Internet DRAFT - draft-schinazi-quic-h3-datagram
draft-schinazi-quic-h3-datagram
Network Working Group D. Schinazi
Internet-Draft Google LLC
Intended status: Experimental 12 October 2020
Expires: 15 April 2021
Using QUIC Datagrams with HTTP/3
draft-schinazi-quic-h3-datagram-05
Abstract
The QUIC DATAGRAM extension provides application protocols running
over QUIC with a mechanism to send unreliable data while leveraging
the security and congestion-control properties of QUIC. However,
QUIC DATAGRAM frames do not provide a means to demultiplex
application contexts. This document defines how to use QUIC DATAGRAM
frames when the application protocol running over QUIC is HTTP/3 by
adding an identifier at the start of the frame payload.
Discussion of this work is encouraged to happen on the QUIC IETF
mailing list (quic@ietf.org (mailto:quic@ietf.org)) or on the GitHub
repository which contains the draft:
https://github.com/DavidSchinazi/draft-h3-datagram.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 15 April 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions and Definitions . . . . . . . . . . . . . . . 3
2. HTTP/3 DATAGRAM Frame Format . . . . . . . . . . . . . . . . 3
2.1. Flow Identifiers . . . . . . . . . . . . . . . . . . . . 3
3. Flow Identifier Allocation . . . . . . . . . . . . . . . . . 4
4. The H3_DATAGRAM HTTP/3 SETTINGS Parameter . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Normative References . . . . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The QUIC DATAGRAM extension [DGRAM] provides application protocols
running over QUIC [QUIC] with a mechanism to send unreliable data
while leveraging the security and congestion-control properties of
QUIC. However, QUIC DATAGRAM frames do not provide a means to
demultiplex application contexts. This document defines how to use
QUIC DATAGRAM frames when the application protocol running over QUIC
is HTTP/3 [H3] by adding an identifier at the start of the frame
payload.
This design mimics the use of Stream Types in HTTP/3, which provide a
demultiplexing identifier at the start of each unidirectional stream.
Discussion of this work is encouraged to happen on the QUIC IETF
mailing list (quic@ietf.org (mailto:quic@ietf.org)) or on the GitHub
repository which contains the draft:
https://github.com/DavidSchinazi/draft-h3-datagram.
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1.1. 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.
2. HTTP/3 DATAGRAM Frame Format
When used with HTTP/3, the Datagram Data field of QUIC DATAGRAM
frames uses the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Identifier (i) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HTTP/3 Datagram Payload (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: HTTP/3 DATAGRAM Frame Format
Flow Identifier: A variable-length integer indicating the Flow
Identifier of the datagram (see Section 2.1).
HTTP/3 Datagram Payload: The payload of the datagram, whose
semantics are defined by individual applications.
2.1. Flow Identifiers
Flow identifiers represent bidirectional flows of datagrams within a
single QUIC connection. These are conceptually similar to streams in
the sense that they allow multiplexing of application data. Of
course flows lack any of the ordering or reliability guarantees of
streams.
Beyond this, a sender SHOULD ensure that DATAGRAM frames within a
single flow are transmitted in order relative to one another. If
multiple DATAGRAM frames can be packed into a single QUIC packet, the
sender SHOULD group them by flow identifier to promote fate-sharing
within a specific flow and improve the ability to process batches of
datagram messages efficiently on the receiver.
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3. Flow Identifier Allocation
Implementations of HTTP/3 that support the DATAGRAM extension MUST
provide a flow identifier allocation service. That service will
allow applications co-located with HTTP/3 to request a unique flow
identifier that they can subsequently use for their own purposes.
The HTTP/3 implementation will then parse the flow identifier of
incoming DATAGRAM frames and use it to deliver the frame to the
appropriate application.
Even flow identifiers are client-initiated, while odd flow
identifiers are server-initiated. This means that an HTTP/3 client
implementation of the flow identifier allocation service MUST only
provide even identifiers, while a server implementation MUST only
provide odd identifiers. Note that, once allocated, any flow
identifier can be used by both client and server - only allocation
carries separate namespaces to avoid requiring synchronization.
4. The H3_DATAGRAM HTTP/3 SETTINGS Parameter
Implementations of HTTP/3 that support this mechanism can indicate
that to their peer by sending the H3_DATAGRAM SETTINGS parameter with
a value of 1. The value of the H3_DATAGRAM SETTINGS parameter MUST
be either 0 or 1. A value of 0 indicates that this mechanism is not
supported. An endpoint that receives the H3_DATAGRAM SETTINGS
parameter with a value that is neither 0 or 1 MUST terminate the
connection with error H3_SETTINGS_ERROR.
And endpoint that sends the H3_DATAGRAM SETTINGS parameter with a
value of 1 MUST send the max_datagram_frame_size QUIC Transport
Parameter [DGRAM]. An endpoint that receives the H3_DATAGRAM
SETTINGS parameter with a value of 1 on a QUIC connection that did
not also receive the max_datagram_frame_size QUIC Transport Parameter
MUST terminate the connection with error H3_SETTINGS_ERROR.
When clients use 0-RTT, they MAY store the value of the server's
H3_DATAGRAM SETTINGS parameter. Doing so allows the client to use
HTTP/3 datagrams in 0-RTT packets. When servers decide to accept
0-RTT data, they MUST send a H3_DATAGRAM SETTINGS parameter greater
or equal to the value they sent to the client in the connection where
they sent them the NewSessionTicket message. If a client stores the
value of the H3_DATAGRAM SETTINGS parameter with their 0-RTT state,
they MUST validate that the new value of the H3_DATAGRAM SETTINGS
parameter sent by the server in the handshake is greater or equal to
the stored value; if not, the client MUST terminate the connection
with error H3_SETTINGS_ERROR.
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5. Security Considerations
This document currently does not have additional security
considerations beyond those defined in [QUIC] and [DGRAM].
6. IANA Considerations
This document will request IANA to register the following entry in
the "HTTP/3 Settings" registry:
+--------------+-------+---------------+---------+
| Setting Name | Value | Specification | Default |
+==============+=======+===============+=========+
| H3_DATAGRAM | 0x276 | This Document | 0 |
+--------------+-------+---------------+---------+
7. Normative References
[DGRAM] Pauly, T., Kinnear, E., and D. Schinazi, "An Unreliable
Datagram Extension to QUIC", Work in Progress, Internet-
Draft, draft-ietf-quic-datagram-01, 24 August 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
datagram-01.txt>.
[H3] Bishop, M., "Hypertext Transfer Protocol Version 3
(HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
quic-http-31, 24 September 2020, <http://www.ietf.org/
internet-drafts/draft-ietf-quic-http-31.txt>.
[QUIC] Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
and Secure Transport", Work in Progress, Internet-Draft,
draft-ietf-quic-transport-31, 24 September 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
transport-31.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
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Acknowledgments
The DATAGRAM frame identifier was previously part of the DATAGRAM
frame definition itself, the author would like to acknowledge the
authors of that document and the members of the IETF QUIC working
group for their suggestions. Additionally, the author would like to
thank Martin Thomson for suggesting the use of an HTTP/3 SETTINGS
parameter.
Author's Address
David Schinazi
Google LLC
1600 Amphitheatre Parkway
Mountain View, California 94043,
United States of America
Email: dschinazi.ietf@gmail.com
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