.section.5.2.1" rel="Chapter" title="5.2.1 Client Packet Handling">
<link href="#rfc.section.5.2.2" rel="Chapter" title="5.2.2 Server Packet Handling">
<link href="#rfc.section.5.3" rel="Chapter" title="5.3 Life of a QUIC Connection">
<link href="#rfc.section.6" rel="Chapter" title="6 Version Negotiation">
<link href="#rfc.section.6.1" rel="Chapter" title="6.1 Sending Version Negotiation Packets">
<link href="#rfc.section.6.2" rel="Chapter" title="6.2 Handling Version Negotiation Packets">
<link href="#rfc.section.6.2.1" rel="Chapter" title="6.2.1 Version Negotiation Between Draft Versions">
<link href="#rfc.section.6.3" rel="Chapter" title="6.3 Using Reserved Versions">
<link href="#rfc.section.7" rel="Chapter" title="7 Cryptographic and Transport Handshake">
<link href="#rfc.section.7.1" rel="Chapter" title="7.1 Example Handshake Flows">
<link href="#rfc.section.7.2" rel="Chapter" title="7.2 Negotiating Connection IDs">
<link href="#rfc.section.7.3" rel="Chapter" title="7.3 Transport Parameters">
<link href="#rfc.section.7.3.1" rel="Chapter" title="7.3.1 Values of Transport Parameters for 0-RTT">
<link href="#rfc.section.7.3.2" rel="Chapter" title="7.3.2 New Transport Parameters">
<link href="#rfc.section.7.4" rel="Chapter" title="7.4 Cryptographic Message Buffering">
<link href="#rfc.section.8" rel="Chapter" title="8 Address Validation">
<link href="#rfc.section.8.1" rel="Chapter" title="8.1 Address Validation During Connection Establishment">
<link href="#rfc.section.8.1.1" rel="Chapter" title="8.1.1 Address Validation using Retry Packets">
<link href="#rfc.section.8.1.2" rel="Chapter" title="8.1.2 Address Validation for Future Connections">
<link href="#rfc.section.8.1.3" rel="Chapter" title="8.1.3 Address Validation Token Integrity">
<link href="#rfc.section.8.2" rel="Chapter" title="8.2 Path Validation">
<link href="#rfc.section.8.3" rel="Chapter" title="8.3 Initiating Path Validation">
<link href="#rfc.section.8.4" rel="Chapter" title="8.4 Path Validation Responses">
<link href="#rfc.section.8.5" rel="Chapter" title="8.5 Successful Path Validation">
<link href="#rfc.section.8.6" rel="Chapter" title="8.6 Failed Path Validation">
<link href="#rfc.section.9" rel="Chapter" title="9 Connection Migration">
<link href="#rfc.section.9.1" rel="Chapter" title="9.1 Probing a New Path">
<link href="#rfc.section.9.2" rel="Chapter" title="9.2 Initiating Connection Migration">
<link href="#rfc.section.9.3" rel="Chapter" title="9.3 Responding to Connection Migration">
<link href="#rfc.section.9.3.1" rel="Chapter" title="9.3.1 Peer Address Spoofing">
<link href="#rfc.section.9.3.2" rel="Chapter" title="9.3.2 On-Path Address Spoofing">
<link href="#rfc.section.9.3.3" rel="Chapter" title="9.3.3 Off-Path Packet Forwarding">
<link href="#rfc.section.9.4" rel="Chapter" title="9.4 Loss Detection and Congestion Control">
<link href="#rfc.section.9.5" rel="Chapter" title="9.5 Privacy Implications of Connection Migration">
<link href="#rfc.section.9.6" rel="Chapter" title="9.6 Server’s Preferred Address">
<link href="#rfc.section.9.6.1" rel="Chapter" title="9.6.1 Communicating A Preferred Address">
<link href="#rfc.section.9.6.2" rel="Chapter" title="9.6.2 Responding to Connection Migration">
<link href="#rfc.section.9.6.3" rel="Chapter" title="9.6.3 Interaction of Client Migration and Preferred Address">
<link href="#rfc.section.9.7" rel="Chapter" title="9.7 Use of IPv6 Flow-Label and Migration">
<link href="#rfc.section.10" rel="Chapter" title="10 Connection Termination">
<link href="#rfc.section.10.1" rel="Chapter" title="10.1 Closing and Draining Connection States">
<link href="#rfc.section.10.2" rel="Chapter" title="10.2 Idle Timeout">
<link href="#rfc.section.10.3" rel="Chapter" title="10.3 Immediate Close">
<link href="#rfc.section.10.4" rel="Chapter" title="10.4 Stateless Reset">
<link href="#rfc.section.10.4.1" rel="Chapter" title="10.4.1 Detecting a Stateless Reset">
<link href="#rfc.section.10.4.2" rel="Chapter" title="10.4.2 Calculating a Stateless Reset Token">
<link href="#rfc.section.10.4.3" rel="Chapter" title="10.4.3 Looping">
<link href="#rfc.section.11" rel="Chapter" title="11 Error Handling">
<link href="#rfc.section.11.1" rel="Chapter" title="11.1 Connection Errors">
<link href="#rfc.section.11.2" rel="Chapter" title="11.2 Stream Errors">
<link href="#rfc.section.12" rel="Chapter" title="12 Packets and Frames">
<link href="#rfc.section.12.1" rel="Chapter" title="12.1 Protected Packets">
<link href="#rfc.section.12.2" rel="Chapter" title="12.2 Coalescing Packets">
<link href="#rfc.section.12.3" rel="Chapter" title="12.3 Packet Numbers">
<link href="#rfc.section.12.4" rel="Chapter" title="12.4 Frames and Frame Types">
<link href="#rfc.section.13" rel="Chapter" title="13 Packetization and Reliability">
<link href="#rfc.section.13.1" rel="Chapter" title="13.1 Packet Processing and Acknowledgment">
<link href="#rfc.section.13.1.1" rel="Chapter" title="13.1.1 Sending ACK Frames">
<link href="#rfc.section.13.1.2" rel="Chapter" title="13.1.2 ACK Frames and Packet Protection">
<link href="#rfc.section.13.2" rel="Chapter" title="13.2 Retransmission of Information">
<link href="#rfc.section.13.3" rel="Chapter" title="13.3 Explicit Congestion Notification">
<link href="#rfc.section.13.3.1" rel="Chapter" title="13.3.1 ECN Counts">
<link href="#rfc.section.13.3.2" rel="Chapter" title="13.3.2 ECN Verification">
<link href="#rfc.section.14" rel="Chapter" title="14 Packet Size">
<link href="#rfc.section.14.1" rel="Chapter" title="14.1 Path Maximum Transmission Unit (PMTU)">
<link href="#rfc.section.14.2" rel="Chapter" title="14.2 ICMP Packet Too Big Messages">
<link href="#rfc.section.14.3" rel="Chapter" title="14.3 Datagram Packetization Layer PMTU Discovery">
<link href="#rfc.section.14.3.1" rel="Chapter" title="14.3.1 PMTU Probes Containing Source Connection ID">
<link href="#rfc.section.15" rel="Chapter" title="15 Versions">
<link href="#rfc.section.16" rel="Chapter" title="16 Variable-Length Integer Encoding">
<link href="#rfc.section.17" rel="Chapter" title="17 Packet Formats">
<link href="#rfc.section.17.1" rel="Chapter" title="17.1 Packet Number Encoding and Decoding">
<link href="#rfc.section.17.2" rel="Chapter" title="17.2 Long Header Packets">
<link href="#rfc.section.17.2.1" rel="Chapter" title="17.2.1 Version Negotiation Packet">
<link href="#rfc.section.17.2.2" rel="Chapter" title="17.2.2 Initial Packet">
<link href="#rfc.section.17.2.3" rel="Chapter" title="17.2.3 0-RTT">
<link href="#rfc.section.17.2.4" rel="Chapter" title="17.2.4 Handshake Packet">
<link href="#rfc.section.17.2.5" rel="Chapter" title="17.2.5 Retry Packet">
<link href="#rfc.section.17.3" rel="Chapter" title="17.3 Short Header Packets">
<link href="#rfc.section.17.3.1" rel="Chapter" title="17.3.1 Latency Spin Bit">
<link href="#rfc.section.18" rel="Chapter" title="18 Transport Parameter Encoding">
<link href="#rfc.section.18.1" rel="Chapter" title="18.1 Transport Parameter Definitions">
<link href="#rfc.section.19" rel="Chapter" title="19 Frame Types and Formats">
<link href="#rfc.section.19.1" rel="Chapter" title="19.1 PADDING Frame">
<link href="#rfc.section.19.2" rel="Chapter" title="19.2 PING Frame">
<link href="#rfc.section.19.3" rel="Chapter" title="19.3 ACK Frames">
<link href="#rfc.section.19.3.1" rel="Chapter" title="19.3.1 ACK Ranges">
<link href="#rfc.section.19.3.2" rel="Chapter" title="19.3.2 ECN Counts">
<link href="#rfc.section.19.4" rel="Chapter" title="19.4 RESET_STREAM Frame">
<link href="#rfc.section.19.5" rel="Chapter" title="19.5 STOP_SENDING Frame">
<link href="#rfc.section.19.6" rel="Chapter" title="19.6 CRYPTO Frame">
<link href="#rfc.section.19.7" rel="Chapter" title="19.7 NEW_TOKEN Frame">
<link href="#rfc.section.19.8" rel="Chapter" title="19.8 STREAM Frames">
<link href="#rfc.section.19.9" rel="Chapter" title="19.9 MAX_DATA Frame">
<link href="#rfc.section.19.10" rel="Chapter" title="19.10 MAX_STREAM_DATA Frame">
<link href="#rfc.section.19.11" rel="Chapter" title="19.11 MAX_STREAMS Frames">
<link href="#rfc.section.19.12" rel="Chapter" title="19.12 DATA_BLOCKED Frame">
<link href="#rfc.section.19.13" rel="Chapter" title="19.13 STREAM_DATA_BLOCKED Frame">
<link href="#rfc.section.19.14" rel="Chapter" title="19.14 STREAMS_BLOCKED Frames">
<link href="#rfc.section.19.15" rel="Chapter" title="19.15 NEW_CONNECTION_ID Frame">
<link href="#rfc.section.19.16" rel="Chapter" title="19.16 RETIRE_CONNECTION_ID Frame">
<link href="#rfc.section.19.17" rel="Chapter" title="19.17 PATH_CHALLENGE Frame">
<link href="#rfc.section.19.18" rel="Chapter" title="19.18 PATH_RESPONSE Frame">
<link href="#rfc.section.19.19" rel="Chapter" title="19.19 CONNECTION_CLOSE Frames">
<link href="#rfc.section.19.20" rel="Chapter" title="19.20 Extension Frames">
<link href="#rfc.section.20" rel="Chapter" title="20 Transport Error Codes">
<link href="#rfc.section.20.1" rel="Chapter" title="20.1 Application Protocol Error Codes">
<link href="#rfc.section.21" rel="Chapter" title="21 Security Considerations">
<link href="#rfc.section.21.1" rel="Chapter" title="21.1 Handshake Denial of Service">
<link href="#rfc.section.21.2" rel="Chapter" title="21.2 Amplification Attack">
<link href="#rfc.section.21.3" rel="Chapter" title="21.3 Optimistic ACK Attack">
<link href="#rfc.section.21.4" rel="Chapter" title="21.4 Slowloris Attacks">
<link href="#rfc.section.21.5" rel="Chapter" title="21.5 Stream Fragmentation and Reassembly Attacks">
<link href="#rfc.section.21.6" rel="Chapter" title="21.6 Stream Commitment Attack">
<link href="#rfc.section.21.7" rel="Chapter" title="21.7 Explicit Congestion Notification Attacks">
<link href="#rfc.section.21.8" rel="Chapter" title="21.8 Stateless Reset Oracle">
<link href="#rfc.section.21.9" rel="Chapter" title="21.9 Version Downgrade">
<link href="#rfc.section.21.10" rel="Chapter" title="21.10 Targeted Attacks by Routing">
<link href="#rfc.section.22" rel="Chapter" title="22 IANA Considerations">
<link href="#rfc.section.22.1" rel="Chapter" title="22.1 QUIC Transport Parameter Registry">
<link href="#rfc.section.22.2" rel="Chapter" title="22.2 QUIC Frame Type Registry">
<link href="#rfc.section.22.3" rel="Chapter" title="22.3 QUIC Transport Error Codes Registry">
<link href="#rfc.references" rel="Chapter" title="23 References">
<link href="#rfc.references.1" rel="Chapter" title="23.1 Normative References">
<link href="#rfc.references.2" rel="Chapter" title="23.2 Informative References">
<link href="#rfc.appendix.A" rel="Chapter" title="A Sample Packet Number Decoding Algorithm">
<link href="#rfc.appendix.B" rel="Chapter" title="B Change Log">
<link href="#rfc.appendix.B.1" rel="Chapter" title="B.1 Since draft-ietf-quic-transport-19">
<link href="#rfc.appendix.B.2" rel="Chapter" title="B.2 Since draft-ietf-quic-transport-18">
<link href="#rfc.appendix.B.3" rel="Chapter" title="B.3 Since draft-ietf-quic-transport-17">
<link href="#rfc.appendix.B.4" rel="Chapter" title="B.4 Since draft-ietf-quic-transport-16">
<link href="#rfc.appendix.B.5" rel="Chapter" title="B.5 Since draft-ietf-quic-transport-15">
<link href="#rfc.appendix.B.6" rel="Chapter" title="B.6 Since draft-ietf-quic-transport-14">
<link href="#rfc.appendix.B.7" rel="Chapter" title="B.7 Since draft-ietf-quic-transport-13">
<link href="#rfc.appendix.B.8" rel="Chapter" title="B.8 Since draft-ietf-quic-transport-12">
<link href="#rfc.appendix.B.9" rel="Chapter" title="B.9 Since draft-ietf-quic-transport-11">
<link href="#rfc.appendix.B.10" rel="Chapter" title="B.10 Since draft-ietf-quic-transport-10">
<link href="#rfc.appendix.B.11" rel="Chapter" title="B.11 Since draft-ietf-quic-transport-09">
<link href="#rfc.appendix.B.12" rel="Chapter" title="B.12 Since draft-ietf-quic-transport-08">
<link href="#rfc.appendix.B.13" rel="Chapter" title="B.13 Since draft-ietf-quic-transport-07">
<link href="#rfc.appendix.B.14" rel="Chapter" title="B.14 Since draft-ietf-quic-transport-06">
<link href="#rfc.appendix.B.15" rel="Chapter" title="B.15 Since draft-ietf-quic-transport-05">
<link href="#rfc.appendix.B.16" rel="Chapter" title="B.16 Since draft-ietf-quic-transport-04">
<link href="#rfc.appendix.B.17" rel="Chapter" title="B.17 Since draft-ietf-quic-transport-03">
<link href="#rfc.appendix.B.18" rel="Chapter" title="B.18 Since draft-ietf-quic-transport-02">
<link href="#rfc.appendix.B.19" rel="Chapter" title="B.19 Since draft-ietf-quic-transport-01">
<link href="#rfc.appendix.B.20" rel="Chapter" title="B.20 Since draft-ietf-quic-transport-00">
<link href="#rfc.appendix.B.21" rel="Chapter" title="B.21 Since draft-hamilton-quic-transport-protocol-01">
<link href="#rfc.acknowledgments" rel="Chapter">
<link href="#rfc.contributors" rel="Chapter">
<link href="#rfc.authors" rel="Chapter">
<meta name="generator" content="xml2rfc version 2.22.2 - https://tools.ietf.org/tools/xml2rfc" />
<link rel="schema.dct" href="http://purl.org/dc/terms/" />
<meta name="dct.creator" content="Iyengar, J., Ed. and M. Thomson, Ed." />
<meta name="dct.identifier" content="urn:ietf:id:draft-ietf-quic-transport-latest" />
<meta name="dct.issued" scheme="ISO8601" content="2019-06-24" />
<meta name="dct.abstract" content="This document defines the core of the QUIC transport protocol. Accompanying documents describe QUIC’s loss detection and congestion control and the use of TLS for key negotiation." />
<meta name="description" content="This document defines the core of the QUIC transport protocol. Accompanying documents describe QUIC’s loss detection and congestion control and the use of TLS for key negotiation." />
</head>
<body>
<table class="header">
<tbody>
<tr>
<td class="left">QUIC</td>
<td class="right">J. Iyengar, Ed.</td>
</tr>
<tr>
<td class="left">Internet-Draft</td>
<td class="right">Fastly</td>
</tr>
<tr>
<td class="left">Intended status: Standards Track</td>
<td class="right">M. Thomson, Ed.</td>
</tr>
<tr>
<td class="left">Expires: December 26, 2019</td>
<td class="right">Mozilla</td>
</tr>
<tr>
<td class="left"></td>
<td class="right">June 24, 2019</td>
</tr>
</tbody>
</table>
<p class="title">QUIC: A UDP-Based Multiplexed and Secure Transport<br />
<span class="filename">draft-ietf-quic-transport-latest</span></p>
<h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1>
<p>This document defines the core of the QUIC transport protocol. Accompanying documents describe QUIC’s loss detection and congestion control and the use of TLS for key negotiation.</p>
<h1><a>Note to Readers</a></h1>
<p>Discussion of this draft takes place on the QUIC working group mailing list (quic@ietf.org), which is archived at <https://mailarchive.ietf.org/arch/search/?email_list=quic>.</p>
<p>Working Group information can be found at <https://github.com/quicwg>; source code and issues list for this draft can be found at <https://github.com/quicwg/base-drafts/labels/-transport>.</p>
<h1 id="rfc.status"><a href="#rfc.status">Status of This Memo</a></h1>
<p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
<p>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/.</p>
<p>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."</p>
<p>This Internet-Draft will expire on December 26, 2019.</p>
<h1 id="rfc.copyrightnotice"><a href="#rfc.copyrightnotice">Copyright Notice</a></h1>
<p>Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
<p>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.</p>
<hr class="noprint" />
<h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
<ul class="toc">
<li>1. <a href="#rfc.section.1">Introduction</a>
</li>
<ul><li>1.1. <a href="#rfc.section.1.1">Document Structure</a>
</li>
<li>1.2. <a href="#rfc.section.1.2">Terms and Definitions</a>
</li>
<li>1.3. <a href="#rfc.section.1.3">Notational Conventions</a>
</li>
</ul><li>2. <a href="#rfc.section.2">Streams</a>
</li>
<ul><li>2.1. <a href="#rfc.section.2.1">Stream Types and Identifiers</a>
</li>
<li>2.2. <a href="#rfc.section.2.2">Sending and Receiving Data</a>
</li>
<li>2.3. <a href="#rfc.section.2.3">Stream Prioritization</a>
</li>
</ul><li>3. <a href="#rfc.section.3">Stream States</a>
</li>
<ul><li>3.1. <a href="#rfc.section.3.1">Sending Stream States</a>
</li>
<li>3.2. <a href="#rfc.section.3.2">Receiving Stream States</a>
</li>
<li>3.3. <a href="#rfc.section.3.3">Permitted Frame Types</a>
</li>
<li>3.4. <a href="#rfc.section.3.4">Bidirectional Stream States</a>
</li>
<li>3.5. <a href="#rfc.section.3.5">Solicited State Transitions</a>
</li>
</ul><li>4. <a href="#rfc.section.4">Flow Control</a>
</li>
<ul><li>4.1. <a href="#rfc.section.4.1">Data Flow Control</a>
</li>
<li>4.2. <a href="#rfc.section.4.2">Flow Credit Increments</a>
</li>
<li>4.3. <a href="#rfc.section.4.3">Handling Stream Cancellation</a>
</li>
<li>4.4. <a href="#rfc.section.4.4">Stream Final Size</a>
</li>
<li>4.5. <a href="#rfc.section.4.5">Controlling Concurrency</a>
</li>
</ul><li>5. <a href="#rfc.section.5">Connections</a>
</li>
<ul><li>5.1. <a href="#rfc.section.5.1">Connection ID</a>
</li>
<ul><li>5.1.1. <a href="#rfc.section.5.1.1">Issuing Connection IDs</a>
</li>
<li>5.1.2. <a href="#rfc.section.5.1.2">Consuming and Retiring Connection IDs</a>
</li>
</ul><li>5.2. <a href="#rfc.section.5.2">Matching Packets to Connections</a>
</li>
<ul><li>5.2.1. <a href="#rfc.section.5.2.1">Client Packet Handling</a>
</li>
<li>5.2.2. <a href="#rfc.section.5.2.2">Server Packet Handling</a>
</li>
</ul><li>5.3. <a href="#rfc.section.5.3">Life of a QUIC Connection</a>
</li>
</ul><li>6. <a href="#rfc.section.6">Version Negotiation</a>
</li>
<ul><li>6.1. <a href="#rfc.section.6.1">Sending Version Negotiation Packets</a>
</li>
<li>6.2. <a href="#rfc.section.6.2">Handling Version Negotiation Packets</a>
</li>
<ul><li>6.2.1. <a href="#rfc.section.6.2.1">Version Negotiation Between Draft Versions</a>
</li>
</ul><li>6.3. <a href="#rfc.section.6.3">Using Reserved Versions</a>
</li>
</ul><li>7. <a href="#rfc.section.7">Cryptographic and Transport Handshake</a>
</li>
<ul><li>7.1. <a href="#rfc.section.7.1">Example Handshake Flows</a>
</li>
<li>7.2. <a href="#rfc.section.7.2">Negotiating Connection IDs</a>
</li>
<li>7.3. <a href="#rfc.section.7.3">Transport Parameters</a>
</li>
<ul><li>7.3.1. <a href="#rfc.section.7.3.1">Values of Transport Parameters for 0-RTT</a>
</li>
<li>7.3.2. <a href="#rfc.section.7.3.2">New Transport Parameters</a>
</li>
</ul><li>7.4. <a href="#rfc.section.7.4">Cryptographic Message Buffering</a>
</li>
</ul><li>8. <a href="#rfc.section.8">Address Validation</a>
</li>
<ul><li>8.1. <a href="#rfc.section.8.1">Address Validation During Connection Establishment</a>
</li>
<ul><li>8.1.1. <a href="#rfc.section.8.1.1">Address Validation using Retry Packets</a>
</li>
<li>8.1.2. <a href="#rfc.section.8.1.2">Address Validation for Future Connections</a>
</li>
<li>8.1.3. <a href="#rfc.section.8.1.3">Address Validation Token Integrity</a>
</li>
</ul><li>8.2. <a href="#rfc.section.8.2">Path Validation</a>
</li>
<li>8.3. <a href="#rfc.section.8.3">Initiating Path Validation</a>
</li>
<li>8.4. <a href="#rfc.section.8.4">Path Validation Responses</a>
</li>
<li>8.5. <a href="#rfc.section.8.5">Successful Path Validation</a>
</li>
<li>8.6. <a href="#rfc.section.8.6">Failed Path Validation</a>
</li>
</ul><li>9. <a href="#rfc.section.9">Connection Migration</a>
</li>
<ul><li>9.1. <a href="#rfc.section.9.1">Probing a New Path</a>
</li>
<li>9.2. <a href="#rfc.section.9.2">Initiating Connection Migration</a>
</li>
<li>9.3. <a href="#rfc.section.9.3">Responding to Connection Migration</a>
</li>
<ul><li>9.3.1. <a href="#rfc.section.9.3.1">Peer Address Spoofing</a>
</li>
<li>9.3.2. <a href="#rfc.section.9.3.2">On-Path Address Spoofing</a>
</li>
<li>9.3.3. <a href="#rfc.section.9.3.3">Off-Path Packet Forwarding</a>
</li>
</ul><li>9.4. <a href="#rfc.section.9.4">Loss Detection and Congestion Control</a>
</li>
<li>9.5. <a href="#rfc.section.9.5">Privacy Implications of Connection Migration</a>
</li>
<li>9.6. <a href="#rfc.section.9.6">Server’s Preferred Address</a>
</li>
<ul><li>9.6.1. <a href="#rfc.section.9.6.1">Communicating A Preferred Address</a>
</li>
<li>9.6.2. <a href="#rfc.section.9.6.2">Responding to Connection Migration</a>
</li>
<li>9.6.3. <a href="#rfc.section.9.6.3">Interaction of Client Migration and Preferred Address</a>
</li>
</ul><li>9.7. <a href="#rfc.section.9.7">Use of IPv6 Flow-Label and Migration</a>
</li>
</ul><li>10. <a href="#rfc.section.10">Connection Termination</a>
</li>
<ul><li>10.1. <a href="#rfc.section.10.1">Closing and Draining Connection States</a>
</li>
<li>10.2. <a href="#rfc.section.10.2">Idle Timeout</a>
</li>
<li>10.3. <a href="#rfc.section.10.3">Immediate Close</a>
</li>
<li>10.4. <a href="#rfc.section.10.4">Stateless Reset</a>
</li>
<ul><li>10.4.1. <a href="#rfc.section.10.4.1">Detecting a Stateless Reset</a>
</li>
<li>10.4.2. <a href="#rfc.section.10.4.2">Calculating a Stateless Reset Token</a>
</li>
<li>10.4.3. <a href="#rfc.section.10.4.3">Looping</a>
</li>
</ul></ul><li>11. <a href="#rfc.section.11">Error Handling</a>
</li>
<ul><li>11.1. <a href="#rfc.section.11.1">Connection Errors</a>
</li>
<li>11.2. <a href="#rfc.section.11.2">Stream Errors</a>
</li>
</ul><li>12. <a href="#rfc.section.12">Packets and Frames</a>
</li>
<ul><li>12.1. <a href="#rfc.section.12.1">Protected Packets</a>
</li>
<li>12.2. <a href="#rfc.section.12.2">Coalescing Packets</a>
</li>
<li>12.3. <a href="#rfc.section.12.3">Packet Numbers</a>
</li>
<li>12.4. <a href="#rfc.section.12.4">Frames and Frame Types</a>
</li>
</ul><li>13. <a href="#rfc.section.13">Packetization and Reliability</a>
</li>
<ul><li>13.1. <a href="#rfc.section.13.1">Packet Processing and Acknowledgment</a>
</li>
<ul><li>13.1.1. <a href="#rfc.section.13.1.1">Sending ACK Frames</a>
</li>
<li>13.1.2. <a href="#rfc.section.13.1.2">ACK Frames and Packet Protection</a>
</li>
</ul><li>13.2. <a href="#rfc.section.13.2">Retransmission of Information</a>
</li>
<li>13.3. <a href="#rfc.section.13.3">Explicit Congestion Notification</a>
</li>
<ul><li>13.3.1. <a href="#rfc.section.13.3.1">ECN Counts</a>
</li>
<li>13.3.2. <a href="#rfc.section.13.3.2">ECN Verification</a>
</li>
</ul></ul><li>14. <a href="#rfc.section.14">Packet Size</a>
</li>
<ul><li>14.1. <a href="#rfc.section.14.1">Path Maximum Transmission Unit (PMTU)</a>
</li>
<li>14.2. <a href="#rfc.section.14.2">ICMP Packet Too Big Messages</a>
</li>
<li>14.3. <a href="#rfc.section.14.3">Datagram Packetization Layer PMTU Discovery</a>
</li>
<ul><li>14.3.1. <a href="#rfc.section.14.3.1">PMTU Probes Containing Source Connection ID</a>
</li>
</ul></ul><li>15. <a href="#rfc.section.15">Versions</a>
</li>
<li>16. <a href="#rfc.section.16">Variable-Length Integer Encoding</a>
</li>
<li>17. <a href="#rfc.section.17">Packet Formats</a>
</li>
<ul><li>17.1. <a href="#rfc.section.17.1">Packet Number Encoding and Decoding</a>
</li>
<li>17.2. <a href="#rfc.section.17.2">Long Header Packets</a>
</li>
<ul><li>17.2.1. <a href="#rfc.section.17.2.1">Version Negotiation Packet</a>
</li>
<li>17.2.2. <a href="#rfc.section.17.2.2">Initial Packet</a>
</li>
<li>17.2.3. <a href="#rfc.section.17.2.3">0-RTT</a>
</li>
<li>17.2.4. <a href="#rfc.section.17.2.4">Handshake Packet</a>
</li>
<li>17.2.5. <a href="#rfc.section.17.2.5">Retry Packet</a>
</li>
</ul><li>17.3. <a href="#rfc.section.17.3">Short Header Packets</a>
</li>
<ul><li>17.3.1. <a href="#rfc.section.17.3.1">Latency Spin Bit</a>
</li>
</ul></ul><li>18. <a href="#rfc.section.18">Transport Parameter Encoding</a>
</li>
<ul><li>18.1. <a href="#rfc.section.18.1">Transport Parameter Definitions</a>
</li>
</ul><li>19. <a href="#rfc.section.19">Frame Types and Formats</a>
</li>
<ul><li>19.1. <a href="#rfc.section.19.1">PADDING Frame</a>
</li>
<li>19.2. <a href="#rfc.section.19.2">PING Frame</a>
</li>
<li>19.3. <a href="#rfc.section.19.3">ACK Frames</a>
</li>
<ul><li>19.3.1. <a href="#rfc.section.19.3.1">ACK Ranges</a>
</li>
<li>19.3.2. <a href="#rfc.section.19.3.2">ECN Counts</a>
</li>
</ul><li>19.4. <a href="#rfc.section.19.4">RESET_STREAM Frame</a>
</li>
<li>19.5. <a href="#rfc.section.19.5">STOP_SENDING Frame</a>
</li>
<li>19.6. <a href="#rfc.section.19.6">CRYPTO Frame</a>
</li>
<li>19.7. <a href="#rfc.section.19.7">NEW_TOKEN Frame</a>
</li>
<li>19.8. <a href="#rfc.section.19.8">STREAM Frames</a>
</li>
<li>19.9. <a href="#rfc.section.19.9">MAX_DATA Frame</a>
</li>
<li>19.10. <a href="#rfc.section.19.10">MAX_STREAM_DATA Frame</a>
</li>
<li>19.11. <a href="#rfc.section.19.11">MAX_STREAMS Frames</a>
</li>
<li>19.12. <a href="#rfc.section.19.12">DATA_BLOCKED Frame</a>
</li>
<li>19.13. <a href="#rfc.section.19.13">STREAM_DATA_BLOCKED Frame</a>
</li>
<li>19.14. <a href="#rfc.section.19.14">STREAMS_BLOCKED Frames</a>
</li>
<li>19.15. <a href="#rfc.section.19.15">NEW_CONNECTION_ID Frame</a>
</li>
<li>19.16. <a href="#rfc.section.19.16">RETIRE_CONNECTION_ID Frame</a>
</li>
<li>19.17. <a href="#rfc.section.19.17">PATH_CHALLENGE Frame</a>
</li>
<li>19.18. <a href="#rfc.section.19.18">PATH_RESPONSE Frame</a>
</li>
<li>19.19. <a href="#rfc.section.19.19">CONNECTION_CLOSE Frames</a>
</li>
<li>19.20. <a href="#rfc.section.19.20">Extension Frames</a>
</li>
</ul><li>20. <a href="#rfc.section.20">Transport Error Codes</a>
</li>
<ul><li>20.1. <a href="#rfc.section.20.1">Application Protocol Error Codes</a>
</li>
</ul><li>21. <a href="#rfc.section.21">Security Considerations</a>
</li>
<ul><li>21.1. <a href="#rfc.section.21.1">Handshake Denial of Service</a>
</li>
<li>21.2. <a href="#rfc.section.21.2">Amplification Attack</a>
</li>
<li>21.3. <a href="#rfc.section.21.3">Optimistic ACK Attack</a>
</li>
<li>21.4. <a href="#rfc.section.21.4">Slowloris Attacks</a>
</li>
<li>21.5. <a href="#rfc.section.21.5">Stream Fragmentation and Reassembly Attacks</a>
</li>
<li>21.6. <a href="#rfc.section.21.6">Stream Commitment Attack</a>
</li>
<li>21.7. <a href="#rfc.section.21.7">Explicit Congestion Notification Attacks</a>
</li>
<li>21.8. <a href="#rfc.section.21.8">Stateless Reset Oracle</a>
</li>
<li>21.9. <a href="#rfc.section.21.9">Version Downgrade</a>
</li>
<li>21.10. <a href="#rfc.section.21.10">Targeted Attacks by Routing</a>
</li>
</ul><li>22. <a href="#rfc.section.22">IANA Considerations</a>
</li>
<ul><li>22.1. <a href="#rfc.section.22.1">QUIC Transport Parameter Registry</a>
</li>
<li>22.2. <a href="#rfc.section.22.2">QUIC Frame Type Registry</a>
</li>
<li>22.3. <a href="#rfc.section.22.3">QUIC Transport Error Codes Registry</a>
</li>
</ul><li>23. <a href="#rfc.references">References</a>
</li>
<ul><li>23.1. <a href="#rfc.references.1">Normative References</a>
</li>
<li>23.2. <a href="#rfc.references.2">Informative References</a>
</li>
</ul><li>Appendix A. <a href="#rfc.appendix.A">Sample Packet Number Decoding Algorithm</a>
</li>
<li>Appendix B. <a href="#rfc.appendix.B">Change Log</a>
</li>
<ul><li>B.1. <a href="#rfc.appendix.B.1">Since draft-ietf-quic-transport-19</a>
</li>
<li>B.2. <a href="#rfc.appendix.B.2">Since draft-ietf-quic-transport-18</a>
</li>
<li>B.3. <a href="#rfc.appendix.B.3">Since draft-ietf-quic-transport-17</a>
</li>
<li>B.4. <a href="#rfc.appendix.B.4">Since draft-ietf-quic-transport-16</a>
</li>
<li>B.5. <a href="#rfc.appendix.B.5">Since draft-ietf-quic-transport-15</a>
</li>
<li>B.6. <a href="#rfc.appendix.B.6">Since draft-ietf-quic-transport-14</a>
</li>
<li>B.7. <a href="#rfc.appendix.B.7">Since draft-ietf-quic-transport-13</a>
</li>
<li>B.8. <a href="#rfc.appendix.B.8">Since draft-ietf-quic-transport-12</a>
</li>
<li>B.9. <a href="#rfc.appendix.B.9">Since draft-ietf-quic-transport-11</a>
</li>
<li>B.10. <a href="#rfc.appendix.B.10">Since draft-ietf-quic-transport-10</a>
</li>
<li>B.11. <a href="#rfc.appendix.B.11">Since draft-ietf-quic-transport-09</a>
</li>
<li>B.12. <a href="#rfc.appendix.B.12">Since draft-ietf-quic-transport-08</a>
</li>
<li>B.13. <a href="#rfc.appendix.B.13">Since draft-ietf-quic-transport-07</a>
</li>
<li>B.14. <a href="#rfc.appendix.B.14">Since draft-ietf-quic-transport-06</a>
</li>
<li>B.15. <a href="#rfc.appendix.B.15">Since draft-ietf-quic-transport-05</a>
</li>
<li>B.16. <a href="#rfc.appendix.B.16">Since draft-ietf-quic-transport-04</a>
</li>
<li>B.17. <a href="#rfc.appendix.B.17">Since draft-ietf-quic-transport-03</a>
</li>
<li>B.18. <a href="#rfc.appendix.B.18">Since draft-ietf-quic-transport-02</a>
</li>
<li>B.19. <a href="#rfc.appendix.B.19">Since draft-ietf-quic-transport-01</a>
</li>
<li>B.20. <a href="#rfc.appendix.B.20">Since draft-ietf-quic-transport-00</a>
</li>
<li>B.21. <a href="#rfc.appendix.B.21">Since draft-hamilton-quic-transport-protocol-01</a>
</li>
</ul><li><a href="#rfc.acknowledgments">Acknowledgments</a>
</li>
<li><a href="#rfc.contributors">Contributors</a>
</li>
<li><a href="#rfc.authors">Authors' Addresses</a>
</li>
</ul>
<h1 id="rfc.section.1">
<a href="#rfc.section.1">1.</a> <a href="#introduction" id="introduction">Introduction</a>
</h1>
<p id="rfc.section.1.p.1">QUIC is a multiplexed and secure general-purpose transport protocol that provides:</p>
<p></p>
<ul>
<li>Stream multiplexing</li>
<li>Stream and connection-level flow control</li>
<li>Low-latency connection establishment</li>
<li>Connection migration and resilience to NAT rebinding</li>
<li>Authenticated and encrypted header and payload</li>
</ul>
<p id="rfc.section.1.p.3">QUIC uses UDP as a substrate to avoid requiring changes to legacy client operating systems and middleboxes. QUIC authenticates all of its headers and encrypts most of the data it exchanges, including its signaling, to avoid incurring a dependency on middleboxes.</p>
<h2 id="rfc.section.1.1">
<a href="#rfc.section.1.1">1.1.</a> <a href="#document-structure" id="document-structure">Document Structure</a>
</h2>
<p id="rfc.section.1.1.p.1">This document describes the core QUIC protocol and is structured as follows.</p>
<p></p>
<ul>
<li>Streams are the basic service abstraction that QUIC provides. <ul>
<li>
<a href="#streams" class="xref">Section 2</a> describes core concepts related to streams,</li>
<li>
<a href="#stream-states" class="xref">Section 3</a> provides a reference model for stream states, and</li>
<li>
<a href="#flow-control" class="xref">Section 4</a> outlines the operation of flow control.</li>
</ul>
</li>
<li>Connections are the context in which QUIC endpoints communicate. <ul>
<li>
<a href="#connections" class="xref">Section 5</a> describes core concepts related to connections,</li>
<li>
<a href="#version-negotiation" class="xref">Section 6</a> describes version negotiation,</li>
<li>
<a href="#handshake" class="xref">Section 7</a> details the process for establishing connections,</li>
<li>
<a href="#address-validation" class="xref">Section 8</a> specifies critical denial of service mitigation mechanisms,</li>
<li>
<a href="#migration" class="xref">Section 9</a> describes how endpoints migrate a connection to a new network path,</li>
<li>
<a href="#termination" class="xref">Section 10</a> lists the options for terminating an open connection, and</li>
<li>
<a href="#error-handling" class="xref">Section 11</a> provides general guidance for error handling.</li>
</ul>
</li>
<li>Packets and frames are the basic unit used by QUIC to communicate. <ul>
<li>
<a href="#packets-frames" class="xref">Section 12</a> describes concepts related to packets and frames,</li>
<li>
<a href="#packetization" class="xref">Section 13</a> defines models for the transmission, retransmission, and acknowledgement of data, and</li>
<li>
<a href="#packet-size" class="xref">Section 14</a> specifies rules for managing the size of packets.</li>
</ul>
</li>
<li>Finally, encoding details of QUIC protocol elements are described in: <ul>
<li>
<a href="#versions" class="xref">Section 15</a> (Versions),</li>
<li>
<a href="#integer-encoding" class="xref">Section 16</a> (Integer Encoding),</li>
<li>
<a href="#packet-formats" class="xref">Section 17</a> (Packet Headers),</li>
<li>
<a href="#transport-parameter-encoding" class="xref">Section 18</a> (Transport Parameters),</li>
<li>
<a href="#frame-formats" class="xref">Section 19</a> (Frames), and</li>
<li>
<a href="#error-codes" class="xref">Section 20</a> (Errors).</li>
</ul>
</li>
</ul>
<p id="rfc.section.1.1.p.3">Accompanying documents describe QUIC’s loss detection and congestion control <a href="#QUIC-RECOVERY" class="xref">[QUIC-RECOVERY]</a>, and the use of TLS for key negotiation <a href="#QUIC-TLS" class="xref">[QUIC-TLS]</a>.</p>
<p id="rfc.section.1.1.p.4">This document defines QUIC version 1, which conforms to the protocol invariants in <a href="#QUIC-INVARIANTS" class="xref">[QUIC-INVARIANTS]</a>.</p>
<h2 id="rfc.section.1.2">
<a href="#rfc.section.1.2">1.2.</a> <a href="#terms-and-definitions" id="terms-and-definitions">Terms and Definitions</a>
</h2>
<p id="rfc.section.1.2.p.1">The keywords “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 <a href="#RFC2119" class="xref">[RFC2119]</a> <a href="#RFC8174" class="xref">[RFC8174]</a> when, and only when, they appear in all capitals, as shown here.</p>
<p id="rfc.section.1.2.p.2">Commonly used terms in the document are described below.</p>
<p></p>
<dl>
<dt>QUIC:</dt>
<dd style="margin-left: 8">The transport protocol described by this document. QUIC is a name, not an acronym.</dd>
<dt>QUIC packet:</dt>
<dd style="margin-left: 8">The smallest unit of QUIC that can be encapsulated in a UDP datagram. Multiple QUIC packets can be encapsulated in a single UDP datagram.</dd>
<dt>Endpoint:</dt>
<dd style="margin-left: 8">An entity that can participate in a QUIC connection by generating, receiving, and processing QUIC packets. There are only two types of endpoint in QUIC: client and server.</dd>
<dt>Client:</dt>
<dd style="margin-left: 8">The endpoint initiating a QUIC connection.</dd>
<dt>Server:</dt>
<dd style="margin-left: 8">The endpoint accepting incoming QUIC connections.</dd>
<dt>Connection ID:</dt>
<dd style="margin-left: 8">An opaque identifier that is used to identify a QUIC connection at an endpoint. Each endpoint sets a value for its peer to include in packets sent towards the endpoint.</dd>
<dt>Stream:</dt>
<dd style="margin-left: 8">A unidirectional or bidirectional channel of ordered bytes within a QUIC connection. A QUIC connection can carry multiple simultaneous streams.</dd>
<dt>Application:</dt>
<dd style="margin-left: 8">An entity that uses QUIC to send and receive data.</dd>
</dl>
<h2 id="rfc.section.1.3">
<a href="#rfc.section.1.3">1.3.</a> <a href="#notational-conventions" id="notational-conventions">Notational Conventions</a>
</h2>
<p id="rfc.section.1.3.p.1">Packet and frame diagrams in this document use the format described in Section 3.1 of <a href="#RFC2360" class="xref">[RFC2360]</a>, with the following additional conventions:</p>
<p></p>
<dl>
<dt>[x]:</dt>
<dd style="margin-left: 8">Indicates that x is optional</dd>
<dt>x (A):</dt>
<dd style="margin-left: 8">Indicates that x is A bits long</dd>
<dt>x (A/B/C) …:</dt>
<dd style="margin-left: 8">Indicates that x is one of A, B, or C bits long</dd>
<dt>x (i) …:</dt>
<dd style="margin-left: 8">Indicates that x uses the variable-length encoding in <a href="#integer-encoding" class="xref">Section 16</a>
</dd>
<dt>x (*) …:</dt>
<dd style="margin-left: 8">Indicates that x is variable-length</dd>
</dl>
<h1 id="rfc.section.2">