rfc9297.original.xml   rfc9297.xml 
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<front> <front>
<title abbrev="HTTP Datagrams">HTTP Datagrams and the Capsule Protocol</titl e> <title abbrev="HTTP Datagrams">HTTP Datagrams and the Capsule Protocol</titl e>
<seriesInfo name="Internet-Draft" value="draft-ietf-masque-h3-datagram-11"/> <seriesInfo name="RFC" value="9297"/>
<author initials="D." surname="Schinazi" fullname="David Schinazi"> <author initials="D." surname="Schinazi" fullname="David Schinazi">
<organization>Google LLC</organization> <organization>Google LLC</organization>
<address> <address>
<postal> <postal>
<street>1600 Amphitheatre Parkway</street> <street>1600 Amphitheatre Parkway</street>
<city>Mountain View</city> <city>Mountain View</city>
<region>CA</region> <region>CA</region>
<code>94043</code> <code>94043</code>
<country>United States of America</country> <country>United States of America</country>
</postal> </postal>
<email>dschinazi.ietf@gmail.com</email> <email>dschinazi.ietf@gmail.com</email>
</address> </address>
</author> </author>
<author initials="L." surname="Pardue" fullname="Lucas Pardue"> <author initials="L." surname="Pardue" fullname="Lucas Pardue">
<organization>Cloudflare</organization> <organization>Cloudflare</organization>
<address> <address>
<email>lucaspardue.24.7@gmail.com</email> <email>lucaspardue.24.7@gmail.com</email>
</address> </address>
</author> </author>
<date year="2022" month="June" day="17"/> <date year="2022" month="August"/>
<area>Transport</area> <area>Transport</area>
<workgroup>MASQUE</workgroup> <workgroup>MASQUE</workgroup>
<keyword>quic</keyword> <keyword>quic</keyword>
<keyword>http</keyword> <keyword>http</keyword>
<keyword>datagram</keyword> <keyword>datagram</keyword>
<keyword>fast</keyword> <keyword>fast</keyword>
<keyword>tunnels</keyword> <keyword>tunnels</keyword>
<keyword>turtles all the way down</keyword> <keyword>turtles all the way down</keyword>
<keyword>masque</keyword> <keyword>masque</keyword>
<keyword>http-ng</keyword> <keyword>http-ng</keyword>
<abstract> <abstract>
<t>This document describes HTTP Datagrams, a convention for conveying mult iplexed, <t>This document describes HTTP Datagrams, a convention for conveying mult iplexed,
potentially unreliable datagrams inside an HTTP connection.</t> potentially unreliable datagrams inside an HTTP connection.</t>
<t>In HTTP/3, HTTP Datagrams can be sent unreliably using the QUIC DATAGRA M <t>In HTTP/3, HTTP Datagrams can be sent unreliably using the QUIC DATAGRA M
extension. When the QUIC DATAGRAM frame is unavailable or undesirable, they can extension. When the QUIC DATAGRAM frame is unavailable or undesirable, HTTP
be sent using the Capsule Protocol, a more general convention for conveying data Datagrams can be sent using the Capsule Protocol, which is a more general
in HTTP connections.</t> convention for conveying data in HTTP connections.</t>
<t>HTTP Datagrams and the Capsule Protocol are intended for use by HTTP ex tensions, <t>HTTP Datagrams and the Capsule Protocol are intended for use by HTTP ex tensions,
not applications.</t> not applications.</t>
</abstract> </abstract>
<note removeInRFC="true">
<name>About This Document</name>
<t>
The latest revision of this draft can be found at <eref target="https://
ietf-wg-masque.github.io/draft-ietf-masque-h3-datagram/draft-ietf-masque-h3-data
gram.html"/>.
Status information for this document may be found at <eref target="https
://datatracker.ietf.org/doc/draft-ietf-masque-h3-datagram/"/>.
</t>
<t>
Discussion of this document takes place on the
MASQUE Working Group mailing list (<eref target="mailto:masque@ietf.org"
/>),
which is archived at <eref target="https://mailarchive.ietf.org/arch/bro
wse/masque/"/>.
</t>
<t>Source for this draft and an issue tracker can be found at
<eref target="https://github.com/ietf-wg-masque/draft-ietf-masque-h3-dat
agram"/>.</t>
</note>
</front> </front>
<middle> <middle>
<section anchor="intro"> <section anchor="intro">
<name>Introduction</name> <name>Introduction</name>
<t>HTTP extensions (as defined in <xref section="16" sectionFormat="of" ta rget="HTTP"/>) sometimes need <t>HTTP extensions (as defined in <xref section="16" sectionFormat="of" ta rget="RFC9110"/>) sometimes need
to access underlying transport protocol features such as unreliable delivery (as to access underlying transport protocol features such as unreliable delivery (as
offered by <xref target="DGRAM"/>) to enable desirable features. For example, th offered by <xref target="RFC9221"/>) to enable desirable features. For example,
is this could allow for the introduction of an unreliable version of the CONNECT
could allow introducing an unreliable version of the CONNECT method, or adding method and the addition of unreliable delivery to WebSockets
unreliable delivery to WebSockets <xref target="WEBSOCKET"/>.</t> <xref target="RFC6455"/>.</t>
<t>In <xref target="datagrams"/>, this document describes HTTP Datagrams, <t>In <xref target="datagrams"/>, this document describes HTTP Datagrams,
a convention that a convention
supports the bidirectional and optionally multiplexed exchange of data inside an for conveying bidirectional and potentially unreliable datagrams inside
HTTP connection. While HTTP Datagrams are associated with HTTP requests, they an HTTP connection, with multiplexing when possible. While HTTP Datagrams are a
are not part of message content; instead, they are intended for use by HTTP ssociated with HTTP requests, they
extensions (such as the CONNECT method), and are compatible with all versions of are not a 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.</t> HTTP.</t>
<t>When HTTP is running over a transport protocol that supports unreliable delivery <t>When HTTP is running over a transport protocol that supports unreliable delivery
(such as when the QUIC DATAGRAM extension <xref target="DGRAM"/> is available to (such as when the QUIC DATAGRAM extension <xref target="RFC9221"/> is available
HTTP/3 to HTTP/3
<xref target="H3"/>), HTTP Datagrams can use that capability.</t> <xref target="RFC9114"/>), HTTP Datagrams can use that capability.</t>
<t>This document also describes the HTTP Capsule Protocol in <xref target= <t>In <xref target="capsule"/>, this document describes the HTTP Capsule P
"capsule"/>, to allow rotocol, which allows the conveyance of HTTP Datagrams using reliable delivery.
conveyance of HTTP Datagrams using reliable delivery. This addresses HTTP/3 This addresses HTTP/3 cases where
cases where use of the QUIC DATAGRAM frame is unavailable or undesirable, or use of the QUIC DATAGRAM frame is unavailable or undesirable or where the
where the transport protocol only provides reliable delivery, such as with transport protocol only provides reliable delivery, such as with HTTP/1.1 <xref
HTTP/1.1 <xref target="H1"/> or HTTP/2 <xref target="H2"/> over TCP <xref target target="RFC9112"/>
="TCP"/>.</t> or HTTP/2 <xref target="RFC9113"/> over TCP <xref target="RFC0793"/>.</t>
<section anchor="defs"> <section anchor="defs">
<name>Conventions and Definitions</name> <name>Conventions and Definitions</name>
<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp 14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL <t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp 14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECO MMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECO MMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to be i nterpreted as "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to be i nterpreted as
described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they described in BCP&nbsp;14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they
appear in all capitals, as shown here.</t> appear in all capitals, as shown here.</t>
<t>This document uses terminology from <xref target="QUIC"/>.</t> <t>This document uses terminology from <xref target="RFC9000"/>.</t>
<t>Where this document defines protocol types, the definition format use s the <t>Where this document defines protocol types, the definition format use s the
notation from <xref section="1.3" sectionFormat="of" target="QUIC"/>. Where fiel notation from <xref section="1.3" sectionFormat="of" target="RFC9000"/>. Where f
ds within types are integers, ields within types are integers,
they are encoded using the variable-length integer encoding from <xref section=" they are encoded using the variable-length integer encoding from <xref section="
16" sectionFormat="of" target="QUIC"/>. Integer values do not need to be encoded 16" sectionFormat="of" target="RFC9000"/>. Integer values do not need to be enco
on the minimum number of bytes ded on the minimum number of bytes
necessary.</t> necessary.</t>
<t>In this document, the term "intermediary" refers to an HTTP intermedi ary as <t>In this document, the term "intermediary" refers to an HTTP intermedi ary as
defined in <xref section="3.7" sectionFormat="of" target="HTTP"/>.</t> defined in <xref section="3.7" sectionFormat="of" target="RFC9110"/>.</t>
</section> </section>
</section> </section>
<section anchor="datagrams"> <section anchor="datagrams">
<name>HTTP Datagrams</name> <name>HTTP Datagrams</name>
<t>HTTP Datagrams are a convention for conveying bidirectional and potenti ally <t>HTTP Datagrams are a convention for conveying bidirectional and potenti ally
unreliable datagrams inside an HTTP connection, with multiplexing when unreliable datagrams inside an HTTP connection with multiplexing when
possible. All HTTP Datagrams are associated with an HTTP request.</t> possible. All HTTP Datagrams are associated with an HTTP request.</t>
<t>When HTTP Datagrams are conveyed on an HTTP/3 connection, the QUIC DATA GRAM <t>When HTTP Datagrams are conveyed on an HTTP/3 connection, the QUIC DATA GRAM
frame can be used to achieve these goals, including unreliable delivery; see frame can be used to provide demultiplexing and unreliable delivery; see
<xref target="format"/>. Negotiating the use of QUIC DATAGRAM frames for HTTP Da tagrams is <xref target="format"/>. Negotiating the use of QUIC DATAGRAM frames for HTTP Da tagrams is
achieved via the exchange of HTTP/3 settings; see <xref target="setting"/>.</t> achieved via the exchange of HTTP/3 settings; see <xref target="setting"/>.</t>
<t>When running over HTTP/2, demultiplexing is provided by the HTTP/2 fram ing <t>When running over HTTP/2, demultiplexing is provided by the HTTP/2 fram ing
layer, but unreliable delivery is unavailable. HTTP Datagrams are negotiated layer, but unreliable delivery is unavailable. HTTP Datagrams are negotiated
and conveyed using the Capsule Protocol; see <xref target="datagram-capsule"/>.< /t> and conveyed using the Capsule Protocol; see <xref target="datagram-capsule"/>.< /t>
<t>When running over HTTP/1.x, requests are strictly serialized in the con <t>When running over HTTP/1.x, requests are strictly serialized in the con
nection, nection;
and therefore demultiplexing is not available. Unreliable delivery is likewise therefore, demultiplexing is not available. Unreliable delivery is likewise not
not available. HTTP Datagrams are negotiated and conveyed using the Capsule available. HTTP Datagrams are negotiated and conveyed using the Capsule
Protocol; see <xref target="datagram-capsule"/>.</t> Protocol; see <xref target="datagram-capsule"/>.</t>
<t>HTTP Datagrams <bcp14>MUST</bcp14> only be sent with an association to an HTTP request that <t>HTTP Datagrams <bcp14>MUST</bcp14> only be sent with an association to an HTTP request that
explicitly supports them. For example, existing HTTP methods GET and POST do not explicitly supports them. For example, existing HTTP methods GET and POST do not
define semantics for associated HTTP Datagrams; therefore, HTTP Datagrams cannot define semantics for associated HTTP Datagrams; therefore, HTTP Datagrams
be sent associated with GET or POST request streams.</t> associated with GET or POST request streams cannot be sent.</t>
<t>If an HTTP Datagram is received and it is associated with a request tha t has no <t>If an HTTP Datagram is received and it is associated with a request tha t has no
known semantics for HTTP Datagrams, the receiver <bcp14>MUST</bcp14> terminate t he request; if known semantics for HTTP Datagrams, the receiver <bcp14>MUST</bcp14> terminate t he request. If
HTTP/3 is in use, the request stream <bcp14>MUST</bcp14> be aborted with H3_DATA GRAM_ERROR HTTP/3 is in use, the request stream <bcp14>MUST</bcp14> be aborted with H3_DATA GRAM_ERROR
(0x33). HTTP extensions <bcp14>MAY</bcp14> override these requirements by defini ng a (0x33). HTTP extensions <bcp14>MAY</bcp14> override these requirements by defini ng a
negotiation mechanism and semantics for HTTP Datagrams.</t> negotiation mechanism and semantics for HTTP Datagrams.</t>
<section anchor="format"> <section anchor="format">
<name>HTTP/3 Datagrams</name> <name>HTTP/3 Datagrams</name>
<t>When used with HTTP/3, the Datagram Data field of QUIC DATAGRAM frame s uses the <t>When used with HTTP/3, the Datagram Data field of QUIC DATAGRAM frame s uses the
following format:</t> following format:</t>
<figure anchor="h3-datagram-format"> <figure anchor="h3-datagram-format">
<name>HTTP/3 Datagram Format</name> <name>HTTP/3 Datagram Format</name>
<artwork type="ascii-art"><![CDATA[ <artwork><![CDATA[
HTTP/3 Datagram { HTTP/3 Datagram {
Quarter Stream ID (i), Quarter Stream ID (i),
HTTP Datagram Payload (..), HTTP Datagram Payload (..),
} }
]]></artwork> ]]></artwork>
</figure> </figure>
<dl> <dl>
<dt>Quarter Stream ID:</dt> <dt>Quarter Stream ID:</dt>
<dd> <dd>
<t>A variable-length integer that contains the value of the client-i nitiated <t>A variable-length integer that contains the value of the client-i nitiated
bidirectional stream that this datagram is associated with, divided by four (the 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 division by four stems from the fact that HTTP requests are sent on
client-initiated bidirectional streams, and those have stream IDs that are client-initiated bidirectional streams, which have stream IDs that are divisible
divisible by four). The largest legal QUIC stream ID value is 2<sup>62</sup>-1, by four). The largest legal QUIC stream ID value is 2<sup>62</sup>-1, so the
so the largest legal value of Quarter Stream ID is 2<sup>60</sup>-1. Receipt of largest legal value of the Quarter Stream ID field is 2<sup>60</sup>-1. Receipt
an HTTP/3 Datagram that includes a larger value <bcp14>MUST</bcp14> be treated a of an HTTP/3 Datagram that includes a larger value <bcp14>MUST</bcp14> be treate
s an HTTP/3 d as an HTTP/3
connection error of type H3_DATAGRAM_ERROR (0x33).</t> connection error of type H3_DATAGRAM_ERROR (0x33).</t>
</dd> </dd>
<dt>HTTP Datagram Payload:</dt> <dt>HTTP Datagram Payload:</dt>
<dd> <dd>
<t>The payload of the datagram, whose semantics are defined by the e xtension that <t>The payload of the datagram, whose semantics are defined by the e xtension that
is using HTTP Datagrams. Note that this field can be empty.</t> is using HTTP Datagrams. Note that this field can be empty.</t>
</dd> </dd>
</dl> </dl>
<t>Receipt of a QUIC DATAGRAM frame whose payload is too short to allow parsing the <t>Receipt of a QUIC DATAGRAM frame whose payload is too short to allow parsing the
Quarter Stream ID field <bcp14>MUST</bcp14> be treated as an HTTP/3 connection e rror of type Quarter Stream ID field <bcp14>MUST</bcp14> be treated as an HTTP/3 connection e rror of type
H3_DATAGRAM_ERROR (0x33).</t> H3_DATAGRAM_ERROR (0x33).</t>
<t>HTTP/3 Datagrams <bcp14>MUST NOT</bcp14> be sent unless the correspon ding stream's send side is <t>HTTP/3 Datagrams <bcp14>MUST NOT</bcp14> be sent unless the correspon ding stream's send side is
open. If a datagram is received after the corresponding stream's receive side is open. If a datagram is received after the corresponding stream's receive side is
closed, the received datagrams <bcp14>MUST</bcp14> be silently dropped.</t> closed, the received datagrams <bcp14>MUST</bcp14> be silently dropped.</t>
<t>If an HTTP/3 Datagram is received and its Quarter Stream ID maps to a <t>If an HTTP/3 Datagram is received and its Quarter Stream ID field map
stream s to a
that has not yet been created, the receiver <bcp14>SHALL</bcp14> either drop tha stream that has not yet been created, the receiver <bcp14>SHALL</bcp14> either d
t datagram rop that
silently or buffer it temporarily (on the order of a round trip) while awaiting datagram silently or buffer it temporarily (on the order of a round trip) while
the creation of the corresponding stream.</t> awaiting the creation of the corresponding stream.</t>
<t>If an HTTP/3 Datagram is received and its Quarter Stream ID maps to a <t>If an HTTP/3 Datagram is received and its Quarter Stream ID field map
stream s to a
that cannot be created due to client-initiated bidirectional stream limits, it stream that cannot be created due to client-initiated bidirectional stream
<bcp14>SHOULD</bcp14> be treated as an HTTP/3 connection error of type H3_ID_ERR limits, it <bcp14>SHOULD</bcp14> be treated as an HTTP/3 connection error of typ
OR. Generating e H3_ID_ERROR.
an error is not mandatory in this case because HTTP/3 implementations might have Generating an error is not mandatory because the QUIC stream limit might be
practical barriers to determining the active stream concurrency limit that is unknown to the HTTP/3 layer.</t>
applied by the QUIC layer.</t>
<t>Prioritization of HTTP/3 Datagrams is not defined in this document. F uture <t>Prioritization of HTTP/3 Datagrams is not defined in this document. F uture
extensions <bcp14>MAY</bcp14> define how to prioritize datagrams, and <bcp14>MAY </bcp14> define signaling to extensions <bcp14>MAY</bcp14> define how to prioritize datagrams and <bcp14>MAY< /bcp14> define signaling to
allow communicating prioritization preferences.</t> allow communicating prioritization preferences.</t>
<section anchor="setting"> <section anchor="setting">
<name>The SETTINGS_H3_DATAGRAM HTTP/3 Setting</name> <name>The SETTINGS_H3_DATAGRAM HTTP/3 Setting</name>
<t>Endpoints can indicate to their peer that they are willing to recei <t>An endpoint can indicate to its peer that it is willing to receive
ve HTTP/3 HTTP/3
Datagrams by sending the SETTINGS_H3_DATAGRAM (0x33) setting with a Datagrams by sending the SETTINGS_H3_DATAGRAM (0x33) setting with a value of 1.<
value of 1.</t> /t>
<t>The value of the SETTINGS_H3_DATAGRAM setting <bcp14>MUST</bcp14> b e either 0 or 1. A value <t>The value of the SETTINGS_H3_DATAGRAM setting <bcp14>MUST</bcp14> b e either 0 or 1. A value
of 0 indicates that the implementation is not willing to receive HTTP Datagrams. of 0 indicates that the implementation is not willing to receive HTTP Datagrams.
If the SETTINGS_H3_DATAGRAM setting is received with a value that is neither 0 If the SETTINGS_H3_DATAGRAM setting is received with a value that is neither 0
nor 1, the receiver <bcp14>MUST</bcp14> terminate the connection with error H3_S ETTINGS_ERROR.</t> nor 1, the receiver <bcp14>MUST</bcp14> terminate the connection with error H3_S ETTINGS_ERROR.</t>
<t>QUIC DATAGRAM frames <bcp14>MUST NOT</bcp14> be sent until the SETT INGS_H3_DATAGRAM setting <t>QUIC DATAGRAM frames <bcp14>MUST NOT</bcp14> be sent until the SETT INGS_H3_DATAGRAM setting
has been both sent and received with a value of 1.</t> has been both sent and received with a value of 1.</t>
<t>When clients use 0-RTT, they <bcp14>MAY</bcp14> store the value of the server's <t>When clients use 0-RTT, they <bcp14>MAY</bcp14> store the value of the server's
SETTINGS_H3_DATAGRAM setting. Doing so allows the client to send QUIC DATAGRAM SETTINGS_H3_DATAGRAM setting. Doing so allows the client to send QUIC DATAGRAM
frames in 0-RTT packets. When servers decide to accept 0-RTT data, they <bcp14>M UST</bcp14> frames in 0-RTT packets. When servers decide to accept 0-RTT data, they <bcp14>M UST</bcp14>
send a SETTINGS_H3_DATAGRAM setting greater than or equal to the value they sent send a SETTINGS_H3_DATAGRAM setting greater than or equal to the value they sent
skipping to change at line 209 skipping to change at line 194
message. If a client stores the value of the SETTINGS_H3_DATAGRAM setting with message. If a client stores the value of the SETTINGS_H3_DATAGRAM setting with
their 0-RTT state, they <bcp14>MUST</bcp14> validate that the new value of the their 0-RTT state, they <bcp14>MUST</bcp14> validate that the new value of the
SETTINGS_H3_DATAGRAM setting sent by the server in the handshake is greater than SETTINGS_H3_DATAGRAM setting sent by the server in the handshake is greater than
or equal to the stored value; if not, the client <bcp14>MUST</bcp14> terminate t he connection or equal to the stored value; if not, the client <bcp14>MUST</bcp14> terminate t he connection
with error H3_SETTINGS_ERROR. In all cases, the maximum permitted value of the with error H3_SETTINGS_ERROR. In all cases, the maximum permitted value of the
SETTINGS_H3_DATAGRAM setting parameter is 1.</t> SETTINGS_H3_DATAGRAM setting parameter is 1.</t>
<t>It is <bcp14>RECOMMENDED</bcp14> that implementations that support receiving HTTP/3 Datagrams <t>It is <bcp14>RECOMMENDED</bcp14> that implementations that support receiving HTTP/3 Datagrams
always send the SETTINGS_H3_DATAGRAM setting with a value of 1, always send the SETTINGS_H3_DATAGRAM setting with a value of 1,
even if the application does not intend to use HTTP/3 Datagrams. This helps to even if the application does not intend to use HTTP/3 Datagrams. This helps to
avoid "sticking out"; see <xref target="security"/>.</t> avoid "sticking out"; see <xref target="security"/>.</t>
<section anchor="note-about-draft-versions">
<name>Note About Draft Versions</name>
<t>[[RFC editor: please remove this section before publication.]]</t
>
<t>Some revisions of this draft specification use a different value
(the Identifier
field of a Setting in the HTTP/3 SETTINGS frame) for the SETTINGS_H3_DATAGRAM
setting. This allows new draft revisions to make incompatible changes. Multiple
draft versions <bcp14>MAY</bcp14> be supported by sending multiple values for
SETTINGS_H3_DATAGRAM. Once SETTINGS have been sent and received, an
implementation that supports multiple drafts <bcp14>MUST</bcp14> compute the int
ersection of
the values it has sent and received, and then it <bcp14>MUST</bcp14> select and
use the most
recent draft version from the intersection set. This ensures that both peers
negotiate the same draft version.</t>
</section>
</section> </section>
</section> </section>
<section anchor="http-datagrams-using-capsules"> <section anchor="http-datagrams-using-capsules">
<name>HTTP Datagrams using Capsules</name> <name>HTTP Datagrams Using Capsules</name>
<t>When HTTP/3 Datagrams are unavailable or undesirable, HTTP Datagrams can be sent <t>When HTTP/3 Datagrams are unavailable or undesirable, HTTP Datagrams can be sent
using the Capsule Protocol, see <xref target="datagram-capsule"/>.</t> using the Capsule Protocol; see <xref target="datagram-capsule"/>.</t>
</section> </section>
</section> </section>
<section anchor="capsule"> <section anchor="capsule">
<name>Capsules</name> <name>Capsules</name>
<t>One mechanism to extend HTTP is to introduce new HTTP Upgrade Tokens (s <t>One mechanism to extend HTTP is to introduce new HTTP upgrade tokens; s
ee ee
<xref section="16.7" sectionFormat="of" target="HTTP"/>). In HTTP/1.x, these tok <xref section="16.7" sectionFormat="of" target="RFC9110"/>. In HTTP/1.x, these t
ens are used via the Upgrade okens are used via the Upgrade
mechanism (see <xref section="7.8" sectionFormat="of" target="HTTP"/>). In HTTP/ mechanism; see <xref section="7.8" sectionFormat="of" target="RFC9110"/>. In HTT
2 and HTTP/3, these tokens are P/2 and HTTP/3, these tokens are
used via the Extended CONNECT mechanism (see <xref target="EXT-CONNECT2"/> and used via the Extended CONNECT mechanism; see <xref target="RFC8441"/> and
<xref target="EXT-CONNECT3"/>).</t> <xref target="RFC9220"/>.</t>
<t>This specification introduces the Capsule Protocol. The Capsule Protoco l is a <t>This specification introduces the Capsule Protocol. The Capsule Protoco l is a
sequence of type-length-value tuples that definitions of new HTTP Upgrade Tokens 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 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 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, 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 which is necessary when HTTP is running over a transport that does not support
the QUIC DATAGRAM frame. The Capsule Protocol can also be used to communicate the QUIC DATAGRAM frame. The Capsule Protocol can also be used to communicate
reliable and bidirectional control messages associated with a datagram-based reliable and bidirectional control messages associated with a datagram-based
protocol even when HTTP/3 Datagrams are in use.</t> protocol even when HTTP/3 Datagrams are in use.</t>
<section anchor="data-stream"> <section anchor="data-stream">
<name>HTTP Data Streams</name> <name>HTTP Data Streams</name>
<t>This specification defines the "data stream" of an HTTP request as th e <t>This specification defines the "data stream" of an HTTP request as th e
bidirectional stream of bytes that follows the header section of the request bidirectional stream of bytes that follows the header section of the request
message and the final response message that is either successful (i.e., 2xx) or message and the final response message that is either successful (i.e., 2xx) or
upgraded (i.e., 101).</t> upgraded (i.e., 101).</t>
<t>In HTTP/1.x, the data stream consists of all bytes on the connection that follow <t>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 final the blank line that concludes either the request header section or the final
response header section. As a result, only the last HTTP request on an HTTP/1.x response header section. As a result, only the last HTTP request on an HTTP/1.x
connection can start the capsule protocol.</t> connection can start the Capsule Protocol.</t>
<t>In HTTP/2 and HTTP/3, the data stream of a given HTTP request consist s of all <t>In HTTP/2 and HTTP/3, the data stream of a given HTTP request consist s of all
bytes sent in DATA frames with the corresponding stream ID.</t> bytes sent in DATA frames with the corresponding stream ID.</t>
<t>The concept of a data stream is particularly relevant for methods suc h as <t>The concept of a data stream is particularly relevant for methods suc h as
CONNECT where there is no HTTP message content after the headers.</t> CONNECT, where there is no HTTP message content after the headers.</t>
<t>Data streams can be prioritized using any means suited to stream or r equest <t>Data streams can be prioritized using any means suited to stream or r equest
prioritization. For example, see <xref section="11" sectionFormat="of" target="P prioritization. For example, see <xref section="11" sectionFormat="of" target="R
RIORITY"/>.</t> FC9218"/>.</t>
<t>Data streams are subject to the flow control mechanisms of the underl <t>Data streams are subject to the flow control mechanisms of the underl
ying layers ying
(for example, HTTP/2 stream flow control, HTTP/2 connection flow control, and layers; examples include HTTP/2 stream flow control, HTTP/2 connection flow
TCP flow control).</t> control, and TCP flow control.</t>
</section> </section>
<section anchor="capsule-protocol"> <section anchor="capsule-protocol">
<name>The Capsule Protocol</name> <name>The Capsule Protocol</name>
<t>Definitions of new HTTP Upgrade Tokens can state that their associate <t>Definitions of new HTTP upgrade tokens can state that their associate
d request's d request's
data stream uses the Capsule Protocol. If they do so, that means that the data stream uses the Capsule Protocol. If they do so, the contents of the
contents of the associated request's data stream uses the following format:</t> associated request's data stream uses the following format:</t>
<figure anchor="capsule-stream-format"> <figure anchor="capsule-stream-format">
<name>Capsule Protocol Stream Format</name> <name>Capsule Protocol Stream Format</name>
<artwork type="ascii-art"><![CDATA[ <artwork><![CDATA[
Capsule Protocol { Capsule Protocol {
Capsule (..) ..., Capsule (..) ...,
} }
]]></artwork> ]]></artwork>
</figure> </figure>
<figure anchor="capsule-format"> <figure anchor="capsule-format">
<name>Capsule Format</name> <name>Capsule Format</name>
<artwork type="ascii-art"><![CDATA[ <artwork><![CDATA[
Capsule { Capsule {
Capsule Type (i), Capsule Type (i),
Capsule Length (i), Capsule Length (i),
Capsule Value (..), Capsule Value (..),
} }
]]></artwork> ]]></artwork>
</figure> </figure>
<dl> <dl>
<dt>Capsule Type:</dt> <dt>Capsule Type:</dt>
<dd> <dd>
<t>A variable-length integer indicating the Type of the capsule. An IANA registry <t>A variable-length integer indicating the type of the capsule. An IANA registry
is used to manage the assignment of Capsule Types; see <xref target="iana-types" />.</t> is used to manage the assignment of Capsule Types; see <xref target="iana-types" />.</t>
</dd> </dd>
<dt>Capsule Length:</dt> <dt>Capsule Length:</dt>
<dd> <dd>
<t>The length in bytes of the Capsule Value field following this fie <t>The length, in bytes, of the Capsule Value field, which follows t
ld, encoded his field,
as a variable-length integer. Note that this field can have a value of zero.</t> encoded as a variable-length integer. Note that this field can have a value of
zero.</t>
</dd> </dd>
<dt>Capsule Value:</dt> <dt>Capsule Value:</dt>
<dd> <dd>
<t>The payload of this capsule. Its semantics are determined by the value of the <t>The payload of this Capsule. Its semantics are determined by the value of the
Capsule Type field.</t> Capsule Type field.</t>
</dd> </dd>
</dl> </dl>
<t>An intermediary can identify the use of the capsule protocol either t hrough the <t>An intermediary can identify the use of the Capsule Protocol either t hrough the
presence of the Capsule-Protocol header field (<xref target="hdr"/>) or by under standing the presence of the Capsule-Protocol header field (<xref target="hdr"/>) or by under standing the
chosen HTTP Upgrade token.</t> chosen HTTP Upgrade token.</t>
<t>Because new protocols or extensions might define new capsule types, <t>Because new protocols or extensions might define new Capsule Types,
intermediaries that wish to allow for future extensibility <bcp14>SHOULD</bcp14> forward intermediaries that wish to allow for future extensibility <bcp14>SHOULD</bcp14> forward
capsules without modification, unless the definition of the Capsule Type in use Capsules without modification unless the definition of the Capsule Type in use
specifies additional intermediary processing. One such Capsule Type is the specifies additional intermediary processing. One such Capsule Type is the
DATAGRAM capsule; see <xref target="datagram-capsule"/>. In particular, intermed iaries <bcp14>SHOULD</bcp14> DATAGRAM Capsule; see <xref target="datagram-capsule"/>. In particular, intermed iaries <bcp14>SHOULD</bcp14>
forward Capsules with an unknown Capsule Type without modification.</t> forward Capsules with an unknown Capsule Type without modification.</t>
<t>Endpoints which receive a Capsule with an unknown Capsule Type <bcp14 >MUST</bcp14> silently <t>Endpoints that receive a Capsule with an unknown Capsule Type <bcp14> MUST</bcp14> silently
drop that Capsule and skip over it to parse the next Capsule.</t> drop that Capsule and skip over it to parse the next Capsule.</t>
<t>By virtue of the definition of the data stream:</t> <t>By virtue of the definition of the data stream:</t>
<ul spacing="normal"> <ul spacing="normal">
<li>The Capsule Protocol is not in use unless the response includes a 2xx <li>The Capsule Protocol is not in use unless the response includes a 2xx
(Successful) or 101 (Switching Protocols) status code.</li> (Successful) or 101 (Switching Protocols) status code.</li>
<li>When the Capsule Protocol is in use, the associated HTTP request a nd response <li>When the Capsule Protocol is in use, the associated HTTP request a nd response
do not carry HTTP content. A future extension <bcp14>MAY</bcp14> define a new ca psule type to do not carry HTTP content. A future extension <bcp14>MAY</bcp14> define a new Ca psule Type to
carry HTTP content.</li> carry HTTP content.</li>
</ul> </ul>
<t>Since the Capsule Protocol only applies to definitions of new HTTP Up <t>The Capsule Protocol only applies to definitions of new HTTP upgrade
grade tokens;
Tokens, in HTTP/2 and HTTP/3 it can only be used with the CONNECT method. thus, in HTTP/2 and HTTP/3, it can only be used with the CONNECT method.
Therefore, once both endpoints agree to use the Capsule Protocol, the frame Therefore, once both endpoints agree to use the Capsule Protocol, the frame
usage requirements of the stream change as specified in <xref section="8.5" sect usage requirements of the stream change as specified in <xref section="8.5" sect
ionFormat="of" target="H2"/> ionFormat="of" target="RFC9113"/>
and <xref section="4.2" sectionFormat="of" target="H3"/>.</t> and <xref section="4.4" sectionFormat="of" target="RFC9114"/>.</t>
<t>The Capsule Protocol <bcp14>MUST NOT</bcp14> be used with messages th at contain Content-Length, <t>The Capsule Protocol <bcp14>MUST NOT</bcp14> be used with messages th at contain Content-Length,
Content-Type, or Transfer-Encoding header fields. Additionally, HTTP status Content-Type, or Transfer-Encoding header fields. Additionally, HTTP status
codes 204 (No Content), 205 (Reset Content), and 206 (Partial Content) <bcp14>MU ST NOT</bcp14> codes 204 (No Content), 205 (Reset Content), and 206 (Partial Content) <bcp14>MU ST NOT</bcp14>
be sent on responses that use the Capsule Protocol. A receiver that observes a be sent on responses that use the Capsule Protocol. A receiver that observes a
violation of these requirements <bcp14>MUST</bcp14> treat the HTTP message as ma lformed.</t> violation of these requirements <bcp14>MUST</bcp14> treat the HTTP message as ma lformed.</t>
<t>When processing capsules, a receiver might be tempted to accumulate t <t>When processing Capsules, a receiver might be tempted to accumulate t
he full he full
length of the capsule value in the data stream before handling it. This approach length of the Capsule Value field in the data stream before handling it. This
<bcp14>SHOULD</bcp14> be avoided, because it can consume flow control in underly approach <bcp14>SHOULD</bcp14> be avoided because it can consume flow control in
ing layers, and underlying
that might lead to deadlocks if the capsule data exhausts the flow control layers, and that might lead to deadlocks if the Capsule data exhausts the flow
window.</t> control window.</t>
</section> </section>
<section anchor="error-handling"> <section anchor="error-handling">
<name>Error Handling</name> <name>Error Handling</name>
<t>When a receiver encounters an error processing the Capsule Protocol, the <t>When a receiver encounters an error processing the Capsule Protocol, the
receiver <bcp14>MUST</bcp14> treat it as if it had received a malformed or incom plete HTTP receiver <bcp14>MUST</bcp14> treat it as if it had received a malformed or incom plete HTTP
message. For HTTP/3, the handling of malformed messages is described in message. For HTTP/3, the handling of malformed messages is described in
<xref section="4.1.3" sectionFormat="of" target="H3"/>. For HTTP/2, the handling <xref section="4.1.2" sectionFormat="of" target="RFC9114"/>. For HTTP/2, the han
of malformed messages is dling of malformed messages is
described in <xref section="8.1.1" sectionFormat="of" target="H2"/>. For HTTP/1. described in <xref section="8.1.1" sectionFormat="of" target="RFC9113"/>. For HT
x, the handling of incomplete TP/1.x, the handling of incomplete
messages is described in <xref section="8" sectionFormat="of" target="H1"/>.</t> messages is described in <xref section="8" sectionFormat="of" target="RFC9112"/>
<t>Each capsule's payload <bcp14>MUST</bcp14> contain exactly the fields .</t>
identified in its <t>Each Capsule's payload <bcp14>MUST</bcp14> contain exactly the fields
description. A capsule payload that contains additional bytes after the identified in its
identified fields or a capsule payload that terminates before the end of the 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 <bcp14>MUST</bcp14> be treated as it if were a malformed or in complete identified fields <bcp14>MUST</bcp14> be treated as it if were a malformed or in complete
message. In particular, redundant length encodings <bcp14>MUST</bcp14> be verifi ed to be message. In particular, redundant length encodings <bcp14>MUST</bcp14> be verifi ed to be
self-consistent.</t> self-consistent.</t>
<t>If the receive side of a stream carrying capsules is terminated clean ly (for <t>If the receive side of a stream carrying Capsules is terminated clean ly (for
example, in HTTP/3 this is defined as receiving a QUIC STREAM frame with the FIN example, in HTTP/3 this is defined as receiving a QUIC STREAM frame with the FIN
bit set) and the last capsule on the stream was truncated, this <bcp14>MUST</bcp 14> be treated bit set) and the last Capsule on the stream was truncated, this <bcp14>MUST</bcp 14> be treated
as if it were a malformed or incomplete message.</t> as if it were a malformed or incomplete message.</t>
</section> </section>
<section anchor="hdr"> <section anchor="hdr">
<name>The Capsule-Protocol Header Field</name> <name>The Capsule-Protocol Header Field</name>
<t>The "Capsule-Protocol" header field is an Item Structured Field, see <t>The "Capsule-Protocol" header field is an Item Structured Field; see
<xref section="3.3" sectionFormat="of" target="STRUCT-FIELD"/>; its value <bcp14 <xref section="3.3" sectionFormat="of" target="RFC8941"/>. Its value <bcp14>MUST
>MUST</bcp14> be a Boolean; any other value </bcp14> be a Boolean; any other
type <bcp14>MUST</bcp14> be handled as if the field were not present by recipien value type <bcp14>MUST</bcp14> be handled as if the field were not present by re
ts (for cipients (for
example, if this field is included multiple times, its type will become a List 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 and the field will be ignored). This document does not define any parameters for
parameters for the Capsule-Protocol header field value, but future documents the Capsule-Protocol header field value, but future documents might define
might define parameters. Receivers <bcp14>MUST</bcp14> ignore unknown parameters parameters. Receivers <bcp14>MUST</bcp14> ignore unknown parameters.</t>
.</t>
<t>Endpoints indicate that the Capsule Protocol is in use on a data stre am by <t>Endpoints indicate that the Capsule Protocol is in use on a data stre am by
sending a Capsule-Protocol header field with a true value. A Capsule-Protocol 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 header field with a false value has the same semantics as when the header is not
present.</t> present.</t>
<t>Intermediaries <bcp14>MAY</bcp14> use this header field to allow proc essing of HTTP Datagrams <t>Intermediaries <bcp14>MAY</bcp14> use this header field to allow proc essing of HTTP Datagrams
for unknown HTTP Upgrade Tokens; note that this is only possible for HTTP for unknown HTTP upgrade tokens. Note that this is only possible for HTTP
Upgrade or Extended CONNECT.</t> Upgrade or Extended CONNECT.</t>
<t>The Capsule-Protocol header field <bcp14>MUST NOT</bcp14> be used on HTTP responses with a <t>The Capsule-Protocol header field <bcp14>MUST NOT</bcp14> be used on HTTP responses with a
status code that is both different from 101 and outside the 2xx range.</t> status code that is both different from 101 (Switching Protocols) and outside
the 2xx (Successful) range.</t>
<t>When using the Capsule Protocol, HTTP endpoints <bcp14>SHOULD</bcp14> send the Capsule-Protocol <t>When using the Capsule Protocol, HTTP endpoints <bcp14>SHOULD</bcp14> send the Capsule-Protocol
header field to simplify intermediary processing. Definitions of new HTTP header field to simplify intermediary processing. Definitions of new HTTP
Upgrade Tokens that use the Capsule Protocol <bcp14>MAY</bcp14> alter this recom mendation.</t> upgrade tokens that use the Capsule Protocol <bcp14>MAY</bcp14> alter this recom mendation.</t>
</section> </section>
<section anchor="datagram-capsule"> <section anchor="datagram-capsule">
<name>The DATAGRAM Capsule</name> <name>The DATAGRAM Capsule</name>
<t>This document defines the DATAGRAM (0x00) capsule type. This capsule allows HTTP <t>This document defines the DATAGRAM (0x00) Capsule Type. This Capsule allows HTTP
Datagrams to be sent on a stream using the Capsule Protocol. This is 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 particularly useful when HTTP is running over a transport that does not support
the QUIC DATAGRAM frame.</t> the QUIC DATAGRAM frame.</t>
<figure anchor="datagram-capsule-format"> <figure anchor="datagram-capsule-format">
<name>DATAGRAM Capsule Format</name> <name>DATAGRAM Capsule Format</name>
<artwork type="ascii-art"><![CDATA[ <artwork type="ascii-art"><![CDATA[
Datagram Capsule { Datagram Capsule {
Type (i) = 0x00, Type (i) = 0x00,
Length (i), Length (i),
HTTP Datagram Payload (..), HTTP Datagram Payload (..),
} }
]]></artwork> ]]></artwork>
</figure> </figure>
<dl> <dl>
<dt>HTTP Datagram Payload:</dt> <dt>HTTP Datagram Payload:</dt>
<dd> <dd>
<t>The payload of the datagram, whose semantics are defined by the e xtension that <t>The payload of the datagram, whose semantics are defined by the e xtension that
is using HTTP Datagrams. Note that this field can be empty.</t> is using HTTP Datagrams. Note that this field can be empty.</t>
</dd> </dd>
</dl> </dl>
<t>HTTP Datagrams sent using the DATAGRAM capsule have the same semantic <t>HTTP Datagrams sent using the DATAGRAM Capsule have the same semantic
s as s as those
those sent in QUIC DATAGRAM frames. In particular, the restrictions on when sent in QUIC DATAGRAM frames. In particular, the restrictions on when it is
it is allowed to send an HTTP Datagram and how to process them from <xref target allowed to send an HTTP Datagram and how to process them (from <xref target="for
="format"/> mat"/>) also
also apply to HTTP Datagrams sent and received using the DATAGRAM capsule.</t> apply to HTTP Datagrams sent and received using the DATAGRAM Capsule.</t>
<t>An intermediary can reencode HTTP Datagrams as it forwards them. In o <t>An intermediary can re-encode HTTP Datagrams as it forwards them. In
ther words, other
an intermediary <bcp14>MAY</bcp14> send a DATAGRAM capsule to forward an HTTP Da words, an intermediary <bcp14>MAY</bcp14> send a DATAGRAM Capsule to forward an
tagram that HTTP Datagram
was received in a QUIC DATAGRAM frame, and vice versa. Intermediaries <bcp14>MUS that was received in a QUIC DATAGRAM frame and vice versa. Intermediaries <bcp14
T NOT</bcp14> >MUST
perform this reencoding unless they have identified the use of the Capsule NOT</bcp14> perform this re-encoding unless they have identified the use of the
Capsule
Protocol on the corresponding request stream; see <xref target="capsule-protocol "/>.</t> Protocol on the corresponding request stream; see <xref target="capsule-protocol "/>.</t>
<t>Note that while DATAGRAM capsules that are sent on a stream are relia <t>Note that while DATAGRAM Capsules, which are sent on a stream, are re
bly liably
delivered in order, intermediaries can reencode DATAGRAM capsules into QUIC delivered in order, intermediaries can re-encode DATAGRAM Capsules into QUIC
DATAGRAM frames when forwarding messages, which could result in loss or DATAGRAM frames when forwarding messages, which could result in loss or
reordering.</t> reordering.</t>
<t>If an intermediary receives an HTTP Datagram in a QUIC DATAGRAM frame and is <t>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 forwarding it on a connection that supports QUIC DATAGRAM frames, the
intermediary <bcp14>SHOULD NOT</bcp14> convert that HTTP Datagram to a DATAGRAM intermediary <bcp14>SHOULD NOT</bcp14> convert that HTTP Datagram to a DATAGRAM
capsule. If the Capsule. If the
HTTP Datagram is too large to fit in a DATAGRAM frame (for example because 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 Path MTU (PMTU) of that QUIC connection is too low or if the maximum UDP payload
advertised on that connection is too low), the intermediary <bcp14>SHOULD</bcp14 size advertised on that connection is too low), the intermediary <bcp14>SHOULD</
> drop the HTTP bcp14> drop the
Datagram instead of converting it to a DATAGRAM capsule. This preserves the HTTP Datagram instead of converting it to a DATAGRAM Capsule. This preserves the
end-to-end unreliability characteristic that methods such as Datagram end-to-end unreliability characteristic that methods such as Datagram
Packetization Layer Path MTU Discovery (DPLPMTUD) depend on Packetization Layer PMTU Discovery (DPLPMTUD) depend on <xref target="RFC8899"/>
<xref target="DPLPMTUD"/>. An intermediary that converts QUIC DATAGRAM frames to .
DATAGRAM capsules allows HTTP Datagrams to be arbitrarily large without An intermediary that converts QUIC DATAGRAM frames to DATAGRAM Capsules allows
suffering any loss; this can misrepresent the true path properties, defeating HTTP Datagrams to be arbitrarily large without suffering any loss. This can
methods such as DPLPMTUD.</t> misrepresent the true path properties, defeating methods such as DPLPMTUD.</t>
<t>While DATAGRAM capsules can theoretically carry a payload of length <t>While DATAGRAM Capsules can theoretically carry a payload of length
2<sup>62</sup>-1, most HTTP extensions that use HTTP Datagrams will have their 2<sup>62</sup>-1, most HTTP extensions that use HTTP Datagrams will have their
own limits on what datagram payload sizes are practical. Implementations <bcp14> SHOULD</bcp14> own limits on what datagram payload sizes are practical. Implementations <bcp14> SHOULD</bcp14>
take those limits into account when parsing DATAGRAM capsules: if an incoming take those limits into account when parsing DATAGRAM Capsules. If an incoming
DATAGRAM capsule has a length that is known to be so large as to not be usable, DATAGRAM Capsule has a length that is known to be so large as to not be usable,
the implementation <bcp14>SHOULD</bcp14> discard the capsule without buffering i the implementation <bcp14>SHOULD</bcp14> discard the Capsule without buffering i
ts contents ts contents
into memory.</t> into memory.</t>
<t>Since QUIC DATAGRAM frames are required to fit within a QUIC packet, <t>Since QUIC DATAGRAM frames are required to fit within a QUIC packet,
implementations that reencode DATAGRAM capsules into QUIC DATAGRAM frames might implementations that re-encode DATAGRAM Capsules into QUIC DATAGRAM frames might
be tempted to accumulate the entire capsule in the stream before reencoding it. be tempted to accumulate the entire Capsule in the stream before re-encoding it.
This <bcp14>SHOULD</bcp14> be avoided, because it can cause flow control problem s; see This <bcp14>SHOULD</bcp14> be avoided, because it can cause flow control problem s; see
<xref target="capsule-protocol"/>.</t> <xref target="capsule-protocol"/>.</t>
<t>Note that it is possible for an HTTP extension to use HTTP Datagrams without <t>Note that it is possible for an HTTP extension to use HTTP Datagrams without
using the Capsule Protocol. For example, if an HTTP extension that uses HTTP using the Capsule Protocol. For example, if an HTTP extension that uses HTTP
Datagrams is only defined over transports that support QUIC DATAGRAM frames, it Datagrams is only defined over transports that support QUIC DATAGRAM frames, it
might not need a stream encoding. Additionally, HTTP extensions can use HTTP might not need a stream encoding. Additionally, HTTP extensions can use HTTP
Datagrams with their own data stream protocol. However, new HTTP extensions that Datagrams with their own data stream protocol. However, new HTTP extensions that
wish to use HTTP Datagrams <bcp14>SHOULD</bcp14> use the Capsule Protocol as fai ling to do so wish to use HTTP Datagrams <bcp14>SHOULD</bcp14> use the Capsule Protocol, as fa iling to do so
will make it harder for the HTTP extension to support versions of HTTP other will make it harder for the HTTP extension to support versions of HTTP other
than HTTP/3 and will prevent interoperability with intermediaries that only than HTTP/3 and will prevent interoperability with intermediaries that only
support the Capsule Protocol.</t> support the Capsule Protocol.</t>
</section> </section>
</section> </section>
<section anchor="security"> <section anchor="security">
<name>Security Considerations</name> <name>Security Considerations</name>
<t>Since transmitting HTTP Datagrams using QUIC DATAGRAM frames requires s ending <t>Since transmitting HTTP Datagrams using QUIC DATAGRAM frames requires s ending
the HTTP/3 SETTINGS_H3_DATAGRAM setting, it "sticks out". In other words, the HTTP/3 SETTINGS_H3_DATAGRAM setting, it "sticks out". In other words,
probing clients can learn whether a server supports HTTP Datagrams over QUIC 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 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 offer application services that use HTTP Datagrams, it's best for all
implementations that support this feature to always send this setting, see implementations that support this feature to always send this setting; see
<xref target="setting"/>.</t> <xref target="setting"/>.</t>
<t>Since use of the Capsule Protocol is restricted to new HTTP Upgrade Tok <t>Since use of the Capsule Protocol is restricted to new HTTP upgrade tok
ens, it ens, it
is not accessible from Web Platform APIs (such as those commonly accessed via is not directly accessible from Web Platform APIs (such as those commonly access
ed via
JavaScript in web browsers).</t> JavaScript in web browsers).</t>
<t>Definitions of new HTTP Upgrade Tokens that use the Capsule Protocol ne <t>Definitions of new HTTP upgrade tokens that use the Capsule Protocol ne
ed to ed to
perform a security analysis that considers the impact of HTTP Datagrams and include a security analysis that considers the impact of HTTP Datagrams and
Capsules in the context of their protocol.</t> Capsules in the context of their protocol.</t>
</section> </section>
<section anchor="iana"> <section anchor="iana">
<name>IANA Considerations</name> <name>IANA Considerations</name>
<section anchor="iana-setting"> <section anchor="iana-setting">
<name>HTTP/3 Setting</name> <name>HTTP/3 Setting</name>
<t>This document will request IANA to register the following entry in th <t>IANA has registered the following entry in the "HTTP/3 Settings" regi
e stry
"HTTP/3 Settings" registry maintained at maintained at &lt;<eref target="https://www.iana.org/assignments/http3-parameter
&lt;<eref target="https://www.iana.org/assignments/http3-parameters"/>&gt;:</t> s"/>&gt;:</t>
<dl spacing="compact"> <dl spacing="compact">
<dt>Value:</dt> <dt>Value:</dt>
<dd> <dd>
<t>0x33</t> <t>0x33</t>
</dd> </dd>
<dt>Setting Name:</dt> <dt>Setting Name:</dt>
<dd> <dd>
<t>SETTINGS_H3_DATAGRAM</t> <t>SETTINGS_H3_DATAGRAM</t>
</dd> </dd>
<dt>Default:</dt> <dt>Default:</dt>
<dd> <dd>
<t>0</t> <t>0</t>
</dd> </dd>
<dt>Status:</dt> <dt>Status:</dt>
<dd> <dd>
<t>provisional (permanent if this document is approved)</t> <t>permanent</t>
</dd> </dd>
<dt>Specification:</dt> <dt>Reference:</dt>
<dd> <dd>
<t>This Document</t> <t>RFC 9297</t>
</dd> </dd>
<dt>Change Controller:</dt> <dt>Change Controller:</dt>
<dd> <dd>
<t>IETF</t> <t>IETF</t>
</dd> </dd>
<dt>Contact:</dt> <dt>Contact:</dt>
<dd> <dd>
<t>HTTP_WG; HTTP working group; ietf-http-wg@w3.org</t> <t>HTTP_WG; HTTP working group; ietf-http-wg@w3.org</t>
</dd> </dd>
<dt>Notes:</dt>
<dd>
<t>None</t>
</dd>
</dl> </dl>
</section> </section>
<section anchor="iana-error"> <section anchor="iana-error">
<name>HTTP/3 Error Code</name> <name>HTTP/3 Error Code</name>
<t>This document will request IANA to register the following entry in th <t>IANA has registered the following entry in the "HTTP/3 Error Codes" r
e egistry
"HTTP/3 Error Codes" registry maintained at maintained at &lt;<eref target="https://www.iana.org/assignments/http3-parameter
&lt;<eref target="https://www.iana.org/assignments/http3-parameters"/>&gt;:</t> s"/>&gt;:</t>
<dl spacing="compact"> <dl spacing="compact">
<dt>Value:</dt> <dt>Value:</dt>
<dd> <dd>
<t>0x33</t> <t>0x33</t>
</dd> </dd>
<dt>Name:</dt> <dt>Name:</dt>
<dd> <dd>
<t>H3_DATAGRAM_ERROR</t> <t>H3_DATAGRAM_ERROR</t>
</dd> </dd>
<dt>Description:</dt> <dt>Description:</dt>
<dd> <dd>
<t>Datagram or capsule protocol parse error</t> <t>Datagram or Capsule Protocol parse error</t>
</dd> </dd>
<dt>Status:</dt> <dt>Status:</dt>
<dd> <dd>
<t>provisional (permanent if this document is approved)</t> <t>permanent</t>
</dd> </dd>
<dt>Specification:</dt> <dt>Reference:</dt>
<dd> <dd>
<t>This Document</t> <t>RFC 9297</t>
</dd> </dd>
<dt>Change Controller:</dt> <dt>Change Controller:</dt>
<dd> <dd>
<t>IETF</t> <t>IETF</t>
</dd> </dd>
<dt>Contact:</dt> <dt>Contact:</dt>
<dd> <dd>
<t>HTTP_WG; HTTP working group; ietf-http-wg@w3.org</t> <t>HTTP_WG; HTTP working group; ietf-http-wg@w3.org</t>
</dd> </dd>
<dt>Notes:</dt>
<dd>
<t>None</t>
</dd>
</dl> </dl>
</section> </section>
<section anchor="iana-hdr"> <section anchor="iana-hdr">
<name>HTTP Header Field Name</name> <name>HTTP Header Field Name</name>
<t>This document will request IANA to register the following entry in th <t>IANA has registered the following entry in the "Hypertext Transfer Pr
e "HTTP otocol
Field Name" registry maintained at (HTTP) Field Name Registry" maintained at
&lt;<eref target="https://www.iana.org/assignments/http-fields"/>&gt;:</t> &lt;<eref target="https://www.iana.org/assignments/http-fields"/>&gt;:</t>
<dl spacing="compact"> <dl spacing="compact">
<dt>Field Name:</dt> <dt>Field Name:</dt>
<dd> <dd>
<t>Capsule-Protocol</t> <t>Capsule-Protocol</t>
</dd> </dd>
<dt>Template:</dt> <dt>Template:</dt>
<dd> <dd>
<t>None</t> <t>None</t>
</dd> </dd>
<dt>Status:</dt> <dt>Status:</dt>
<dd> <dd>
<t>provisional (permanent if this document is approved)</t> <t>permanent</t>
</dd> </dd>
<dt>Reference:</dt> <dt>Reference:</dt>
<dd> <dd>
<t>This document</t> <t>RFC 9297</t>
</dd> </dd>
<dt>Comments:</dt> <dt>Comments:</dt>
<dd> <dd>
<t>None</t> <t>None</t>
</dd> </dd>
</dl> </dl>
</section> </section>
<section anchor="iana-types"> <section anchor="iana-types">
<name>Capsule Types</name> <name>Capsule Types</name>
<t>This document establishes a registry for HTTP capsule type codes. The <t>This document establishes a registry for HTTP Capsule Type codes. The
"HTTP "HTTP
Capsule Types" registry governs a 62-bit space, and operates under the QUIC Capsule Types" registry governs a 62-bit space and operates under the QUIC
registration policy documented in <xref section="22.1" sectionFormat="of" target registration policy documented in <xref section="22.1" sectionFormat="of" target
="QUIC"/>. This new registry ="RFC9000"/>. This new registry
includes the common set of fields listed in <xref section="22.1.1" sectionFormat includes the common set of fields listed in <xref section="22.1.1" sectionFormat
="of" target="QUIC"/>. In ="of" target="RFC9000"/>. In
addition to those common fields, all registrations in this registry <bcp14>MUST< /bcp14> include addition to those common fields, all registrations in this registry <bcp14>MUST< /bcp14> include
a "Capsule Type" field which contains a short name or label for the capsule type .</t> a "Capsule Type" field that contains a short name or label for the Capsule Type. </t>
<t>Permanent registrations in this registry are assigned using the Speci fication <t>Permanent registrations in this registry are assigned using the Speci fication
Required policy (<xref section="4.6" sectionFormat="of" target="IANA-POLICY"/>), except for values Required policy (<xref section="4.6" sectionFormat="of" target="RFC8126"/>), exc ept for values
between 0x00 and 0x3f (in hexadecimal; inclusive), which are assigned using between 0x00 and 0x3f (in hexadecimal; inclusive), which are assigned using
Standards Action or IESG Approval as defined in Sections <xref target="IANA-POLI Standards Action or IESG Approval as defined in Sections <xref target="RFC8126"
CY" section="4.9" sectionFormat="bare"/> and <xref target="IANA-POLICY" section= section="4.9" sectionFormat="bare"/> and <xref target="RFC8126" section="4.10" s
"4.10" sectionFormat="bare"/> of <xref target="IANA-POLICY"/>.</t> ectionFormat="bare"/> of <xref target="RFC8126"/>.</t>
<t>Capsule types with a value of the form 0x29 * N + 0x17 for integer va <t>Capsule Types with a value of the form 0x29 * N + 0x17 for integer va
lues of N lues of N
are reserved to exercise the requirement that unknown capsule types be ignored. are reserved to exercise the requirement that unknown Capsule Types be ignored.
These capsules have no semantics and can carry arbitrary values. These values These Capsules have no semantics and can carry arbitrary values. These values
<bcp14>MUST NOT</bcp14> be assigned by IANA and <bcp14>MUST NOT</bcp14> appear i n the listing of assigned <bcp14>MUST NOT</bcp14> be assigned by IANA and <bcp14>MUST NOT</bcp14> appear i n the listing of assigned
values.</t> values.</t>
<t>This registry initially contains the following entry:</t> <t>This registry initially contains the following entry:</t>
<dl spacing="compact"> <dl spacing="compact">
<dt>Value:</dt> <dt>Value:</dt>
<dd> <dd>
<t>0x00</t> <t>0x00</t>
</dd> </dd>
<dt>Capsule Type:</dt> <dt>Capsule Type:</dt>
<dd> <dd>
<t>DATAGRAM</t> <t>DATAGRAM</t>
</dd> </dd>
<dt>Status:</dt> <dt>Status:</dt>
<dd> <dd>
<t>permanent</t> <t>permanent</t>
</dd> </dd>
<dt>Specification:</dt> <dt>Reference:</dt>
<dd> <dd>
<t>This document</t> <t>RFC 9297</t>
</dd> </dd>
<dt>Change Controller:</dt> <dt>Change Controller:</dt>
<dd> <dd>
<t>IETF</t> <t>IETF</t>
</dd> </dd>
<dt>Contact:</dt> <dt>Contact:</dt>
<dd> <dd>
<t>MASQUE Working Group <eref target="mailto:masque@ietf.org">masque @ietf.org</eref></t> <t>MASQUE Working Group <eref target="mailto:masque@ietf.org">masque @ietf.org</eref></t>
</dd> </dd>
<dt>Notes:</dt> <dt>Notes:</dt>
<dd> <dd>
<t>None</t> <t>None</t>
</dd> </dd>
</dl> </dl>
</section> </section>
</section> </section>
</middle> </middle>
<back> <back>
<displayreference target="H1" to="HTTP/1.1"/>
<displayreference target="H2" to="HTTP/2"/> <displayreference target="RFC9221" to="QUIC-DGRAM"/>
<displayreference target="H3" to="HTTP/3"/> <displayreference target="RFC9110" to="HTTP"/>
<references> <displayreference target="RFC9112" to="HTTP/1.1"/>
<displayreference target="RFC9113" to="HTTP/2"/>
<displayreference target="RFC9114" to="HTTP/3"/>
<displayreference target="RFC8126" to="IANA-POLICY"/>
<displayreference target="RFC9000" to="QUIC"/>
<displayreference target="RFC8941" to="STRUCTURED-FIELDS"/>
<displayreference target="RFC0793" to="TCP"/>
<displayreference target="RFC8899" to="DPLPMTUD"/>
<displayreference target="RFC8441" to="EXT-CONNECT2"/>
<displayreference target="RFC9220" to="EXT-CONNECT3"/>
<displayreference target="RFC9218" to="PRIORITY"/>
<displayreference target="RFC6455" to="WEBSOCKET"/>
<references>
<name>References</name> <name>References</name>
<references> <references>
<name>Normative References</name> <name>Normative References</name>
<reference anchor="H1"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9221.
<front> xml"/>
<title>HTTP/1.1</title> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9110.
<author fullname="R. Fielding" initials="R." role="editor" surname=" xml"/>
Fielding"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9112.
<organization/> xml"/>
</author> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9113.
<author fullname="M. Nottingham" initials="M." role="editor" surname xml"/>
="Nottingham"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9114.
<organization/> xml"/>
</author> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8126.
<author fullname="J. Reschke" initials="J." role="editor" surname="R xml"/>
eschke"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9000.
<organization/> xml"/>
</author> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.
<date month="June" year="2022"/> xml"/>
<abstract> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.
<t>The Hypertext Transfer Protocol (HTTP) is a stateless applicati xml"/>
on-level protocol for distributed, collaborative, hypertext information systems. <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8941.
This document specifies the HTTP/1.1 message syntax, message parsing, connectio xml"/>
n management, and related security concerns. </t> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.0793.
<t>This document obsoletes portions of RFC 7230.</t> xml"/>
</abstract>
</front>
<seriesInfo name="STD" value="99"/>
<seriesInfo name="RFC" value="9112"/>
<seriesInfo name="DOI" value="10.17487/RFC9112"/>
</reference>
<reference anchor="H2">
<front>
<title>HTTP/2</title>
<author fullname="M. Thomson" initials="M." role="editor" surname="T
homson">
<organization/>
</author>
<author fullname="C. Benfield" initials="C." role="editor" surname="
Benfield">
<organization/>
</author>
<date month="June" year="2022"/>
<abstract>
<t>This specification describes an optimized expression of the sem
antics of the Hypertext Transfer Protocol (HTTP), referred to as HTTP version 2
(HTTP/2). HTTP/2 enables a more efficient use of network resources and a reduced
latency by introducing field compression and allowing multiple concurrent excha
nges on the same connection.</t>
<t>This document obsoletes RFCs 7540 and 8740.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9113"/>
<seriesInfo name="DOI" value="10.17487/RFC9113"/>
</reference>
<reference anchor="H3">
<front>
<title>HTTP/3</title>
<author fullname="M. Bishop" initials="M." role="editor" surname="Bi
shop">
<organization/>
</author>
<date month="June" year="2022"/>
<abstract>
<t>The QUIC transport protocol has several features that are desir
able in a transport for HTTP, such as stream multiplexing, per-stream flow contr
ol, and low-latency connection establishment. This document describes a mapping
of HTTP semantics over QUIC. This document also identifies HTTP/2 features tha
t are subsumed by QUIC and describes how HTTP/2 extensions can be ported to HTTP
/3.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9114"/>
<seriesInfo name="DOI" value="10.17487/RFC9114"/>
</reference>
<reference anchor="HTTP">
<front>
<title>HTTP Semantics</title>
<author fullname="R. Fielding" initials="R." role="editor" surname="
Fielding">
<organization/>
</author>
<author fullname="M. Nottingham" initials="M." role="editor" surname
="Nottingham">
<organization/>
</author>
<author fullname="J. Reschke" initials="J." role="editor" surname="R
eschke">
<organization/>
</author>
<date month="June" year="2022"/>
<abstract>
<t>The Hypertext Transfer Protocol (HTTP) is a stateless applicati
on-level protocol for distributed, collaborative, hypertext information systems.
This document describes the overall architecture of HTTP, establishes common te
rminology, and defines aspects of the protocol that are shared by all versions.
In this definition are core protocol elements, extensibility mechanisms, and the
"http" and "https" Uniform Resource Identifier (URI) schemes. </t>
<t>This document updates RFC 3864 and obsoletes RFCs 2818, 7231, 7
232, 7233, 7235, 7538, 7615, 7694, and portions of 7230.</t>
</abstract>
</front>
<seriesInfo name="STD" value="97"/>
<seriesInfo name="RFC" value="9110"/>
<seriesInfo name="DOI" value="10.17487/RFC9110"/>
</reference>
<reference anchor="DGRAM">
<front>
<title>An Unreliable Datagram Extension to QUIC</title>
<author fullname="T. Pauly" initials="T." surname="Pauly">
<organization/>
</author>
<author fullname="E. Kinnear" initials="E." surname="Kinnear">
<organization/>
</author>
<author fullname="D. Schinazi" initials="D." surname="Schinazi">
<organization/>
</author>
<date month="March" year="2022"/>
<abstract>
<t>This document defines an extension to the QUIC transport protoc
ol to add support for sending and receiving unreliable datagrams over a QUIC con
nection.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9221"/>
<seriesInfo name="DOI" value="10.17487/RFC9221"/>
</reference>
<reference anchor="TCP">
<front>
<title>Transmission Control Protocol</title>
<author fullname="J. Postel" initials="J." surname="Postel">
<organization/>
</author>
<date month="September" year="1981"/>
</front>
<seriesInfo name="STD" value="7"/>
<seriesInfo name="RFC" value="793"/>
<seriesInfo name="DOI" value="10.17487/RFC0793"/>
</reference>
<reference anchor="RFC2119">
<front>
<title>Key words for use in RFCs to Indicate Requirement Levels</tit
le>
<author fullname="S. Bradner" initials="S." surname="Bradner">
<organization/>
</author>
<date month="March" year="1997"/>
<abstract>
<t>In many standards track documents several words are used to sig
nify the requirements in the specification. These words are often capitalized.
This document defines these words as they should be interpreted in IETF document
s. This document specifies an Internet Best Current Practices for the Internet
Community, and requests discussion and suggestions for improvements.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="2119"/>
<seriesInfo name="DOI" value="10.17487/RFC2119"/>
</reference>
<reference anchor="RFC8174">
<front>
<title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</ti
tle>
<author fullname="B. Leiba" initials="B." surname="Leiba">
<organization/>
</author>
<date month="May" year="2017"/>
<abstract>
<t>RFC 2119 specifies common key words that may be used in protoco
l specifications. This document aims to reduce the ambiguity by clarifying tha
t only UPPERCASE usage of the key words have the defined special meanings.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="8174"/>
<seriesInfo name="DOI" value="10.17487/RFC8174"/>
</reference>
<reference anchor="QUIC">
<front>
<title>QUIC: A UDP-Based Multiplexed and Secure Transport</title>
<author fullname="J. Iyengar" initials="J." role="editor" surname="I
yengar">
<organization/>
</author>
<author fullname="M. Thomson" initials="M." role="editor" surname="T
homson">
<organization/>
</author>
<date month="May" year="2021"/>
<abstract>
<t>This document defines the core of the QUIC transport protocol.
QUIC provides applications with flow-controlled streams for structured communic
ation, low-latency connection establishment, and network path migration. QUIC in
cludes security measures that ensure confidentiality, integrity, and availabilit
y in a range of deployment circumstances. Accompanying documents describe the i
ntegration of TLS for key negotiation, loss detection, and an exemplary congesti
on control algorithm.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9000"/>
<seriesInfo name="DOI" value="10.17487/RFC9000"/>
</reference>
<reference anchor="STRUCT-FIELD">
<front>
<title>Structured Field Values for HTTP</title>
<author fullname="M. Nottingham" initials="M." surname="Nottingham">
<organization/>
</author>
<author fullname="P-H. Kamp" initials="P-H." surname="Kamp">
<organization/>
</author>
<date month="February" year="2021"/>
<abstract>
<t>This document describes a set of data types and associated algo
rithms that are intended to make it easier and safer to define and handle HTTP h
eader and trailer fields, known as "Structured Fields", "Structured Headers", or
"Structured Trailers". It is intended for use by specifications of new HTTP fie
lds that wish to use a common syntax that is more restrictive than traditional H
TTP field values.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="8941"/>
<seriesInfo name="DOI" value="10.17487/RFC8941"/>
</reference>
<reference anchor="IANA-POLICY">
<front>
<title>Guidelines for Writing an IANA Considerations Section in RFCs
</title>
<author fullname="M. Cotton" initials="M." surname="Cotton">
<organization/>
</author>
<author fullname="B. Leiba" initials="B." surname="Leiba">
<organization/>
</author>
<author fullname="T. Narten" initials="T." surname="Narten">
<organization/>
</author>
<date month="June" year="2017"/>
<abstract>
<t>Many protocols make use of points of extensibility that use con
stants to identify various protocol parameters. To ensure that the values in th
ese fields do not have conflicting uses and to promote interoperability, their a
llocations are often coordinated by a central record keeper. For IETF protocols
, that role is filled by the Internet Assigned Numbers Authority (IANA).</t>
<t>To make assignments in a given registry prudently, guidance des
cribing the conditions under which new values should be assigned, as well as whe
n and how modifications to existing values can be made, is needed. This documen
t defines a framework for the documentation of these guidelines by specification
authors, in order to assure that the provided guidance for the IANA Considerati
ons is clear and addresses the various issues that are likely in the operation o
f a registry.</t>
<t>This is the third edition of this document; it obsoletes RFC 52
26.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="26"/>
<seriesInfo name="RFC" value="8126"/>
<seriesInfo name="DOI" value="10.17487/RFC8126"/>
</reference>
</references> </references>
<references> <references>
<name>Informative References</name> <name>Informative References</name>
<reference anchor="WEBSOCKET"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8899.
<front> xml"/>
<title>The WebSocket Protocol</title> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8441.
<author fullname="I. Fette" initials="I." surname="Fette"> xml"/>
<organization/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9220.
</author> xml"/>
<author fullname="A. Melnikov" initials="A." surname="Melnikov"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.9218.
<organization/> xml"/>
</author> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6455.
<date month="December" year="2011"/> xml"/>
<abstract>
<t>The WebSocket Protocol enables two-way communication between a
client running untrusted code in a controlled environment to a remote host that
has opted-in to communications from that code. The security model used for this
is the origin-based security model commonly used by web browsers. The protocol
consists of an opening handshake followed by basic message framing, layered ove
r TCP. The goal of this technology is to provide a mechanism for browser-based
applications that need two-way communication with servers that does not rely on
opening multiple HTTP connections (e.g., using XMLHttpRequest or &lt;iframe&gt;s
and long polling). [STANDARDS-TRACK]</t>
</abstract>
</front>
<seriesInfo name="RFC" value="6455"/>
<seriesInfo name="DOI" value="10.17487/RFC6455"/>
</reference>
<reference anchor="EXT-CONNECT2">
<front>
<title>Bootstrapping WebSockets with HTTP/2</title>
<author fullname="P. McManus" initials="P." surname="McManus">
<organization/>
</author>
<date month="September" year="2018"/>
<abstract>
<t>This document defines a mechanism for running the WebSocket Pro
tocol (RFC 6455) over a single stream of an HTTP/2 connection.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="8441"/>
<seriesInfo name="DOI" value="10.17487/RFC8441"/>
</reference>
<reference anchor="EXT-CONNECT3">
<front>
<title>Bootstrapping WebSockets with HTTP/3</title>
<author fullname="R. Hamilton" initials="R." surname="Hamilton">
<organization/>
</author>
<date month="June" year="2022"/>
<abstract>
<t>The mechanism for running the WebSocket Protocol over a single
stream of an HTTP/2 connection is equally applicable to HTTP/3, but the HTTP-ver
sion-specific details need to be specified. This document describes how the mech
anism is adapted for HTTP/3.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9220"/>
<seriesInfo name="DOI" value="10.17487/RFC9220"/>
</reference>
<reference anchor="PRIORITY">
<front>
<title>Extensible Prioritization Scheme for HTTP</title>
<author fullname="K. Oku" initials="K." surname="Oku">
<organization/>
</author>
<author fullname="L. Pardue" initials="L." surname="Pardue">
<organization/>
</author>
<date month="June" year="2022"/>
<abstract>
<t>This document describes a scheme that allows an HTTP client to
communicate its preferences for how the upstream server prioritizes responses to
its requests, and also allows a server to hint to a downstream intermediary how
its responses should be prioritized when they are forwarded. This document def
ines the Priority header field for communicating the initial priority in an HTTP
version-independent manner, as well as HTTP/2 and HTTP/3 frames for reprioritiz
ing responses. These share a common format structure that is designed to provide
future extensibility.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9218"/>
<seriesInfo name="DOI" value="10.17487/RFC9218"/>
</reference>
<reference anchor="DPLPMTUD">
<front>
<title>Packetization Layer Path MTU Discovery for Datagram Transport
s</title>
<author fullname="G. Fairhurst" initials="G." surname="Fairhurst">
<organization/>
</author>
<author fullname="T. Jones" initials="T." surname="Jones">
<organization/>
</author>
<author fullname="M. Tüxen" initials="M." surname="Tüxen">
<organization/>
</author>
<author fullname="I. Rüngeler" initials="I." surname="Rüngeler">
<organization/>
</author>
<author fullname="T. Völker" initials="T." surname="Völker">
<organization/>
</author>
<date month="September" year="2020"/>
<abstract>
<t>This document specifies Datagram Packetization Layer Path MTU D
iscovery (DPLPMTUD). This is a robust method for Path MTU Discovery (PMTUD) for
datagram Packetization Layers (PLs). It allows a PL, or a datagram application t
hat uses a PL, to discover whether a network path can support the current size o
f datagram. This can be used to detect and reduce the message size when a sende
r encounters a packet black hole. It can also probe a network path to discover w
hether the maximum packet size can be increased. This provides functionality fo
r datagram transports that is equivalent to the PLPMTUD specification for TCP, s
pecified in RFC 4821, which it updates. It also updates the UDP Usage Guidelines
to refer to this method for use with UDP datagrams and updates SCTP.</t>
<t>The document provides implementation notes for incorporating Da
tagram PMTUD into IETF datagram transports or applications that use datagram tra
nsports.</t>
<t>This specification updates RFC 4960, RFC 4821, RFC 6951, RFC 80
85, and RFC 8261.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="8899"/>
<seriesInfo name="DOI" value="10.17487/RFC8899"/>
</reference>
</references> </references>
</references> </references>
<section numbered="false" anchor="acks"> <section numbered="false" anchor="acks">
<name>Acknowledgments</name> <name>Acknowledgments</name>
<t>Portions of this document were previously part of the QUIC DATAGRAM fra me <t>Portions of this document were previously part of the QUIC DATAGRAM fra me
definition itself, the authors would like to acknowledge the authors of that 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. 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 Additionally, the authors would like to thank <contact fullname="Martin Thomson" /> for suggesting the
use of an HTTP/3 setting. Furthermore, the authors would like to use of an HTTP/3 setting. Furthermore, the authors would like to
thank Ben Schwartz for writing the first proposal that used two layers of thank <contact fullname="Ben Schwartz"/> for substantive input. The final design
indirection. The final design in this document came out of the HTTP Datagrams in this document came out of the HTTP Datagrams
Design Team, whose members were Alan Frindell, Alex Chernyakhovsky, Ben Design Team, whose members were <contact fullname="Alan Frindell"/>,
Schwartz, Eric Rescorla, Marcus Ihlar, Martin Thomson, Mike Bishop, Tommy Pauly, <contact fullname="Alex Chernyakhovsky"/>, <contact fullname="Ben
Victor Vasiliev, and the authors of this document. The authors thank Mark Schwartz"/>, <contact fullname="Eric Rescorla"/>, <contact fullname="Marcus Ihla
Nottingham and Philipp Tiesel for their helpful comments.</t> r"/>,
<contact fullname="Martin Thomson"/>, <contact fullname="Mike Bishop"/>, <contac
t fullname="Tommy Pauly"/>,
<contact fullname="Victor Vasiliev"/>, and the authors of this document. The aut
hors thank
<contact fullname="Mark Nottingham"/> and <contact fullname="Philipp Tiesel"/> f
or their helpful comments.</t>
</section> </section>
</back> </back>
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