HTTP Datagrams and the Capsule Protocol
draft-ietf-masque-h3-datagram-08
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (masque WG) | |
|---|---|---|---|
| Authors | David Schinazi , Lucas Pardue | ||
| Last updated | 2022-03-28 | ||
| Replaces | draft-schinazi-masque-h3-datagram | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html xml htmlized pdfized bibtex | ||
| Stream | WG state | In WG Last Call | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-masque-h3-datagram-08
MASQUE D. Schinazi
Internet-Draft Google LLC
Intended status: Standards Track L. Pardue
Expires: 29 September 2022 Cloudflare
28 March 2022
HTTP Datagrams and the Capsule Protocol
draft-ietf-masque-h3-datagram-08
Abstract
This document describes HTTP Datagrams, a convention for conveying
multiplexed, potentially unreliable datagrams inside an HTTP
connection.
In HTTP/3, HTTP Datagrams can be conveyed natively using the QUIC
DATAGRAM extension. When the QUIC DATAGRAM frame is unavailable or
undesirable, they can be sent using the Capsule Protocol, a more
general convention for conveying data in HTTP connections.
Both are intended for use by HTTP extensions, not applications.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the MASQUE WG mailing list
(masque@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/masque/.
Source for this draft and an issue tracker can be found at
https://github.com/ietf-wg-masque/draft-ietf-masque-h3-datagram.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Schinazi & Pardue Expires 29 September 2022 [Page 1]
Internet-Draft HTTP Datagrams March 2022
This Internet-Draft will expire on 29 September 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions and Definitions . . . . . . . . . . . . . . . 3
2. HTTP Datagrams . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. HTTP/3 Datagrams . . . . . . . . . . . . . . . . . . . . 4
2.1.1. The H3_DATAGRAM HTTP/3 SETTINGS Parameter . . . . . . 5
2.2. HTTP Datagrams using Capsules . . . . . . . . . . . . . . 6
3. Capsules . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. HTTP Data Streams . . . . . . . . . . . . . . . . . . . . 7
3.2. The Capsule Protocol . . . . . . . . . . . . . . . . . . 7
3.3. Error Handling . . . . . . . . . . . . . . . . . . . . . 8
3.4. The Capsule-Protocol Header Field . . . . . . . . . . . . 9
3.5. The DATAGRAM Capsule . . . . . . . . . . . . . . . . . . 9
4. Security Considerations . . . . . . . . . . . . . . . . . . . 11
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
5.1. HTTP/3 SETTINGS Parameter . . . . . . . . . . . . . . . . 11
5.2. HTTP/3 Error Code . . . . . . . . . . . . . . . . . . . . 12
5.3. HTTP Header Field Name . . . . . . . . . . . . . . . . . 12
5.4. Capsule Types . . . . . . . . . . . . . . . . . . . . . . 12
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1. Normative References . . . . . . . . . . . . . . . . . . 13
6.2. Informative References . . . . . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
Schinazi & Pardue Expires 29 September 2022 [Page 2]
Internet-Draft HTTP Datagrams March 2022
1. Introduction
HTTP extensions sometimes need to access underlying transport
protocol features such as unreliable delivery (as offered by [DGRAM])
to enable desirable features like an unreliable version of the
CONNECT method, and unreliable delivery in WebSockets [RFC6455] (or
its successors).
In Section 2, this document describes HTTP Datagrams, a convention
that supports the bidirectional and possibly multiplexed exchange of
data inside an HTTP connection. While HTTP datagrams are associated
with HTTP requests, they are not part of message content; instead,
they are intended for use by HTTP extensions (such as the CONNECT
method), and are compatible with all versions of HTTP. When the
underlying transport protocol supports unreliable delivery (such as
when the QUIC DATAGRAM extension is available in HTTP/3), they can
use that capability.
This document also describes the HTTP Capsule Protocol in Section 3,
to allow conveyance of HTTP Datagrams when the QUIC DATAGRAM frame is
unavailable or undesirable, such as when earlier versions of HTTP are
in use.
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 Datagrams
HTTP Datagrams are a convention for conveying bidirectional and
potentially unreliable datagrams inside an HTTP connection, with
multiplexing when possible. All HTTP Datagrams are associated with
an HTTP request.
When HTTP Datagrams are conveyed on an HTTP/3 connection, the QUIC
DATAGRAM frame can be used to achieve these goals, including
unreliable delivery; see Section 2.1. Negotiation is achieved using
a setting; see Section 2.1.1.
When running over HTTP/2, demultiplexing is provided by the HTTP/2
framing layer, but unreliable delivery is unavailable. HTTP
Datagrams are negotiated and conveyed using the Capsule Protocol; see
Section 3.5.
Schinazi & Pardue Expires 29 September 2022 [Page 3]
Internet-Draft HTTP Datagrams March 2022
When running over HTTP/1, requests are strictly serialized in the
connection, and therefore demultiplexing is not available.
Unreliable delivery is likewise not available. HTTP Datagrams are
negotiated and conveyed using the Capsule Protocol; see Section 3.5.
HTTP Datagrams MUST only be sent with an association to a stream
whose HTTP semantics explicitly supports HTTP Datagrams. For
example, existing HTTP methods GET and POST do not define semantics
for associated HTTP Datagrams; therefore, HTTP Datagrams cannot be
sent associated with GET or POST request streams.
If an HTTP Datagram associated with a method that has no known
semantics for HTTP Datagrams is received, the receiver MUST abort the
corresponding stream; if HTTP/3 is in use, the stream MUST be aborted
with H3_DATAGRAM_ERROR. HTTP extensions can override these
requirements by defining a negotiation mechanism and semantics for
HTTP Datagrams.
2.1. HTTP/3 Datagrams
When used with HTTP/3, the Datagram Data field of QUIC DATAGRAM
frames uses the following format (using the notation from the
"Notational Conventions" section of [QUIC]):
HTTP/3 Datagram {
Quarter Stream ID (i),
HTTP Datagram Payload (..),
}
Figure 1: HTTP/3 Datagram Format
Quarter Stream ID: A variable-length integer that contains the value
of the client-initiated bidirectional stream that this datagram is
associated with, divided by four (the division by four stems from
the fact that HTTP requests are sent on client-initiated
bidirectional streams, and those have stream IDs that are
divisible by four). The largest legal QUIC stream ID value is
2^62-1, so the largest legal value of Quarter Stream ID is 2^60-1.
Receipt of an HTTP/3 Datagram that includes a larger value MUST be
treated as an HTTP/3 connection error of type H3_DATAGRAM_ERROR.
HTTP Datagram Payload: The payload of the datagram, whose semantics
are defined by the extension that is using HTTP Datagrams. Note
that this field can be empty.
Receipt of a QUIC DATAGRAM frame whose payload is too short to allow
parsing the Quarter Stream ID field MUST be treated as an HTTP/3
connection error of type H3_DATAGRAM_ERROR.
Schinazi & Pardue Expires 29 September 2022 [Page 4]
Internet-Draft HTTP Datagrams March 2022
HTTP/3 Datagrams MUST NOT be sent unless the corresponding stream's
send side is open. Once the receive side of a stream is closed,
incoming datagrams for this stream are no longer expected so related
state can be released. State MAY be kept for a short time to account
for reordering. Once the state is released, the received associated
datagrams MUST be silently dropped.
If an HTTP/3 datagram is received and its Quarter Stream ID maps to a
stream that has not yet been created, the receiver SHALL either drop
that datagram silently or buffer it temporarily (on the order of a
round trip) while awaiting the creation of the corresponding stream.
If an HTTP/3 datagram is received and its Quarter Stream ID maps to a
stream that cannot be created due to client-initiated bidirectional
stream limits, it SHOULD be treated as an HTTP/3 connection error of
type H3_ID_ERROR. Generating an error is not mandatory in this case
because HTTP/3 implementations might have practical barriers to
determining the active stream concurrency limit that is applied by
the QUIC layer.
Prioritization of HTTP/3 datagrams is not defined in this document.
Future extensions MAY define how to prioritize datagrams, and MAY
define signaling to allow communicating prioritization preferences.
2.1.1. The H3_DATAGRAM HTTP/3 SETTINGS Parameter
Implementations of HTTP/3 that support HTTP Datagrams 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 HTTP Datagrams are not supported. If
the H3_DATAGRAM SETTINGS parameter is received with a value that is
neither 0 or 1, the receiver MUST terminate the connection with error
H3_SETTINGS_ERROR.
QUIC DATAGRAM frames MUST NOT be sent until the H3_DATAGRAM SETTINGS
parameter has been both sent and received with a value of 1.
When clients use 0-RTT, they MAY store the value of the server's
H3_DATAGRAM SETTINGS parameter. Doing so allows the client to send
QUIC DATAGRAM frames in 0-RTT packets. When servers decide to accept
0-RTT data, they MUST send a H3_DATAGRAM SETTINGS parameter greater
than 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
Schinazi & Pardue Expires 29 September 2022 [Page 5]
Internet-Draft HTTP Datagrams March 2022
than or equal to the stored value; if not, the client MUST terminate
the connection with error H3_SETTINGS_ERROR. In all cases, the
maximum permitted value of the H3_DATAGRAM SETTINGS parameter is 1.
It is RECOMMENDED that implementations that support receiving HTTP
Datagrams using QUIC always send the H3_DATAGRAM SETTINGS parameter
with a value of 1, even if the application does not intend to use
HTTP Datagrams. This helps to avoid "sticking out"; see Section 4.
2.1.1.1. Note About Draft Versions
[[RFC editor: please remove this section before publication.]]
Some revisions of this draft specification use a different value (the
Identifier field of a Setting in the HTTP/3 SETTINGS frame) for the
H3_DATAGRAM Settings Parameter. This allows new draft revisions to
make incompatible changes. Multiple draft versions MAY be supported
by sending multiple values for H3_DATAGRAM. Once SETTINGS have been
sent and received, an implementation that supports multiple drafts
MUST compute the intersection of the values it has sent and received,
and then it MUST select and use the most recent draft version from
the intersection set. This ensures that both peers negotiate the
same draft version.
2.2. HTTP Datagrams using Capsules
When HTTP/3 Datagrams are unavailable or undesirable, HTTP Datagrams
can be sent using the Capsule Protocol, see Section 3.5.
3. Capsules
One mechanism to extend HTTP is to introduce new HTTP Upgrade Tokens
(see Section 16.7 of [HTTP]). In HTTP/1.x, these tokens are used via
the Upgrade mechanism (see Section 7.8 of [HTTP]). In HTTP/2 and
HTTP/3, these tokens are used via the Extended CONNECT mechanism (see
[EXT-CONNECT2] and [EXT-CONNECT3]).
This specification introduces the Capsule Protocol. The Capsule
Protocol is a sequence of type-length-value tuples that definitions
of new HTTP Upgrade Tokens can choose to use. It allows endpoints to
reliably communicate request-related information end-to-end on HTTP
request streams, even in the presence of HTTP intermediaries. The
Capsule Protocol can be used to exchange HTTP Datagrams, which is
necessary when HTTP is running over a transport that does not support
the QUIC DATAGRAM frame.
Schinazi & Pardue Expires 29 September 2022 [Page 6]
Internet-Draft HTTP Datagrams March 2022
3.1. HTTP Data Streams
This specification defines the "data stream" of an HTTP request as
the bidirectional stream of bytes that follows the header section of
the request message and the final, successful (i.e., 2xx) response
message.
In HTTP/1.x, the data stream consists of all bytes on the connection
that follow the blank line that concludes either the request header
section, or the response header section. As a result, only a single
HTTP request starting the capsule protocol can be sent on HTTP/1.x
connections.
In HTTP/2 and HTTP/3, the data stream of a given HTTP request
consists of all bytes sent in DATA frames with the corresponding
stream ID.
The concept of a data stream is particularly relevant for methods
such as CONNECT where there is no HTTP message content after the
headers.
Data streams can be prioritized using any means suited to stream or
request prioritization. For example, see Section 11 of [PRIORITY].
3.2. The Capsule Protocol
Definitions of new HTTP Upgrade Tokens can state that their
associated request's data stream uses the Capsule Protocol. If they
do so, that means that the contents of the associated request's data
stream uses the following format (using the notation from the
"Notational Conventions" section of [QUIC]):
Capsule Protocol {
Capsule (..) ...,
}
Figure 2: Capsule Protocol Stream Format
Capsule {
Capsule Type (i),
Capsule Length (i),
Capsule Value (..),
}
Figure 3: Capsule Format
Capsule Type: A variable-length integer indicating the Type of the
capsule.
Schinazi & Pardue Expires 29 September 2022 [Page 7]
Internet-Draft HTTP Datagrams March 2022
Capsule Length: The length of the Capsule Value field following this
field, encoded as a variable-length integer. Note that this field
can have a value of zero.
Capsule Value: The payload of this capsule. Its semantics are
determined by the value of the Capsule Type field.
An intermediary can identify the use of the capsule protocol either
through the presence of the Capsule-Protocol header field
(Section 3.4) or by understanding the chosen HTTP Upgrade token.
Because new protocols or extensions might define new capsule types,
intermediaries that wish to allow for future extensibility SHOULD
forward capsules without modification, unless the definition of the
Capsule Type in use specifies additional intermediary processing.
One such Capsule Type is the DATAGRAM capsule; see Section 3.5. In
particular, intermediaries SHOULD forward Capsules with an unknown
Capsule Type without modification.
Endpoints which receive a Capsule with an unknown Capsule Type MUST
silently drop that Capsule and skip over it to parse the next
Capsule.
By virtue of the definition of the data stream, the Capsule Protocol
is not in use on responses unless the response includes a 2xx
(Successful) status code.
The Capsule Protocol MUST NOT be used with messages that contain
Content-Length, Content-Type, or Transfer-Encoding header fields.
Additionally, HTTP status codes 204 (No Content), 205 (Reset
Content), and 206 (Partial Content) MUST NOT be sent on responses
that use the Capsule Protocol. A receiver that observes a violation
of these requirements MUST treat the HTTP message as malformed.
3.3. Error Handling
When an error occurs in processing the Capsule Protocol, the receiver
MUST treat the message as malformed or incomplete, according to the
underlying transport protocol. For HTTP/3, the handling of malformed
messages is described in Section 4.1.3 of [H3]. For HTTP/2, the
handling of malformed messages is described in Section 8.1.1 of [H2].
For HTTP/1.1, the handling of incomplete messages is described in
Section 8 of [H1].
Schinazi & Pardue Expires 29 September 2022 [Page 8]
Internet-Draft HTTP Datagrams March 2022
Each capsule's payload MUST contain exactly the fields identified in
its description. A capsule payload that contains additional bytes
after the identified fields or a capsule payload that terminates
before the end of the identified fields MUST be treated as a
malformed or incomplete message. In particular, redundant length
encodings MUST be verified to be self-consistent.
When a stream carrying capsules terminates cleanly, if the last
capsule on the stream was truncated, this MUST be treated as a
malformed or incomplete message.
3.4. The Capsule-Protocol Header Field
The "Capsule-Protocol" header field is an Item Structured Field, see
Section 3.3 of [STRUCT-FIELD]; its value MUST be a Boolean; any other
value type MUST be handled as if the field were not present by
recipients (for example, if this field is included multiple times,
its type will become a List and the field will therefore be ignored).
This document does not define any parameters for the Capsule-Protocol
header field value, but future documents might define parameters.
Receivers MUST ignore unknown parameters.
Endpoints indicate that the Capsule Protocol is in use on a data
stream by sending a Capsule-Protocol header field with a true value.
A Capsule-Protocol header field with a false value has the same
semantics as when the header is not present.
Intermediaries MAY use this header field to allow processing of HTTP
Datagrams for unknown HTTP Upgrade Tokens; note that this is only
possible for HTTP Upgrade or Extended CONNECT.
The Capsule-Protocol header field MUST NOT be used on HTTP responses
with a status code outside the 2xx range.
When using the Capsule Protocol, HTTP endpoints SHOULD send the
Capsule-Protocol header field to simplify intermediary processing.
Definitions of new HTTP Upgrade Tokens that use the Capsule Protocol
MAY alter this recommendation.
3.5. The DATAGRAM Capsule
This document defines the DATAGRAM capsule type (see Section 5.4 for
the value of the capsule type). This capsule allows HTTP Datagrams
to be sent on a stream using the Capsule Protocol. This is
particularly useful when HTTP is running over a transport that does
not support the QUIC DATAGRAM frame.
Schinazi & Pardue Expires 29 September 2022 [Page 9]
Internet-Draft HTTP Datagrams March 2022
Datagram Capsule {
Type (i) = DATAGRAM,
Length (i),
HTTP Datagram Payload (..),
}
Figure 4: DATAGRAM Capsule Format
HTTP Datagram Payload: The payload of the datagram, whose semantics
are defined by the extension that is using HTTP Datagrams. Note
that this field can be empty.
HTTP Datagrams sent using the DATAGRAM capsule have the same
semantics as those sent in QUIC DATAGRAM frames. In particular, the
restrictions on when it is allowed to send an HTTP Datagram and how
to process them from Section 2.1 also apply to HTTP Datagrams sent
and received using the DATAGRAM capsule.
An intermediary can reencode HTTP Datagrams as it forwards them. In
other words, an intermediary MAY send a DATAGRAM capsule to forward
an HTTP Datagram which was received in a QUIC DATAGRAM frame, and
vice versa.
Note that while DATAGRAM capsules that are sent on a stream are
reliably delivered in order, intermediaries can reencode DATAGRAM
capsules into QUIC DATAGRAM frames when forwarding messages, which
could result in loss or reordering.
If an intermediary receives an HTTP Datagram in a QUIC DATAGRAM frame
and is forwarding it on a connection that supports QUIC DATAGRAM
frames, the intermediary SHOULD NOT convert that HTTP Datagram to a
DATAGRAM capsule. If the HTTP Datagram is too large to fit in a
DATAGRAM frame (for example because the path MTU of that QUIC
connection is too low or if the maximum UDP payload size advertised
on that connection is too low), the intermediary SHOULD drop the HTTP
Datagram instead of converting it to a DATAGRAM capsule. This
preserves the end-to-end unreliability characteristic that methods
such as Datagram Packetization Layer Path MTU Discovery (DPLPMTUD)
depend on [DPLPMTUD]. An intermediary that converts QUIC DATAGRAM
frames to DATAGRAM capsules allows HTTP Datagrams to be arbitrarily
large without suffering any loss; this can misrepresent the true path
properties, defeating methods such as DPLPMTUD.
While DATAGRAM capsules can theoretically carry a payload of length
2^62-1, most HTTP extensions that use HTTP Datagrams will have their
own limits on what datagram payload sizes are practical.
Implementations SHOULD take those limits into account when parsing
DATAGRAM capsules: if an incoming DATAGRAM capsule has a length that
Schinazi & Pardue Expires 29 September 2022 [Page 10]
Internet-Draft HTTP Datagrams March 2022
is known to be so large as to not be usable, the implementation
SHOULD discard the capsule without buffering its contents into
memory.
Note that use of the Capsule Protocol is not required to use HTTP
Datagrams. If an HTTP extension that uses HTTP Datagrams is only
defined over transports that support QUIC DATAGRAM frames, it might
not need a stream encoding. Additionally, HTTP extensions can use
HTTP Datagrams with their own data stream protocol. However, new
HTTP extensions that wish to use HTTP Datagrams SHOULD use the
Capsule Protocol unless they have a good reason not to.
4. Security Considerations
Since transmitting HTTP Datagrams using QUIC DATAGRAM frames requires
sending an HTTP/3 Settings parameter, it "sticks out". In other
words, probing clients can learn whether a server supports HTTP
Datagrams over QUIC DATAGRAM frames. As some servers might wish to
obfuscate the fact that they offer application services that use HTTP
datagrams, it's best for all implementations that support this
feature to always send this Settings parameter, see Section 2.1.1.
Since use of the Capsule Protocol is restricted to new HTTP Upgrade
Tokens, it is not accessible from Web Platform APIs (such as those
commonly accessed via JavaScript in web browsers).
5. IANA Considerations
5.1. HTTP/3 SETTINGS Parameter
This document will request IANA to register the following entry in
the "HTTP/3 Settings" registry:
Value: 0xffd277 (note that this will switch to a lower value before
publication)
Setting Name: H3_DATAGRAM
Default: 0
Status: provisional (permanent if this document is approved)
Specification: This Document
Change Controller: IETF
Contact: HTTP_WG; HTTP working group; ietf-http-wg@w3.org
Schinazi & Pardue Expires 29 September 2022 [Page 11]
Internet-Draft HTTP Datagrams March 2022
5.2. HTTP/3 Error Code
This document will request IANA to register the following entry in
the "HTTP/3 Error Codes" registry:
Value: 0x4A1268 (note that this will switch to a lower value before
publication)
Name: H3_DATAGRAM_ERROR
Description: Datagram or capsule protocol parse error
Status: provisional (permanent if this document is approved)
Specification: This Document
Change Controller: IETF
Contact: HTTP_WG; HTTP working group; ietf-http-wg@w3.org
5.3. HTTP Header Field Name
This document will request IANA to register the following entry in
the "HTTP Field Name" registry:
Field Name: Capsule-Protocol
Template: None
Status: provisional (permanent if this document is approved)
Reference: This document
Comments: None
5.4. Capsule Types
This document establishes a registry for HTTP capsule type codes.
The "HTTP Capsule Types" registry governs a 62-bit space.
Registrations in this registry MUST include the following fields:
Type: A name or label for the capsule type.
Value: The value of the Capsule Type field (see Section 3.2) is a
62-bit integer.
Reference: An optional reference to a specification for the type.
This field MAY be empty.
Schinazi & Pardue Expires 29 September 2022 [Page 12]
Internet-Draft HTTP Datagrams March 2022
Registrations follow the "First Come First Served" policy (see
Section 4.4 of [IANA-POLICY]) where two registrations MUST NOT have
the same Type.
This registry initially contains the following entry:
Capsule Type: DATAGRAM
Value: 0xff37a5 (note that this will switch to a lower value before
publication)
Reference: This document
Capsule types with a value of the form 41 * N + 23 for integer values
of N are reserved to exercise the requirement that unknown capsule
types be ignored. These capsules have no semantics and can carry
arbitrary values. These values MUST NOT be assigned by IANA and MUST
NOT appear in the listing of assigned values.
6. References
6.1. 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-10, 4 February 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-quic-
datagram-10>.
[H1] Fielding, R. T., Nottingham, M., and J. Reschke,
"HTTP/1.1", Work in Progress, Internet-Draft, draft-ietf-
httpbis-messaging-19, 12 September 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-
messaging-19>.
[H2] Thomson, M. and C. Benfield, "HTTP/2", Work in Progress,
Internet-Draft, draft-ietf-httpbis-http2bis-07, 24 January
2022, <https://datatracker.ietf.org/doc/html/draft-ietf-
httpbis-http2bis-07>.
[H3] Bishop, M., "Hypertext Transfer Protocol Version 3
(HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
quic-http-34, 2 February 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-quic-
http-34>.
Schinazi & Pardue Expires 29 September 2022 [Page 13]
Internet-Draft HTTP Datagrams March 2022
[HTTP] Fielding, R. T., Nottingham, M., and J. Reschke, "HTTP
Semantics", Work in Progress, Internet-Draft, draft-ietf-
httpbis-semantics-19, 12 September 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-
semantics-19>.
[IANA-POLICY]
Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[QUIC] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
[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/rfc/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/rfc/rfc8174>.
[STRUCT-FIELD]
Nottingham, M. and P-H. Kamp, "Structured Field Values for
HTTP", RFC 8941, DOI 10.17487/RFC8941, February 2021,
<https://www.rfc-editor.org/rfc/rfc8941>.
6.2. Informative References
[DPLPMTUD] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T.
Völker, "Packetization Layer Path MTU Discovery for
Datagram Transports", RFC 8899, DOI 10.17487/RFC8899,
September 2020, <https://www.rfc-editor.org/rfc/rfc8899>.
[EXT-CONNECT2]
McManus, P., "Bootstrapping WebSockets with HTTP/2",
RFC 8441, DOI 10.17487/RFC8441, September 2018,
<https://www.rfc-editor.org/rfc/rfc8441>.
Schinazi & Pardue Expires 29 September 2022 [Page 14]
Internet-Draft HTTP Datagrams March 2022
[EXT-CONNECT3]
Hamilton, R., "Bootstrapping WebSockets with HTTP/3", Work
in Progress, Internet-Draft, draft-ietf-httpbis-h3-
websockets-04, 8 February 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-
h3-websockets-04>.
[PRIORITY] Oku, K. and L. Pardue, "Extensible Prioritization Scheme
for HTTP", Work in Progress, Internet-Draft, draft-ietf-
httpbis-priority-12, 17 January 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-
priority-12>.
[RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol",
RFC 6455, DOI 10.17487/RFC6455, December 2011,
<https://www.rfc-editor.org/rfc/rfc6455>.
Acknowledgments
Portions of this document were previously part of the QUIC DATAGRAM
frame definition itself, the authors would like to acknowledge the
authors of that document and the members of the IETF MASQUE working
group for their suggestions. Additionally, the authors would like to
thank Martin Thomson for suggesting the use of an HTTP/3 SETTINGS
parameter. Furthermore, the authors would like to thank Ben Schwartz
for writing the first proposal that used two layers of indirection.
The final design in this document came out of the HTTP Datagrams
Design Team, whose members were Alan Frindell, Alex Chernyakhovsky,
Ben Schwartz, Eric Rescorla, Marcus Ihlar, Martin Thomson, Mike
Bishop, Tommy Pauly, Victor Vasiliev, and the authors of this
document. The authors thank Mark Nottingham and Philipp Tiesel for
their helpful comments.
Authors' Addresses
David Schinazi
Google LLC
1600 Amphitheatre Parkway
Mountain View, California 94043,
United States of America
Email: dschinazi.ietf@gmail.com
Lucas Pardue
Cloudflare
Email: lucaspardue.24.7@gmail.com
Schinazi & Pardue Expires 29 September 2022 [Page 15]