Internet-Draft HTTP/3 on Streams February 2024
Oku & Pardue Expires 19 August 2024 [Page]
Intended Status:
Standards Track
K. Oku
L. Pardue

HTTP/3 on Streams


This document specifies how to use HTTP/3 on top of bi-directional, byte-oriented streams such as TLS over TCP.

Discussion Venues

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Status of This Memo

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This Internet-Draft will expire on 19 August 2024.

1. Introduction

As of 2023, HTTP/2 [HTTP2] remains the most widely used version of HTTP across the Internet, although the adoption rate of HTTP/3 [HTTP3] is increasing rapidly.

HTTP/3 has several advantages over HTTP/2, primarily due to its use of QUIC [QUIC] as the transport layer protocol, which provides features like stream multiplexing without head-of-line blocking and low-latency connection establishment.

However, given that QUIC's availability and accessibility are not as universal as TCP's, a complete migration of all HTTP/2 traffic to QUIC-based HTTP/3 seems unlikely.

This situation necessitates HTTP deployments to support both transport protocols and their respective HTTP versions for the foreseeable future.

Maintaining dual support is costly, as the two protocols differ in many aspects such as wire-encoding, flow control and stream multiplexing machinery, and HTTP header compression. Extensions operating at the HTTP wire encoding layer must be developed and implemented for both HTTP/2 and HTTP/3, and both protocol stacks require ongoing maintenance to address bugs, performance issues, and vulnerabilities.

To address this redundancy, this specification defines the method of running HTTP/3 over TCP, utilizing QUIC on Streams [QUIC-ON-STREAMS] as the basis. QUIC on Streams, acting as a polyfill of QUIC atop bi-directional byte streams, enables the operation of HTTP/3 over TCP without any modifications.

Consequently, design, implementation, and maintenance efforts can concentrate on a single HTTP version: HTTP/3.

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. The Protocol

HTTP/3 functions over QUIC version 1, employing the set of operations (i.e., API) defined in Section 2.4 and Section 5.3 of [QUIC]. Conversely, HTTP/3 on Streams utilizes the same set of operations but functions over QUIC on Streams instead.

4. Starting HTTP/3 on Streams

HTTP/3 on Streams can be used for “http” and “https” URI schemes defined in Section 4.2 of [HTTP-SEMANTICS] with the same default port numbers as HTTP/1.1 [HTTP1].

When starting HTTP/3 on Streams for “https” URIs, clients use the TLS [TLS13] with the ALPN [ALPN] extension: “h3s”.

Also, clients may learn that a particular server supports HTTP/3 on Streams by other means. A client that knows that a server supports HTTP/3 on Streams can establish a TCP connection and start exchanging HTTP/3 frames using QUIC on Streams.

The latter is the only way to discover HTTP/3 on Streams for “http” URIs.

When used in cleartext, servers can determine if or not the client is speaking HTTP/3 on Streams by comparing the first eight bytes to the encoded form of the QS_TRANSPORT_PARAMETERS frame type (Section 4.2 of [QUIC-ON-STREAMS]).

5. Support for Extended CONNECT

Servers speaking HTTP/3 on Streams MUST implement the Extended CONNECT scheme defined in [EXT-CONNECT3].

7. IANA Considerations

This document has no IANA actions.

8. References

8.1. Normative References

Friedl, S., Popov, A., Langley, A., and E. Stephan, "Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301, , <>.
Hamilton, R., "Bootstrapping WebSockets with HTTP/3", RFC 9220, DOI 10.17487/RFC9220, , <>.
Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, , <>.
Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP/1.1", STD 99, RFC 9112, DOI 10.17487/RFC9112, , <>.
Bishop, M., Ed., "HTTP/3", RFC 9114, DOI 10.17487/RFC9114, , <>.
Oku, K. and L. Pardue, "QUIC on Streams", Work in Progress, Internet-Draft, draft-kazuho-quic-quic-on-streams-00, , <>.
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <>.

8.2. Informative References

Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113, DOI 10.17487/RFC9113, , <>.
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, , <>.


TODO acknowledge.

Authors' Addresses

Kazuho Oku
Lucas Pardue