draft-ietf-quic-http-29.txt   draft-ietf-quic-http-30.txt 
QUIC M. Bishop, Ed. QUIC M. Bishop, Ed.
Internet-Draft Akamai Internet-Draft Akamai
Intended status: Standards Track 9 June 2020 Intended status: Standards Track September 10, 2020
Expires: 11 December 2020 Expires: March 14, 2021
Hypertext Transfer Protocol Version 3 (HTTP/3) Hypertext Transfer Protocol Version 3 (HTTP/3)
draft-ietf-quic-http-29 draft-ietf-quic-http-30
Abstract Abstract
The QUIC transport protocol has several features that are desirable The QUIC transport protocol has several features that are desirable
in a transport for HTTP, such as stream multiplexing, per-stream flow in a transport for HTTP, such as stream multiplexing, per-stream flow
control, and low-latency connection establishment. This document control, and low-latency connection establishment. This document
describes a mapping of HTTP semantics over QUIC. This document also describes a mapping of HTTP semantics over QUIC. This document also
identifies HTTP/2 features that are subsumed by QUIC, and describes identifies HTTP/2 features that are subsumed by QUIC, and describes
how HTTP/2 extensions can be ported to HTTP/3. how HTTP/2 extensions can be ported to HTTP/3.
Note to Readers Note to Readers
Discussion of this draft takes place on the QUIC working group Discussion of this draft takes place on the QUIC working group
mailing list (quic@ietf.org (mailto:quic@ietf.org)), which is mailing list (quic@ietf.org), which is archived at
archived at https://mailarchive.ietf.org/arch/ https://mailarchive.ietf.org/arch/search/?email_list=quic.
search/?email_list=quic.
Working Group information can be found at https://github.com/quicwg; Working Group information can be found at https://github.com/quicwg;
source code and issues list for this draft can be found at source code and issues list for this draft can be found at
https://github.com/quicwg/base-drafts/labels/-http. https://github.com/quicwg/base-drafts/labels/-http.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 11 December 2020. This Internet-Draft will expire on March 14, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
skipping to change at page 2, line 30 skipping to change at page 2, line 30
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Prior versions of HTTP . . . . . . . . . . . . . . . . . 5 1.1. Prior versions of HTTP . . . . . . . . . . . . . . . . . 5
1.2. Delegation to QUIC . . . . . . . . . . . . . . . . . . . 5 1.2. Delegation to QUIC . . . . . . . . . . . . . . . . . . . 5
2. HTTP/3 Protocol Overview . . . . . . . . . . . . . . . . . . 5 2. HTTP/3 Protocol Overview . . . . . . . . . . . . . . . . . . 5
2.1. Document Organization . . . . . . . . . . . . . . . . . . 6 2.1. Document Organization . . . . . . . . . . . . . . . . . . 6
2.2. Conventions and Terminology . . . . . . . . . . . . . . . 7 2.2. Conventions and Terminology . . . . . . . . . . . . . . . 7
3. Connection Setup and Management . . . . . . . . . . . . . . . 8 3. Connection Setup and Management . . . . . . . . . . . . . . . 8
3.1. Draft Version Identification . . . . . . . . . . . . . . 8 3.1. Draft Version Identification . . . . . . . . . . . . . . 8
3.2. Discovering an HTTP/3 Endpoint . . . . . . . . . . . . . 9 3.2. Discovering an HTTP/3 Endpoint . . . . . . . . . . . . . 9
3.2.1. HTTP Alternative Services . . . . . . . . . . . . . . 10 3.2.1. HTTP Alternative Services . . . . . . . . . . . . . . 9
3.2.2. Other Schemes . . . . . . . . . . . . . . . . . . . . 10 3.2.2. Other Schemes . . . . . . . . . . . . . . . . . . . . 10
3.3. Connection Establishment . . . . . . . . . . . . . . . . 10 3.3. Connection Establishment . . . . . . . . . . . . . . . . 10
3.4. Connection Reuse . . . . . . . . . . . . . . . . . . . . 11 3.4. Connection Reuse . . . . . . . . . . . . . . . . . . . . 11
4. HTTP Request Lifecycle . . . . . . . . . . . . . . . . . . . 12 4. HTTP Request Lifecycle . . . . . . . . . . . . . . . . . . . 12
4.1. HTTP Message Exchanges . . . . . . . . . . . . . . . . . 12 4.1. HTTP Message Exchanges . . . . . . . . . . . . . . . . . 12
4.1.1. Field Formatting and Compression . . . . . . . . . . 14 4.1.1. Field Formatting and Compression . . . . . . . . . . 14
4.1.2. Request Cancellation and Rejection . . . . . . . . . 17 4.1.2. Request Cancellation and Rejection . . . . . . . . . 17
4.1.3. Malformed Requests and Responses . . . . . . . . . . 18 4.1.3. Malformed Requests and Responses . . . . . . . . . . 18
4.2. The CONNECT Method . . . . . . . . . . . . . . . . . . . 19 4.2. The CONNECT Method . . . . . . . . . . . . . . . . . . . 19
4.3. HTTP Upgrade . . . . . . . . . . . . . . . . . . . . . . 20 4.3. HTTP Upgrade . . . . . . . . . . . . . . . . . . . . . . 20
4.4. Server Push . . . . . . . . . . . . . . . . . . . . . . . 21 4.4. Server Push . . . . . . . . . . . . . . . . . . . . . . . 20
5. Connection Closure . . . . . . . . . . . . . . . . . . . . . 23 5. Connection Closure . . . . . . . . . . . . . . . . . . . . . 22
5.1. Idle Connections . . . . . . . . . . . . . . . . . . . . 23 5.1. Idle Connections . . . . . . . . . . . . . . . . . . . . 22
5.2. Connection Shutdown . . . . . . . . . . . . . . . . . . . 23 5.2. Connection Shutdown . . . . . . . . . . . . . . . . . . . 23
5.3. Immediate Application Closure . . . . . . . . . . . . . . 25 5.3. Immediate Application Closure . . . . . . . . . . . . . . 25
5.4. Transport Closure . . . . . . . . . . . . . . . . . . . . 26 5.4. Transport Closure . . . . . . . . . . . . . . . . . . . . 25
6. Stream Mapping and Usage . . . . . . . . . . . . . . . . . . 26 6. Stream Mapping and Usage . . . . . . . . . . . . . . . . . . 25
6.1. Bidirectional Streams . . . . . . . . . . . . . . . . . . 26 6.1. Bidirectional Streams . . . . . . . . . . . . . . . . . . 26
6.2. Unidirectional Streams . . . . . . . . . . . . . . . . . 27 6.2. Unidirectional Streams . . . . . . . . . . . . . . . . . 26
6.2.1. Control Streams . . . . . . . . . . . . . . . . . . . 28 6.2.1. Control Streams . . . . . . . . . . . . . . . . . . . 28
6.2.2. Push Streams . . . . . . . . . . . . . . . . . . . . 29 6.2.2. Push Streams . . . . . . . . . . . . . . . . . . . . 28
6.2.3. Reserved Stream Types . . . . . . . . . . . . . . . . 29 6.2.3. Reserved Stream Types . . . . . . . . . . . . . . . . 29
7. HTTP Framing Layer . . . . . . . . . . . . . . . . . . . . . 30 7. HTTP Framing Layer . . . . . . . . . . . . . . . . . . . . . 29
7.1. Frame Layout . . . . . . . . . . . . . . . . . . . . . . 31 7.1. Frame Layout . . . . . . . . . . . . . . . . . . . . . . 30
7.2. Frame Definitions . . . . . . . . . . . . . . . . . . . . 31 7.2. Frame Definitions . . . . . . . . . . . . . . . . . . . . 31
7.2.1. DATA . . . . . . . . . . . . . . . . . . . . . . . . 31 7.2.1. DATA . . . . . . . . . . . . . . . . . . . . . . . . 31
7.2.2. HEADERS . . . . . . . . . . . . . . . . . . . . . . . 32 7.2.2. HEADERS . . . . . . . . . . . . . . . . . . . . . . . 31
7.2.3. CANCEL_PUSH . . . . . . . . . . . . . . . . . . . . . 32 7.2.3. CANCEL_PUSH . . . . . . . . . . . . . . . . . . . . . 32
7.2.4. SETTINGS . . . . . . . . . . . . . . . . . . . . . . 33 7.2.4. SETTINGS . . . . . . . . . . . . . . . . . . . . . . 33
7.2.5. PUSH_PROMISE . . . . . . . . . . . . . . . . . . . . 36 7.2.5. PUSH_PROMISE . . . . . . . . . . . . . . . . . . . . 36
7.2.6. GOAWAY . . . . . . . . . . . . . . . . . . . . . . . 38 7.2.6. GOAWAY . . . . . . . . . . . . . . . . . . . . . . . 38
7.2.7. MAX_PUSH_ID . . . . . . . . . . . . . . . . . . . . . 38 7.2.7. MAX_PUSH_ID . . . . . . . . . . . . . . . . . . . . . 38
7.2.8. Reserved Frame Types . . . . . . . . . . . . . . . . 39 7.2.8. Reserved Frame Types . . . . . . . . . . . . . . . . 39
8. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 39 8. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 39
8.1. HTTP/3 Error Codes . . . . . . . . . . . . . . . . . . . 40 8.1. HTTP/3 Error Codes . . . . . . . . . . . . . . . . . . . 40
9. Extensions to HTTP/3 . . . . . . . . . . . . . . . . . . . . 41 9. Extensions to HTTP/3 . . . . . . . . . . . . . . . . . . . . 41
10. Security Considerations . . . . . . . . . . . . . . . . . . . 42 10. Security Considerations . . . . . . . . . . . . . . . . . . . 42
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11.1. Registration of HTTP/3 Identification String . . . . . . 47 11.1. Registration of HTTP/3 Identification String . . . . . . 47
11.2. New Registries . . . . . . . . . . . . . . . . . . . . . 48 11.2. New Registries . . . . . . . . . . . . . . . . . . . . . 48
11.2.1. Frame Types . . . . . . . . . . . . . . . . . . . . 48 11.2.1. Frame Types . . . . . . . . . . . . . . . . . . . . 48
11.2.2. Settings Parameters . . . . . . . . . . . . . . . . 49 11.2.2. Settings Parameters . . . . . . . . . . . . . . . . 49
11.2.3. Error Codes . . . . . . . . . . . . . . . . . . . . 50 11.2.3. Error Codes . . . . . . . . . . . . . . . . . . . . 50
11.2.4. Stream Types . . . . . . . . . . . . . . . . . . . . 53 11.2.4. Stream Types . . . . . . . . . . . . . . . . . . . . 53
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 53 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 53
12.1. Normative References . . . . . . . . . . . . . . . . . . 53 12.1. Normative References . . . . . . . . . . . . . . . . . . 53
12.2. Informative References . . . . . . . . . . . . . . . . . 55 12.2. Informative References . . . . . . . . . . . . . . . . . 55
Appendix A. Considerations for Transitioning from HTTP/2 . . . . 56 Appendix A. Considerations for Transitioning from HTTP/2 . . . . 56
A.1. Streams . . . . . . . . . . . . . . . . . . . . . . . . . 57 A.1. Streams . . . . . . . . . . . . . . . . . . . . . . . . . 56
A.2. HTTP Frame Types . . . . . . . . . . . . . . . . . . . . 57 A.2. HTTP Frame Types . . . . . . . . . . . . . . . . . . . . 57
A.2.1. Prioritization Differences . . . . . . . . . . . . . 58 A.2.1. Prioritization Differences . . . . . . . . . . . . . 58
A.2.2. Field Compression Differences . . . . . . . . . . . . 58 A.2.2. Field Compression Differences . . . . . . . . . . . . 58
A.2.3. Guidance for New Frame Type Definitions . . . . . . . 58 A.2.3. Flow Control Differences . . . . . . . . . . . . . . 58
A.2.4. Mapping Between HTTP/2 and HTTP/3 Frame Types . . . . 59 A.2.4. Guidance for New Frame Type Definitions . . . . . . . 58
A.2.5. Mapping Between HTTP/2 and HTTP/3 Frame Types . . . . 59
A.3. HTTP/2 SETTINGS Parameters . . . . . . . . . . . . . . . 60 A.3. HTTP/2 SETTINGS Parameters . . . . . . . . . . . . . . . 60
A.4. HTTP/2 Error Codes . . . . . . . . . . . . . . . . . . . 61 A.4. HTTP/2 Error Codes . . . . . . . . . . . . . . . . . . . 61
A.4.1. Mapping Between HTTP/2 and HTTP/3 Errors . . . . . . 62 A.4.1. Mapping Between HTTP/2 and HTTP/3 Errors . . . . . . 62
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 63
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 62 B.1. Since draft-ietf-quic-http-29 . . . . . . . . . . . . . . 63
B.1. Since draft-ietf-quic-http-28 . . . . . . . . . . . . . . 63 B.2. Since draft-ietf-quic-http-28 . . . . . . . . . . . . . . 63
B.2. Since draft-ietf-quic-http-27 . . . . . . . . . . . . . . 63 B.3. Since draft-ietf-quic-http-27 . . . . . . . . . . . . . . 63
B.3. Since draft-ietf-quic-http-26 . . . . . . . . . . . . . . 63 B.4. Since draft-ietf-quic-http-26 . . . . . . . . . . . . . . 63
B.4. Since draft-ietf-quic-http-25 . . . . . . . . . . . . . . 63 B.5. Since draft-ietf-quic-http-25 . . . . . . . . . . . . . . 64
B.5. Since draft-ietf-quic-http-24 . . . . . . . . . . . . . . 63 B.6. Since draft-ietf-quic-http-24 . . . . . . . . . . . . . . 64
B.6. Since draft-ietf-quic-http-23 . . . . . . . . . . . . . . 63 B.7. Since draft-ietf-quic-http-23 . . . . . . . . . . . . . . 64
B.7. Since draft-ietf-quic-http-22 . . . . . . . . . . . . . . 64 B.8. Since draft-ietf-quic-http-22 . . . . . . . . . . . . . . 64
B.8. Since draft-ietf-quic-http-21 . . . . . . . . . . . . . . 64 B.9. Since draft-ietf-quic-http-21 . . . . . . . . . . . . . . 65
B.9. Since draft-ietf-quic-http-20 . . . . . . . . . . . . . . 65 B.10. Since draft-ietf-quic-http-20 . . . . . . . . . . . . . . 65
B.10. Since draft-ietf-quic-http-19 . . . . . . . . . . . . . . 65 B.11. Since draft-ietf-quic-http-19 . . . . . . . . . . . . . . 66
B.11. Since draft-ietf-quic-http-18 . . . . . . . . . . . . . . 66 B.12. Since draft-ietf-quic-http-18 . . . . . . . . . . . . . . 66
B.12. Since draft-ietf-quic-http-17 . . . . . . . . . . . . . . 66 B.13. Since draft-ietf-quic-http-17 . . . . . . . . . . . . . . 67
B.13. Since draft-ietf-quic-http-16 . . . . . . . . . . . . . . 66 B.14. Since draft-ietf-quic-http-16 . . . . . . . . . . . . . . 67
B.14. Since draft-ietf-quic-http-15 . . . . . . . . . . . . . . 67 B.15. Since draft-ietf-quic-http-15 . . . . . . . . . . . . . . 67
B.15. Since draft-ietf-quic-http-14 . . . . . . . . . . . . . . 67 B.16. Since draft-ietf-quic-http-14 . . . . . . . . . . . . . . 67
B.16. Since draft-ietf-quic-http-13 . . . . . . . . . . . . . . 67 B.17. Since draft-ietf-quic-http-13 . . . . . . . . . . . . . . 68
B.17. Since draft-ietf-quic-http-12 . . . . . . . . . . . . . . 67 B.18. Since draft-ietf-quic-http-12 . . . . . . . . . . . . . . 68
B.18. Since draft-ietf-quic-http-11 . . . . . . . . . . . . . . 68 B.19. Since draft-ietf-quic-http-11 . . . . . . . . . . . . . . 68
B.19. Since draft-ietf-quic-http-10 . . . . . . . . . . . . . . 68 B.20. Since draft-ietf-quic-http-10 . . . . . . . . . . . . . . 68
B.20. Since draft-ietf-quic-http-09 . . . . . . . . . . . . . . 68 B.21. Since draft-ietf-quic-http-09 . . . . . . . . . . . . . . 68
B.21. Since draft-ietf-quic-http-08 . . . . . . . . . . . . . . 68 B.22. Since draft-ietf-quic-http-08 . . . . . . . . . . . . . . 69
B.22. Since draft-ietf-quic-http-07 . . . . . . . . . . . . . . 68 B.23. Since draft-ietf-quic-http-07 . . . . . . . . . . . . . . 69
B.23. Since draft-ietf-quic-http-06 . . . . . . . . . . . . . . 68 B.24. Since draft-ietf-quic-http-06 . . . . . . . . . . . . . . 69
B.24. Since draft-ietf-quic-http-05 . . . . . . . . . . . . . . 68 B.25. Since draft-ietf-quic-http-05 . . . . . . . . . . . . . . 69
B.25. Since draft-ietf-quic-http-04 . . . . . . . . . . . . . . 69 B.26. Since draft-ietf-quic-http-04 . . . . . . . . . . . . . . 69
B.26. Since draft-ietf-quic-http-03 . . . . . . . . . . . . . . 69 B.27. Since draft-ietf-quic-http-03 . . . . . . . . . . . . . . 70
B.27. Since draft-ietf-quic-http-02 . . . . . . . . . . . . . . 69 B.28. Since draft-ietf-quic-http-02 . . . . . . . . . . . . . . 70
B.28. Since draft-ietf-quic-http-01 . . . . . . . . . . . . . . 69 B.29. Since draft-ietf-quic-http-01 . . . . . . . . . . . . . . 70
B.29. Since draft-ietf-quic-http-00 . . . . . . . . . . . . . . 70 B.30. Since draft-ietf-quic-http-00 . . . . . . . . . . . . . . 70
B.30. Since draft-shade-quic-http2-mapping-00 . . . . . . . . . 70 B.31. Since draft-shade-quic-http2-mapping-00 . . . . . . . . . 71
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 70 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 71
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 72 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 72
1. Introduction 1. Introduction
HTTP semantics [SEMANTICS] are used for a broad range of services on HTTP semantics ([SEMANTICS]) are used for a broad range of services
the Internet. These semantics have most commonly been used with two on the Internet. These semantics have most commonly been used with
different TCP mappings, HTTP/1.1 and HTTP/2. HTTP/3 supports the HTTP/1.1, over a variety of transport and session layers, and with
same semantics over a new transport protocol, QUIC. HTTP/2 over TLS. HTTP/3 supports the same semantics over a new
transport protocol, QUIC.
1.1. Prior versions of HTTP 1.1. Prior versions of HTTP
HTTP/1.1 [HTTP11] is a TCP mapping which uses whitespace-delimited HTTP/1.1 ([HTTP11]) uses whitespace-delimited text fields to convey
text fields to convey HTTP messages. While these exchanges are HTTP messages. While these exchanges are human-readable, using
human-readable, using whitespace for message formatting leads to whitespace for message formatting leads to parsing complexity and
parsing complexity and motivates tolerance of variant behavior. excessive tolerance of variant behavior. Because HTTP/1.x does not
Because each connection can transfer only a single HTTP request or include a multiplexing layer, multiple TCP connections are often used
response at a time in each direction, multiple parallel TCP to service requests in parallel. However, that has a negative impact
connections are often used, reducing the ability of the congestion on congestion control and network efficiency, since TCP does not
controller to effectively manage traffic between endpoints. share congestion control across multiple connections.
HTTP/2 [HTTP2] introduced a binary framing and multiplexing layer to HTTP/2 ([HTTP2]) introduced a binary framing and multiplexing layer
improve latency without modifying the transport layer. However, to improve latency without modifying the transport layer. However,
because the parallel nature of HTTP/2's multiplexing is not visible because the parallel nature of HTTP/2's multiplexing is not visible
to TCP's loss recovery mechanisms, a lost or reordered packet causes to TCP's loss recovery mechanisms, a lost or reordered packet causes
all active transactions to experience a stall regardless of whether all active transactions to experience a stall regardless of whether
that transaction was directly impacted by the lost packet. that transaction was directly impacted by the lost packet.
1.2. Delegation to QUIC 1.2. Delegation to QUIC
The QUIC transport protocol incorporates stream multiplexing and per- The QUIC transport protocol incorporates stream multiplexing and per-
stream flow control, similar to that provided by the HTTP/2 framing stream flow control, similar to that provided by the HTTP/2 framing
layer. By providing reliability at the stream level and congestion layer. By providing reliability at the stream level and congestion
control across the entire connection, it has the capability to control across the entire connection, it has the capability to
improve the performance of HTTP compared to a TCP mapping. QUIC also improve the performance of HTTP compared to a TCP mapping. QUIC also
incorporates TLS 1.3 [TLS13] at the transport layer, offering incorporates TLS 1.3 ([TLS13]) at the transport layer, offering
comparable security to running TLS over TCP, with the improved comparable security to running TLS over TCP, with the improved
connection setup latency of TCP Fast Open [TFO]. connection setup latency of TCP Fast Open ([TFO]).
This document defines a mapping of HTTP semantics over the QUIC This document defines a mapping of HTTP semantics over the QUIC
transport protocol, drawing heavily on the design of HTTP/2. While transport protocol, drawing heavily on the design of HTTP/2. While
delegating stream lifetime and flow control issues to QUIC, a similar delegating stream lifetime and flow control issues to QUIC, a similar
binary framing is used on each stream. Some HTTP/2 features are binary framing is used on each stream. Some HTTP/2 features are
subsumed by QUIC, while other features are implemented atop QUIC. subsumed by QUIC, while other features are implemented atop QUIC.
QUIC is described in [QUIC-TRANSPORT]. For a full description of QUIC is described in [QUIC-TRANSPORT]. For a full description of
HTTP/2, see [HTTP2]. HTTP/2, see [HTTP2].
skipping to change at page 6, line 16 skipping to change at page 6, line 16
(Section 7.2). Each frame type serves a different purpose. For (Section 7.2). Each frame type serves a different purpose. For
example, HEADERS and DATA frames form the basis of HTTP requests and example, HEADERS and DATA frames form the basis of HTTP requests and
responses (Section 4.1). responses (Section 4.1).
Multiplexing of requests is performed using the QUIC stream Multiplexing of requests is performed using the QUIC stream
abstraction, described in Section 2 of [QUIC-TRANSPORT]. Each abstraction, described in Section 2 of [QUIC-TRANSPORT]. Each
request-response pair consumes a single QUIC stream. Streams are request-response pair consumes a single QUIC stream. Streams are
independent of each other, so one stream that is blocked or suffers independent of each other, so one stream that is blocked or suffers
packet loss does not prevent progress on other streams. packet loss does not prevent progress on other streams.
Server push is an interaction mode introduced in HTTP/2 [HTTP2] which Server push is an interaction mode introduced in HTTP/2 ([HTTP2])
permits a server to push a request-response exchange to a client in that permits a server to push a request-response exchange to a client
anticipation of the client making the indicated request. This trades in anticipation of the client making the indicated request. This
off network usage against a potential latency gain. Several HTTP/3 trades off network usage against a potential latency gain. Several
frames are used to manage server push, such as PUSH_PROMISE, HTTP/3 frames are used to manage server push, such as PUSH_PROMISE,
MAX_PUSH_ID, and CANCEL_PUSH. MAX_PUSH_ID, and CANCEL_PUSH.
As in HTTP/2, request and response fields are compressed for As in HTTP/2, request and response fields are compressed for
transmission. Because HPACK [HPACK] relies on in-order transmission transmission. Because HPACK ([HPACK]) relies on in-order
of compressed field sections (a guarantee not provided by QUIC), transmission of compressed field sections (a guarantee not provided
HTTP/3 replaces HPACK with QPACK [QPACK]. QPACK uses separate by QUIC), HTTP/3 replaces HPACK with QPACK ([QPACK]). QPACK uses
unidirectional streams to modify and track field table state, while separate unidirectional streams to modify and track field table
encoded field sections refer to the state of the table without state, while encoded field sections refer to the state of the table
modifying it. without modifying it.
2.1. Document Organization 2.1. Document Organization
The following sections provide a detailed overview of the connection The following sections provide a detailed overview of the connection
lifecycle and key concepts: lifecycle and key concepts:
* Connection Setup and Management (Section 3) covers how an HTTP/3 * Connection Setup and Management (Section 3) covers how an HTTP/3
endpoint is discovered and a connection is established. endpoint is discovered and a connection is established.
* HTTP Request Lifecycle (Section 4) describes how HTTP semantics * HTTP Request Lifecycle (Section 4) describes how HTTP semantics
skipping to change at page 7, line 25 skipping to change at page 7, line 25
in Appendix A. in Appendix A.
2.2. Conventions and Terminology 2.2. Conventions and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Field definitions are given in Augmented Backus-Naur Form (ABNF), as
defined in [RFC5234].
This document uses the variable-length integer encoding from This document uses the variable-length integer encoding from
[QUIC-TRANSPORT]. [QUIC-TRANSPORT].
The following terms are used: The following terms are used:
abort: An abrupt termination of a connection or stream, possibly due abort: An abrupt termination of a connection or stream, possibly due
to an error condition. to an error condition.
client: The endpoint that initiates an HTTP/3 connection. Clients client: The endpoint that initiates an HTTP/3 connection. Clients
send HTTP requests and receive HTTP responses. send HTTP requests and receive HTTP responses.
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sender: An endpoint that is transmitting frames. sender: An endpoint that is transmitting frames.
server: The endpoint that accepts an HTTP/3 connection. Servers server: The endpoint that accepts an HTTP/3 connection. Servers
receive HTTP requests and send HTTP responses. receive HTTP requests and send HTTP responses.
stream: A bidirectional or unidirectional bytestream provided by the stream: A bidirectional or unidirectional bytestream provided by the
QUIC transport. QUIC transport.
stream error: An error on the individual HTTP/3 stream. stream error: An error on the individual HTTP/3 stream.
The term "payload body" is defined in Section 6.3.3 of [SEMANTICS]. The term "payload body" is defined in Section 7.3.3 of [SEMANTICS].
Finally, the terms "gateway", "intermediary", "proxy", and "tunnel" Finally, the terms "gateway", "intermediary", "proxy", and "tunnel"
are defined in Section 2.2 of [SEMANTICS]. Intermediaries act as are defined in Section 2.2 of [SEMANTICS]. Intermediaries act as
both client and server at different times. both client and server at different times.
Packet diagrams in this document use the format defined in
Section 1.3 of [QUIC-TRANSPORT] to illustrate the order and size of
fields.
3. Connection Setup and Management 3. Connection Setup and Management
3.1. Draft Version Identification 3.1. Draft Version Identification
*RFC Editor's Note:* Please remove this section prior to *RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document. publication of a final version of this document.
HTTP/3 uses the token "h3" to identify itself in ALPN and Alt-Svc. HTTP/3 uses the token "h3" to identify itself in ALPN and Alt-Svc.
Only implementations of the final, published RFC can identify Only implementations of the final, published RFC can identify
themselves as "h3". Until such an RFC exists, implementations MUST themselves as "h3". Until such an RFC exists, implementations MUST
skipping to change at page 9, line 13 skipping to change at page 9, line 8
"h3-01". "h3-01".
Draft versions MUST use the corresponding draft transport version as Draft versions MUST use the corresponding draft transport version as
their transport. For example, the application protocol defined in their transport. For example, the application protocol defined in
draft-ietf-quic-http-25 uses the transport defined in draft-ietf- draft-ietf-quic-http-25 uses the transport defined in draft-ietf-
quic-transport-25. quic-transport-25.
Non-compatible experiments that are based on these draft versions Non-compatible experiments that are based on these draft versions
MUST append the string "-" and an experiment name to the identifier. MUST append the string "-" and an experiment name to the identifier.
For example, an experimental implementation based on draft-ietf-quic- For example, an experimental implementation based on draft-ietf-quic-
http-09 which reserves an extra stream for unsolicited transmission http-09 that reserves an extra stream for unsolicited transmission of
of 1980s pop music might identify itself as "h3-09-rickroll". Note 1980s pop music might identify itself as "h3-09-rickroll". Note that
that any label MUST conform to the "token" syntax defined in any label MUST conform to the "token" syntax defined in
Section 4.4.1.1 of [SEMANTICS]. Experimenters are encouraged to Section 5.4.1.1 of [SEMANTICS]. Experimenters are encouraged to
coordinate their experiments on the quic@ietf.org coordinate their experiments on the quic@ietf.org mailing list.
(mailto:quic@ietf.org) mailing list.
3.2. Discovering an HTTP/3 Endpoint 3.2. Discovering an HTTP/3 Endpoint
HTTP relies on the notion of an authoritative response: a response HTTP relies on the notion of an authoritative response: a response
that has been determined to be the most appropriate response for that that has been determined to be the most appropriate response for that
request given the state of the target resource at the time of request given the state of the target resource at the time of
response message origination by (or at the direction of) the origin response message origination by (or at the direction of) the origin
server identified within the target URI. Locating an authoritative server identified within the target URI. Locating an authoritative
server for an HTTP URL is discussed in Section 5.4 of [SEMANTICS]. server for an HTTP URL is discussed in Section 6.4 of [SEMANTICS].
The "https" scheme associates authority with possession of a The "https" scheme associates authority with possession of a
certificate that the client considers to be trustworthy for the host certificate that the client considers to be trustworthy for the host
identified by the authority component of the URL. If a server identified by the authority component of the URL. If a server
presents a certificate and proof that it controls the corresponding presents a certificate and proof that it controls the corresponding
private key, then a client will accept a secured connection to that private key, then a client will accept a secured connection to that
server as being authoritative for all origins with the "https" scheme server as being authoritative for all origins with the "https" scheme
and a host identified in the certificate. and a host identified in the certificate.
A client MAY attempt access to a resource with an "https" URI by A client MAY attempt access to a resource with an "https" URI by
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based versions of HTTP in this case. based versions of HTTP in this case.
Servers MAY serve HTTP/3 on any UDP port; an alternative service Servers MAY serve HTTP/3 on any UDP port; an alternative service
advertisement always includes an explicit port, and URLs contain advertisement always includes an explicit port, and URLs contain
either an explicit port or a default port associated with the scheme. either an explicit port or a default port associated with the scheme.
3.2.1. HTTP Alternative Services 3.2.1. HTTP Alternative Services
An HTTP origin advertises the availability of an equivalent HTTP/3 An HTTP origin advertises the availability of an equivalent HTTP/3
endpoint via the Alt-Svc HTTP response header field or the HTTP/2 endpoint via the Alt-Svc HTTP response header field or the HTTP/2
ALTSVC frame ([ALTSVC]), using the ALPN token defined in Section 3.3. ALTSVC frame ([ALTSVC]), using the Application Layer Protocol
Negotiation (ALPN; see [RFC7301]) token defined in Section 3.3.
For example, an origin could indicate in an HTTP response that HTTP/3 For example, an origin could indicate in an HTTP response that HTTP/3
was available on UDP port 50781 at the same hostname by including the was available on UDP port 50781 at the same hostname by including the
following header field: following header field:
Alt-Svc: h3=":50781" Alt-Svc: h3=":50781"
On receipt of an Alt-Svc record indicating HTTP/3 support, a client On receipt of an Alt-Svc record indicating HTTP/3 support, a client
MAY attempt to establish a QUIC connection to the indicated host and MAY attempt to establish a QUIC connection to the indicated host and
port and, if successful, send HTTP requests using the mapping port; if this connection is successful, the client can send HTTP
described in this document. requests using the mapping described in this document.
3.2.2. Other Schemes 3.2.2. Other Schemes
Although HTTP is independent of the transport protocol, the "http" Although HTTP is independent of the transport protocol, the "http"
scheme associates authority with the ability to receive TCP scheme associates authority with the ability to receive TCP
connections on the indicated port of whatever host is identified connections on the indicated port of whatever host is identified
within the authority component. Because HTTP/3 does not use TCP, within the authority component. Because HTTP/3 does not use TCP,
HTTP/3 cannot be used for direct access to the authoritative server HTTP/3 cannot be used for direct access to the authoritative server
for a resource identified by an "http" URI. However, protocol for a resource identified by an "http" URI. However, protocol
extensions such as [ALTSVC] permit the authoritative server to extensions such as [ALTSVC] permit the authoritative server to
identify other services which are also authoritative and which might identify other services that are also authoritative and that might be
be reachable over HTTP/3. reachable over HTTP/3.
Prior to making requests for an origin whose scheme is not "https", Prior to making requests for an origin whose scheme is not "https",
the client MUST ensure the server is willing to serve that scheme. the client MUST ensure the server is willing to serve that scheme.
If the client intends to make requests for an origin whose scheme is If the client intends to make requests for an origin whose scheme is
"http", this means that it MUST obtain a valid "http-opportunistic" "http", this means that it MUST obtain a valid "http-opportunistic"
response for the origin as described in [RFC8164] prior to making any response for the origin as described in [RFC8164] prior to making any
such requests. Other schemes might define other mechanisms. such requests. Other schemes might define other mechanisms.
3.3. Connection Establishment 3.3. Connection Establishment
HTTP/3 relies on QUIC version 1 as the underlying transport. The use HTTP/3 relies on QUIC version 1 as the underlying transport. The use
of other QUIC transport versions with HTTP/3 MAY be defined by future of other QUIC transport versions with HTTP/3 MAY be defined by future
specifications. specifications.
QUIC version 1 uses TLS version 1.3 or greater as its handshake QUIC version 1 uses TLS version 1.3 or greater as its handshake
protocol. HTTP/3 clients MUST support a mechanism to indicate the protocol. HTTP/3 clients MUST support a mechanism to indicate the
target host to the server during the TLS handshake. If the server is target host to the server during the TLS handshake. If the server is
identified by a DNS name, clients MUST send the Server Name identified by a DNS name, clients MUST send the Server Name
Indication (SNI) [RFC6066] TLS extension unless an alternative Indication (SNI; [RFC6066]) TLS extension unless an alternative
mechanism to indicate the target host is used. mechanism to indicate the target host is used.
QUIC connections are established as described in [QUIC-TRANSPORT]. QUIC connections are established as described in [QUIC-TRANSPORT].
During connection establishment, HTTP/3 support is indicated by During connection establishment, HTTP/3 support is indicated by
selecting the ALPN token "h3" in the TLS handshake. Support for selecting the ALPN token "h3" in the TLS handshake. Support for
other application-layer protocols MAY be offered in the same other application-layer protocols MAY be offered in the same
handshake. handshake.
While connection-level options pertaining to the core QUIC protocol While connection-level options pertaining to the core QUIC protocol
are set in the initial crypto handshake, HTTP/3-specific settings are are set in the initial crypto handshake, HTTP/3-specific settings are
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reused for requests with multiple different URI authority components. reused for requests with multiple different URI authority components.
In general, a server is considered authoritative for all URIs with In general, a server is considered authoritative for all URIs with
the "https" scheme for which the hostname in the URI is present in the "https" scheme for which the hostname in the URI is present in
the authenticated certificate provided by the server, either as the the authenticated certificate provided by the server, either as the
CN field of the certificate subject or as a dNSName in the CN field of the certificate subject or as a dNSName in the
subjectAltName field of the certificate; see [RFC6125]. For a host subjectAltName field of the certificate; see [RFC6125]. For a host
that is an IP address, the client MUST verify that the address that is an IP address, the client MUST verify that the address
appears as an iPAddress in the subjectAltName field of the appears as an iPAddress in the subjectAltName field of the
certificate. If the hostname or address is not present in the certificate. If the hostname or address is not present in the
certificate, the client MUST NOT consider the server authoritative certificate, the client MUST NOT consider the server authoritative
for origins containing that hostname or address. See Section 5.4 of for origins containing that hostname or address. See Section 6.4 of
[SEMANTICS] for more detail on authoritative access. [SEMANTICS] for more detail on authoritative access.
Clients SHOULD NOT open more than one HTTP/3 connection to a given Clients SHOULD NOT open more than one HTTP/3 connection to a given
host and port pair, where the host is derived from a URI, a selected host and port pair, where the host is derived from a URI, a selected
alternative service [ALTSVC], or a configured proxy. A client MAY alternative service ([ALTSVC]), or a configured proxy. A client MAY
open multiple connections to the same IP address and UDP port using open multiple connections to the same IP address and UDP port using
different transport or TLS configurations but SHOULD avoid creating different transport or TLS configurations but SHOULD avoid creating
multiple connections with the same configuration. multiple connections with the same configuration.
Servers are encouraged to maintain open connections for as long as Servers are encouraged to maintain open connections for as long as
possible but are permitted to terminate idle connections if possible but are permitted to terminate idle connections if
necessary. When either endpoint chooses to close the HTTP/3 session, necessary. When either endpoint chooses to close the HTTP/3
the terminating endpoint SHOULD first send a GOAWAY frame connection, the terminating endpoint SHOULD first send a GOAWAY frame
(Section 5.2) so that both endpoints can reliably determine whether (Section 5.2) so that both endpoints can reliably determine whether
previously sent frames have been processed and gracefully complete or previously sent frames have been processed and gracefully complete or
terminate any necessary remaining tasks. terminate any necessary remaining tasks.
A server that does not wish clients to reuse connections for a A server that does not wish clients to reuse connections for a
particular origin can indicate that it is not authoritative for a particular origin can indicate that it is not authoritative for a
request by sending a 421 (Misdirected Request) status code in request by sending a 421 (Misdirected Request) status code in
response to the request; see Section 9.1.2 of [HTTP2]. response to the request; see Section 9.1.2 of [HTTP2].
4. HTTP Request Lifecycle 4. HTTP Request Lifecycle
4.1. HTTP Message Exchanges 4.1. HTTP Message Exchanges
A client sends an HTTP request on a client-initiated bidirectional A client sends an HTTP request on a client-initiated bidirectional
QUIC stream. A client MUST send only a single request on a given QUIC stream. A client MUST send only a single request on a given
stream. A server sends zero or more interim HTTP responses on the stream. A server sends zero or more interim HTTP responses on the
same stream as the request, followed by a single final HTTP response, same stream as the request, followed by a single final HTTP response,
as detailed below. as detailed below. See Section 10 of [SEMANTICS] for a description
of interim and final HTTP responses.
Pushed responses are sent on a server-initiated unidirectional QUIC Pushed responses are sent on a server-initiated unidirectional QUIC
stream; see Section 6.2.2. A server sends zero or more interim HTTP stream; see Section 6.2.2. A server sends zero or more interim HTTP
responses, followed by a single final HTTP response, in the same responses, followed by a single final HTTP response, in the same
manner as a standard response. Push is described in more detail in manner as a standard response. Push is described in more detail in
Section 4.4. Section 4.4.
On a given stream, receipt of multiple requests or receipt of an On a given stream, receipt of multiple requests or receipt of an
additional HTTP response following a final HTTP response MUST be additional HTTP response following a final HTTP response MUST be
treated as malformed (Section 4.1.3). treated as malformed (Section 4.1.3).
An HTTP message (request or response) consists of: An HTTP message (request or response) consists of:
1. the header field section (see Section 4 of [SEMANTICS]), sent as 1. the header field section, sent as a single HEADERS frame (see
a single HEADERS frame (see Section 7.2.2), Section 7.2.2),
2. optionally, the payload body, if present (see Section 6.3.3 of 2. optionally, the payload body, if present, sent as a series of
[SEMANTICS]), sent as a series of DATA frames (see DATA frames (see Section 7.2.1), and
Section 7.2.1),
3. optionally, the trailer field section, if present (see 3. optionally, the trailer field section, if present, sent as a
Section 4.6 of [SEMANTICS]), sent as a single HEADERS frame. single HEADERS frame.
Header and trailer field sections are described in Section 5 of
[SEMANTICS]; the payload body is described in Section 7.3.3 of
[SEMANTICS].
Receipt of an invalid sequence of frames MUST be treated as a Receipt of an invalid sequence of frames MUST be treated as a
connection error of type H3_FRAME_UNEXPECTED (Section 8). In connection error of type H3_FRAME_UNEXPECTED (Section 8). In
particular, a DATA frame before any HEADERS frame, or a HEADERS or particular, a DATA frame before any HEADERS frame, or a HEADERS or
DATA frame after the trailing HEADERS frame is considered invalid. DATA frame after the trailing HEADERS frame is considered invalid.
A server MAY send one or more PUSH_PROMISE frames (see Section 7.2.5) A server MAY send one or more PUSH_PROMISE frames (Section 7.2.5)
before, after, or interleaved with the frames of a response message. before, after, or interleaved with the frames of a response message.
These PUSH_PROMISE frames are not part of the response; see These PUSH_PROMISE frames are not part of the response; see
Section 4.4 for more details. These frames are not permitted in Section 4.4 for more details. These frames are not permitted in
pushed responses; a pushed response which includes PUSH_PROMISE pushed responses; a pushed response that includes PUSH_PROMISE frames
frames MUST be treated as a connection error of type MUST be treated as a connection error of type H3_FRAME_UNEXPECTED.
H3_FRAME_UNEXPECTED.
Frames of unknown types (Section 9), including reserved frames Frames of unknown types (Section 9), including reserved frames
(Section 7.2.8) MAY be sent on a request or push stream before, (Section 7.2.8) MAY be sent on a request or push stream before,
after, or interleaved with other frames described in this section. after, or interleaved with other frames described in this section.
The HEADERS and PUSH_PROMISE frames might reference updates to the The HEADERS and PUSH_PROMISE frames might reference updates to the
QPACK dynamic table. While these updates are not directly part of QPACK dynamic table. While these updates are not directly part of
the message exchange, they must be received and processed before the the message exchange, they must be received and processed before the
message can be consumed. See Section 4.1.1 for more details. message can be consumed. See Section 4.1.1 for more details.
The "chunked" transfer encoding defined in Section 7.1 of [HTTP11] The "chunked" transfer encoding defined in Section 7.1 of [HTTP11]
MUST NOT be used. MUST NOT be used.
A response MAY consist of multiple messages when and only when one or A response MAY consist of multiple messages when and only when one or
more informational responses (1xx; see Section 9.2 of [SEMANTICS]) more interim responses (1xx; see Section 10.2 of [SEMANTICS]) precede
precede a final response to the same request. Interim responses do a final response to the same request. Interim responses do not
not contain a payload body or trailers. contain a payload body or trailers.
An HTTP request/response exchange fully consumes a client-initiated An HTTP request/response exchange fully consumes a client-initiated
bidirectional QUIC stream. After sending a request, a client MUST bidirectional QUIC stream. After sending a request, a client MUST
close the stream for sending. Unless using the CONNECT method (see close the stream for sending. Unless using the CONNECT method (see
Section 4.2), clients MUST NOT make stream closure dependent on Section 4.2), clients MUST NOT make stream closure dependent on
receiving a response to their request. After sending a final receiving a response to their request. After sending a final
response, the server MUST close the stream for sending. At this response, the server MUST close the stream for sending. At this
point, the QUIC stream is fully closed. point, the QUIC stream is fully closed.
When a stream is closed, this indicates the end of an HTTP message. When a stream is closed, this indicates the end of the final HTTP
Because some messages are large or unbounded, endpoints SHOULD begin message. Because some messages are large or unbounded, endpoints
processing partial HTTP messages once enough of the message has been SHOULD begin processing partial HTTP messages once enough of the
received to make progress. If a client stream terminates without message has been received to make progress. If a client-initiated
enough of the HTTP message to provide a complete response, the server stream terminates without enough of the HTTP message to provide a
SHOULD abort its response with the error code H3_REQUEST_INCOMPLETE. complete response, the server SHOULD abort its response with the
error code H3_REQUEST_INCOMPLETE.
A server can send a complete response prior to the client sending an A server can send a complete response prior to the client sending an
entire request if the response does not depend on any portion of the entire request if the response does not depend on any portion of the
request that has not been sent and received. When the server does request that has not been sent and received. When the server does
not need to receive the remainder of the request, it MAY abort not need to receive the remainder of the request, it MAY abort
reading the request stream, send a complete response, and cleanly reading the request stream, send a complete response, and cleanly
close the sending part of the stream. The error code H3_NO_ERROR close the sending part of the stream. The error code H3_NO_ERROR
SHOULD be used when requesting that the client stop sending on the SHOULD be used when requesting that the client stop sending on the
request stream. Clients MUST NOT discard complete responses as a request stream. Clients MUST NOT discard complete responses as a
result of having their request terminated abruptly, though clients result of having their request terminated abruptly, though clients
can always discard responses at their discretion for other reasons. can always discard responses at their discretion for other reasons.
If the server sends a partial or complete response but does not abort If the server sends a partial or complete response but does not abort
reading, clients SHOULD continue sending the body of the request and reading the request, clients SHOULD continue sending the body of the
close the stream normally. request and close the stream normally.
4.1.1. Field Formatting and Compression 4.1.1. Field Formatting and Compression
HTTP messages carry metadata as a series of key-value pairs, called HTTP messages carry metadata as a series of key-value pairs, called
HTTP fields. For a listing of registered HTTP fields, see the HTTP fields. For a listing of registered HTTP fields, see the
"Hypertext Transfer Protocol (HTTP) Field Name Registry" maintained "Hypertext Transfer Protocol (HTTP) Field Name Registry" maintained
at https://www.iana.org/assignments/http-fields/. at https://www.iana.org/assignments/http-fields/.
As in previous versions of HTTP, field names are strings containing a As in previous versions of HTTP, field names are strings containing a
subset of ASCII characters that are compared in a case-insensitive subset of ASCII characters that are compared in a case-insensitive
fashion. Properties of HTTP field names and values are discussed in fashion. Properties of HTTP field names and values are discussed in
more detail in Section 4.3 of [SEMANTICS]. As in HTTP/2, characters more detail in Section 5.3 of [SEMANTICS]. As in HTTP/2, characters
in field names MUST be converted to lowercase prior to their in field names MUST be converted to lowercase prior to their
encoding. A request or response containing uppercase characters in encoding. A request or response containing uppercase characters in
field names MUST be treated as malformed (Section 4.1.3). field names MUST be treated as malformed (Section 4.1.3).
Like HTTP/2, HTTP/3 does not use the Connection header field to Like HTTP/2, HTTP/3 does not use the Connection header field to
indicate connection-specific fields; in this protocol, connection- indicate connection-specific fields; in this protocol, connection-
specific metadata is conveyed by other means. An endpoint MUST NOT specific metadata is conveyed by other means. An endpoint MUST NOT
generate an HTTP/3 field section containing connection-specific generate an HTTP/3 field section containing connection-specific
fields; any message containing connection-specific fields MUST be fields; any message containing connection-specific fields MUST be
treated as malformed (Section 4.1.3). treated as malformed (Section 4.1.3).
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undefined or invalid pseudo-header fields as malformed undefined or invalid pseudo-header fields as malformed
(Section 4.1.3). (Section 4.1.3).
All pseudo-header fields MUST appear in the header field section All pseudo-header fields MUST appear in the header field section
before regular header fields. Any request or response that contains before regular header fields. Any request or response that contains
a pseudo-header field that appears in a header field section after a a pseudo-header field that appears in a header field section after a
regular header field MUST be treated as malformed (Section 4.1.3). regular header field MUST be treated as malformed (Section 4.1.3).
The following pseudo-header fields are defined for requests: The following pseudo-header fields are defined for requests:
":method": Contains the HTTP method (Section 7 of [SEMANTICS]) ":method": Contains the HTTP method (Section 8 of [SEMANTICS])
":scheme": Contains the scheme portion of the target URI ":scheme": Contains the scheme portion of the target URI
(Section 3.1 of [RFC3986]) (Section 3.1 of [RFC3986])
":scheme" is not restricted to "http" and "https" schemed URIs. A ":scheme" is not restricted to "http" and "https" schemed URIs. A
proxy or gateway can translate requests for non-HTTP schemes, proxy or gateway can translate requests for non-HTTP schemes,
enabling the use of HTTP to interact with non-HTTP services. enabling the use of HTTP to interact with non-HTTP services.
":authority": Contains the authority portion of the target URI ":authority": Contains the authority portion of the target URI
(Section 3.2 of [RFC3986]). The authority MUST NOT include the (Section 3.2 of [RFC3986]). The authority MUST NOT include the
skipping to change at page 16, line 30 skipping to change at page 16, line 9
URIs; "http" or "https" URIs that do not contain a path component URIs; "http" or "https" URIs that do not contain a path component
MUST include a value of '/'. The exception to this rule is an MUST include a value of '/'. The exception to this rule is an
OPTIONS request for an "http" or "https" URI that does not include OPTIONS request for an "http" or "https" URI that does not include
a path component; these MUST include a ":path" pseudo-header field a path component; these MUST include a ":path" pseudo-header field
with a value of '*'; see Section 3.2.4 of [HTTP11]. with a value of '*'; see Section 3.2.4 of [HTTP11].
All HTTP/3 requests MUST include exactly one value for the ":method", All HTTP/3 requests MUST include exactly one value for the ":method",
":scheme", and ":path" pseudo-header fields, unless it is a CONNECT ":scheme", and ":path" pseudo-header fields, unless it is a CONNECT
request; see Section 4.2. request; see Section 4.2.
If the ":scheme" pseudo-header field identifies a scheme which has a If the ":scheme" pseudo-header field identifies a scheme that has a
mandatory authority component (including "http" and "https"), the mandatory authority component (including "http" and "https"), the
request MUST contain either an ":authority" pseudo-header field or a request MUST contain either an ":authority" pseudo-header field or a
"Host" header field. If these fields are present, they MUST NOT be "Host" header field. If these fields are present, they MUST NOT be
empty. If both fields are present, they MUST contain the same value. empty. If both fields are present, they MUST contain the same value.
If the scheme does not have a mandatory authority component and none If the scheme does not have a mandatory authority component and none
is provided in the request target, the request MUST NOT contain the is provided in the request target, the request MUST NOT contain the
":authority" pseudo-header and "Host" header fields. ":authority" pseudo-header or "Host" header fields.
An HTTP request that omits mandatory pseudo-header fields or contains An HTTP request that omits mandatory pseudo-header fields or contains
invalid values for those pseudo-header fields is malformed invalid values for those pseudo-header fields is malformed
(Section 4.1.3). (Section 4.1.3).
HTTP/3 does not define a way to carry the version identifier that is HTTP/3 does not define a way to carry the version identifier that is
included in the HTTP/1.1 request line. included in the HTTP/1.1 request line.
For responses, a single ":status" pseudo-header field is defined that For responses, a single ":status" pseudo-header field is defined that
carries the HTTP status code; see Section 9 of [SEMANTICS]. This carries the HTTP status code; see Section 10 of [SEMANTICS]. This
pseudo-header field MUST be included in all responses; otherwise, the pseudo-header field MUST be included in all responses; otherwise, the
response is malformed (Section 4.1.3). response is malformed (Section 4.1.3).
HTTP/3 does not define a way to carry the version or reason phrase HTTP/3 does not define a way to carry the version or reason phrase
that is included in an HTTP/1.1 status line. that is included in an HTTP/1.1 status line.
4.1.1.2. Field Compression 4.1.1.2. Field Compression
HTTP/3 uses QPACK field compression as described in [QPACK], a HTTP/3 uses QPACK field compression as described in [QPACK], a
variation of HPACK which allows the flexibility to avoid compression- variation of HPACK that allows the flexibility to avoid compression-
induced head-of-line blocking. See that document for additional induced head-of-line blocking. See that document for additional
details. details.
To allow for better compression efficiency, the "Cookie" field To allow for better compression efficiency, the "Cookie" field
[RFC6265] MAY be split into separate field lines, each with one or ([RFC6265]) MAY be split into separate field lines, each with one or
more cookie-pairs, before compression. If a decompressed field more cookie-pairs, before compression. If a decompressed field
section contains multiple cookie field lines, these MUST be section contains multiple cookie field lines, these MUST be
concatenated into a single octet string using the two-octet delimiter concatenated into a single octet string using the two-octet delimiter
of 0x3B, 0x20 (the ASCII string "; ") before being passed into a of 0x3b, 0x20 (the ASCII string "; ") before being passed into a
context other than HTTP/2 or HTTP/3, such as an HTTP/1.1 connection, context other than HTTP/2 or HTTP/3, such as an HTTP/1.1 connection,
or a generic HTTP server application. or a generic HTTP server application.
4.1.1.3. Header Size Constraints 4.1.1.3. Header Size Constraints
An HTTP/3 implementation MAY impose a limit on the maximum size of An HTTP/3 implementation MAY impose a limit on the maximum size of
the message header it will accept on an individual HTTP message. A the message header it will accept on an individual HTTP message. A
server that receives a larger header section than it is willing to server that receives a larger header section than it is willing to
handle can send an HTTP 431 (Request Header Fields Too Large) status handle can send an HTTP 431 (Request Header Fields Too Large) status
code ([RFC6585]). A client can discard responses that it cannot code ([RFC6585]). A client can discard responses that it cannot
process. The size of a field list is calculated based on the process. The size of a field list is calculated based on the
uncompressed size of fields, including the length of the name and uncompressed size of fields, including the length of the name and
value in bytes plus an overhead of 32 bytes for each field. value in bytes plus an overhead of 32 bytes for each field.
If an implementation wishes to advise its peer of this limit, it can If an implementation wishes to advise its peer of this limit, it can
be conveyed as a number of bytes in the be conveyed as a number of bytes in the
SETTINGS_MAX_FIELD_SECTION_SIZE parameter. An implementation which SETTINGS_MAX_FIELD_SECTION_SIZE parameter. An implementation that
has received this parameter SHOULD NOT send an HTTP message header has received this parameter SHOULD NOT send an HTTP message header
which exceeds the indicated size, as the peer will likely refuse to that exceeds the indicated size, as the peer will likely refuse to
process it. However, because this limit is applied at each hop, process it. However, because this limit is applied at each hop,
messages below this limit are not guaranteed to be accepted. messages below this limit are not guaranteed to be accepted.
4.1.2. Request Cancellation and Rejection 4.1.2. Request Cancellation and Rejection
Clients can cancel requests by resetting and aborting the request Once a request stream has been opened, the request MAY be cancelled
stream with an error code of H3_REQUEST_CANCELLED (Section 8.1). by either endpoint. Clients cancel requests if the response is no
When the client aborts reading a response, it indicates that this longer of interest; servers cancel requests if they are unable to or
response is no longer of interest. Implementations SHOULD cancel choose not to respond. When possible, it is RECOMMENDED that servers
requests by abruptly terminating any directions of a stream that are send an HTTP response with an appropriate status code rather than
still open. canceling a request it has already begun processing.
Implementations SHOULD cancel requests by abruptly terminating any
directions of a stream that are still open. This means resetting the
sending parts of streams and aborting reading on receiving parts of
streams; see Section 2.4 of [QUIC-TRANSPORT].
When the server cancels a request without performing any application
processing, the request is considered "rejected." The server SHOULD
abort its response stream with the error code H3_REQUEST_REJECTED.
In this context, "processed" means that some data from the stream was
passed to some higher layer of software that might have taken some
action as a result. The client can treat requests rejected by the
server as though they had never been sent at all, thereby allowing
them to be retried later.
When the server rejects a request without performing any application
processing, it SHOULD abort its response stream with the error code
H3_REQUEST_REJECTED. In this context, "processed" means that some
data from the stream was passed to some higher layer of software that
might have taken some action as a result. The client can treat
requests rejected by the server as though they had never been sent at
all, thereby allowing them to be retried later on a new connection.
Servers MUST NOT use the H3_REQUEST_REJECTED error code for requests Servers MUST NOT use the H3_REQUEST_REJECTED error code for requests
which were partially or fully processed. When a server abandons a that were partially or fully processed. When a server abandons a
response after partial processing, it SHOULD abort its response response after partial processing, it SHOULD abort its response
stream with the error code H3_REQUEST_CANCELLED. stream with the error code H3_REQUEST_CANCELLED.
When a client resets a request with the error code Client SHOULD use the error code H3_REQUEST_CANCELLED to cancel
H3_REQUEST_CANCELLED, a server MAY abruptly terminate the response requests. Upon receipt of this error code, a server MAY abruptly
using the error code H3_REQUEST_REJECTED if no processing was terminate the response using the error code H3_REQUEST_REJECTED if no
performed. Clients MUST NOT use the H3_REQUEST_REJECTED error code, processing was performed. Clients MUST NOT use the
except when a server has requested closure of the request stream with H3_REQUEST_REJECTED error code, except when a server has requested
this error code. closure of the request stream with this error code.
If a stream is cancelled after receiving a complete response, the If a stream is canceled after receiving a complete response, the
client MAY ignore the cancellation and use the response. However, if client MAY ignore the cancellation and use the response. However, if
a stream is cancelled after receiving a partial response, the a stream is cancelled after receiving a partial response, the
response SHOULD NOT be used. Automatically retrying such requests is response SHOULD NOT be used. Automatically retrying such requests is
not possible, unless this is otherwise permitted (e.g., idempotent not possible, unless this is otherwise permitted (e.g., idempotent
actions like GET, PUT, or DELETE). actions like GET, PUT, or DELETE).
4.1.3. Malformed Requests and Responses 4.1.3. Malformed Requests and Responses
A malformed request or response is one that is an otherwise valid A malformed request or response is one that is an otherwise valid
sequence of frames but is invalid due to: sequence of frames but is invalid due to:
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* an invalid sequence of HTTP messages, * an invalid sequence of HTTP messages,
* the inclusion of uppercase field names, or * the inclusion of uppercase field names, or
* the inclusion of invalid characters in field names or values * the inclusion of invalid characters in field names or values
A request or response that includes a payload body can include a A request or response that includes a payload body can include a
Content-Length header field. A request or response is also malformed Content-Length header field. A request or response is also malformed
if the value of a content-length header field does not equal the sum if the value of a content-length header field does not equal the sum
of the DATA frame payload lengths that form the body. A response of the DATA frame payload lengths that form the body. A response
that is defined to have no payload, as described in Section 6.3.3 of that is defined to have no payload, as described in Section 7.3.3 of
[SEMANTICS] can have a non-zero content-length field, even though no [SEMANTICS] can have a non-zero content-length field, even though no
content is included in DATA frames. content is included in DATA frames.
Intermediaries that process HTTP requests or responses (i.e., any Intermediaries that process HTTP requests or responses (i.e., any
intermediary not acting as a tunnel) MUST NOT forward a malformed intermediary not acting as a tunnel) MUST NOT forward a malformed
request or response. Malformed requests or responses that are request or response. Malformed requests or responses that are
detected MUST be treated as a stream error (Section 8) of type detected MUST be treated as a stream error (Section 8) of type
H3_GENERAL_PROTOCOL_ERROR. H3_GENERAL_PROTOCOL_ERROR.
For malformed requests, a server MAY send an HTTP response prior to For malformed requests, a server MAY send an HTTP response indicating
closing or resetting the stream. Clients MUST NOT accept a malformed the error prior to closing or resetting the stream. Clients MUST NOT
response. Note that these requirements are intended to protect accept a malformed response. Note that these requirements are
against several types of common attacks against HTTP; they are intended to protect against several types of common attacks against
deliberately strict because being permissive can expose HTTP; they are deliberately strict because being permissive can
implementations to these vulnerabilities. expose implementations to these vulnerabilities.
4.2. The CONNECT Method 4.2. The CONNECT Method
The CONNECT method requests that the recipient establish a tunnel to The CONNECT method requests that the recipient establish a tunnel to
the destination origin server identified by the request-target the destination origin server identified by the request-target
(Section 3.2 of [HTTP11]). It is primarily used with HTTP proxies to (Section 3.2 of [HTTP11]). It is primarily used with HTTP proxies to
establish a TLS session with an origin server for the purposes of establish a TLS session with an origin server for the purposes of
interacting with "https" resources. interacting with "https" resources.
In HTTP/1.x, CONNECT is used to convert an entire HTTP connection In HTTP/1.x, CONNECT is used to convert an entire HTTP connection
skipping to change at page 20, line 9 skipping to change at page 19, line 42
of CONNECT requests; see Section 3.2.3 of [HTTP11]) of CONNECT requests; see Section 3.2.3 of [HTTP11])
The request stream remains open at the end of the request to carry The request stream remains open at the end of the request to carry
the data to be transferred. A CONNECT request that does not conform the data to be transferred. A CONNECT request that does not conform
to these restrictions is malformed; see Section 4.1.3. to these restrictions is malformed; see Section 4.1.3.
A proxy that supports CONNECT establishes a TCP connection A proxy that supports CONNECT establishes a TCP connection
([RFC0793]) to the server identified in the ":authority" pseudo- ([RFC0793]) to the server identified in the ":authority" pseudo-
header field. Once this connection is successfully established, the header field. Once this connection is successfully established, the
proxy sends a HEADERS frame containing a 2xx series status code to proxy sends a HEADERS frame containing a 2xx series status code to
the client, as defined in Section 9.3 of [SEMANTICS]. the client, as defined in Section 10.3 of [SEMANTICS].
All DATA frames on the stream correspond to data sent or received on All DATA frames on the stream correspond to data sent or received on
the TCP connection. Any DATA frame sent by the client is transmitted the TCP connection. The payload of any DATA frame sent by the client
by the proxy to the TCP server; data received from the TCP server is is transmitted by the proxy to the TCP server; data received from the
packaged into DATA frames by the proxy. Note that the size and TCP server is packaged into DATA frames by the proxy. Note that the
number of TCP segments is not guaranteed to map predictably to the size and number of TCP segments is not guaranteed to map predictably
size and number of HTTP DATA or QUIC STREAM frames. to the size and number of HTTP DATA or QUIC STREAM frames.
Once the CONNECT method has completed, only DATA frames are permitted Once the CONNECT method has completed, only DATA frames are permitted
to be sent on the stream. Extension frames MAY be used if to be sent on the stream. Extension frames MAY be used if
specifically permitted by the definition of the extension. Receipt specifically permitted by the definition of the extension. Receipt
of any other frame type MUST be treated as a connection error of type of any other known frame type MUST be treated as a connection error
H3_FRAME_UNEXPECTED. of type H3_FRAME_UNEXPECTED.
The TCP connection can be closed by either peer. When the client The TCP connection can be closed by either peer. When the client
ends the request stream (that is, the receive stream at the proxy ends the request stream (that is, the receive stream at the proxy
enters the "Data Recvd" state), the proxy will set the FIN bit on its enters the "Data Recvd" state), the proxy will set the FIN bit on its
connection to the TCP server. When the proxy receives a packet with connection to the TCP server. When the proxy receives a packet with
the FIN bit set, it will terminate the send stream that it sends to the FIN bit set, it will close the send stream that it sends to the
the client. TCP connections which remain half-closed in a single client. TCP connections that remain half-closed in a single
direction are not invalid, but are often handled poorly by servers, direction are not invalid, but are often handled poorly by servers,
so clients SHOULD NOT close a stream for sending while they still so clients SHOULD NOT close a stream for sending while they still
expect to receive data from the target of the CONNECT. expect to receive data from the target of the CONNECT.
A TCP connection error is signaled by abruptly terminating the A TCP connection error is signaled by abruptly terminating the
stream. A proxy treats any error in the TCP connection, which stream. A proxy treats any error in the TCP connection, which
includes receiving a TCP segment with the RST bit set, as a stream includes receiving a TCP segment with the RST bit set, as a stream
error of type H3_CONNECT_ERROR (Section 8.1). Correspondingly, if a error of type H3_CONNECT_ERROR (Section 8.1). Correspondingly, if a
proxy detects an error with the stream or the QUIC connection, it proxy detects an error with the stream or the QUIC connection, it
MUST close the TCP connection. If the underlying TCP implementation MUST close the TCP connection. If the underlying TCP implementation
permits it, the proxy SHOULD send a TCP segment with the RST bit set. permits it, the proxy SHOULD send a TCP segment with the RST bit set.
4.3. HTTP Upgrade 4.3. HTTP Upgrade
HTTP/3 does not support the HTTP Upgrade mechanism (Section 9.9 of HTTP/3 does not support the HTTP Upgrade mechanism (Section 6.7 of
[HTTP11]) or 101 (Switching Protocols) informational status code {{!SEMANTICS}) or 101 (Switching Protocols) informational status code
(Section 9.2.2 of [SEMANTICS]). (Section 10.2.2 of [SEMANTICS]).
4.4. Server Push 4.4. Server Push
Server push is an interaction mode which permits a server to push a Server push is an interaction mode that permits a server to push a
request-response exchange to a client in anticipation of the client request-response exchange to a client in anticipation of the client
making the indicated request. This trades off network usage against making the indicated request. This trades off network usage against
a potential latency gain. HTTP/3 server push is similar to what is a potential latency gain. HTTP/3 server push is similar to what is
described in HTTP/2 [HTTP2], but uses different mechanisms. described in Section 8.2 of [HTTP2], but uses different mechanisms.
Each server push is identified by a unique Push ID. This Push ID is Each server push is assigned a unique Push ID by the server. The
used in one or more PUSH_PROMISE frames (see Section 7.2.5) that Push ID is used to refer to the push in various contexts throughout
carry the request fields, then included with the push stream which the lifetime of the connection.
ultimately fulfills those promises. When the same Push ID is
promised on multiple request streams, the decompressed request field
sections MUST contain the same fields in the same order, and both the
name and the value in each field MUST be exact matches.
Server push is only enabled on a connection when a client sends a The Push ID space begins at zero, and ends at a maximum value set by
MAX_PUSH_ID frame; see Section 7.2.7. A server cannot use server the MAX_PUSH_ID frame; see Section 7.2.7. In particular, a server is
push until it receives a MAX_PUSH_ID frame. A client sends not able to push until after the client sends a MAX_PUSH_ID frame. A
additional MAX_PUSH_ID frames to control the number of pushes that a client sends MAX_PUSH_ID frames to control the number of pushes that
server can promise. A server SHOULD use Push IDs sequentially, a server can promise. A server SHOULD use Push IDs sequentially,
starting at 0. A client MUST treat receipt of a push stream with a beginning from zero. A client MUST treat receipt of a push stream as
Push ID that is greater than the maximum Push ID as a connection a connection error of type H3_ID_ERROR when no MAX_PUSH_ID frame has
error of type H3_ID_ERROR. been sent or when the stream references a Push ID that is greater
than the maximum Push ID.
The header section of the request message is carried by a The Push ID is used in one or more PUSH_PROMISE frames
PUSH_PROMISE frame (see Section 7.2.5) on the request stream which (Section 7.2.5) that carry the header section of the request message.
generated the push. This allows the server push to be associated These frames are sent on the request stream that generated the push.
with a client request. This allows the server push to be associated with a client request.
When the same Push ID is promised on multiple request streams, the
decompressed request field sections MUST contain the same fields in
the same order, and both the name and the value in each field MUST be
identical.
Not all requests can be pushed. A server MAY push requests which The Push ID is then included with the push stream that ultimately
have the following properties: fulfills those promises; see Section 6.2.2. The push stream
identifies the Push ID of the promise that it fulfills, then contains
a response to the promised request as described in Section 4.1.
* cacheable; see Section 7.2.3 of [SEMANTICS] Finally, the Push ID can be used in CANCEL_PUSH frames; see
Section 7.2.3. Clients use this frame to indicate they do not wish
to receive a promised resource. Servers use this frame to indicate
they will not be fulfilling a previous promise.
* safe; see Section 7.2.1 of [SEMANTICS] Not all requests can be pushed. A server MAY push requests that have
the following properties:
* cacheable; see Section 8.2.3 of [SEMANTICS]
* safe; see Section 8.2.1 of [SEMANTICS]
* does not include a request body or trailer section * does not include a request body or trailer section
The server MUST include a value in the ":authority" pseudo-header The server MUST include a value in the ":authority" pseudo-header
field for which the server is authoritative; see Section 3.4. field for which the server is authoritative; see Section 3.4.
Clients SHOULD send a CANCEL_PUSH frame upon receipt of a Clients SHOULD send a CANCEL_PUSH frame upon receipt of a
PUSH_PROMISE frame carrying a request which is not cacheable, is not PUSH_PROMISE frame carrying a request that is not cacheable, is not
known to be safe, that indicates the presence of a request body, or known to be safe, that indicates the presence of a request body, or
for which it does not consider the server authoritative. for which it does not consider the server authoritative.
Each pushed response is associated with one or more client requests. Each pushed response is associated with one or more client requests.
The push is associated with the request stream on which the The push is associated with the request stream on which the
PUSH_PROMISE frame was received. The same server push can be PUSH_PROMISE frame was received. The same server push can be
associated with additional client requests using a PUSH_PROMISE frame associated with additional client requests using a PUSH_PROMISE frame
with the same Push ID on multiple request streams. These with the same Push ID on multiple request streams. These
associations do not affect the operation of the protocol, but MAY be associations do not affect the operation of the protocol, but MAY be
considered by user agents when deciding how to use pushed resources. considered by user agents when deciding how to use pushed resources.
Ordering of a PUSH_PROMISE in relation to certain parts of the Ordering of a PUSH_PROMISE frame in relation to certain parts of the
response is important. The server SHOULD send PUSH_PROMISE frames response is important. The server SHOULD send PUSH_PROMISE frames
prior to sending HEADERS or DATA frames that reference the promised prior to sending HEADERS or DATA frames that reference the promised
responses. This reduces the chance that a client requests a resource responses. This reduces the chance that a client requests a resource
that will be pushed by the server. that will be pushed by the server.
When a server later fulfills a promise, the server push response is
conveyed on a push stream; see Section 6.2.2. The push stream
identifies the Push ID of the promise that it fulfills, then contains
a response to the promised request using the same format described
for responses in Section 4.1.
Due to reordering, push stream data can arrive before the Due to reordering, push stream data can arrive before the
corresponding PUSH_PROMISE frame. When a client receives a new push corresponding PUSH_PROMISE frame. When a client receives a new push
stream with an as-yet-unknown Push ID, both the associated client stream with an as-yet-unknown Push ID, both the associated client
request and the pushed request header fields are unknown. The client request and the pushed request header fields are unknown. The client
can buffer the stream data in expectation of the matching can buffer the stream data in expectation of the matching
PUSH_PROMISE. The client can use stream flow control (see section PUSH_PROMISE. The client can use stream flow control (see section
4.1 of [QUIC-TRANSPORT]) to limit the amount of data a server may 4.1 of [QUIC-TRANSPORT]) to limit the amount of data a server may
commit to the pushed stream. commit to the pushed stream.
If a promised server push is not needed by the client, the client Push stream data can also arrive after a client has canceled a push.
SHOULD send a CANCEL_PUSH frame. If the push stream is already open In this case, the client can abort reading the stream with an error
or opens after sending the CANCEL_PUSH frame, the client can abort code of H3_REQUEST_CANCELLED. This asks the server not to transfer
reading the stream with an error code of H3_REQUEST_CANCELLED. This additional data and indicates that it will be discarded upon receipt.
asks the server not to transfer additional data and indicates that it
will be discarded upon receipt.
Pushed responses that are cacheable (see Section 3 of [CACHING]) can Pushed responses that are cacheable (see Section 3 of [CACHING]) can
be stored by the client, if it implements an HTTP cache. Pushed be stored by the client, if it implements an HTTP cache. Pushed
responses are considered successfully validated on the origin server responses are considered successfully validated on the origin server
(e.g., if the "no-cache" cache response directive is present (e.g., if the "no-cache" cache response directive is present; see
(Section 5.2.2.3 of [CACHING])) at the time the pushed response is Section 5.2.2.3 of [CACHING]) at the time the pushed response is
received. received.
Pushed responses that are not cacheable MUST NOT be stored by any Pushed responses that are not cacheable MUST NOT be stored by any
HTTP cache. They MAY be made available to the application HTTP cache. They MAY be made available to the application
separately. separately.
5. Connection Closure 5. Connection Closure
Once established, an HTTP/3 connection can be used for many requests Once established, an HTTP/3 connection can be used for many requests
and responses over time until the connection is closed. Connection and responses over time until the connection is closed. Connection
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Each QUIC endpoint declares an idle timeout during the handshake. If Each QUIC endpoint declares an idle timeout during the handshake. If
the connection remains idle (no packets received) for longer than the connection remains idle (no packets received) for longer than
this duration, the peer will assume that the connection has been this duration, the peer will assume that the connection has been
closed. HTTP/3 implementations will need to open a new connection closed. HTTP/3 implementations will need to open a new connection
for new requests if the existing connection has been idle for longer for new requests if the existing connection has been idle for longer
than the server's advertised idle timeout, and SHOULD do so if than the server's advertised idle timeout, and SHOULD do so if
approaching the idle timeout. approaching the idle timeout.
HTTP clients are expected to request that the transport keep HTTP clients are expected to request that the transport keep
connections open while there are responses outstanding for requests connections open while there are responses outstanding for requests
or server pushes, as described in Section 10.2.2 of [QUIC-TRANSPORT]. or server pushes, as described in Section 10.1.2 of [QUIC-TRANSPORT].
If the client is not expecting a response from the server, allowing If the client is not expecting a response from the server, allowing
an idle connection to time out is preferred over expending effort an idle connection to time out is preferred over expending effort
maintaining a connection that might not be needed. A gateway MAY maintaining a connection that might not be needed. A gateway MAY
maintain connections in anticipation of need rather than incur the maintain connections in anticipation of need rather than incur the
latency cost of connection establishment to servers. Servers SHOULD latency cost of connection establishment to servers. Servers SHOULD
NOT actively keep connections open. NOT actively keep connections open.
5.2. Connection Shutdown 5.2. Connection Shutdown
Even when a connection is not idle, either endpoint can decide to Even when a connection is not idle, either endpoint can decide to
stop using the connection and initiate a graceful connection close. stop using the connection and initiate a graceful connection close.
Endpoints initiate the graceful shutdown of a connection by sending a Endpoints initiate the graceful shutdown of a connection by sending a
GOAWAY frame (Section 7.2.6). The GOAWAY frame contains an GOAWAY frame (Section 7.2.6). The GOAWAY frame contains an
identifier that indicates to the receiver the range of requests or identifier that indicates to the receiver the range of requests or
pushes that were or might be processed in this connection. The pushes that were or might be processed in this connection. The
server sends a client-initiated bidirectional Stream ID; the client server sends a client-initiated bidirectional Stream ID; the client
sends a Push ID. Requests or pushes with the indicated identifier or sends a Push ID (Section 4.4). Requests or pushes with the indicated
greater are rejected by the sender of the GOAWAY. This identifier identifier or greater are rejected (Section 4.1.2) by the sender of
MAY be zero if no requests or pushes were processed. the GOAWAY. This identifier MAY be zero if no requests or pushes
were processed.
The information in the GOAWAY frame enables a client and server to The information in the GOAWAY frame enables a client and server to
agree on which requests or pushes were accepted prior to the agree on which requests or pushes were accepted prior to the
connection shutdown. Upon sending a GOAWAY frame, the endpoint connection shutdown. Upon sending a GOAWAY frame, the endpoint
SHOULD explicitly cancel (see Section 4.1.2 and Section 7.2.3) any SHOULD explicitly cancel (see Section 4.1.2 and Section 7.2.3) any
requests or pushes that have identifiers greater than or equal to requests or pushes that have identifiers greater than or equal to
that indicated, in order to clean up transport state for the affected that indicated, in order to clean up transport state for the affected
streams. The endpoint SHOULD continue to do so as more requests or streams. The endpoint SHOULD continue to do so as more requests or
pushes arrive. pushes arrive.
Endpoints MUST NOT initiate new requests or promise new pushes on the Endpoints MUST NOT initiate new requests or promise new pushes on the
connection after receipt of a GOAWAY frame from the peer. Clients connection after receipt of a GOAWAY frame from the peer. Clients
MAY establish a new connection to send additional requests. MAY establish a new connection to send additional requests.
Some requests or pushes might already be in transit: Some requests or pushes might already be in transit:
* Upon receipt of a GOAWAY frame, if the client has already sent * Upon receipt of a GOAWAY frame, if the client has already sent
requests with a Stream ID greater than or equal to the identifier requests with a Stream ID greater than or equal to the identifier
received in a GOAWAY frame, those requests will not be processed. contained in the GOAWAY frame, those requests will not be
Clients can safely retry unprocessed requests on a different processed. Clients can safely retry unprocessed requests on a
different connection. A client that is unable to retry requests
loses all requests that are in flight when the server closes the
connection. connection.
Requests on Stream IDs less than the Stream ID in a GOAWAY frame Requests on Stream IDs less than the Stream ID in a GOAWAY frame
from the server might have been processed; their status cannot be from the server might have been processed; their status cannot be
known until a response is received, the stream is reset known until a response is received, the stream is reset
individually, another GOAWAY is received, or the connection individually, another GOAWAY is received, or the connection
terminates. terminates.
Servers MAY reject individual requests on streams below the Servers MAY reject individual requests on streams below the
indicated ID if these requests were not processed. indicated ID if these requests were not processed.
* If a server receives a GOAWAY frame after having promised pushes * If a server receives a GOAWAY frame after having promised pushes
with a Push ID greater than or equal to the identifier received in with a Push ID greater than or equal to the identifier contained
a GOAWAY frame, those pushes will not be accepted. in the GOAWAY frame, those pushes will not be accepted.
Servers SHOULD send a GOAWAY frame when the closing of a connection Servers SHOULD send a GOAWAY frame when the closing of a connection
is known in advance, even if the advance notice is small, so that the is known in advance, even if the advance notice is small, so that the
remote peer can know whether a request has been partially processed remote peer can know whether a request has been partially processed
or not. For example, if an HTTP client sends a POST at the same time or not. For example, if an HTTP client sends a POST at the same time
that a server closes a QUIC connection, the client cannot know if the that a server closes a QUIC connection, the client cannot know if the
server started to process that POST request if the server does not server started to process that POST request if the server does not
send a GOAWAY frame to indicate what streams it might have acted on. send a GOAWAY frame to indicate what streams it might have acted on.
A client that is unable to retry requests loses all requests that are An endpoint MAY send multiple GOAWAY frames indicating different
in flight when the server closes the connection. An endpoint MAY identifiers, but the identifier in each frame MUST NOT be greater
send multiple GOAWAY frames indicating different identifiers, but the than the identifier in any previous frame, since clients might
identifier in each frame MUST NOT be greater than the identifier in already have retried unprocessed requests on another connection.
any previous frame, since clients might already have retried Receiving a GOAWAY containing a larger identifier than previously
unprocessed requests on another connection. Receiving a GOAWAY received MUST be treated as a connection error of type H3_ID_ERROR.
containing a larger identifier than previously received MUST be
treated as a connection error of type H3_ID_ERROR.
An endpoint that is attempting to gracefully shut down a connection An endpoint that is attempting to gracefully shut down a connection
can send a GOAWAY frame with a value set to the maximum possible can send a GOAWAY frame with a value set to the maximum possible
value (2^62-4 for servers, 2^62-1 for clients). This ensures that value (2^62-4 for servers, 2^62-1 for clients). This ensures that
the peer stops creating new requests or pushes. After allowing time the peer stops creating new requests or pushes. After allowing time
for any in-flight requests or pushes to arrive, the endpoint can send for any in-flight requests or pushes to arrive, the endpoint can send
another GOAWAY frame indicating which requests or pushes it might another GOAWAY frame indicating which requests or pushes it might
accept before the end of the connection. This ensures that a accept before the end of the connection. This ensures that a
connection can be cleanly shut down without losing requests. connection can be cleanly shut down without losing requests.
A client has more flexibility in the value it chooses for the Push ID A client has more flexibility in the value it chooses for the Push ID
in a GOAWAY that it sends. A value of 2^62 - 1 indicates that the in a GOAWAY that it sends. A value of 2^62 - 1 indicates that the
server can continue fulfilling pushes which have already been server can continue fulfilling pushes that have already been
promised, and the client can continue granting push credit as needed; promised. A smaller value indicates the client will reject pushes
see Section 7.2.7. A smaller value indicates the client will reject with Push IDs greater than or equal to this value. Like the server,
pushes with Push IDs greater than or equal to this value. Like the the client MAY send subsequent GOAWAY frames so long as the specified
server, the client MAY send subsequent GOAWAY frames so long as the Push ID is no greater than any previously sent value.
specified Push ID is strictly smaller than all previously sent
values.
Even when a GOAWAY indicates that a given request or push will not be Even when a GOAWAY indicates that a given request or push will not be
processed or accepted upon receipt, the underlying transport processed or accepted upon receipt, the underlying transport
resources still exist. The endpoint that initiated these requests resources still exist. The endpoint that initiated these requests
can cancel them to clean up transport state. can cancel them to clean up transport state.
Once all accepted requests and pushes have been processed, the Once all accepted requests and pushes have been processed, the
endpoint can permit the connection to become idle, or MAY initiate an endpoint can permit the connection to become idle, or MAY initiate an
immediate closure of the connection. An endpoint that completes a immediate closure of the connection. An endpoint that completes a
graceful shutdown SHOULD use the H3_NO_ERROR code when closing the graceful shutdown SHOULD use the H3_NO_ERROR error code when closing
connection. the connection.
If a client has consumed all available bidirectional stream IDs with If a client has consumed all available bidirectional stream IDs with
requests, the server need not send a GOAWAY frame, since the client requests, the server need not send a GOAWAY frame, since the client
is unable to make further requests. is unable to make further requests.
5.3. Immediate Application Closure 5.3. Immediate Application Closure
An HTTP/3 implementation can immediately close the QUIC connection at An HTTP/3 implementation can immediately close the QUIC connection at
any time. This results in sending a QUIC CONNECTION_CLOSE frame to any time. This results in sending a QUIC CONNECTION_CLOSE frame to
the peer indicating that the application layer has terminated the the peer indicating that the application layer has terminated the
connection. The application error code in this frame indicates to connection. The application error code in this frame indicates to
the peer why the connection is being closed. See Section 8 for error the peer why the connection is being closed. See Section 8 for error
codes which can be used when closing a connection in HTTP/3. codes that can be used when closing a connection in HTTP/3.
Before closing the connection, a GOAWAY frame MAY be sent to allow Before closing the connection, a GOAWAY frame MAY be sent to allow
the client to retry some requests. Including the GOAWAY frame in the the client to retry some requests. Including the GOAWAY frame in the
same packet as the QUIC CONNECTION_CLOSE frame improves the chances same packet as the QUIC CONNECTION_CLOSE frame improves the chances
of the frame being received by clients. of the frame being received by clients.
5.4. Transport Closure 5.4. Transport Closure
For various reasons, the QUIC transport could indicate to the For various reasons, the QUIC transport could indicate to the
application layer that the connection has terminated. This might be application layer that the connection has terminated. This might be
due to an explicit closure by the peer, a transport-level error, or a due to an explicit closure by the peer, a transport-level error, or a
change in network topology which interrupts connectivity. change in network topology that interrupts connectivity.
If a connection terminates without a GOAWAY frame, clients MUST If a connection terminates without a GOAWAY frame, clients MUST
assume that any request which was sent, whether in whole or in part, assume that any request that was sent, whether in whole or in part,
might have been processed. might have been processed.
6. Stream Mapping and Usage 6. Stream Mapping and Usage
A QUIC stream provides reliable in-order delivery of bytes, but makes A QUIC stream provides reliable in-order delivery of bytes, but makes
no guarantees about order of delivery with regard to bytes on other no guarantees about order of delivery with regard to bytes on other
streams. On the wire, data is framed into QUIC STREAM frames, but streams. On the wire, data is framed into QUIC STREAM frames, but
this framing is invisible to the HTTP framing layer. The transport this framing is invisible to the HTTP framing layer. The transport
layer buffers and orders received QUIC STREAM frames, exposing the layer buffers and orders received QUIC STREAM frames, exposing the
data contained within as a reliable byte stream to the application. data contained within as a reliable byte stream to the application.
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as a variable-length integer at the start of the stream. The format as a variable-length integer at the start of the stream. The format
and structure of data that follows this integer is determined by the and structure of data that follows this integer is determined by the
stream type. stream type.
Unidirectional Stream Header { Unidirectional Stream Header {
Stream Type (i), Stream Type (i),
} }
Figure 1: Unidirectional Stream Header Figure 1: Unidirectional Stream Header
Some stream types are reserved (Section 6.2.3). Two stream types are Two stream types are defined in this document: control streams
defined in this document: control streams (Section 6.2.1) and push (Section 6.2.1) and push streams (Section 6.2.2). [QPACK] defines
streams (Section 6.2.2). [QPACK] defines two additional stream two additional stream types. Other stream types can be defined by
types. Other stream types can be defined by extensions to HTTP/3; extensions to HTTP/3; see Section 9 for more details. Some stream
see Section 9 for more details. types are reserved (Section 6.2.3).
The performance of HTTP/3 connections in the early phase of their The performance of HTTP/3 connections in the early phase of their
lifetime is sensitive to the creation and exchange of data on lifetime is sensitive to the creation and exchange of data on
unidirectional streams. Endpoints that excessively restrict the unidirectional streams. Endpoints that excessively restrict the
number of streams or the flow control window of these streams will number of streams or the flow control window of these streams will
increase the chance that the remote peer reaches the limit early and increase the chance that the remote peer reaches the limit early and
becomes blocked. In particular, implementations should consider that becomes blocked. In particular, implementations should consider that
remote peers may wish to exercise reserved stream behavior remote peers may wish to exercise reserved stream behavior
(Section 6.2.3) with some of the unidirectional streams they are (Section 6.2.3) with some of the unidirectional streams they are
permitted to use. To avoid blocking, the transport parameters sent permitted to use. To avoid blocking, the transport parameters sent
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credit to each stream. credit to each stream.
Note that an endpoint is not required to grant additional credits to Note that an endpoint is not required to grant additional credits to
create more unidirectional streams if its peer consumes all the create more unidirectional streams if its peer consumes all the
initial credits before creating the critical unidirectional streams. initial credits before creating the critical unidirectional streams.
Endpoints SHOULD create the HTTP control stream as well as the Endpoints SHOULD create the HTTP control stream as well as the
unidirectional streams required by mandatory extensions (such as the unidirectional streams required by mandatory extensions (such as the
QPACK encoder and decoder streams) first, and then create additional QPACK encoder and decoder streams) first, and then create additional
streams as allowed by their peer. streams as allowed by their peer.
If the stream header indicates a stream type which is not supported If the stream header indicates a stream type that is not supported by
by the recipient, the remainder of the stream cannot be consumed as the recipient, the remainder of the stream cannot be consumed as the
the semantics are unknown. Recipients of unknown stream types MAY semantics are unknown. Recipients of unknown stream types MAY abort
abort reading of the stream with an error code of reading of the stream with an error code of H3_STREAM_CREATION_ERROR
H3_STREAM_CREATION_ERROR, but MUST NOT consider such streams to be a or a reserved error code (Section 8.1), but MUST NOT consider such
connection error of any kind. streams to be a connection error of any kind.
Implementations MAY send stream types before knowing whether the peer Implementations MAY send stream types before knowing whether the peer
supports them. However, stream types which could modify the state or supports them. However, stream types that could modify the state or
semantics of existing protocol components, including QPACK or other semantics of existing protocol components, including QPACK or other
extensions, MUST NOT be sent until the peer is known to support them. extensions, MUST NOT be sent until the peer is known to support them.
A sender can close or reset a unidirectional stream unless otherwise A sender can close or reset a unidirectional stream unless otherwise
specified. A receiver MUST tolerate unidirectional streams being specified. A receiver MUST tolerate unidirectional streams being
closed or reset prior to the reception of the unidirectional stream closed or reset prior to the reception of the unidirectional stream
header. header.
6.2.1. Control Streams 6.2.1. Control Streams
A control stream is indicated by a stream type of 0x00. Data on this A control stream is indicated by a stream type of 0x00. Data on this
stream consists of HTTP/3 frames, as defined in Section 7.2. stream consists of HTTP/3 frames, as defined in Section 7.2.
Each side MUST initiate a single control stream at the beginning of Each side MUST initiate a single control stream at the beginning of
the connection and send its SETTINGS frame as the first frame on this the connection and send its SETTINGS frame as the first frame on this
stream. If the first frame of the control stream is any other frame stream. If the first frame of the control stream is any other frame
type, this MUST be treated as a connection error of type type, this MUST be treated as a connection error of type
H3_MISSING_SETTINGS. Only one control stream per peer is permitted; H3_MISSING_SETTINGS. Only one control stream per peer is permitted;
receipt of a second stream which claims to be a control stream MUST receipt of a second stream claiming to be a control stream MUST be
be treated as a connection error of type H3_STREAM_CREATION_ERROR. treated as a connection error of type H3_STREAM_CREATION_ERROR. The
The sender MUST NOT close the control stream, and the receiver MUST sender MUST NOT close the control stream, and the receiver MUST NOT
NOT request that the sender close the control stream. If either request that the sender close the control stream. If either control
control stream is closed at any point, this MUST be treated as a stream is closed at any point, this MUST be treated as a connection
connection error of type H3_CLOSED_CRITICAL_STREAM. error of type H3_CLOSED_CRITICAL_STREAM.
A pair of unidirectional streams is used rather than a single A pair of unidirectional streams is used rather than a single
bidirectional stream. This allows either peer to send data as soon bidirectional stream. This allows either peer to send data as soon
as it is able. Depending on whether 0-RTT is enabled on the as it is able. Depending on whether 0-RTT is enabled on the
connection, either client or server might be able to send stream data connection, either client or server might be able to send stream data
first after the cryptographic handshake completes. first after the cryptographic handshake completes.
6.2.2. Push Streams 6.2.2. Push Streams
Server push is an optional feature introduced in HTTP/2 that allows a Server push is an optional feature introduced in HTTP/2 that allows a
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6.2.3. Reserved Stream Types 6.2.3. Reserved Stream Types
Stream types of the format "0x1f * N + 0x21" for non-negative integer Stream types of the format "0x1f * N + 0x21" for non-negative integer
values of N are reserved to exercise the requirement that unknown values of N are reserved to exercise the requirement that unknown
types be ignored. These streams have no semantics, and can be sent types be ignored. These streams have no semantics, and can be sent
when application-layer padding is desired. They MAY also be sent on when application-layer padding is desired. They MAY also be sent on
connections where no data is currently being transferred. Endpoints connections where no data is currently being transferred. Endpoints
MUST NOT consider these streams to have any meaning upon receipt. MUST NOT consider these streams to have any meaning upon receipt.
The payload and length of the stream are selected in any manner the The payload and length of the stream are selected in any manner the
implementation chooses. Implementations MAY terminate these streams sending implementation chooses. When sending a reserved stream type,
cleanly, or MAY abruptly terminate them. When terminating abruptly, the implementation MAY either terminate the stream cleanly or reset
the error code H3_NO_ERROR or a reserved error code (Section 8.1) it. When resetting the stream, either the H3_NO_ERROR error code or
SHOULD be used. a reserved error code (Section 8.1) SHOULD be used.
7. HTTP Framing Layer 7. HTTP Framing Layer
HTTP frames are carried on QUIC streams, as described in Section 6. HTTP frames are carried on QUIC streams, as described in Section 6.
HTTP/3 defines three stream types: control stream, request stream, HTTP/3 defines three stream types: control stream, request stream,
and push stream. This section describes HTTP/3 frame formats and the and push stream. This section describes HTTP/3 frame formats and
streams types on which they are permitted; see Table 1 for an their permitted stream types; see Table 1 for an overview. A
overview. A comparison between HTTP/2 and HTTP/3 frames is provided comparison between HTTP/2 and HTTP/3 frames is provided in
in Appendix A.2. Appendix A.2.
+--------------+----------------+----------------+--------+---------+ +==============+================+================+========+=========+
| Frame | Control Stream | Request | Push | Section | | Frame | Control Stream | Request | Push | Section |
| | | Stream | Stream | | | | | Stream | Stream | |
+==============+================+================+========+=========+ +==============+================+================+========+=========+
| DATA | No | Yes | Yes | Section | | DATA | No | Yes | Yes | Section |
| | | | | 7.2.1 | | | | | | 7.2.1 |
+--------------+----------------+----------------+--------+---------+ +--------------+----------------+----------------+--------+---------+
| HEADERS | No | Yes | Yes | Section | | HEADERS | No | Yes | Yes | Section |
| | | | | 7.2.2 | | | | | | 7.2.2 |
+--------------+----------------+----------------+--------+---------+ +--------------+----------------+----------------+--------+---------+
| CANCEL_PUSH | Yes | No | No | Section | | CANCEL_PUSH | Yes | No | No | Section |
skipping to change at page 31, line 14 skipping to change at page 31, line 4
7.1. Frame Layout 7.1. Frame Layout
All frames have the following format: All frames have the following format:
HTTP/3 Frame Format { HTTP/3 Frame Format {
Type (i), Type (i),
Length (i), Length (i),
Frame Payload (..), Frame Payload (..),
} }
Figure 3: HTTP/3 Frame Format Figure 3: HTTP/3 Frame Format
A frame includes the following fields: A frame includes the following fields:
Type: A variable-length integer that identifies the frame type. Type: A variable-length integer that identifies the frame type.
Length: A variable-length integer that describes the length in bytes Length: A variable-length integer that describes the length in bytes
of the Frame Payload. of the Frame Payload.
Frame Payload: A payload, the semantics of which are determined by Frame Payload: A payload, the semantics of which are determined by
the Type field. the Type field.
Each frame's payload MUST contain exactly the fields identified in Each frame's payload MUST contain exactly the fields identified in
its description. A frame payload that contains additional bytes its description. A frame payload that contains additional bytes
after the identified fields or a frame payload that terminates before after the identified fields or a frame payload that terminates before
the end of the identified fields MUST be treated as a connection the end of the identified fields MUST be treated as a connection
error of type H3_FRAME_ERROR. error (Section 8) of type H3_FRAME_ERROR.
When a stream terminates cleanly, if the last frame on the stream was When a stream terminates cleanly, if the last frame on the stream was
truncated, this MUST be treated as a connection error (Section 8) of truncated, this MUST be treated as a connection error (Section 8) of
type H3_FRAME_ERROR. Streams which terminate abruptly may be reset type H3_FRAME_ERROR. Streams that terminate abruptly may be reset at
at any point in a frame. any point in a frame.
7.2. Frame Definitions 7.2. Frame Definitions
7.2.1. DATA 7.2.1. DATA
DATA frames (type=0x0) convey arbitrary, variable-length sequences of DATA frames (type=0x0) convey arbitrary, variable-length sequences of
bytes associated with an HTTP request or response payload. bytes associated with an HTTP request or response payload body.
DATA frames MUST be associated with an HTTP request or response. If DATA frames MUST be associated with an HTTP request or response. If
a DATA frame is received on a control stream, the recipient MUST a DATA frame is received on a control stream, the recipient MUST
respond with a connection error (Section 8) of type respond with a connection error (Section 8) of type
H3_FRAME_UNEXPECTED. H3_FRAME_UNEXPECTED.
DATA Frame { DATA Frame {
Type (i) = 0x0, Type (i) = 0x0,
Length (i), Length (i),
Data (..), Data (..),
skipping to change at page 32, line 26 skipping to change at page 32, line 13
encoded using QPACK. See [QPACK] for more details. encoded using QPACK. See [QPACK] for more details.
HEADERS Frame { HEADERS Frame {
Type (i) = 0x1, Type (i) = 0x1,
Length (i), Length (i),
Encoded Field Section (..), Encoded Field Section (..),
} }
Figure 5: HEADERS Frame Figure 5: HEADERS Frame
HEADERS frames can only be sent on request / push streams. If a HEADERS frames can only be sent on request or push streams. If a
HEADERS frame is received on a control stream, the recipient MUST HEADERS frame is received on a control stream, the recipient MUST
respond with a connection error (Section 8) of type respond with a connection error (Section 8) of type
H3_FRAME_UNEXPECTED. H3_FRAME_UNEXPECTED.
7.2.3. CANCEL_PUSH 7.2.3. CANCEL_PUSH
The CANCEL_PUSH frame (type=0x3) is used to request cancellation of a The CANCEL_PUSH frame (type=0x3) is used to request cancellation of a
server push prior to the push stream being received. The CANCEL_PUSH server push prior to the push stream being received. The CANCEL_PUSH
frame identifies a server push by Push ID (see Section 7.2.5), frame identifies a server push by Push ID (see Section 4.4), encoded
encoded as a variable-length integer. as a variable-length integer.
When a client sends CANCEL_PUSH, it is indicating that it does not When a client sends CANCEL_PUSH, it is indicating that it does not
wish to receive the promised resource. The server SHOULD abort wish to receive the promised resource. The server SHOULD abort
sending the resource, but the mechanism to do so depends on the state sending the resource, but the mechanism to do so depends on the state
of the corresponding push stream. If the server has not yet created of the corresponding push stream. If the server has not yet created
a push stream, it does not create one. If the push stream is open, a push stream, it does not create one. If the push stream is open,
the server SHOULD abruptly terminate that stream. If the push stream the server SHOULD abruptly terminate that stream. If the push stream
has already ended, the server MAY still abruptly terminate the stream has already ended, the server MAY still abruptly terminate the stream
or MAY take no action. or MAY take no action.
When a server sends CANCEL_PUSH, it is indicating that it will not be When a server sends CANCEL_PUSH, it is indicating that it will not be
fulfilling a promise. The client cannot expect the corresponding fulfilling a promise. The client cannot expect the corresponding
promise to be fulfilled, unless it has already received and processed promise to be fulfilled, unless it has already received and processed
the promised response. A server SHOULD send a CANCEL_PUSH even if it the promised response. A server SHOULD send a CANCEL_PUSH frame even
has opened the corresponding stream. if it has opened the corresponding stream.
Sending CANCEL_PUSH has no direct effect on the state of existing Sending a CANCEL_PUSH frame has no direct effect on the state of
push streams. A client SHOULD NOT send a CANCEL_PUSH when it has existing push streams. A client SHOULD NOT send a CANCEL_PUSH frame
already received a corresponding push stream. A push stream could when it has already received a corresponding push stream. A push
arrive after a client has sent CANCEL_PUSH, because a server might stream could arrive after a client has sent a CANCEL_PUSH frame,
not have processed the CANCEL_PUSH. The client SHOULD abort reading because a server might not have processed the CANCEL_PUSH. The
the stream with an error code of H3_REQUEST_CANCELLED. client SHOULD abort reading the stream with an error code of
H3_REQUEST_CANCELLED.
A CANCEL_PUSH frame is sent on the control stream. Receiving a A CANCEL_PUSH frame is sent on the control stream. Receiving a
CANCEL_PUSH frame on a stream other than the control stream MUST be CANCEL_PUSH frame on a stream other than the control stream MUST be
treated as a connection error of type H3_FRAME_UNEXPECTED. treated as a connection error of type H3_FRAME_UNEXPECTED.
CANCEL_PUSH Frame { CANCEL_PUSH Frame {
Type (i) = 0x3, Type (i) = 0x3,
Length (i), Length (i),
Push ID (..), Push ID (..),
} }
Figure 6: CANCEL_PUSH Frame Figure 6: CANCEL_PUSH Frame
The CANCEL_PUSH frame carries a Push ID encoded as a variable-length The CANCEL_PUSH frame carries a Push ID encoded as a variable-length
integer. The Push ID identifies the server push that is being integer. The Push ID identifies the server push that is being
cancelled; see Section 7.2.5. If a CANCEL_PUSH frame is received cancelled; see Section 4.4. If a CANCEL_PUSH frame is received that
which references a Push ID greater than currently allowed on the references a Push ID greater than currently allowed on the
connection, this MUST be treated as a connection error of type connection, this MUST be treated as a connection error of type
H3_ID_ERROR. H3_ID_ERROR.
If the client receives a CANCEL_PUSH frame, that frame might identify If the client receives a CANCEL_PUSH frame, that frame might identify
a Push ID that has not yet been mentioned by a PUSH_PROMISE frame due a Push ID that has not yet been mentioned by a PUSH_PROMISE frame due
to reordering. If a server receives a CANCEL_PUSH frame for a Push to reordering. If a server receives a CANCEL_PUSH frame for a Push
ID that has not yet been mentioned by a PUSH_PROMISE frame, this MUST ID that has not yet been mentioned by a PUSH_PROMISE frame, this MUST
be treated as a connection error of type H3_ID_ERROR. be treated as a connection error of type H3_ID_ERROR.
7.2.4. SETTINGS 7.2.4. SETTINGS
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subsequently. If an endpoint receives a second SETTINGS frame on the subsequently. If an endpoint receives a second SETTINGS frame on the
control stream, the endpoint MUST respond with a connection error of control stream, the endpoint MUST respond with a connection error of
type H3_FRAME_UNEXPECTED. type H3_FRAME_UNEXPECTED.
SETTINGS frames MUST NOT be sent on any stream other than the control SETTINGS frames MUST NOT be sent on any stream other than the control
stream. If an endpoint receives a SETTINGS frame on a different stream. If an endpoint receives a SETTINGS frame on a different
stream, the endpoint MUST respond with a connection error of type stream, the endpoint MUST respond with a connection error of type
H3_FRAME_UNEXPECTED. H3_FRAME_UNEXPECTED.
SETTINGS parameters are not negotiated; they describe characteristics SETTINGS parameters are not negotiated; they describe characteristics
of the sending peer, which can be used by the receiving peer. of the sending peer that can be used by the receiving peer. However,
However, a negotiation can be implied by the use of SETTINGS - each a negotiation can be implied by the use of SETTINGS - each peer uses
peer uses SETTINGS to advertise a set of supported values. The SETTINGS to advertise a set of supported values. The definition of
definition of the setting would describe how each peer combines the the setting would describe how each peer combines the two sets to
two sets to conclude which choice will be used. SETTINGS does not conclude which choice will be used. SETTINGS does not provide a
provide a mechanism to identify when the choice takes effect. mechanism to identify when the choice takes effect.
Different values for the same parameter can be advertised by each Different values for the same parameter can be advertised by each
peer. For example, a client might be willing to consume a very large peer. For example, a client might be willing to consume a very large
response field section, while servers are more cautious about request response field section, while servers are more cautious about request
size. size.
The same setting identifier MUST NOT occur more than once in the The same setting identifier MUST NOT occur more than once in the
SETTINGS frame. A receiver MAY treat the presence of duplicate SETTINGS frame. A receiver MAY treat the presence of duplicate
setting identifiers as a connection error of type H3_SETTINGS_ERROR. setting identifiers as a connection error of type H3_SETTINGS_ERROR.
skipping to change at page 35, line 15 skipping to change at page 35, line 15
Setting identifiers of the format "0x1f * N + 0x21" for non-negative Setting identifiers of the format "0x1f * N + 0x21" for non-negative
integer values of N are reserved to exercise the requirement that integer values of N are reserved to exercise the requirement that
unknown identifiers be ignored. Such settings have no defined unknown identifiers be ignored. Such settings have no defined
meaning. Endpoints SHOULD include at least one such setting in their meaning. Endpoints SHOULD include at least one such setting in their
SETTINGS frame. Endpoints MUST NOT consider such settings to have SETTINGS frame. Endpoints MUST NOT consider such settings to have
any meaning upon receipt. any meaning upon receipt.
Because the setting has no defined meaning, the value of the setting Because the setting has no defined meaning, the value of the setting
can be any value the implementation selects. can be any value the implementation selects.
Setting identifiers which were used in HTTP/2 where there is no
corresponding HTTP/3 setting have also been reserved
(Section 11.2.2). These settings MUST NOT be sent, and their receipt
MUST be treated as a connection error of type H3_SETTINGS_ERROR.
Additional settings can be defined by extensions to HTTP/3; see Additional settings can be defined by extensions to HTTP/3; see
Section 9 for more details. Section 9 for more details.
7.2.4.2. Initialization 7.2.4.2. Initialization
An HTTP implementation MUST NOT send frames or requests which would An HTTP implementation MUST NOT send frames or requests that would be
be invalid based on its current understanding of the peer's settings. invalid based on its current understanding of the peer's settings.
All settings begin at an initial value. Each endpoint SHOULD use All settings begin at an initial value. Each endpoint SHOULD use
these initial values to send messages before the peer's SETTINGS these initial values to send messages before the peer's SETTINGS
frame has arrived, as packets carrying the settings can be lost or frame has arrived, as packets carrying the settings can be lost or
delayed. When the SETTINGS frame arrives, any settings are changed delayed. When the SETTINGS frame arrives, any settings are changed
to their new values. to their new values.
This removes the need to wait for the SETTINGS frame before sending This removes the need to wait for the SETTINGS frame before sending
messages. Endpoints MUST NOT require any data to be received from messages. Endpoints MUST NOT require any data to be received from
the peer prior to sending the SETTINGS frame; settings MUST be sent the peer prior to sending the SETTINGS frame; settings MUST be sent
as soon as the transport is ready to send data. as soon as the transport is ready to send data.
For servers, the initial value of each client setting is the default For servers, the initial value of each client setting is the default
value. value.
For clients using a 1-RTT QUIC connection, the initial value of each For clients using a 1-RTT QUIC connection, the initial value of each
server setting is the default value. 1-RTT keys will always become server setting is the default value. 1-RTT keys will always become
available prior to SETTINGS arriving, even if the server sends available prior to the packet containing SETTINGS being processed by
SETTINGS immediately. Clients SHOULD NOT wait indefinitely for QUIC, even if the server sends SETTINGS immediately. Clients SHOULD
SETTINGS to arrive before sending requests, but SHOULD process NOT wait indefinitely for SETTINGS to arrive before sending requests,
received datagrams in order to increase the likelihood of processing but SHOULD process received datagrams in order to increase the
SETTINGS before sending the first request. likelihood of processing SETTINGS before sending the first request.
When a 0-RTT QUIC connection is being used, the initial value of each When a 0-RTT QUIC connection is being used, the initial value of each
server setting is the value used in the previous session. Clients server setting is the value used in the previous session. Clients
SHOULD store the settings the server provided in the connection where SHOULD store the settings the server provided in the connection where
resumption information was provided, but MAY opt not to store resumption information was provided, but MAY opt not to store
settings in certain cases (e.g., if the session ticket is received settings in certain cases (e.g., if the session ticket is received
before the SETTINGS frame). A client MUST comply with stored before the SETTINGS frame). A client MUST comply with stored
settings - or default values, if no values are stored - when settings - or default values, if no values are stored - when
attempting 0-RTT. Once a server has provided new settings, clients attempting 0-RTT. Once a server has provided new settings, clients
MUST comply with those values. MUST comply with those values.
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settings values in determining whether to accept 0-RTT data. If the settings values in determining whether to accept 0-RTT data. If the
server cannot determine that the settings remembered by a client are server cannot determine that the settings remembered by a client are
compatible with its current settings, it MUST NOT accept 0-RTT data. compatible with its current settings, it MUST NOT accept 0-RTT data.
Remembered settings are compatible if a client complying with those Remembered settings are compatible if a client complying with those
settings would not violate the server's current settings. settings would not violate the server's current settings.
A server MAY accept 0-RTT and subsequently provide different settings A server MAY accept 0-RTT and subsequently provide different settings
in its SETTINGS frame. If 0-RTT data is accepted by the server, its in its SETTINGS frame. If 0-RTT data is accepted by the server, its
SETTINGS frame MUST NOT reduce any limits or alter any values that SETTINGS frame MUST NOT reduce any limits or alter any values that
might be violated by the client with its 0-RTT data. The server MUST might be violated by the client with its 0-RTT data. The server MUST
include all settings which differ from their default values. If a include all settings that differ from their default values. If a
server accepts 0-RTT but then sends settings that are not compatible server accepts 0-RTT but then sends settings that are not compatible
with the previously specified settings, this MUST be treated as a with the previously specified settings, this MUST be treated as a
connection error of type H3_SETTINGS_ERROR. If a server accepts connection error of type H3_SETTINGS_ERROR. If a server accepts
0-RTT but then sends a SETTINGS frame that omits a setting value that 0-RTT but then sends a SETTINGS frame that omits a setting value that
the client understands (apart from reserved setting identifiers) that the client understands (apart from reserved setting identifiers) that
was previously specified to have a non-default value, this MUST be was previously specified to have a non-default value, this MUST be
treated as a connection error of type H3_SETTINGS_ERROR. treated as a connection error of type H3_SETTINGS_ERROR.
7.2.5. PUSH_PROMISE 7.2.5. PUSH_PROMISE
skipping to change at page 37, line 6 skipping to change at page 37, line 4
Length (i), Length (i),
Push ID (i), Push ID (i),
Encoded Field Section (..), Encoded Field Section (..),
} }
Figure 8: PUSH_PROMISE Frame Figure 8: PUSH_PROMISE Frame
The payload consists of: The payload consists of:
Push ID: A variable-length integer that identifies the server push Push ID: A variable-length integer that identifies the server push
operation. A Push ID is used in push stream headers operation. A Push ID is used in push stream headers (Section 4.4)
(Section 4.4), CANCEL_PUSH frames (Section 7.2.3). and CANCEL_PUSH frames (Section 7.2.3).
Encoded Field Section: QPACK-encoded request header fields for the Encoded Field Section: QPACK-encoded request header fields for the
promised response. See [QPACK] for more details. promised response. See [QPACK] for more details.
A server MUST NOT use a Push ID that is larger than the client has A server MUST NOT use a Push ID that is larger than the client has
provided in a MAX_PUSH_ID frame (Section 7.2.7). A client MUST treat provided in a MAX_PUSH_ID frame (Section 7.2.7). A client MUST treat
receipt of a PUSH_PROMISE frame that contains a larger Push ID than receipt of a PUSH_PROMISE frame that contains a larger Push ID than
the client has advertised as a connection error of H3_ID_ERROR. the client has advertised as a connection error of H3_ID_ERROR.
A server MAY use the same Push ID in multiple PUSH_PROMISE frames. A server MAY use the same Push ID in multiple PUSH_PROMISE frames.
If so, the decompressed request header sets MUST contain the same If so, the decompressed request header sets MUST contain the same
fields in the same order, and both the name and the value in each fields in the same order, and both the name and the value in each
field MUST be exact matches. Clients SHOULD compare the request field MUST be exact matches. Clients SHOULD compare the request
header sections for resources promised multiple times. If a client header sections for resources promised multiple times. If a client
receives a Push ID that has already been promised and detects a receives a Push ID that has already been promised and detects a
mismatch, it MUST respond with a connection error of type mismatch, it MUST respond with a connection error of type
H3_GENERAL_PROTOCOL_ERROR. If the decompressed field sections match H3_GENERAL_PROTOCOL_ERROR. If the decompressed field sections match
exactly, the client SHOULD associate the pushed content with each exactly, the client SHOULD associate the pushed content with each
stream on which a PUSH_PROMISE was received. stream on which a PUSH_PROMISE frame was received.
Allowing duplicate references to the same Push ID is primarily to Allowing duplicate references to the same Push ID is primarily to
reduce duplication caused by concurrent requests. A server SHOULD reduce duplication caused by concurrent requests. A server SHOULD
avoid reusing a Push ID over a long period. Clients are likely to avoid reusing a Push ID over a long period. Clients are likely to
consume server push responses and not retain them for reuse over consume server push responses and not retain them for reuse over
time. Clients that see a PUSH_PROMISE that uses a Push ID that they time. Clients that see a PUSH_PROMISE frame that uses a Push ID that
have already consumed and discarded are forced to ignore the they have already consumed and discarded are forced to ignore the
PUSH_PROMISE. promise.
If a PUSH_PROMISE frame is received on the control stream, the client If a PUSH_PROMISE frame is received on the control stream, the client
MUST respond with a connection error (Section 8) of type MUST respond with a connection error (Section 8) of type
H3_FRAME_UNEXPECTED. H3_FRAME_UNEXPECTED.
A client MUST NOT send a PUSH_PROMISE frame. A server MUST treat the A client MUST NOT send a PUSH_PROMISE frame. A server MUST treat the
receipt of a PUSH_PROMISE frame as a connection error of type receipt of a PUSH_PROMISE frame as a connection error of type
H3_FRAME_UNEXPECTED. H3_FRAME_UNEXPECTED.
See Section 4.4 for a description of the overall server push See Section 4.4 for a description of the overall server push
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encoded as a variable-length integer. encoded as a variable-length integer.
The GOAWAY frame applies to the connection, not a specific stream. A The GOAWAY frame applies to the connection, not a specific stream. A
client MUST treat a GOAWAY frame on a stream other than the control client MUST treat a GOAWAY frame on a stream other than the control
stream as a connection error (Section 8) of type H3_FRAME_UNEXPECTED. stream as a connection error (Section 8) of type H3_FRAME_UNEXPECTED.
See Section 5.2 for more information on the use of the GOAWAY frame. See Section 5.2 for more information on the use of the GOAWAY frame.
7.2.7. MAX_PUSH_ID 7.2.7. MAX_PUSH_ID
The MAX_PUSH_ID frame (type=0xD) is used by clients to control the The MAX_PUSH_ID frame (type=0xd) is used by clients to control the
number of server pushes that the server can initiate. This sets the number of server pushes that the server can initiate. This sets the
maximum value for a Push ID that the server can use in PUSH_PROMISE maximum value for a Push ID that the server can use in PUSH_PROMISE
and CANCEL_PUSH frames. Consequently, this also limits the number of and CANCEL_PUSH frames. Consequently, this also limits the number of
push streams that the server can initiate in addition to the limit push streams that the server can initiate in addition to the limit
maintained by the QUIC transport. maintained by the QUIC transport.
The MAX_PUSH_ID frame is always sent on the control stream. Receipt The MAX_PUSH_ID frame is always sent on the control stream. Receipt
of a MAX_PUSH_ID frame on any other stream MUST be treated as a of a MAX_PUSH_ID frame on any other stream MUST be treated as a
connection error of type H3_FRAME_UNEXPECTED. connection error of type H3_FRAME_UNEXPECTED.
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receipt of a MAX_PUSH_ID frame as a connection error of type receipt of a MAX_PUSH_ID frame as a connection error of type
H3_FRAME_UNEXPECTED. H3_FRAME_UNEXPECTED.
The maximum Push ID is unset when a connection is created, meaning The maximum Push ID is unset when a connection is created, meaning
that a server cannot push until it receives a MAX_PUSH_ID frame. A that a server cannot push until it receives a MAX_PUSH_ID frame. A
client that wishes to manage the number of promised server pushes can client that wishes to manage the number of promised server pushes can
increase the maximum Push ID by sending MAX_PUSH_ID frames as the increase the maximum Push ID by sending MAX_PUSH_ID frames as the
server fulfills or cancels server pushes. server fulfills or cancels server pushes.
MAX_PUSH_ID Frame { MAX_PUSH_ID Frame {
Type (i) = 0x1, Type (i) = 0xd,
Length (i), Length (i),
Push ID (..), Push ID (i),
} }
Figure 10: MAX_PUSH_ID Frame Payload Figure 10: MAX_PUSH_ID Frame
The MAX_PUSH_ID frame carries a single variable-length integer that The MAX_PUSH_ID frame carries a single variable-length integer that
identifies the maximum value for a Push ID that the server can use; identifies the maximum value for a Push ID that the server can use;
see Section 7.2.5. A MAX_PUSH_ID frame cannot reduce the maximum see Section 4.4. A MAX_PUSH_ID frame cannot reduce the maximum Push
Push ID; receipt of a MAX_PUSH_ID that contains a smaller value than ID; receipt of a MAX_PUSH_ID frame that contains a smaller value than
previously received MUST be treated as a connection error of type previously received MUST be treated as a connection error of type
H3_ID_ERROR. H3_ID_ERROR.
7.2.8. Reserved Frame Types 7.2.8. Reserved Frame Types
Frame types of the format "0x1f * N + 0x21" for non-negative integer Frame types of the format "0x1f * N + 0x21" for non-negative integer
values of N are reserved to exercise the requirement that unknown values of N are reserved to exercise the requirement that unknown
types be ignored (Section 9). These frames have no semantics, and types be ignored (Section 9). These frames have no semantics, and
can be sent on any open stream when application-layer padding is can be sent on any open stream when application-layer padding is
desired. They MAY also be sent on connections where no data is desired. They MAY also be sent on connections where no data is
currently being transferred. Endpoints MUST NOT consider these currently being transferred. Endpoints MUST NOT consider these
frames to have any meaning upon receipt. frames to have any meaning upon receipt.
The payload and length of the frames are selected in any manner the The payload and length of the frames are selected in any manner the
implementation chooses. implementation chooses.
Frame types which were used in HTTP/2 where there is no corresponding Frame types that were used in HTTP/2 where there is no corresponding
HTTP/3 frame have also been reserved (Section 11.2.1). These frame HTTP/3 frame have also been reserved (Section 11.2.1). These frame
types MUST NOT be sent, and receipt MAY be treated as an error of types MUST NOT be sent, and their receipt MUST be treated as a
type H3_FRAME_UNEXPECTED. connection error of type H3_FRAME_UNEXPECTED.
8. Error Handling 8. Error Handling
QUIC allows the application to abruptly terminate (reset) individual QUIC allows the application to abruptly terminate (reset) individual
streams or the entire connection when an error is encountered. These streams or the entire connection; see Sections 2.4 and 5.3 of
are referred to as "stream errors" or "connection errors" and are [QUIC-TRANSPORT]. These are referred to as "stream errors" or
described in more detail in [QUIC-TRANSPORT]. "connection errors" (see Section 11 of [QUIC-TRANSPORT]) and have
associated error codes, but do not necessarily indicate a problem
with the connection or either implementation. For example, a stream
can be reset if the requested resource is no longer needed.
An endpoint MAY choose to treat a stream error as a connection error An endpoint MAY choose to treat a stream error as a connection error
under certain circumstances. Implementations need to consider the under certain circumstances. Implementations need to consider the
impact on outstanding requests before making this choice. impact on outstanding requests before making this choice.
Because new error codes can be defined without negotiation (see Because new error codes can be defined without negotiation (see
Section 9), use of an error code in an unexpected context or receipt Section 9), use of an error code in an unexpected context or receipt
of an unknown error code MUST be treated as equivalent to of an unknown error code MUST be treated as equivalent to
H3_NO_ERROR. However, closing a stream can have other effects H3_NO_ERROR. However, closing a stream can have other effects
regardless of the error code; see Section 4.1. regardless of the error code; for example, see Section 4.1.
This section describes HTTP/3-specific error codes which can be used This section describes HTTP/3-specific error codes that can be used
to express the cause of a connection or stream error. to express the cause of a connection or stream error.
8.1. HTTP/3 Error Codes 8.1. HTTP/3 Error Codes
The following error codes are defined for use when abruptly The following error codes are defined for use when abruptly
terminating streams, aborting reading of streams, or immediately terminating streams, aborting reading of streams, or immediately
closing connections. closing connections.
H3_NO_ERROR (0x100): No error. This is used when the connection or H3_NO_ERROR (0x100): No error. This is used when the connection or
stream needs to be closed, but there is no error to signal. stream needs to be closed, but there is no error to signal.
H3_GENERAL_PROTOCOL_ERROR (0x101): Peer violated protocol H3_GENERAL_PROTOCOL_ERROR (0x101): Peer violated protocol
requirements in a way which doesn't match a more specific error requirements in a way that does not match a more specific error
code, or endpoint declines to use the more specific error code. code, or endpoint declines to use the more specific error code.
H3_INTERNAL_ERROR (0x102): An internal error has occurred in the H3_INTERNAL_ERROR (0x102): An internal error has occurred in the
HTTP stack. HTTP stack.
H3_STREAM_CREATION_ERROR (0x103): The endpoint detected that its H3_STREAM_CREATION_ERROR (0x103): The endpoint detected that its
peer created a stream that it will not accept. peer created a stream that it will not accept.
H3_CLOSED_CRITICAL_STREAM (0x104): A stream required by the H3_CLOSED_CRITICAL_STREAM (0x104): A stream required by the
connection was closed or reset. connection was closed or reset.
H3_FRAME_UNEXPECTED (0x105): A frame was received which was not H3_FRAME_UNEXPECTED (0x105): A frame was received that was not
permitted in the current state or on the current stream. permitted in the current state or on the current stream.
H3_FRAME_ERROR (0x106): A frame that fails to satisfy layout H3_FRAME_ERROR (0x106): A frame that fails to satisfy layout
requirements or with an invalid size was received. requirements or with an invalid size was received.
H3_EXCESSIVE_LOAD (0x107): The endpoint detected that its peer is H3_EXCESSIVE_LOAD (0x107): The endpoint detected that its peer is
exhibiting a behavior that might be generating excessive load. exhibiting a behavior that might be generating excessive load.
H3_ID_ERROR (0x108): A Stream ID or Push ID was used incorrectly, H3_ID_ERROR (0x108): A Stream ID or Push ID was used incorrectly,
such as exceeding a limit, reducing a limit, or being reused. such as exceeding a limit, reducing a limit, or being reused.
H3_SETTINGS_ERROR (0x109): An endpoint detected an error in the H3_SETTINGS_ERROR (0x109): An endpoint detected an error in the
payload of a SETTINGS frame. payload of a SETTINGS frame.
H3_MISSING_SETTINGS (0x10A): No SETTINGS frame was received at the H3_MISSING_SETTINGS (0x10a): No SETTINGS frame was received at the
beginning of the control stream. beginning of the control stream.
H3_REQUEST_REJECTED (0x10B): A server rejected a request without H3_REQUEST_REJECTED (0x10b): A server rejected a request without
performing any application processing. performing any application processing.
H3_REQUEST_CANCELLED (0x10C): The request or its response (including H3_REQUEST_CANCELLED (0x10c): The request or its response (including
pushed response) is cancelled. pushed response) is cancelled.
H3_REQUEST_INCOMPLETE (0x10D): The client's stream terminated H3_REQUEST_INCOMPLETE (0x10d): The client's stream terminated
without containing a fully-formed request. without containing a fully-formed request.
H3_CONNECT_ERROR (0x10F): The connection established in response to H3_CONNECT_ERROR (0x10f): The connection established in response to
a CONNECT request was reset or abnormally closed. a CONNECT request was reset or abnormally closed.
H3_VERSION_FALLBACK (0x110): The requested operation cannot be H3_VERSION_FALLBACK (0x110): The requested operation cannot be
served over HTTP/3. The peer should retry over HTTP/1.1. served over HTTP/3. The peer should retry over HTTP/1.1.
Error codes of the format "0x1f * N + 0x21" for non-negative integer Error codes of the format "0x1f * N + 0x21" for non-negative integer
values of N are reserved to exercise the requirement that unknown values of N are reserved to exercise the requirement that unknown
error codes be treated as equivalent to H3_NO_ERROR (Section 9). error codes be treated as equivalent to H3_NO_ERROR (Section 9).
Implementations SHOULD select an error code from this space with some Implementations SHOULD select an error code from this space with some
probability when they would have sent H3_NO_ERROR. probability when they would have sent H3_NO_ERROR.
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requirement and SHOULD be treated as an error. requirement and SHOULD be treated as an error.
Extensions that could change the semantics of existing protocol Extensions that could change the semantics of existing protocol
components MUST be negotiated before being used. For example, an components MUST be negotiated before being used. For example, an
extension that changes the layout of the HEADERS frame cannot be used extension that changes the layout of the HEADERS frame cannot be used
until the peer has given a positive signal that this is acceptable. until the peer has given a positive signal that this is acceptable.
Coordinating when such a revised layout comes into effect could prove Coordinating when such a revised layout comes into effect could prove
complex. As such, allocating new identifiers for new definitions of complex. As such, allocating new identifiers for new definitions of
existing protocol elements is likely to be more effective. existing protocol elements is likely to be more effective.
This document doesn't mandate a specific method for negotiating the This document does not mandate a specific method for negotiating the
use of an extension but notes that a setting (Section 7.2.4.1) could use of an extension but notes that a setting (Section 7.2.4.1) could
be used for that purpose. If both peers set a value that indicates be used for that purpose. If both peers set a value that indicates
willingness to use the extension, then the extension can be used. If willingness to use the extension, then the extension can be used. If
a setting is used for extension negotiation, the default value MUST a setting is used for extension negotiation, the default value MUST
be defined in such a fashion that the extension is disabled if the be defined in such a fashion that the extension is disabled if the
setting is omitted. setting is omitted.
10. Security Considerations 10. Security Considerations
The security considerations of HTTP/3 should be comparable to those The security considerations of HTTP/3 should be comparable to those
of HTTP/2 with TLS. However, many of the considerations from of HTTP/2 with TLS. However, many of the considerations from
Section 10 of [HTTP2] apply to [QUIC-TRANSPORT] and are discussed in Section 10 of [HTTP2] apply to [QUIC-TRANSPORT] and are discussed in
that document. that document.
10.1. Server Authority 10.1. Server Authority
HTTP/3 relies on the HTTP definition of authority. The security HTTP/3 relies on the HTTP definition of authority. The security
considerations of establishing authority are discussed in considerations of establishing authority are discussed in
Section 11.1 of [SEMANTICS]. Section 12.1 of [SEMANTICS].
10.2. Cross-Protocol Attacks 10.2. Cross-Protocol Attacks
The use of ALPN in the TLS and QUIC handshakes establishes the target The use of ALPN in the TLS and QUIC handshakes establishes the target
application protocol before application-layer bytes are processed. application protocol before application-layer bytes are processed.
Because all QUIC packets are encrypted, it is difficult for an Because all QUIC packets are encrypted, it is difficult for an
attacker to control the plaintext bytes of an HTTP/3 connection which attacker to control the plaintext bytes of an HTTP/3 connection,
could be used in a cross-protocol attack on a plaintext protocol. which could be used in a cross-protocol attack on a plaintext
protocol.
10.3. Intermediary Encapsulation Attacks 10.3. Intermediary Encapsulation Attacks
The HTTP/3 field encoding allows the expression of names that are not The HTTP/3 field encoding allows the expression of names that are not
valid field names in the syntax used by HTTP (Section 4.3 of valid field names in the syntax used by HTTP (Section 5.3 of
[SEMANTICS]). Requests or responses containing invalid field names [SEMANTICS]). Requests or responses containing invalid field names
MUST be treated as malformed (Section 4.1.3). An intermediary MUST be treated as malformed (Section 4.1.3). An intermediary
therefore cannot translate an HTTP/3 request or response containing therefore cannot translate an HTTP/3 request or response containing
an invalid field name into an HTTP/1.1 message. an invalid field name into an HTTP/1.1 message.
Similarly, HTTP/3 allows field values that are not valid. While most Similarly, HTTP/3 can transport field values that are not valid.
of the values that can be encoded will not alter field parsing, While most values that can be encoded will not alter field parsing,
carriage return (CR, ASCII 0xd), line feed (LF, ASCII 0xa), and the carriage return (CR, ASCII 0xd), line feed (LF, ASCII 0xa), and the
zero character (NUL, ASCII 0x0) might be exploited by an attacker if zero character (NUL, ASCII 0x0) might be exploited by an attacker if
they are translated verbatim. Any request or response that contains they are translated verbatim. Any request or response that contains
a character not permitted in a field value MUST be treated as a character not permitted in a field value MUST be treated as
malformed (Section 4.1.3). Valid characters are defined by the malformed (Section 4.1.3). Valid characters are defined by the
"field-content" ABNF rule in Section 4.4 of [SEMANTICS]. "field-content" ABNF rule in Section 5.4 of [SEMANTICS].
10.4. Cacheability of Pushed Responses 10.4. Cacheability of Pushed Responses
Pushed responses do not have an explicit request from the client; the Pushed responses do not have an explicit request from the client; the
request is provided by the server in the PUSH_PROMISE frame. request is provided by the server in the PUSH_PROMISE frame.
Caching responses that are pushed is possible based on the guidance Caching responses that are pushed is possible based on the guidance
provided by the origin server in the Cache-Control header field. provided by the origin server in the Cache-Control header field.
However, this can cause issues if a single server hosts more than one However, this can cause issues if a single server hosts more than one
tenant. For example, a server might offer multiple users each a tenant. For example, a server might offer multiple users each a
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ensure that memory commitments for these features are strictly ensure that memory commitments for these features are strictly
bounded. bounded.
The number of PUSH_PROMISE frames is constrained in a similar The number of PUSH_PROMISE frames is constrained in a similar
fashion. A client that accepts server push SHOULD limit the number fashion. A client that accepts server push SHOULD limit the number
of Push IDs it issues at a time. of Push IDs it issues at a time.
Processing capacity cannot be guarded as effectively as state Processing capacity cannot be guarded as effectively as state
capacity. capacity.
The ability to send undefined protocol elements which the peer is The ability to send undefined protocol elements that the peer is
required to ignore can be abused to cause a peer to expend additional required to ignore can be abused to cause a peer to expend additional
processing time. This might be done by setting multiple undefined processing time. This might be done by setting multiple undefined
SETTINGS parameters, unknown frame types, or unknown stream types. SETTINGS parameters, unknown frame types, or unknown stream types.
Note, however, that some uses are entirely legitimate, such as Note, however, that some uses are entirely legitimate, such as
optional-to-understand extensions and padding to increase resistance optional-to-understand extensions and padding to increase resistance
to traffic analysis. to traffic analysis.
Compression of field sections also offers some opportunities to waste Compression of field sections also offers some opportunities to waste
processing resources; see Section 7 of [QPACK] for more details on processing resources; see Section 7 of [QPACK] for more details on
potential abuses. potential abuses.
All these features - i.e., server push, unknown protocol elements, All these features - i.e., server push, unknown protocol elements,
field compression - have legitimate uses. These features become a field compression - have legitimate uses. These features become a
burden only when they are used unnecessarily or to excess. burden only when they are used unnecessarily or to excess.
An endpoint that doesn't monitor this behavior exposes itself to a An endpoint that does not monitor this behavior exposes itself to a
risk of denial-of-service attack. Implementations SHOULD track the risk of denial-of-service attack. Implementations SHOULD track the
use of these features and set limits on their use. An endpoint MAY use of these features and set limits on their use. An endpoint MAY
treat activity that is suspicious as a connection error (Section 8) treat activity that is suspicious as a connection error (Section 8)
of type H3_EXCESSIVE_LOAD, but false positives will result in of type H3_EXCESSIVE_LOAD, but false positives will result in
disrupting valid connections and requests. disrupting valid connections and requests.
10.5.1. Limits on Field Section Size 10.5.1. Limits on Field Section Size
A large field section (Section 4.1) can cause an implementation to A large field section (Section 4.1) can cause an implementation to
commit a large amount of state. Header fields that are critical for commit a large amount of state. Header fields that are critical for
routing can appear toward the end of a header field section, which routing can appear toward the end of a header field section, which
prevents streaming of the header field section to its ultimate prevents streaming of the header field section to its ultimate
destination. This ordering and other reasons, such as ensuring cache destination. This ordering and other reasons, such as ensuring cache
correctness, mean that an endpoint likely needs to buffer the entire correctness, mean that an endpoint likely needs to buffer the entire
header field section. Since there is no hard limit to the size of a header field section. Since there is no hard limit to the size of a
field section, some endpoints could be forced to commit a large field section, some endpoints could be forced to commit a large
amount of available memory for header fields. amount of available memory for header fields.
An endpoint can use the SETTINGS_MAX_HEADER_LIST_SIZE An endpoint can use the SETTINGS_MAX_FIELD_SECTION_SIZE
(Section 7.2.4.1) setting to advise peers of limits that might apply (Section 4.1.1.3) setting to advise peers of limits that might apply
on the size of field sections. This setting is only advisory, so on the size of field sections. This setting is only advisory, so
endpoints MAY choose to send field sections that exceed this limit endpoints MAY choose to send field sections that exceed this limit
and risk having the request or response being treated as malformed. and risk having the request or response being treated as malformed.
This setting is specific to a connection, so any request or response This setting is specific to a connection, so any request or response
could encounter a hop with a lower, unknown limit. An intermediary could encounter a hop with a lower, unknown limit. An intermediary
can attempt to avoid this problem by passing on values presented by can attempt to avoid this problem by passing on values presented by
different peers, but they are not obligated to do so. different peers, but they are not obligated to do so.
A server that receives a larger field section than it is willing to A server that receives a larger field section than it is willing to
handle can send an HTTP 431 (Request Header Fields Too Large) status handle can send an HTTP 431 (Request Header Fields Too Large) status
code [RFC6585]. A client can discard responses that it cannot code ([RFC6585]). A client can discard responses that it cannot
process. process.
10.5.2. CONNECT Issues 10.5.2. CONNECT Issues
The CONNECT method can be used to create disproportionate load on an The CONNECT method can be used to create disproportionate load on a
proxy, since stream creation is relatively inexpensive when compared proxy, since stream creation is relatively inexpensive when compared
to the creation and maintenance of a TCP connection. A proxy might to the creation and maintenance of a TCP connection. A proxy might
also maintain some resources for a TCP connection beyond the closing also maintain some resources for a TCP connection beyond the closing
of the stream that carries the CONNECT request, since the outgoing of the stream that carries the CONNECT request, since the outgoing
TCP connection remains in the TIME_WAIT state. Therefore, a proxy TCP connection remains in the TIME_WAIT state. Therefore, a proxy
cannot rely on QUIC stream limits alone to control the resources cannot rely on QUIC stream limits alone to control the resources
consumed by CONNECT requests. consumed by CONNECT requests.
10.6. Use of Compression 10.6. Use of Compression
Compression can allow an attacker to recover secret data when it is Compression can allow an attacker to recover secret data when it is
compressed in the same context as data under attacker control. compressed in the same context as data under attacker control.
HTTP/3 enables compression of fields (Section 4.1.1); the following HTTP/3 enables compression of fields (Section 4.1.1); the following
concerns also apply to the use of HTTP compressed content-codings; concerns also apply to the use of HTTP compressed content-codings;
see Section 6.1.2 of [SEMANTICS]. see Section 7.1.2 of [SEMANTICS].
There are demonstrable attacks on compression that exploit the There are demonstrable attacks on compression that exploit the
characteristics of the web (e.g., [BREACH]). The attacker induces characteristics of the web (e.g., [BREACH]). The attacker induces
multiple requests containing varying plaintext, observing the length multiple requests containing varying plaintext, observing the length
of the resulting ciphertext in each, which reveals a shorter length of the resulting ciphertext in each, which reveals a shorter length
when a guess about the secret is correct. when a guess about the secret is correct.
Implementations communicating on a secure channel MUST NOT compress Implementations communicating on a secure channel MUST NOT compress
content that includes both confidential and attacker-controlled data content that includes both confidential and attacker-controlled data
unless separate compression dictionaries are used for each source of unless separate compression contexts are used for each source of
data. Compression MUST NOT be used if the source of data cannot be data. Compression MUST NOT be used if the source of data cannot be
reliably determined. reliably determined.
Further considerations regarding the compression of fields sections Further considerations regarding the compression of fields sections
are described in [QPACK]. are described in [QPACK].
10.7. Padding and Traffic Analysis 10.7. Padding and Traffic Analysis
Padding can be used to obscure the exact size of frame content and is Padding can be used to obscure the exact size of frame content and is
provided to mitigate specific attacks within HTTP, for example, provided to mitigate specific attacks within HTTP, for example,
skipping to change at page 48, line 22 skipping to change at page 48, line 22
The initial allocations in these registries created in this document The initial allocations in these registries created in this document
are all assigned permanent status and list as contact both the IESG are all assigned permanent status and list as contact both the IESG
(iesg@ietf.org) and the HTTP working group (ietf-http-wg@w3.org). (iesg@ietf.org) and the HTTP working group (ietf-http-wg@w3.org).
11.2.1. Frame Types 11.2.1. Frame Types
This document establishes a registry for HTTP/3 frame type codes. This document establishes a registry for HTTP/3 frame type codes.
The "HTTP/3 Frame Type" registry governs a 62-bit space. This The "HTTP/3 Frame Type" registry governs a 62-bit space. This
registry follows the QUIC registry policy; see Section 11.2. registry follows the QUIC registry policy; see Section 11.2.
Permanent registrations in this registry are assigned using the Permanent registrations in this registry are assigned using the
Specification Required policy [RFC8126], except for values between Specification Required policy ([RFC8126]), except for values between
0x00 and 0x3f (in hexadecimal; inclusive), which are assigned using 0x00 and 0x3f (in hexadecimal; inclusive), which are assigned using
Standards Action or IESG Approval as defined in Section 4.9 and 4.10 Standards Action or IESG Approval as defined in Section 4.9 and 4.10
of [RFC8126]. of [RFC8126].
While this registry is separate from the "HTTP/2 Frame Type" registry While this registry is separate from the "HTTP/2 Frame Type" registry
defined in [HTTP2], it is preferable that the assignments parallel defined in [HTTP2], it is preferable that the assignments parallel
each other where the code spaces overlap. If an entry is present in each other where the code spaces overlap. If an entry is present in
only one registry, every effort SHOULD be made to avoid assigning the only one registry, every effort SHOULD be made to avoid assigning the
corresponding value to an unrelated operation. corresponding value to an unrelated operation.
skipping to change at page 49, line 5 skipping to change at page 49, line 5
registrations in this registry MUST include the following field: registrations in this registry MUST include the following field:
Frame Type: A name or label for the frame type. Frame Type: A name or label for the frame type.
Specifications of frame types MUST include a description of the frame Specifications of frame types MUST include a description of the frame
layout and its semantics, including any parts of the frame that are layout and its semantics, including any parts of the frame that are
conditionally present. conditionally present.
The entries in Table 2 are registered by this document. The entries in Table 2 are registered by this document.
+--------------+-------+---------------+ +==============+=======+===============+
| Frame Type | Value | Specification | | Frame Type | Value | Specification |
+==============+=======+===============+ +==============+=======+===============+
| DATA | 0x0 | Section 7.2.1 | | DATA | 0x0 | Section 7.2.1 |
+--------------+-------+---------------+ +--------------+-------+---------------+
| HEADERS | 0x1 | Section 7.2.2 | | HEADERS | 0x1 | Section 7.2.2 |
+--------------+-------+---------------+ +--------------+-------+---------------+
| Reserved | 0x2 | N/A | | Reserved | 0x2 | N/A |
+--------------+-------+---------------+ +--------------+-------+---------------+
| CANCEL_PUSH | 0x3 | Section 7.2.3 | | CANCEL_PUSH | 0x3 | Section 7.2.3 |
+--------------+-------+---------------+ +--------------+-------+---------------+
skipping to change at page 49, line 28 skipping to change at page 49, line 28
| PUSH_PROMISE | 0x5 | Section 7.2.5 | | PUSH_PROMISE | 0x5 | Section 7.2.5 |
+--------------+-------+---------------+ +--------------+-------+---------------+
| Reserved | 0x6 | N/A | | Reserved | 0x6 | N/A |
+--------------+-------+---------------+ +--------------+-------+---------------+
| GOAWAY | 0x7 | Section 7.2.6 | | GOAWAY | 0x7 | Section 7.2.6 |
+--------------+-------+---------------+ +--------------+-------+---------------+
| Reserved | 0x8 | N/A | | Reserved | 0x8 | N/A |
+--------------+-------+---------------+ +--------------+-------+---------------+
| Reserved | 0x9 | N/A | | Reserved | 0x9 | N/A |
+--------------+-------+---------------+ +--------------+-------+---------------+
| MAX_PUSH_ID | 0xD | Section 7.2.7 | | MAX_PUSH_ID | 0xd | Section 7.2.7 |
+--------------+-------+---------------+ +--------------+-------+---------------+
Table 2: Initial HTTP/3 Frame Types Table 2: Initial HTTP/3 Frame Types
Additionally, each code of the format "0x1f * N + 0x21" for non- Additionally, each code of the format "0x1f * N + 0x21" for non-
negative integer values of N (that is, 0x21, 0x40, ..., through negative integer values of N (that is, 0x21, 0x40, ..., through
0x3FFFFFFFFFFFFFFE) MUST NOT be assigned by IANA. 0x3FFFFFFFFFFFFFFE) MUST NOT be assigned by IANA.
11.2.2. Settings Parameters 11.2.2. Settings Parameters
This document establishes a registry for HTTP/3 settings. The This document establishes a registry for HTTP/3 settings. The
"HTTP/3 Settings" registry governs a 62-bit space. This registry "HTTP/3 Settings" registry governs a 62-bit space. This registry
follows the QUIC registry policy; see Section 11.2. Permanent follows the QUIC registry policy; see Section 11.2. Permanent
registrations in this registry are assigned using the Specification registrations in this registry are assigned using the Specification
Required policy [RFC8126], except for values between 0x00 and 0x3f Required policy ([RFC8126]), except for values between 0x00 and 0x3f
(in hexadecimal; inclusive), which are assigned using Standards (in hexadecimal; inclusive), which are assigned using Standards
Action or IESG Approval as defined in Section 4.9 and 4.10 of Action or IESG Approval as defined in Section 4.9 and 4.10 of
[RFC8126]. [RFC8126].
While this registry is separate from the "HTTP/2 Settings" registry While this registry is separate from the "HTTP/2 Settings" registry
defined in [HTTP2], it is preferable that the assignments parallel defined in [HTTP2], it is preferable that the assignments parallel
each other. If an entry is present in only one registry, every each other. If an entry is present in only one registry, every
effort SHOULD be made to avoid assigning the corresponding value to effort SHOULD be made to avoid assigning the corresponding value to
an unrelated operation. an unrelated operation.
skipping to change at page 50, line 16 skipping to change at page 50, line 16
registrations in this registry MUST include the following fields: registrations in this registry MUST include the following fields:
Setting Name: A symbolic name for the setting. Specifying a setting Setting Name: A symbolic name for the setting. Specifying a setting
name is optional. name is optional.
Default: The value of the setting unless otherwise indicated. A Default: The value of the setting unless otherwise indicated. A
default SHOULD be the most restrictive possible value. default SHOULD be the most restrictive possible value.
The entries in Table 3 are registered by this document. The entries in Table 3 are registered by this document.
+------------------------+-------+-----------------+-----------+ +========================+=======+=================+===========+
| Setting Name | Value | Specification | Default | | Setting Name | Value | Specification | Default |
+========================+=======+=================+===========+ +========================+=======+=================+===========+
| Reserved | 0x2 | N/A | N/A | | Reserved | 0x2 | N/A | N/A |
+------------------------+-------+-----------------+-----------+ +------------------------+-------+-----------------+-----------+
| Reserved | 0x3 | N/A | N/A | | Reserved | 0x3 | N/A | N/A |
+------------------------+-------+-----------------+-----------+ +------------------------+-------+-----------------+-----------+
| Reserved | 0x4 | N/A | N/A | | Reserved | 0x4 | N/A | N/A |
+------------------------+-------+-----------------+-----------+ +------------------------+-------+-----------------+-----------+
| Reserved | 0x5 | N/A | N/A | | Reserved | 0x5 | N/A | N/A |
+------------------------+-------+-----------------+-----------+ +------------------------+-------+-----------------+-----------+
| MAX_FIELD_SECTION_SIZE | 0x6 | Section 7.2.4.1 | Unlimited | | MAX_FIELD_SECTION_SIZE | 0x6 | Section 7.2.4.1 | Unlimited |
+------------------------+-------+-----------------+-----------+ +------------------------+-------+-----------------+-----------+
Table 3: Initial HTTP/3 Settings Table 3: Initial HTTP/3 Settings
Additionally, each code of the format "0x1f * N + 0x21" for non- Additionally, each code of the format "0x1f * N + 0x21" for non-
negative integer values of N (that is, 0x21, 0x40, ..., through negative integer values of N (that is, 0x21, 0x40, ..., through
0x3FFFFFFFFFFFFFFE) MUST NOT be assigned by IANA. 0x3ffffffffffffffe) MUST NOT be assigned by IANA.
11.2.3. Error Codes 11.2.3. Error Codes
This document establishes a registry for HTTP/3 error codes. The This document establishes a registry for HTTP/3 error codes. The
"HTTP/3 Error Code" registry manages a 62-bit space. This registry "HTTP/3 Error Code" registry manages a 62-bit space. This registry
follows the QUIC registry policy; see Section 11.2. Permanent follows the QUIC registry policy; see Section 11.2. Permanent
registrations in this registry are assigned using the Specification registrations in this registry are assigned using the Specification
Required policy [RFC8126], except for values between 0x00 and 0x3f Required policy ([RFC8126]), except for values between 0x00 and 0x3f
(in hexadecimal; inclusive), which are assigned using Standards (in hexadecimal; inclusive), which are assigned using Standards
Action or IESG Approval as defined in Section 4.9 and 4.10 of Action or IESG Approval as defined in Section 4.9 and 4.10 of
[RFC8126]. [RFC8126].
Registrations for error codes are required to include a description Registrations for error codes are required to include a description
of the error code. An expert reviewer is advised to examine new of the error code. An expert reviewer is advised to examine new
registrations for possible duplication with existing error codes. registrations for possible duplication with existing error codes.
Use of existing registrations is to be encouraged, but not mandated. Use of existing registrations is to be encouraged, but not mandated.
In addition to common fields as described in Section 11.2, permanent In addition to common fields as described in Section 11.2, this
registrations in this registry MUST include the following fields: registry includes two additional fields. Permanent registrations in
this registry MUST include the following field:
Name: A name for the error code. Specifying an error code name is Name: A name for the error code.
optional.
Description: A brief description of the error code semantics. Description: A brief description of the error code semantics.
The entries in the Table 4 are registered by this document. The entries in Table 4 are registered by this document.
+---------------------------+--------+--------------+---------------+ +===========================+========+==============+===============+
| Name | Value | Description | Specification | | Name | Value | Description | Specification |
+===========================+========+==============+===============+ +===========================+========+==============+===============+
| H3_NO_ERROR | 0x0100 | No error | Section 8.1 | | H3_NO_ERROR | 0x0100 | No error | Section 8.1 |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_GENERAL_PROTOCOL_ERROR | 0x0101 | General | Section 8.1 | | H3_GENERAL_PROTOCOL_ERROR | 0x0101 | General | Section 8.1 |
| | | protocol | | | | | protocol | |
| | | error | | | | | error | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_INTERNAL_ERROR | 0x0102 | Internal | Section 8.1 | | H3_INTERNAL_ERROR | 0x0102 | Internal | Section 8.1 |
| | | error | | | | | error | |
skipping to change at page 52, line 13 skipping to change at page 52, line 13
| | | identifier | | | | | identifier | |
| | | was used | | | | | was used | |
| | | incorrectly | | | | | incorrectly | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_SETTINGS_ERROR | 0x0109 | SETTINGS | Section 8.1 | | H3_SETTINGS_ERROR | 0x0109 | SETTINGS | Section 8.1 |
| | | frame | | | | | frame | |
| | | contained | | | | | contained | |
| | | invalid | | | | | invalid | |
| | | values | | | | | values | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_MISSING_SETTINGS | 0x010A | No SETTINGS | Section 8.1 | | H3_MISSING_SETTINGS | 0x010a | No SETTINGS | Section 8.1 |
| | | frame | | | | | frame | |
| | | received | | | | | received | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_REQUEST_REJECTED | 0x010B | Request not | Section 8.1 | | H3_REQUEST_REJECTED | 0x010b | Request not | Section 8.1 |
| | | processed | | | | | processed | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_REQUEST_CANCELLED | 0x010C | Data no | Section 8.1 | | H3_REQUEST_CANCELLED | 0x010c | Data no | Section 8.1 |
| | | longer | | | | | longer | |
| | | needed | | | | | needed | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_REQUEST_INCOMPLETE | 0x010D | Stream | Section 8.1 | | H3_REQUEST_INCOMPLETE | 0x010d | Stream | Section 8.1 |
| | | terminated | | | | | terminated | |
| | | early | | | | | early | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_CONNECT_ERROR | 0x010F | TCP reset | Section 8.1 | | H3_CONNECT_ERROR | 0x010f | TCP reset | Section 8.1 |
| | | or error on | | | | | or error on | |
| | | CONNECT | | | | | CONNECT | |
| | | request | | | | | request | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
| H3_VERSION_FALLBACK | 0x0110 | Retry over | Section 8.1 | | H3_VERSION_FALLBACK | 0x0110 | Retry over | Section 8.1 |
| | | HTTP/1.1 | | | | | HTTP/1.1 | |
+---------------------------+--------+--------------+---------------+ +---------------------------+--------+--------------+---------------+
Table 4: Initial HTTP/3 Error Codes Table 4: Initial HTTP/3 Error Codes
Additionally, each code of the format "0x1f * N + 0x21" for non- Additionally, each code of the format "0x1f * N + 0x21" for non-
negative integer values of N (that is, 0x21, 0x40, ..., through negative integer values of N (that is, 0x21, 0x40, ..., through
0x3FFFFFFFFFFFFFFE) MUST NOT be assigned by IANA. 0x3ffffffffffffffe) MUST NOT be assigned by IANA.
11.2.4. Stream Types 11.2.4. Stream Types
This document establishes a registry for HTTP/3 unidirectional stream This document establishes a registry for HTTP/3 unidirectional stream
types. The "HTTP/3 Stream Type" registry governs a 62-bit space. types. The "HTTP/3 Stream Type" registry governs a 62-bit space.
This registry follows the QUIC registry policy; see Section 11.2. This registry follows the QUIC registry policy; see Section 11.2.
Permanent registrations in this registry are assigned using the Permanent registrations in this registry are assigned using the
Specification Required policy [RFC8126], except for values between Specification Required policy ([RFC8126]), except for values between
0x00 and 0x3f (in hexadecimal; inclusive), which are assigned using 0x00 and 0x3f (in hexadecimal; inclusive), which are assigned using
Standards Action or IESG Approval as defined in Section 4.9 and 4.10 Standards Action or IESG Approval as defined in Section 4.9 and 4.10
of [RFC8126]. of [RFC8126].
In addition to common fields as described in Section 11.2, permanent In addition to common fields as described in Section 11.2, permanent
registrations in this registry MUST include the following fields: registrations in this registry MUST include the following fields:
Stream Type: A name or label for the stream type. Stream Type: A name or label for the stream type.
Sender: Which endpoint on a connection may initiate a stream of this Sender: Which endpoint on a connection may initiate a stream of this
type. Values are "Client", "Server", or "Both". type. Values are "Client", "Server", or "Both".
Specifications for permanent registrations MUST include a description Specifications for permanent registrations MUST include a description
of the stream type, including the layout semantics of the stream of the stream type, including the layout and semantics of the stream
contents. contents.
The entries in the following table are registered by this document. The entries in the following table are registered by this document.
+----------------+-------+---------------+--------+ +================+=======+===============+========+
| Stream Type | Value | Specification | Sender | | Stream Type | Value | Specification | Sender |
+================+=======+===============+========+ +================+=======+===============+========+
| Control Stream | 0x00 | Section 6.2.1 | Both | | Control Stream | 0x00 | Section 6.2.1 | Both |
+----------------+-------+---------------+--------+ +----------------+-------+---------------+--------+
| Push Stream | 0x01 | Section 4.4 | Server | | Push Stream | 0x01 | Section 4.4 | Server |
+----------------+-------+---------------+--------+ +----------------+-------+---------------+--------+
Table 5 Table 5
Additionally, each code of the format "0x1f * N + 0x21" for non- Additionally, each code of the format "0x1f * N + 0x21" for non-
negative integer values of N (that is, 0x21, 0x40, ..., through negative integer values of N (that is, 0x21, 0x40, ..., through
0x3FFFFFFFFFFFFFFE) MUST NOT be assigned by IANA. 0x3ffffffffffffffe) MUST NOT be assigned by IANA.
12. References 12. References
12.1. Normative References 12.1. Normative References
[ALTSVC] Nottingham, M., McManus, P., and J. Reschke, "HTTP [ALTSVC] Nottingham, M., McManus, P., and J. Reschke, "HTTP
Alternative Services", RFC 7838, DOI 10.17487/RFC7838, Alternative Services", RFC 7838, DOI 10.17487/RFC7838,
April 2016, <https://www.rfc-editor.org/info/rfc7838>. April 2016, <https://www.rfc-editor.org/info/rfc7838>.
[CACHING] Fielding, R., Nottingham, M., and J. Reschke, "HTTP [CACHING] Fielding, R., Nottingham, M., and J. Reschke, "HTTP
Caching", Work in Progress, Internet-Draft, draft-ietf- Caching", Work in Progress, Internet-Draft, draft-ietf-
httpbis-cache-08, 26 May 2020, <http://www.ietf.org/ httpbis-cache-11, August 27, 2020, <http://www.ietf.org/
internet-drafts/draft-ietf-httpbis-cache-08.txt>. internet-drafts/draft-ietf-httpbis-cache-11.txt>.
[HTTP-REPLAY] [HTTP-REPLAY]
Thomson, M., Nottingham, M., and W. Tarreau, "Using Early Thomson, M., Nottingham, M., and W. Tarreau, "Using Early
Data in HTTP", RFC 8470, DOI 10.17487/RFC8470, September Data in HTTP", RFC 8470, DOI 10.17487/RFC8470, September
2018, <https://www.rfc-editor.org/info/rfc8470>. 2018, <https://www.rfc-editor.org/info/rfc8470>.
[QPACK] Krasic, C., Bishop, M., and A. Frindell, Ed., "QPACK: [QPACK] Krasic, C., Bishop, M., and A. Frindell, Ed., "QPACK:
Header Compression for HTTP over QUIC", Work in Progress, Header Compression for HTTP over QUIC", Work in Progress,
Internet-Draft, draft-ietf-quic-qpack-16, 9 June 2020, Internet-Draft, draft-ietf-quic-qpack-17, September 10,
<https://tools.ietf.org/html/draft-ietf-quic-qpack-16>. 2020,
<https://tools.ietf.org/html/draft-ietf-quic-qpack-17>.
[QUIC-TRANSPORT] [QUIC-TRANSPORT]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", Work in Progress, Multiplexed and Secure Transport", Work in Progress,
Internet-Draft, draft-ietf-quic-transport-28, 9 June 2020, Internet-Draft, draft-ietf-quic-transport-29, September
<https://tools.ietf.org/html/draft-ietf-quic-transport- 10, 2020, <https://tools.ietf.org/html/draft-ietf-quic-
28>. transport-29>.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, [RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, DOI 10.17487/RFC0793, September 1981, RFC 793, DOI 10.17487/RFC0793, September 1981,
<https://www.rfc-editor.org/info/rfc793>. <https://www.rfc-editor.org/info/rfc793>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>. <https://www.rfc-editor.org/info/rfc3986>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS) [RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066, Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011, DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/info/rfc6066>. <https://www.rfc-editor.org/info/rfc6066>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509 within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer (PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>. 2011, <https://www.rfc-editor.org/info/rfc6125>.
[RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265,
DOI 10.17487/RFC6265, April 2011, DOI 10.17487/RFC6265, April 2011,
<https://www.rfc-editor.org/info/rfc6265>. <https://www.rfc-editor.org/info/rfc6265>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/info/rfc7301>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8164] Nottingham, M. and M. Thomson, "Opportunistic Security for [RFC8164] Nottingham, M. and M. Thomson, "Opportunistic Security for
HTTP/2", RFC 8164, DOI 10.17487/RFC8164, May 2017, HTTP/2", RFC 8164, DOI 10.17487/RFC8164, May 2017,
<https://www.rfc-editor.org/info/rfc8164>. <https://www.rfc-editor.org/info/rfc8164>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[SEMANTICS] [SEMANTICS]
Fielding, R., Nottingham, M., and J. Reschke, "HTTP Fielding, R., Nottingham, M., and J. Reschke, "HTTP
Semantics", Work in Progress, Internet-Draft, draft-ietf- Semantics", Work in Progress, Internet-Draft, draft-ietf-
httpbis-semantics-08, 26 May 2020, <http://www.ietf.org/ httpbis-semantics-11, August 27, 2020,
internet-drafts/draft-ietf-httpbis-semantics-08.txt>. <http://www.ietf.org/internet-drafts/draft-ietf-httpbis-
semantics-11.txt>.
12.2. Informative References 12.2. Informative References
[BREACH] Gluck, Y., Harris, N., and A. Prado, "BREACH: Reviving the [BREACH] Gluck, Y., Harris, N., and A. Prado, "BREACH: Reviving the
CRIME Attack", July 2013, CRIME Attack", July 2013,
<http://breachattack.com/resources/ <http://breachattack.com/resources/
BREACH%20-%20SSL,%20gone%20in%2030%20seconds.pdf>. BREACH%20-%20SSL,%20gone%20in%2030%20seconds.pdf>.
[HPACK] Peon, R. and H. Ruellan, "HPACK: Header Compression for [HPACK] Peon, R. and H. Ruellan, "HPACK: Header Compression for
HTTP/2", RFC 7541, DOI 10.17487/RFC7541, May 2015, HTTP/2", RFC 7541, DOI 10.17487/RFC7541, May 2015,
<https://www.rfc-editor.org/info/rfc7541>. <https://www.rfc-editor.org/info/rfc7541>.
[HTTP11] Fielding, R., Nottingham, M., and J. Reschke, "HTTP/1.1 [HTTP11] Fielding, R., Nottingham, M., and J. Reschke, "HTTP/1.1
Messaging", Work in Progress, Internet-Draft, draft-ietf- Messaging", Work in Progress, Internet-Draft, draft-ietf-
httpbis-messaging-08, 26 May 2020, <http://www.ietf.org/ httpbis-messaging-11, August 27, 2020,
internet-drafts/draft-ietf-httpbis-messaging-08.txt>. <http://www.ietf.org/internet-drafts/draft-ietf-httpbis-
messaging-11.txt>.
[HTTP2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext [HTTP2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540, Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
DOI 10.17487/RFC7540, May 2015, DOI 10.17487/RFC7540, May 2015,
<https://www.rfc-editor.org/info/rfc7540>. <https://www.rfc-editor.org/info/rfc7540>.
[RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status
Codes", RFC 6585, DOI 10.17487/RFC6585, April 2012, Codes", RFC 6585, DOI 10.17487/RFC6585, April 2012,
<https://www.rfc-editor.org/info/rfc6585>. <https://www.rfc-editor.org/info/rfc6585>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/info/rfc7301>.
[TFO] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP [TFO] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP
Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014, Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014,
<https://www.rfc-editor.org/info/rfc7413>. <https://www.rfc-editor.org/info/rfc7413>.
[TLS13] Rescorla, E., "The Transport Layer Security (TLS) Protocol [TLS13] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
[URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
skipping to change at page 56, line 46 skipping to change at page 56, line 41
out important differences from HTTP/2, and describes how to map out important differences from HTTP/2, and describes how to map
HTTP/2 extensions into HTTP/3. HTTP/2 extensions into HTTP/3.
HTTP/3 begins from the premise that similarity to HTTP/2 is HTTP/3 begins from the premise that similarity to HTTP/2 is
preferable, but not a hard requirement. HTTP/3 departs from HTTP/2 preferable, but not a hard requirement. HTTP/3 departs from HTTP/2
where QUIC differs from TCP, either to take advantage of QUIC where QUIC differs from TCP, either to take advantage of QUIC
features (like streams) or to accommodate important shortcomings features (like streams) or to accommodate important shortcomings
(such as a lack of total ordering). These differences make HTTP/3 (such as a lack of total ordering). These differences make HTTP/3
similar to HTTP/2 in key aspects, such as the relationship of similar to HTTP/2 in key aspects, such as the relationship of
requests and responses to streams. However, the details of the requests and responses to streams. However, the details of the
HTTP/3 design are substantially different than HTTP/2. HTTP/3 design are substantially different from HTTP/2.
These departures are noted in this section. These departures are noted in this section.
A.1. Streams A.1. Streams
HTTP/3 permits use of a larger number of streams (2^62-1) than HTTP/3 permits use of a larger number of streams (2^62-1) than
HTTP/2. The considerations about exhaustion of stream identifier HTTP/2. The same considerations about exhaustion of stream
space apply, though the space is significantly larger such that it is identifier space apply, though the space is significantly larger such
likely that other limits in QUIC are reached first, such as the limit that it is likely that other limits in QUIC are reached first, such
on the connection flow control window. as the limit on the connection flow control window.
In contrast to HTTP/2, stream concurrency in HTTP/3 is managed by In contrast to HTTP/2, stream concurrency in HTTP/3 is managed by
QUIC. QUIC considers a stream closed when all data has been received QUIC. QUIC considers a stream closed when all data has been received
and sent data has been acknowledged by the peer. HTTP/2 considers a and sent data has been acknowledged by the peer. HTTP/2 considers a
stream closed when the frame containing the END_STREAM bit has been stream closed when the frame containing the END_STREAM bit has been
committed to the transport. As a result, the stream for an committed to the transport. As a result, the stream for an
equivalent exchange could remain "active" for a longer period of equivalent exchange could remain "active" for a longer period of
time. HTTP/3 servers might choose to permit a larger number of time. HTTP/3 servers might choose to permit a larger number of
concurrent client-initiated bidirectional streams to achieve concurrent client-initiated bidirectional streams to achieve
equivalent concurrency to HTTP/2, depending on the expected usage equivalent concurrency to HTTP/2, depending on the expected usage
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Many framing concepts from HTTP/2 can be elided on QUIC, because the Many framing concepts from HTTP/2 can be elided on QUIC, because the
transport deals with them. Because frames are already on a stream, transport deals with them. Because frames are already on a stream,
they can omit the stream number. Because frames do not block they can omit the stream number. Because frames do not block
multiplexing (QUIC's multiplexing occurs below this layer), the multiplexing (QUIC's multiplexing occurs below this layer), the
support for variable-maximum-length packets can be removed. Because support for variable-maximum-length packets can be removed. Because
stream termination is handled by QUIC, an END_STREAM flag is not stream termination is handled by QUIC, an END_STREAM flag is not
required. This permits the removal of the Flags field from the required. This permits the removal of the Flags field from the
generic frame layout. generic frame layout.
Frame payloads are largely drawn from [HTTP2]. However, QUIC Frame payloads are largely drawn from [HTTP2]. However, QUIC
includes many features (e.g., flow control) which are also present in includes many features (e.g., flow control) that are also present in
HTTP/2. In these cases, the HTTP mapping does not re-implement them. HTTP/2. In these cases, the HTTP mapping does not re-implement them.
As a result, several HTTP/2 frame types are not required in HTTP/3. As a result, several HTTP/2 frame types are not required in HTTP/3.
Where an HTTP/2-defined frame is no longer used, the frame ID has Where an HTTP/2-defined frame is no longer used, the frame ID has
been reserved in order to maximize portability between HTTP/2 and been reserved in order to maximize portability between HTTP/2 and
HTTP/3 implementations. However, even equivalent frames between the HTTP/3 implementations. However, even equivalent frames between the
two mappings are not identical. two mappings are not identical.
Many of the differences arise from the fact that HTTP/2 provides an Many of the differences arise from the fact that HTTP/2 provides an
absolute ordering between frames across all streams, while QUIC absolute ordering between frames across all streams, while QUIC
provides this guarantee on each stream only. As a result, if a frame provides this guarantee on each stream only. As a result, if a frame
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A.2.2. Field Compression Differences A.2.2. Field Compression Differences
HPACK was designed with the assumption of in-order delivery. A HPACK was designed with the assumption of in-order delivery. A
sequence of encoded field sections must arrive (and be decoded) at an sequence of encoded field sections must arrive (and be decoded) at an
endpoint in the same order in which they were encoded. This ensures endpoint in the same order in which they were encoded. This ensures
that the dynamic state at the two endpoints remains in sync. that the dynamic state at the two endpoints remains in sync.
Because this total ordering is not provided by QUIC, HTTP/3 uses a Because this total ordering is not provided by QUIC, HTTP/3 uses a
modified version of HPACK, called QPACK. QPACK uses a single modified version of HPACK, called QPACK. QPACK uses a single
unidirectional stream to make all modifications to the dynamic table, unidirectional stream to make all modifications to the dynamic table,
ensuring a total order of updates. All frames which contain encoded ensuring a total order of updates. All frames that contain encoded
fields merely reference the table state at a given time without fields merely reference the table state at a given time without
modifying it. modifying it.
[QPACK] provides additional details. [QPACK] provides additional details.
A.2.3. Guidance for New Frame Type Definitions A.2.3. Flow Control Differences
HTTP/2 specifies a stream flow control mechanism. Although all
HTTP/2 frames are delivered on streams, only the DATA frame payload
is subject to flow control. QUIC provides flow control for stream
data and all HTTP/3 frame types defined in this document are sent on
streams. Therefore, all frame headers and payload are subject to
flow control.
A.2.4. Guidance for New Frame Type Definitions
Frame type definitions in HTTP/3 often use the QUIC variable-length Frame type definitions in HTTP/3 often use the QUIC variable-length
integer encoding. In particular, Stream IDs use this encoding, which integer encoding. In particular, Stream IDs use this encoding, which
allows for a larger range of possible values than the encoding used allows for a larger range of possible values than the encoding used
in HTTP/2. Some frames in HTTP/3 use an identifier rather than a in HTTP/2. Some frames in HTTP/3 use an identifier rather than a
Stream ID (e.g., Push IDs). Redefinition of the encoding of Stream ID (e.g., Push IDs). Redefinition of the encoding of
extension frame types might be necessary if the encoding includes a extension frame types might be necessary if the encoding includes a
Stream ID. Stream ID.
Because the Flags field is not present in generic HTTP/3 frames, Because the Flags field is not present in generic HTTP/3 frames,
those frames which depend on the presence of flags need to allocate those frames that depend on the presence of flags need to allocate
space for flags as part of their frame payload. space for flags as part of their frame payload.
Other than this issue, frame type HTTP/2 extensions are typically Other than these issues, frame type HTTP/2 extensions are typically
portable to QUIC simply by replacing Stream 0 in HTTP/2 with a portable to QUIC simply by replacing Stream 0 in HTTP/2 with a
control stream in HTTP/3. HTTP/3 extensions will not assume control stream in HTTP/3. HTTP/3 extensions will not assume
ordering, but would not be harmed by ordering, and would be portable ordering, but would not be harmed by ordering, and would be portable
to HTTP/2 in the same manner. to HTTP/2 in the same manner.
A.2.4. Mapping Between HTTP/2 and HTTP/3 Frame Types A.2.5. Mapping Between HTTP/2 and HTTP/3 Frame Types
DATA (0x0): Padding is not defined in HTTP/3 frames. See DATA (0x0): Padding is not defined in HTTP/3 frames. See
Section 7.2.1. Section 7.2.1.
HEADERS (0x1): The PRIORITY region of HEADERS is not defined in HEADERS (0x1): The PRIORITY region of HEADERS is not defined in
HTTP/3 frames. Padding is not defined in HTTP/3 frames. See HTTP/3 frames. Padding is not defined in HTTP/3 frames. See
Section 7.2.2. Section 7.2.2.
PRIORITY (0x2): As described in Appendix A.2.1, HTTP/3 does not PRIORITY (0x2): As described in Appendix A.2.1, HTTP/3 does not
provide a means of signaling priority. provide a means of signaling priority.
RST_STREAM (0x3): RST_STREAM frames do not exist, since QUIC RST_STREAM (0x3): RST_STREAM frames do not exist in HTTP/3, since
provides stream lifecycle management. The same code point is used QUIC provides stream lifecycle management. The same code point is
for the CANCEL_PUSH frame (Section 7.2.3). used for the CANCEL_PUSH frame (Section 7.2.3).
SETTINGS (0x4): SETTINGS frames are sent only at the beginning of SETTINGS (0x4): SETTINGS frames are sent only at the beginning of
the connection. See Section 7.2.4 and Appendix A.3. the connection. See Section 7.2.4 and Appendix A.3.
PUSH_PROMISE (0x5): The PUSH_PROMISE does not reference a stream; PUSH_PROMISE (0x5): The PUSH_PROMISE frame does not reference a
instead the push stream references the PUSH_PROMISE frame using a stream; instead the push stream references the PUSH_PROMISE frame
Push ID. See Section 7.2.5. using a Push ID. See Section 7.2.5.
PING (0x6): PING frames do not exist, since QUIC provides equivalent PING (0x6): PING frames do not exist in HTTP/3, as QUIC provides
functionality. equivalent functionality.
GOAWAY (0x7): GOAWAY does not contain an error code. In the client GOAWAY (0x7): GOAWAY does not contain an error code. In the client
to server direction, it carries a Push ID instead of a server to server direction, it carries a Push ID instead of a server
initiated stream ID. See Section 7.2.6. initiated stream ID. See Section 7.2.6.
WINDOW_UPDATE (0x8): WINDOW_UPDATE frames do not exist, since QUIC WINDOW_UPDATE (0x8): WINDOW_UPDATE frames do not exist in HTTP/3,
provides flow control. since QUIC provides flow control.
CONTINUATION (0x9): CONTINUATION frames do not exist; instead, CONTINUATION (0x9): CONTINUATION frames do not exist in HTTP/3;
larger HEADERS/PUSH_PROMISE frames than HTTP/2 are permitted. instead, larger HEADERS/PUSH_PROMISE frames than HTTP/2 are
permitted.
Frame types defined by extensions to HTTP/2 need to be separately Frame types defined by extensions to HTTP/2 need to be separately
registered for HTTP/3 if still applicable. The IDs of frames defined registered for HTTP/3 if still applicable. The IDs of frames defined
in [HTTP2] have been reserved for simplicity. Note that the frame in [HTTP2] have been reserved for simplicity. Note that the frame
type space in HTTP/3 is substantially larger (62 bits versus 8 bits), type space in HTTP/3 is substantially larger (62 bits versus 8 bits),
so many HTTP/3 frame types have no equivalent HTTP/2 code points. so many HTTP/3 frame types have no equivalent HTTP/2 code points.
See Section 11.2.1. See Section 11.2.1.
A.3. HTTP/2 SETTINGS Parameters A.3. HTTP/2 SETTINGS Parameters
An important difference from HTTP/2 is that settings are sent once, An important difference from HTTP/2 is that settings are sent once,
as the first frame of the control stream, and thereafter cannot as the first frame of the control stream, and thereafter cannot
change. This eliminates many corner cases around synchronization of change. This eliminates many corner cases around synchronization of
changes. changes.
Some transport-level options that HTTP/2 specifies via the SETTINGS Some transport-level options that HTTP/2 specifies via the SETTINGS
frame are superseded by QUIC transport parameters in HTTP/3. The frame are superseded by QUIC transport parameters in HTTP/3. The
HTTP-level options that are retained in HTTP/3 have the same value as HTTP-level options that are retained in HTTP/3 have the same value as
in HTTP/2. in HTTP/2. The superseded settings are reserved, and their receipt
is an error. See Section 7.2.4.1 for discussion of both the retained
and reserved values.
Below is a listing of how each HTTP/2 SETTINGS parameter is mapped: Below is a listing of how each HTTP/2 SETTINGS parameter is mapped:
SETTINGS_HEADER_TABLE_SIZE: See [QPACK]. SETTINGS_HEADER_TABLE_SIZE: See [QPACK].
SETTINGS_ENABLE_PUSH: This is removed in favor of the MAX_PUSH_ID SETTINGS_ENABLE_PUSH: This is removed in favor of the MAX_PUSH_ID
which provides a more granular control over server push. frame, which provides a more granular control over server push.
Specifying a setting with the identifier 0x2 (corresponding to the
SETTINGS_ENABLE_PUSH parameter) in the HTTP/3 SETTINGS frame is an
error.
SETTINGS_MAX_CONCURRENT_STREAMS: QUIC controls the largest open SETTINGS_MAX_CONCURRENT_STREAMS: QUIC controls the largest open
Stream ID as part of its flow control logic. Specifying Stream ID as part of its flow control logic. Specifying a setting
SETTINGS_MAX_CONCURRENT_STREAMS in the SETTINGS frame is an error. with the identifier 0x3 (corresponding to the
SETTINGS_MAX_CONCURRENT_STREAMS parameter) in the HTTP/3 SETTINGS
frame is an error.
SETTINGS_INITIAL_WINDOW_SIZE: QUIC requires both stream and SETTINGS_INITIAL_WINDOW_SIZE: QUIC requires both stream and
connection flow control window sizes to be specified in the connection flow control window sizes to be specified in the
initial transport handshake. Specifying initial transport handshake. Specifying a setting with the
SETTINGS_INITIAL_WINDOW_SIZE in the SETTINGS frame is an error. identifier 0x4 (corresponding to the SETTINGS_INITIAL_WINDOW_SIZE
parameter) in the HTTP/3 SETTINGS frame is an error.
SETTINGS_MAX_FRAME_SIZE: This setting has no equivalent in HTTP/3. SETTINGS_MAX_FRAME_SIZE: This setting has no equivalent in HTTP/3.
Specifying it in the SETTINGS frame is an error. Specifying a setting with the identifier 0x5 (corresponding to the
SETTINGS_MAX_FRAME_SIZE parameter) in the HTTP/3 SETTINGS frame is
an error.
SETTINGS_MAX_FIELD_SECTION_SIZE: See Section 7.2.4.1. SETTINGS_MAX_HEADER_LIST_SIZE: This setting identifier has been
renamed SETTINGS_MAX_FIELD_SECTION_SIZE.
In HTTP/3, setting values are variable-length integers (6, 14, 30, or In HTTP/3, setting values are variable-length integers (6, 14, 30, or
62 bits long) rather than fixed-length 32-bit fields as in HTTP/2. 62 bits long) rather than fixed-length 32-bit fields as in HTTP/2.
This will often produce a shorter encoding, but can produce a longer This will often produce a shorter encoding, but can produce a longer
encoding for settings which use the full 32-bit space. Settings encoding for settings that use the full 32-bit space. Settings
ported from HTTP/2 might choose to redefine their value to limit it ported from HTTP/2 might choose to redefine their value to limit it
to 30 bits for more efficient encoding, or to make use of the 62-bit to 30 bits for more efficient encoding, or to make use of the 62-bit
space if more than 30 bits are required. space if more than 30 bits are required.
Settings need to be defined separately for HTTP/2 and HTTP/3. The Settings need to be defined separately for HTTP/2 and HTTP/3. The
IDs of settings defined in [HTTP2] have been reserved for simplicity. IDs of settings defined in [HTTP2] have been reserved for simplicity.
Note that the settings identifier space in HTTP/3 is substantially Note that the settings identifier space in HTTP/3 is substantially
larger (62 bits versus 16 bits), so many HTTP/3 settings have no larger (62 bits versus 16 bits), so many HTTP/3 settings have no
equivalent HTTP/2 code point. See Section 11.2.2. equivalent HTTP/2 code point. See Section 11.2.2.
As QUIC streams might arrive out-of-order, endpoints are advised to As QUIC streams might arrive out of order, endpoints are advised not
not wait for the peers' settings to arrive before responding to other to wait for the peers' settings to arrive before responding to other
streams. See Section 7.2.4.2. streams. See Section 7.2.4.2.
A.4. HTTP/2 Error Codes A.4. HTTP/2 Error Codes
QUIC has the same concepts of "stream" and "connection" errors that QUIC has the same concepts of "stream" and "connection" errors that
HTTP/2 provides. However, the differences between HTTP/2 and HTTP/3 HTTP/2 provides. However, the differences between HTTP/2 and HTTP/3
mean that error codes are not directly portable between versions. mean that error codes are not directly portable between versions.
The HTTP/2 error codes defined in Section 7 of [HTTP2] logically map The HTTP/2 error codes defined in Section 7 of [HTTP2] logically map
to the HTTP/3 error codes as follows: to the HTTP/3 error codes as follows:
NO_ERROR (0x0): H3_NO_ERROR in Section 8.1. NO_ERROR (0x0): H3_NO_ERROR in Section 8.1.
PROTOCOL_ERROR (0x1): This is mapped to H3_GENERAL_PROTOCOL_ERROR PROTOCOL_ERROR (0x1): This is mapped to H3_GENERAL_PROTOCOL_ERROR
except in cases where more specific error codes have been defined. except in cases where more specific error codes have been defined.
This includes H3_FRAME_UNEXPECTED and H3_CLOSED_CRITICAL_STREAM Such cases include H3_FRAME_UNEXPECTED and
defined in Section 8.1. H3_CLOSED_CRITICAL_STREAM defined in Section 8.1.
INTERNAL_ERROR (0x2): H3_INTERNAL_ERROR in Section 8.1. INTERNAL_ERROR (0x2): H3_INTERNAL_ERROR in Section 8.1.
FLOW_CONTROL_ERROR (0x3): Not applicable, since QUIC handles flow FLOW_CONTROL_ERROR (0x3): Not applicable, since QUIC handles flow
control. control.
SETTINGS_TIMEOUT (0x4): Not applicable, since no acknowledgement of SETTINGS_TIMEOUT (0x4): Not applicable, since no acknowledgement of
SETTINGS is defined. SETTINGS is defined.
STREAM_CLOSED (0x5): Not applicable, since QUIC handles stream STREAM_CLOSED (0x5): Not applicable, since QUIC handles stream
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COMPRESSION_ERROR (0x9): Multiple error codes are defined in COMPRESSION_ERROR (0x9): Multiple error codes are defined in
[QPACK]. [QPACK].
CONNECT_ERROR (0xa): H3_CONNECT_ERROR in Section 8.1. CONNECT_ERROR (0xa): H3_CONNECT_ERROR in Section 8.1.
ENHANCE_YOUR_CALM (0xb): H3_EXCESSIVE_LOAD in Section 8.1. ENHANCE_YOUR_CALM (0xb): H3_EXCESSIVE_LOAD in Section 8.1.
INADEQUATE_SECURITY (0xc): Not applicable, since QUIC is assumed to INADEQUATE_SECURITY (0xc): Not applicable, since QUIC is assumed to
provide sufficient security on all connections. provide sufficient security on all connections.
H3_1_1_REQUIRED (0xd): H3_VERSION_FALLBACK in Section 8.1. HTTP_1_1_REQUIRED (0xd): H3_VERSION_FALLBACK in Section 8.1.
Error codes need to be defined for HTTP/2 and HTTP/3 separately. See Error codes need to be defined for HTTP/2 and HTTP/3 separately. See
Section 11.2.3. Section 11.2.3.
A.4.1. Mapping Between HTTP/2 and HTTP/3 Errors A.4.1. Mapping Between HTTP/2 and HTTP/3 Errors
An intermediary that converts between HTTP/2 and HTTP/3 may encounter An intermediary that converts between HTTP/2 and HTTP/3 may encounter
error conditions from either upstream. It is useful to communicate error conditions from either upstream. It is useful to communicate
the occurrence of error to the downstream but error codes largely the occurrence of error to the downstream but error codes largely
reflect connection-local problems that generally do not make sense to reflect connection-local problems that generally do not make sense to
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indicate this by sending an HTTP status code such as 502, which is indicate this by sending an HTTP status code such as 502, which is
suitable for a broad class of errors. suitable for a broad class of errors.
There are some rare cases where it is beneficial to propagate the There are some rare cases where it is beneficial to propagate the
error by mapping it to the closest matching error type to the error by mapping it to the closest matching error type to the
receiver. For example, an intermediary that receives an HTTP/2 receiver. For example, an intermediary that receives an HTTP/2
stream error of type REFUSED_STREAM from the origin has a clear stream error of type REFUSED_STREAM from the origin has a clear
signal that the request was not processed and that the request is signal that the request was not processed and that the request is
safe to retry. Propagating this error condition to the client as an safe to retry. Propagating this error condition to the client as an
HTTP/3 stream error of type H3_REQUEST_REJECTED allows the client to HTTP/3 stream error of type H3_REQUEST_REJECTED allows the client to
take the action it deems most appropriate. In the reverse direction take the action it deems most appropriate. In the reverse direction,
the intermediary might deem it beneficial to pass on client request the intermediary might deem it beneficial to pass on client request
cancellations that are indicated by terminating a stream with cancellations that are indicated by terminating a stream with
H3_REQUEST_CANCELLED. H3_REQUEST_CANCELLED; see Section 4.1.2.
Conversion between errors is described in the logical mapping. The Conversion between errors is described in the logical mapping. The
error codes are defined in non-overlapping spaces in order to protect error codes are defined in non-overlapping spaces in order to protect
against accidental conversion that could result in the use of against accidental conversion that could result in the use of
inappropriate or unknown error codes for the target version. An inappropriate or unknown error codes for the target version. An
intermediary is permitted to promote stream errors to connection intermediary is permitted to promote stream errors to connection
errors but they should be aware of the cost to the connection for errors but they should be aware of the cost to the connection for
what might be a temporary or intermittent error. what might be a temporary or intermittent error.
Appendix B. Change Log Appendix B. Change Log
*RFC Editor's Note:* Please remove this section prior to *RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document. publication of a final version of this document.
B.1. Since draft-ietf-quic-http-28 B.1. Since draft-ietf-quic-http-29
* Require a connection error if a reserved frame type that
corresponds to a frame in HTTP/2 is received (#3991, #3993)
* Require a connection error if a reserved setting that corresponds
to a setting in HTTP/2 is received (#3954, #3955)
B.2. Since draft-ietf-quic-http-28
* CANCEL_PUSH is recommended even when the stream is reset (#3698, * CANCEL_PUSH is recommended even when the stream is reset (#3698,
#3700) #3700)
* Use H3_ID_ERROR when GOAWAY contains a larger identifier (#3631, * Use H3_ID_ERROR when GOAWAY contains a larger identifier (#3631,
#3634) #3634)
B.2. Since draft-ietf-quic-http-27 B.3. Since draft-ietf-quic-http-27
* Updated text to refer to latest HTTP revisions * Updated text to refer to latest HTTP revisions
* Use the HTTP definition of authority for establishing and * Use the HTTP definition of authority for establishing and
coalescing connections (#253, #2223, #3558) coalescing connections (#253, #2223, #3558)
* Define use of GOAWAY from both endpoints (#2632, #3129) * Define use of GOAWAY from both endpoints (#2632, #3129)
* Require either :authority or Host if the URI scheme has a * Require either :authority or Host if the URI scheme has a
mandatory authority component (#3408, #3475) mandatory authority component (#3408, #3475)
B.3. Since draft-ietf-quic-http-26 B.4. Since draft-ietf-quic-http-26
* No changes * No changes
B.4. Since draft-ietf-quic-http-25 B.5. Since draft-ietf-quic-http-25
* Require QUICv1 for HTTP/3 (#3117, #3323) * Require QUICv1 for HTTP/3 (#3117, #3323)
* Remove DUPLICATE_PUSH and allow duplicate PUSH_PROMISE (#3275, * Remove DUPLICATE_PUSH and allow duplicate PUSH_PROMISE (#3275,
#3309) #3309)
* Clarify the definition of "malformed" (#3352, #3345) * Clarify the definition of "malformed" (#3352, #3345)
B.5. Since draft-ietf-quic-http-24 B.6. Since draft-ietf-quic-http-24
* Removed H3_EARLY_RESPONSE error code; H3_NO_ERROR is recommended * Removed H3_EARLY_RESPONSE error code; H3_NO_ERROR is recommended
instead (#3130,#3208) instead (#3130,#3208)
* Unknown error codes are equivalent to H3_NO_ERROR (#3276,#3331) * Unknown error codes are equivalent to H3_NO_ERROR (#3276,#3331)
* Some error codes are reserved for greasing (#3325,#3360) * Some error codes are reserved for greasing (#3325,#3360)
B.6. Since draft-ietf-quic-http-23 B.7. Since draft-ietf-quic-http-23
* Removed "quic" Alt-Svc parameter (#3061,#3118) * Removed "quic" Alt-Svc parameter (#3061,#3118)
* Clients need not persist unknown settings for use in 0-RTT * Clients need not persist unknown settings for use in 0-RTT
(#3110,#3113) (#3110,#3113)
* Clarify error cases around CANCEL_PUSH (#2819,#3083) * Clarify error cases around CANCEL_PUSH (#2819,#3083)
B.7. Since draft-ietf-quic-http-22 B.8. Since draft-ietf-quic-http-22
* Removed priority signaling (#2922,#2924) * Removed priority signaling (#2922,#2924)
* Further changes to error codes (#2662,#2551): * Further changes to error codes (#2662,#2551):
- Error codes renumbered - Error codes renumbered
- HTTP_MALFORMED_FRAME replaced by HTTP_FRAME_ERROR, - HTTP_MALFORMED_FRAME replaced by HTTP_FRAME_ERROR,
HTTP_ID_ERROR, and others HTTP_ID_ERROR, and others
skipping to change at page 64, line 28 skipping to change at page 65, line 4
* Clarify how unknown frame types interact with required frame * Clarify how unknown frame types interact with required frame
sequence (#2867,#2858) sequence (#2867,#2858)
* Describe interactions with the transport in terms of defined * Describe interactions with the transport in terms of defined
interface terms (#2857,#2805) interface terms (#2857,#2805)
* Require the use of the "http-opportunistic" resource (RFC 8164) * Require the use of the "http-opportunistic" resource (RFC 8164)
when scheme is "http" (#2439,#2973) when scheme is "http" (#2439,#2973)
* Settings identifiers cannot be duplicated (#2979) * Settings identifiers cannot be duplicated (#2979)
* Changes to SETTINGS frames in 0-RTT (#2972,#2790,#2945): * Changes to SETTINGS frames in 0-RTT (#2972,#2790,#2945):
- Servers must send all settings with non-default values in their - Servers must send all settings with non-default values in their
SETTINGS frame, even when resuming SETTINGS frame, even when resuming
- If a client doesn't have settings associated with a 0-RTT - If a client doesn't have settings associated with a 0-RTT
ticket, it uses the defaults ticket, it uses the defaults
- Servers can't accept early data if they cannot recover the - Servers can't accept early data if they cannot recover the
settings the client will have remembered settings the client will have remembered
* Clarify that Upgrade and the 101 status code are prohibited * Clarify that Upgrade and the 101 status code are prohibited
(#2898,#2889) (#2898,#2889)
* Clarify that frame types reserved for greasing can occur on any * Clarify that frame types reserved for greasing can occur on any
stream, but frame types reserved due to HTTP/2 correspondence are stream, but frame types reserved due to HTTP/2 correspondence are
prohibited (#2997,#2692,#2693) prohibited (#2997,#2692,#2693)
* Unknown error codes cannot be treated as errors (#2998,#2816) * Unknown error codes cannot be treated as errors (#2998,#2816)
B.8. Since draft-ietf-quic-http-21 B.9. Since draft-ietf-quic-http-21
No changes No changes
B.9. Since draft-ietf-quic-http-20 B.10. Since draft-ietf-quic-http-20
* Prohibit closing the control stream (#2509, #2666) * Prohibit closing the control stream (#2509, #2666)
* Change default priority to use an orphan node (#2502, #2690) * Change default priority to use an orphan node (#2502, #2690)
* Exclusive priorities are restored (#2754, #2781) * Exclusive priorities are restored (#2754, #2781)
* Restrict use of frames when using CONNECT (#2229, #2702) * Restrict use of frames when using CONNECT (#2229, #2702)
* Close and maybe reset streams if a connection error occurs for * Close and maybe reset streams if a connection error occurs for
skipping to change at page 65, line 27 skipping to change at page 66, line 4
* Encourage provision of sufficient unidirectional streams for QPACK * Encourage provision of sufficient unidirectional streams for QPACK
(#2100, #2529, #2762) (#2100, #2529, #2762)
* Allow extensions to use server-initiated bidirectional streams * Allow extensions to use server-initiated bidirectional streams
(#2711, #2773) (#2711, #2773)
* Clarify use of maximum header list size setting (#2516, #2774) * Clarify use of maximum header list size setting (#2516, #2774)
* Extensive changes to error codes and conditions of their sending * Extensive changes to error codes and conditions of their sending
- Require connection errors for more error conditions (#2511, - Require connection errors for more error conditions (#2511,
#2510) #2510)
- Updated the error codes for illegal GOAWAY frames (#2714, - Updated the error codes for illegal GOAWAY frames (#2714,
#2707) #2707)
- Specified error code for HEADERS on control stream (#2708) - Specified error code for HEADERS on control stream (#2708)
- Specified error code for servers receiving PUSH_PROMISE (#2709) - Specified error code for servers receiving PUSH_PROMISE (#2709)
- Specified error code for receiving DATA before HEADERS (#2715) - Specified error code for receiving DATA before HEADERS (#2715)
- Describe malformed messages and their handling (#2410, #2764) - Describe malformed messages and their handling (#2410, #2764)
- Remove HTTP_PUSH_ALREADY_IN_CACHE error (#2812, #2813) - Remove HTTP_PUSH_ALREADY_IN_CACHE error (#2812, #2813)
- Refactor Push ID related errors (#2818, #2820) - Refactor Push ID related errors (#2818, #2820)
- Rationalize HTTP/3 stream creation errors (#2821, #2822) - Rationalize HTTP/3 stream creation errors (#2821, #2822)
B.10. Since draft-ietf-quic-http-19 B.11. Since draft-ietf-quic-http-19
* SETTINGS_NUM_PLACEHOLDERS is 0x9 (#2443,#2530) * SETTINGS_NUM_PLACEHOLDERS is 0x9 (#2443,#2530)
* Non-zero bits in the Empty field of the PRIORITY frame MAY be * Non-zero bits in the Empty field of the PRIORITY frame MAY be
treated as an error (#2501) treated as an error (#2501)
B.11. Since draft-ietf-quic-http-18 B.12. Since draft-ietf-quic-http-18
* Resetting streams following a GOAWAY is recommended, but not * Resetting streams following a GOAWAY is recommended, but not
required (#2256,#2457) required (#2256,#2457)
* Use variable-length integers throughout (#2437,#2233,#2253,#2275) * Use variable-length integers throughout (#2437,#2233,#2253,#2275)
- Variable-length frame types, stream types, and settings - Variable-length frame types, stream types, and settings
identifiers identifiers
- Renumbered stream type assignments - Renumbered stream type assignments
- Modified associated reserved values - Modified associated reserved values
* Frame layout switched from Length-Type-Value to Type-Length-Value * Frame layout switched from Length-Type-Value to Type-Length-Value
(#2395,#2235) (#2395,#2235)
* Specified error code for servers receiving DUPLICATE_PUSH (#2497) * Specified error code for servers receiving DUPLICATE_PUSH (#2497)
* Use connection error for invalid PRIORITY (#2507, #2508) * Use connection error for invalid PRIORITY (#2507, #2508)
B.12. Since draft-ietf-quic-http-17 B.13. Since draft-ietf-quic-http-17
* HTTP_REQUEST_REJECTED is used to indicate a request can be retried * HTTP_REQUEST_REJECTED is used to indicate a request can be retried
(#2106, #2325) (#2106, #2325)
* Changed error code for GOAWAY on the wrong stream (#2231, #2343) * Changed error code for GOAWAY on the wrong stream (#2231, #2343)
B.13. Since draft-ietf-quic-http-16 B.14. Since draft-ietf-quic-http-16
* Rename "HTTP/QUIC" to "HTTP/3" (#1973) * Rename "HTTP/QUIC" to "HTTP/3" (#1973)
* Changes to PRIORITY frame (#1865, #2075) * Changes to PRIORITY frame (#1865, #2075)
- Permitted as first frame of request streams - Permitted as first frame of request streams
- Remove exclusive reprioritization - Remove exclusive reprioritization
- Changes to Prioritized Element Type bits - Changes to Prioritized Element Type bits
skipping to change at page 67, line 13 skipping to change at page 67, line 38
(#1809, #1846, #2038) (#1809, #1846, #2038)
* Clarify message processing rules for streams that aren't closed * Clarify message processing rules for streams that aren't closed
(#1972, #2003) (#1972, #2003)
* Removed reservation of error code 0 and moved HTTP_NO_ERROR to * Removed reservation of error code 0 and moved HTTP_NO_ERROR to
this value (#1922) this value (#1922)
* Removed prohibition of zero-length DATA frames (#2098) * Removed prohibition of zero-length DATA frames (#2098)
B.14. Since draft-ietf-quic-http-15 B.15. Since draft-ietf-quic-http-15
Substantial editorial reorganization; no technical changes. Substantial editorial reorganization; no technical changes.
B.15. Since draft-ietf-quic-http-14 B.16. Since draft-ietf-quic-http-14
* Recommend sensible values for QUIC transport parameters * Recommend sensible values for QUIC transport parameters
(#1720,#1806) (#1720,#1806)
* Define error for missing SETTINGS frame (#1697,#1808) * Define error for missing SETTINGS frame (#1697,#1808)
* Setting values are variable-length integers (#1556,#1807) and do * Setting values are variable-length integers (#1556,#1807) and do
not have separate maximum values (#1820) not have separate maximum values (#1820)
* Expanded discussion of connection closure (#1599,#1717,#1712) * Expanded discussion of connection closure (#1599,#1717,#1712)
skipping to change at page 67, line 28 skipping to change at page 68, line 4
* Recommend sensible values for QUIC transport parameters * Recommend sensible values for QUIC transport parameters
(#1720,#1806) (#1720,#1806)
* Define error for missing SETTINGS frame (#1697,#1808) * Define error for missing SETTINGS frame (#1697,#1808)
* Setting values are variable-length integers (#1556,#1807) and do * Setting values are variable-length integers (#1556,#1807) and do
not have separate maximum values (#1820) not have separate maximum values (#1820)
* Expanded discussion of connection closure (#1599,#1717,#1712) * Expanded discussion of connection closure (#1599,#1717,#1712)
* HTTP_VERSION_FALLBACK falls back to HTTP/1.1 (#1677,#1685) * HTTP_VERSION_FALLBACK falls back to HTTP/1.1 (#1677,#1685)
B.16. Since draft-ietf-quic-http-13 B.17. Since draft-ietf-quic-http-13
* Reserved some frame types for grease (#1333, #1446) * Reserved some frame types for grease (#1333, #1446)
* Unknown unidirectional stream types are tolerated, not errors; * Unknown unidirectional stream types are tolerated, not errors;
some reserved for grease (#1490, #1525) some reserved for grease (#1490, #1525)
* Require settings to be remembered for 0-RTT, prohibit reductions * Require settings to be remembered for 0-RTT, prohibit reductions
(#1541, #1641) (#1541, #1641)
* Specify behavior for truncated requests (#1596, #1643) * Specify behavior for truncated requests (#1596, #1643)
B.17. Since draft-ietf-quic-http-12 B.18. Since draft-ietf-quic-http-12
* TLS SNI extension isn't mandatory if an alternative method is used * TLS SNI extension isn't mandatory if an alternative method is used
(#1459, #1462, #1466) (#1459, #1462, #1466)
* Removed flags from HTTP/3 frames (#1388, #1398) * Removed flags from HTTP/3 frames (#1388, #1398)
* Reserved frame types and settings for use in preserving * Reserved frame types and settings for use in preserving
extensibility (#1333, #1446) extensibility (#1333, #1446)
* Added general error code (#1391, #1397) * Added general error code (#1391, #1397)
* Unidirectional streams carry a type byte and are extensible * Unidirectional streams carry a type byte and are extensible
(#910,#1359) (#910,#1359)
* Priority mechanism now uses explicit placeholders to enable * Priority mechanism now uses explicit placeholders to enable
persistent structure in the tree (#441,#1421,#1422) persistent structure in the tree (#441,#1421,#1422)
B.18. Since draft-ietf-quic-http-11 B.19. Since draft-ietf-quic-http-11
* Moved QPACK table updates and acknowledgments to dedicated streams * Moved QPACK table updates and acknowledgments to dedicated streams
(#1121, #1122, #1238) (#1121, #1122, #1238)
B.19. Since draft-ietf-quic-http-10 B.20. Since draft-ietf-quic-http-10
* Settings need to be remembered when attempting and accepting 0-RTT * Settings need to be remembered when attempting and accepting 0-RTT
(#1157, #1207) (#1157, #1207)
B.20. Since draft-ietf-quic-http-09 B.21. Since draft-ietf-quic-http-09
* Selected QCRAM for header compression (#228, #1117) * Selected QCRAM for header compression (#228, #1117)
* The server_name TLS extension is now mandatory (#296, #495) * The server_name TLS extension is now mandatory (#296, #495)
* Specified handling of unsupported versions in Alt-Svc (#1093, * Specified handling of unsupported versions in Alt-Svc (#1093,
#1097) #1097)
B.21. Since draft-ietf-quic-http-08 B.22. Since draft-ietf-quic-http-08
* Clarified connection coalescing rules (#940, #1024) * Clarified connection coalescing rules (#940, #1024)
B.22. Since draft-ietf-quic-http-07 B.23. Since draft-ietf-quic-http-07
* Changes for integer encodings in QUIC (#595,#905) * Changes for integer encodings in QUIC (#595,#905)
* Use unidirectional streams as appropriate (#515, #240, #281, #886) * Use unidirectional streams as appropriate (#515, #240, #281, #886)
* Improvement to the description of GOAWAY (#604, #898) * Improvement to the description of GOAWAY (#604, #898)
* Improve description of server push usage (#947, #950, #957) * Improve description of server push usage (#947, #950, #957)
B.23. Since draft-ietf-quic-http-06 B.24. Since draft-ietf-quic-http-06
* Track changes in QUIC error code usage (#485) * Track changes in QUIC error code usage (#485)
B.24. Since draft-ietf-quic-http-05 B.25. Since draft-ietf-quic-http-05
* Made push ID sequential, add MAX_PUSH_ID, remove * Made push ID sequential, add MAX_PUSH_ID, remove
SETTINGS_ENABLE_PUSH (#709) SETTINGS_ENABLE_PUSH (#709)
* Guidance about keep-alive and QUIC PINGs (#729) * Guidance about keep-alive and QUIC PINGs (#729)
* Expanded text on GOAWAY and cancellation (#757) * Expanded text on GOAWAY and cancellation (#757)
B.25. Since draft-ietf-quic-http-04 B.26. Since draft-ietf-quic-http-04
* Cite RFC 5234 (#404) * Cite RFC 5234 (#404)
* Return to a single stream per request (#245,#557) * Return to a single stream per request (#245,#557)
* Use separate frame type and settings registries from HTTP/2 (#81) * Use separate frame type and settings registries from HTTP/2 (#81)
* SETTINGS_ENABLE_PUSH instead of SETTINGS_DISABLE_PUSH (#477) * SETTINGS_ENABLE_PUSH instead of SETTINGS_DISABLE_PUSH (#477)
* Restored GOAWAY (#696) * Restored GOAWAY (#696)
* Identify server push using Push ID rather than a stream ID * Identify server push using Push ID rather than a stream ID
(#702,#281) (#702,#281)
* DATA frames cannot be empty (#700) * DATA frames cannot be empty (#700)
B.26. Since draft-ietf-quic-http-03 B.27. Since draft-ietf-quic-http-03
None. None.
B.27. Since draft-ietf-quic-http-02 B.28. Since draft-ietf-quic-http-02
* Track changes in transport draft * Track changes in transport draft
B.28. Since draft-ietf-quic-http-01 B.29. Since draft-ietf-quic-http-01
* SETTINGS changes (#181): * SETTINGS changes (#181):
- SETTINGS can be sent only once at the start of a connection; no - SETTINGS can be sent only once at the start of a connection; no
changes thereafter changes thereafter
- SETTINGS_ACK removed - SETTINGS_ACK removed
- Settings can only occur in the SETTINGS frame a single time - Settings can only occur in the SETTINGS frame a single time
skipping to change at page 70, line 15 skipping to change at page 70, line 39
* Closing the connection control stream or any message control * Closing the connection control stream or any message control
stream is a fatal error (#176) stream is a fatal error (#176)
* HPACK Sequence counter can wrap (#173) * HPACK Sequence counter can wrap (#173)
* 0-RTT guidance added * 0-RTT guidance added
* Guide to differences from HTTP/2 and porting HTTP/2 extensions * Guide to differences from HTTP/2 and porting HTTP/2 extensions
added (#127,#242) added (#127,#242)
B.29. Since draft-ietf-quic-http-00 B.30. Since draft-ietf-quic-http-00
* Changed "HTTP/2-over-QUIC" to "HTTP/QUIC" throughout (#11,#29) * Changed "HTTP/2-over-QUIC" to "HTTP/QUIC" throughout (#11,#29)
* Changed from using HTTP/2 framing within Stream 3 to new framing * Changed from using HTTP/2 framing within Stream 3 to new framing
format and two-stream-per-request model (#71,#72,#73) format and two-stream-per-request model (#71,#72,#73)
* Adopted SETTINGS format from draft-bishop-httpbis-extended- * Adopted SETTINGS format from draft-bishop-httpbis-extended-
settings-01 settings-01
* Reworked SETTINGS_ACK to account for indeterminate inter-stream * Reworked SETTINGS_ACK to account for indeterminate inter-stream
skipping to change at page 70, line 29 skipping to change at page 71, line 4
* Changed from using HTTP/2 framing within Stream 3 to new framing * Changed from using HTTP/2 framing within Stream 3 to new framing
format and two-stream-per-request model (#71,#72,#73) format and two-stream-per-request model (#71,#72,#73)
* Adopted SETTINGS format from draft-bishop-httpbis-extended- * Adopted SETTINGS format from draft-bishop-httpbis-extended-
settings-01 settings-01
* Reworked SETTINGS_ACK to account for indeterminate inter-stream * Reworked SETTINGS_ACK to account for indeterminate inter-stream
order (#75) order (#75)
* Described CONNECT pseudo-method (#95) * Described CONNECT pseudo-method (#95)
* Updated ALPN token and Alt-Svc guidance (#13,#87) * Updated ALPN token and Alt-Svc guidance (#13,#87)
* Application-layer-defined error codes (#19,#74) * Application-layer-defined error codes (#19,#74)
B.30. Since draft-shade-quic-http2-mapping-00 B.31. Since draft-shade-quic-http2-mapping-00
* Adopted as base for draft-ietf-quic-http * Adopted as base for draft-ietf-quic-http
* Updated authors/editors list * Updated authors/editors list
Acknowledgements Acknowledgements
The original authors of this specification were Robbie Shade and Mike The original authors of this specification were Robbie Shade and Mike
Warres. Warres.
 End of changes. 231 change blocks. 
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