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QUIC M. Bishop, Ed.
Internet-Draft Microsoft
Intended status: Standards Track March 13, 2017
Expires: September 14, 2017
Hypertext Transfer Protocol (HTTP) over QUIC
draft-ietf-quic-http-02
Abstract
The QUIC transport protocol has several features that are desirable
in a transport for HTTP, such as stream multiplexing, per-stream flow
control, and low-latency connection establishment. This document
describes a mapping of HTTP semantics over QUIC. This document also
identifies HTTP/2 features that are subsumed by QUIC, and describes
how HTTP/2 extensions can be ported to QUIC.
Note to Readers
Discussion of this draft takes place on the QUIC working group
mailing list (quic@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/search/?email_list=quic .
Working Group information can be found at https://github.com/quicwg ;
source code and issues list for this draft can be found at
https://github.com/quicwg/base-drafts/labels/http .
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 http://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."
This Internet-Draft will expire on September 14, 2017.
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Copyright Notice
Copyright (c) 2017 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
(http://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 Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
2. QUIC Advertisement . . . . . . . . . . . . . . . . . . . . . 3
2.1. QUIC Version Hints . . . . . . . . . . . . . . . . . . . 4
3. Connection Establishment . . . . . . . . . . . . . . . . . . 4
3.1. Draft Version Identification . . . . . . . . . . . . . . 5
4. Stream Mapping and Usage . . . . . . . . . . . . . . . . . . 5
4.1. Stream 3: Connection Control Stream . . . . . . . . . . . 6
4.2. HTTP Message Exchanges . . . . . . . . . . . . . . . . . 6
4.2.1. Header Compression . . . . . . . . . . . . . . . . . 7
4.2.2. The CONNECT Method . . . . . . . . . . . . . . . . . 8
4.3. Stream Priorities . . . . . . . . . . . . . . . . . . . . 9
4.4. Server Push . . . . . . . . . . . . . . . . . . . . . . . 9
5. HTTP Framing Layer . . . . . . . . . . . . . . . . . . . . . 10
5.1. Frame Layout . . . . . . . . . . . . . . . . . . . . . . 10
5.2. Frame Definitions . . . . . . . . . . . . . . . . . . . . 10
5.2.1. HEADERS . . . . . . . . . . . . . . . . . . . . . . . 10
5.2.2. PRIORITY . . . . . . . . . . . . . . . . . . . . . . 11
5.2.3. SETTINGS . . . . . . . . . . . . . . . . . . . . . . 12
5.2.4. PUSH_PROMISE . . . . . . . . . . . . . . . . . . . . 15
6. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 15
6.1. HTTP-Defined QUIC Error Codes . . . . . . . . . . . . . . 16
7. Considerations for Transitioning from HTTP/2 . . . . . . . . 17
7.1. HTTP Frame Types . . . . . . . . . . . . . . . . . . . . 17
7.2. HTTP/2 SETTINGS Parameters . . . . . . . . . . . . . . . 18
7.3. HTTP/2 Error Codes . . . . . . . . . . . . . . . . . . . 19
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
9.1. Registration of HTTP/QUIC Identification String . . . . . 21
9.2. Registration of QUIC Version Hint Alt-Svc Parameter . . . 21
9.3. Existing Frame Types . . . . . . . . . . . . . . . . . . 21
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9.4. Settings Parameters . . . . . . . . . . . . . . . . . . . 22
9.5. Error Codes . . . . . . . . . . . . . . . . . . . . . . . 23
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.1. Normative References . . . . . . . . . . . . . . . . . . 25
10.2. Informative References . . . . . . . . . . . . . . . . . 26
Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 26
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 26
B.1. Since draft-ietf-quic-http-01: . . . . . . . . . . . . . 26
B.2. Since draft-ietf-quic-http-00: . . . . . . . . . . . . . 27
B.3. Since draft-shade-quic-http2-mapping-00: . . . . . . . . 27
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
The QUIC transport protocol has several features that are desirable
in a transport for HTTP, such as stream multiplexing, per-stream flow
control, and low-latency connection establishment. This document
describes a mapping of HTTP semantics over QUIC, drawing heavily on
the existing TCP mapping, HTTP/2. Specifically, this document
identifies HTTP/2 features that are subsumed by QUIC, and describes
how the other features can be implemented atop QUIC.
QUIC is described in [QUIC-TRANSPORT]. For a full description of
HTTP/2, see [RFC7540].
1.1. Notational Conventions
The words "MUST", "MUST NOT", "SHOULD", and "MAY" are used in this
document. It's not shouting; when they are capitalized, they have
the special meaning defined in [RFC2119].
2. QUIC Advertisement
An HTTP origin advertises the availability of an equivalent HTTP/QUIC
endpoint via the Alt-Svc HTTP response header or the HTTP/2 ALTSVC
frame ([RFC7838]), using the ALPN token defined in Section 3.
For example, an origin could indicate in an HTTP/1.1 or HTTP/2
response that HTTP/QUIC was available on UDP port 443 at the same
hostname by including the following header in any response:
Alt-Svc: hq=":443"
On receipt of an Alt-Svc header indicating HTTP/QUIC support, a
client MAY attempt to establish a QUIC connection to the indicated
host and port and, if successful, send HTTP requests using the
mapping described in this document.
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Connectivity problems (e.g. firewall blocking UDP) can result in QUIC
connection establishment failure, in which case the client SHOULD
continue using the existing connection or try another alternative
endpoint offered by the origin.
2.1. QUIC Version Hints
This document defines the "quic" parameter for Alt-Svc, which MAY be
used to provide version-negotiation hints to HTTP/QUIC clients. QUIC
versions are four-octet sequences with no additional constraints on
format. Syntax:
quic = version-number
version-number = 1*8HEXDIG; hex-encoded QUIC version
Leading zeros SHOULD be omitted for brevity. When multiple versions
are supported, the "quic" parameter MAY be repeated multiple times in
a single Alt-Svc entry. For example, if a server supported both
version 0x00000001 and the version rendered in ASCII as "Q034", it
could specify the following header:
Alt-Svc: hq=":443";quic=1;quic=51303334
Where multiple versions are listed, the order of the values reflects
the server's preference (with the first value being the most
preferred version). Origins SHOULD list only versions which are
supported by the alternative, but MAY omit supported versions for any
reason.
3. Connection Establishment
HTTP/QUIC connections are established as described in
[QUIC-TRANSPORT]. During connection establishment, HTTP/QUIC support
is indicated by selecting the ALPN token "hq" in the crypto
handshake.
While connection-level options pertaining to the core QUIC protocol
are set in the initial crypto handshake, HTTP-specific settings are
conveyed in the SETTINGS frame. After the QUIC connection is
established, a SETTINGS frame (Section 5.2.3) MUST be sent as the
initial frame of the HTTP control stream (StreamID 3, see Section 4).
The server MUST NOT send data on any other stream until the client's
SETTINGS frame has been received.
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3.1. Draft Version Identification
*RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document.
Only implementations of the final, published RFC can identify
themselves as "hq". Until such an RFC exists, implementations MUST
NOT identify themselves using this string.
Implementations of draft versions of the protocol MUST add the string
"-" and the corresponding draft number to the identifier. For
example, draft-ietf-quic-http-01 is identified using the string "hq-
01".
Non-compatible experiments that are based on these draft versions
MUST append the string "-" and an experiment name to the identifier.
For example, an experimental implementation based on draft-ietf-quic-
http-09 which reserves an extra stream for unsolicited transmission
of 1980s pop music might identify itself as "hq-09-rickroll". Note
that any label MUST conform to the "token" syntax defined in
Section 3.2.6 of [RFC7230]. Experimenters are encouraged to
coordinate their experiments on the quic@ietf.org mailing list.
4. Stream Mapping and Usage
A QUIC stream provides reliable in-order delivery of bytes, but makes
no guarantees about order of delivery with regard to bytes on other
streams. On the wire, data is framed into QUIC STREAM frames, but
this framing is invisible to the HTTP framing layer. A QUIC receiver
buffers and orders received STREAM frames, exposing the data
contained within as a reliable byte stream to the application.
QUIC reserves Stream 1 for crypto operations (the handshake, crypto
config updates). Stream 3 is reserved for sending and receiving HTTP
control frames, and is analogous to HTTP/2's Stream 0. This
connection control stream is considered critical to the HTTP
connection. If the connection control stream is closed for any
reason, this MUST be treated as a connection error of type
QUIC_CLOSED_CRITICAL_STREAM.
When HTTP headers and data are sent over QUIC, the QUIC layer handles
most of the stream management. An HTTP request/response consumes a
pair of streams: This means that the client's first request occurs on
QUIC streams 5 and 7, the second on stream 9 and 11, and so on. The
server's first push consumes streams 2 and 4. This amounts to the
second least-significant bit differentiating the two streams in a
request.
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The lower-numbered stream is called the message control stream and
carries frames related to the request/response, including HEADERS.
The higher-numbered stream is the data stream and carries the
request/response body with no additional framing. Note that a
request or response without a body will cause this stream to be half-
closed in the corresponding direction without transferring data.
Because the message control stream contains HPACK data which
manipulates connection-level state, the message control stream MUST
NOT be closed with a stream-level error. If an implementation
chooses to reject a request with a QUIC error code, it MUST trigger a
QUIC RST_STREAM on the data stream only. An implementation MAY close
(FIN) a message control stream without completing a full HTTP message
if the data stream has been abruptly closed. Data on message control
streams MUST be fully consumed, or the connection terminated.
All message control streams are considered critical to the HTTP
connection. If a message control stream is terminated abruptly for
any reason, this MUST be treated as a connection error of type
HTTP_RST_CONTROL_STREAM. When a message control stream terminates
cleanly, if the last frame on the stream was truncated, this MUST be
treated as a connection error (see HTTP_MALFORMED_* in Section 6.1).
Pairs of streams must be utilized sequentially, with no gaps. The
data stream is opened at the same time as the message control stream
is opened and is closed after transferring the body. The data stream
is closed immediately after sending the request headers if there is
no body.
HTTP does not need to do any separate multiplexing when using QUIC -
data sent over a QUIC stream always maps to a particular HTTP
transaction. Requests and responses are considered complete when the
corresponding QUIC streams are closed in the appropriate direction.
4.1. Stream 3: Connection Control Stream
Since most connection-level concerns will be managed by QUIC, the
primary use of Stream 3 will be for the SETTINGS frame when the
connection opens and for PRIORITY frames subsequently.
4.2. HTTP Message Exchanges
A client sends an HTTP request on a new pair of QUIC streams. A
server sends an HTTP response on the same streams as the request.
An HTTP message (request or response) consists of:
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1. one header block (see Section 5.2.1) on the control stream
containing the message headers (see [RFC7230], Section 3.2),
2. the payload body (see [RFC7230], Section 3.3), sent on the data
stream,
3. optionally, one header block on the control stream containing the
trailer-part, if present (see [RFC7230], Section 4.1.2).
In addition, prior to sending the message header block indicated
above, a response may contain zero or more header blocks on the
control stream containing the message headers of informational (1xx)
HTTP responses (see [RFC7230], Section 3.2 and [RFC7231],
Section 6.2).
The data stream MUST be half-closed immediately after the transfer of
the body. If the message does not contain a body, the corresponding
data stream MUST still be half-closed without transferring any data.
The "chunked" transfer encoding defined in Section 4.1 of [RFC7230]
MUST NOT be used.
Trailing header fields are carried in an additional header block on
the message control stream. Such a header block is a sequence of
HEADERS frames with End Header Block set on the last frame. Senders
MUST send only one header block in the trailers section; receivers
MUST decode any subsequent header blocks in order to maintain HPACK
decoder state, but the resulting output MUST be discarded.
An HTTP request/response exchange fully consumes a pair of streams.
After sending a request, a client closes the streams for sending;
after sending a response, the server closes its streams for sending
and the QUIC streams are fully closed.
A server can send a complete response prior to the client sending an
entire request if the response does not depend on any portion of the
request that has not been sent and received. When this is true, a
server MAY request that the client abort transmission of a request
without error by sending a RST_STREAM with an error code of NO_ERROR
after sending a complete response and closing its stream. Clients
MUST NOT discard responses as a result of receiving such a
RST_STREAM, though clients can always discard responses at their
discretion for other reasons.
4.2.1. Header Compression
HTTP/QUIC uses HPACK header compression as described in [RFC7541].
HPACK was designed for HTTP/2 with the assumption of in-order
delivery such as that provided by TCP. A sequence of encoded header
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blocks must arrive (and be decoded) at an endpoint in the same order
in which they were encoded. This ensures that the dynamic state at
the two endpoints remains in sync.
QUIC streams provide in-order delivery of data sent on those streams,
but there are no guarantees about order of delivery between streams.
To achieve in-order delivery of HEADERS frames in QUIC, the HPACK-
bearing frames contain a counter which can be used to ensure in-order
processing. Data (request/response bodies) which arrive out of order
are buffered until the corresponding HEADERS arrive.
This does introduce head-of-line blocking: if the packet containing
HEADERS for stream N is lost or reordered then the HEADERS for stream
N+4 cannot be processed until it has been retransmitted successfully,
even though the HEADERS for stream N+4 may have arrived.
DISCUSS: Keep HPACK with HOLB? Redesign HPACK to be order-
invariant? How much do we need to retain compatibility with
HTTP/2's HPACK?
4.2.2. The CONNECT Method
The pseudo-method CONNECT ([RFC7231], Section 4.3.6) is primarily
used with HTTP proxies to establish a TLS session with an origin
server for the purposes of interacting with "https" resources. In
HTTP/1.x, CONNECT is used to convert an entire HTTP connection into a
tunnel to a remote host. In HTTP/2, the CONNECT method is used to
establish a tunnel over a single HTTP/2 stream to a remote host for
similar purposes.
A CONNECT request in HTTP/QUIC functions in the same manner as in
HTTP/2. The request MUST be formatted as described in [RFC7540],
Section 8.3. A CONNECT request that does not conform to these
restrictions is malformed. The message data stream MUST NOT be
closed at the end of the request.
A proxy that supports CONNECT establishes a TCP connection
([RFC0793]) to the server identified in the ":authority" pseudo-
header field. Once this connection is successfully established, the
proxy sends a HEADERS frame containing a 2xx series status code to
the client, as defined in [RFC7231], Section 4.3.6, on the message
control stream.
All QUIC STREAM frames on the message data stream correspond to data
sent on the TCP connection. Any QUIC STREAM frame sent by the client
is transmitted by the proxy to the TCP server; data received from the
TCP server is written to the data stream by the proxy. Note that the
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size and number of TCP segments is not guaranteed to map predictably
to the size and number of QUIC STREAM frames.
The TCP connection can be closed by either peer. When the client
half-closes the data stream, the proxy will set the FIN bit on its
connection to the TCP server. When the proxy receives a packet with
the FIN bit set, it will half-close the corresponding data stream.
TCP connections which remain half-closed in a single direction are
not invalid, but are often handled poorly by servers, so clients
SHOULD NOT half-close connections on which they are still expecting
data.
A TCP connection error is signaled with RST_STREAM. A proxy treats
any error in the TCP connection, which includes receiving a TCP
segment with the RST bit set, as a stream error of type
HTTP_CONNECT_ERROR (Section 6.1). Correspondingly, a proxy MUST send
a TCP segment with the RST bit set if it detects an error with the
stream or the QUIC connection.
4.3. Stream Priorities
HTTP/QUIC uses the priority scheme described in [RFC7540]
Section 5.3. In this priority scheme, a given stream can be
designated as dependent upon another stream, which expresses the
preference that the latter stream (the "parent" stream) be allocated
resources before the former stream (the "dependent" stream). Taken
together, the dependencies across all streams in a connection form a
dependency tree. The structure of the dependency tree changes as
PRIORITY frames add, remove, or change the dependency links between
streams.
For consistency's sake, all PRIORITY frames MUST refer to the message
control stream of the dependent request, not the data stream.
4.4. Server Push
HTTP/QUIC supports server push as described in [RFC7540]. During
connection establishment, the client indicates whether it is willing
to receive server pushes via the SETTINGS_DISABLE_PUSH setting in the
SETTINGS frame (see Section 3), which defaults to 1 (true).
As with server push for HTTP/2, the server initiates a server push by
sending a PUSH_PROMISE frame containing the StreamID of the stream to
be pushed, as well as request header fields attributed to the
request. The PUSH_PROMISE frame is sent on the control stream of the
associated (client-initiated) request, while the Promised Stream ID
field specifies the Stream ID of the control stream for the server-
initiated request.
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The server push response is conveyed in the same way as a non-server-
push response, with response headers and (if present) trailers
carried by HEADERS frames sent on the control stream, and response
body (if any) sent via the corresponding data stream.
5. HTTP Framing Layer
Frames are used only on the connection (stream 3) and message
(streams 5, 9, etc.) control streams. Other streams carry data
payload and are not framed at the HTTP layer.
This section describes HTTP framing in QUIC and highlights some
differences from HTTP/2 framing. For more detail on differences from
HTTP/2, see Section 7.1.
5.1. Frame Layout
All frames have the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (16) | Type (8) | Flags (8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Frame Payload (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: HTTP/QUIC frame format
5.2. Frame Definitions
5.2.1. HEADERS
The HEADERS frame (type=0x1) is used to carry part of a header set,
compressed using HPACK [RFC7541].
One flag is defined:
End Header Block (0x4): This frame concludes a header block.
A HEADERS frame with any other flags set MUST be treated as a
connection error of type HTTP_MALFORMED_HEADERS.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence? (16) | Header Block Fragment (*)...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: HEADERS frame payload
The HEADERS frame payload has the following fields:
Sequence Number: Present only on the first frame of a header block
sequence. This MUST be set to zero on the first header block
sequence, and incremented on each header block.
The next frame on the same stream after a HEADERS frame without the
EHB flag set MUST be another HEADERS frame. A receiver MUST treat
the receipt of any other type of frame as a stream error of type
HTTP_INTERRUPTED_HEADERS. (Note that QUIC can intersperse data from
other streams between frames, or even during transmission of frames,
so multiplexing is not blocked by this requirement.)
A full header block is contained in a sequence of zero or more
HEADERS frames without EHB set, followed by a HEADERS frame with EHB
set.
On receipt, header blocks (HEADERS, PUSH_PROMISE) MUST be processed
by the HPACK decoder in sequence. If a block is missing, all
subsequent HPACK frames MUST be held until it arrives, or the
connection terminated.
When the Sequence counter reaches its maximum value (0xFFFF), the
next increment returns it to zero. An endpoint MUST NOT wrap the
Sequence counter to zero until the previous zero-value header block
has been confirmed received.
5.2.2. PRIORITY
The PRIORITY (type=0x02) frame specifies the sender-advised priority
of a stream and is substantially different from [RFC7540]. In order
to support ordering, it MUST be sent only on the connection control
stream. The format has been modified to accommodate not being sent
on-stream and the larger stream ID space of QUIC.
The semantics of the Stream Dependency, Weight, and E flag are the
same as in HTTP/2.
The flags defined are:
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E (0x01): Indicates that the stream dependency is exclusive (see
[RFC7540] Section 5.3).
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prioritized Stream (32) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Dependent Stream (32) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Weight (8) |
+-+-+-+-+-+-+-+-+
Figure 3: PRIORITY frame payload
The HEADERS frame payload has the following fields:
Prioritized Stream: A 32-bit stream identifier for the message
control stream whose priority is being updated.
Stream Dependency: A 32-bit stream identifier for the stream that
this stream depends on (see Section 4.3 and {!RFC7540}}
Section 5.3).
Weight: An unsigned 8-bit integer representing a priority weight for
the stream (see [RFC7540] Section 5.3). Add one to the value to
obtain a weight between 1 and 256.
A PRIORITY frame MUST have a payload length of nine octets. A
PRIORITY frame of any other length MUST be treated as a connection
error of type HTTP_MALFORMED_PRIORITY.
5.2.3. SETTINGS
The SETTINGS frame (type=0x4) conveys configuration parameters that
affect how endpoints communicate, such as preferences and constraints
on peer behavior, and is substantially different from [RFC7540].
Individually, a SETTINGS parameter can also be referred to as a
"setting".
SETTINGS parameters are not negotiated; they describe characteristics
of the sending peer, which can be used by the receiving peer.
However, a negotiation can be implied by the use of SETTINGS - a peer
uses SETTINGS to advertise a set of supported values. The recipient
can then choose which entries from this list are also acceptable and
proceed with the value it has chosen. (This choice could be
announced in a field of an extension frame, or in its own value in
SETTINGS.)
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Different values for the same parameter can be advertised by each
peer. For example, a client might permit a very large HPACK state
table while a server chooses to use a small one to conserve memory.
Parameters MUST NOT occur more than once. A receiver MAY treat the
presence of the same parameter more than once as a connection error
of type HTTP_MALFORMED_SETTINGS.
The SETTINGS frame defines no flags.
The payload of a SETTINGS frame consists of zero or more parameters,
each consisting of an unsigned 16-bit setting identifier and a
length-prefixed binary value.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier (16) | Length (16) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Contents (?) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: SETTINGS value format
A zero-length content indicates that the setting value is a Boolean
and true. False is indicated by the absence of the setting.
Non-zero-length values MUST be compared against the remaining length
of the SETTINGS frame. Any value which purports to cross the end of
the frame MUST cause the SETTINGS frame to be considered malformed
and trigger a connection error of type HTTP_MALFORMED_SETTINGS.
An implementation MUST ignore the contents for any SETTINGS
identifier it does not understand.
SETTINGS frames always apply to a connection, never a single stream.
A SETTINGS frame MUST be sent as the first frame of the connection
control stream (see Section 4) by each peer, and MUST NOT be sent
subsequently or on any other stream. If an endpoint receives an
SETTINGS frame on a different stream, the endpoint MUST respond with
a connection error of type HTTP_SETTINGS_ON_WRONG_STREAM. If an
endpoint receives a second SETTINGS frame, the endpoint MUST respond
with a connection error of type HTTP_MULTIPLE_SETTINGS.
The SETTINGS frame affects connection state. A badly formed or
incomplete SETTINGS frame MUST be treated as a connection error
(Section 5.4.1) of type HTTP_MALFORMED_SETTINGS.
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5.2.3.1. Integer encoding
Settings which are integers are transmitted in network byte order.
Leading zero octets are permitted, but implementations SHOULD use
only as many bytes as are needed to represent the value. An integer
MUST NOT be represented in more bytes than would be used to transfer
the maximum permitted value.
5.2.3.2. Defined SETTINGS Parameters
The following settings are defined in HTTP/QUIC:
SETTINGS_HEADER_TABLE_SIZE (0x1): An integer with a maximum value of
2^32 - 1.
SETTINGS_DISABLE_PUSH (0x2): Transmitted as a Boolean; replaces
SETTINGS_ENABLE_PUSH
SETTINGS_MAX_HEADER_LIST_SIZE (0x6): An integer with a maximum value
of 2^32 - 1.
5.2.3.3. Usage in 0-RTT
When a 0-RTT QUIC connection is being used, the client's initial
requests will be sent before the arrival of the server's SETTINGS
frame. Clients SHOULD cache at least the following settings about
servers:
o SETTINGS_HEADER_TABLE_SIZE
o SETTINGS_MAX_HEADER_LIST_SIZE
Clients MUST comply with cached settings until the server's current
settings are received. If a client does not have cached values, it
SHOULD assume the following values:
o SETTINGS_HEADER_TABLE_SIZE: 0 octets
o SETTINGS_MAX_HEADER_LIST_SIZE: 16,384 octets
Servers MAY continue processing data from clients which exceed its
current configuration during the initial flight. In this case, the
client MUST apply the new settings immediately upon receipt.
If the connection is closed because these or other constraints were
violated during the 0-RTT flight (e.g. with
HTTP_HPACK_DECOMPRESSION_FAILED), clients MAY establish a new
connection and retry any 0-RTT requests using the settings sent by
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the server on the closed connection. (This assumes that only
requests that are safe to retry are sent in 0-RTT.) If the
connection was closed before the SETTINGS frame was received, clients
SHOULD discard any cached values and use the defaults above on the
next connection.
5.2.4. PUSH_PROMISE
The PUSH_PROMISE frame (type=0x05) is used to carry a request header
set from server to client, as in HTTP/2. It defines no flags.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Promised Stream ID (32) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence? (16) | Header Block (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: PUSH_PROMISE frame payload
The payload consists of:
Promised Stream ID: A 32-bit Stream ID indicating the QUIC stream on
which the response headers will be sent. (The response body
stream is implied by the headers stream, as defined in Section 4.)
HPACK Sequence: A sixteen-bit counter, equivalent to the Sequence
field in HEADERS
Payload: HPACK-compressed request headers for the promised response.
6. Error Handling
QUIC allows the application to abruptly terminate individual streams
or the entire connection when an error is encountered. These are
referred to as "stream errors" or "connection errors" and are
described in more detail in [QUIC-TRANSPORT].
HTTP/QUIC requires that only data streams be terminated abruptly.
Terminating a message control stream will result in an error of type
HTTP_RST_CONTROL_STREAM.
This section describes HTTP-specific error codes which can be used to
express the cause of a connection or stream error.
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6.1. HTTP-Defined QUIC Error Codes
QUIC allocates error codes 0x0000-0x3FFF to application protocol
definition. The following error codes are defined by HTTP for use in
QUIC RST_STREAM, GOAWAY, and CONNECTION_CLOSE frames.
HTTP_PUSH_REFUSED (0x01): The server has attempted to push content
which the client will not accept on this connection.
HTTP_INTERNAL_ERROR (0x02): An internal error has occurred in the
HTTP stack.
HTTP_PUSH_ALREADY_IN_CACHE (0x03): The server has attempted to push
content which the client has cached.
HTTP_REQUEST_CANCELLED (0x04): The client no longer needs the
requested data.
HTTP_HPACK_DECOMPRESSION_FAILED (0x05): HPACK failed to decompress a
frame and cannot continue.
HTTP_CONNECT_ERROR (0x06): The connection established in response to
a CONNECT request was reset or abnormally closed.
HTTP_EXCESSIVE_LOAD (0x07): The endpoint detected that its peer is
exhibiting a behavior that might be generating excessive load.
HTTP_VERSION_FALLBACK (0x08): The requested operation cannot be
served over HTTP/QUIC. The peer should retry over HTTP/2.
HTTP_MALFORMED_HEADERS (0x09): A HEADERS frame has been received
with an invalid format.
HTTP_MALFORMED_PRIORITY (0x0A): A PRIORITY frame has been received
with an invalid format.
HTTP_MALFORMED_SETTINGS (0x0B): A SETTINGS frame has been received
with an invalid format.
HTTP_MALFORMED_PUSH_PROMISE (0x0C): A PUSH_PROMISE frame has been
received with an invalid format.
HTTP_INTERRUPTED_HEADERS (0x0E): A HEADERS frame without the End
Header Block flag was followed by a frame other than HEADERS.
HTTP_SETTINGS_ON_WRONG_STREAM (0x0F): A SETTINGS frame was received
on a request control stream.
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HTTP_MULTIPLE_SETTINGS (0x10): More than one SETTINGS frame was
received.
HTTP_RST_CONTROL_STREAM (0x11): A message control stream closed
abruptly.
7. Considerations for Transitioning from HTTP/2
HTTP/QUIC is strongly informed by HTTP/2, and bears many
similarities. This section points out important differences from
HTTP/2 and describes how to map HTTP/2 extensions into HTTP/QUIC.
7.1. HTTP Frame Types
Many framing concepts from HTTP/2 can be elided away on QUIC, because
the transport deals with them. Because frames are already on a
stream, they can omit the stream number. Because frames do not block
multiplexing (QUIC's multiplexing occurs below this layer), the
support for variable-maximum-length packets can be removed. Because
stream termination is handled by QUIC, an END_STREAM flag is not
required.
Frame payloads are largely drawn from [RFC7540]. However, QUIC
includes many features (e.g. flow control) which are also present in
HTTP/2. In these cases, the HTTP mapping does not re-implement them.
As a result, several HTTP/2 frame types are not required in HTTP/
QUIC. Where an HTTP/2-defined frame is no longer used, the frame ID
has been reserved in order to maximize portability between HTTP/2 and
HTTP/QUIC implementations. However, even equivalent frames between
the two mappings are not identical.
Many of the differences arise from the fact that HTTP/2 provides an
absolute ordering between frames across all streams, while QUIC
provides this guarantee on each stream only. As a result, if a frame
type makes assumptions that frames from different streams will still
be received in the order sent, HTTP/QUIC will break them.
For example, implicit in the HTTP/2 prioritization scheme is the
notion of in-order delivery of priority changes (i.e., dependency
tree mutations): since operations on the dependency tree such as
reparenting a subtree are not commutative, both sender and receiver
must apply them in the same order to ensure that both sides have a
consistent view of the stream dependency tree. HTTP/2 specifies
priority assignments in PRIORITY frames and (optionally) in HEADERS
frames. To achieve in-order delivery of priority changes in HTTP/
QUIC, PRIORITY frames are sent on the connection control stream and
the PRIORITY section is removed from the HEADERS frame.
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Other than this issue, frame type HTTP/2 extensions are typically
portable to QUIC simply by replacing Stream 0 in HTTP/2 with Stream 3
in HTTP/QUIC.
Below is a listing of how each HTTP/2 frame type is mapped:
DATA (0x0): Instead of DATA frames, HTTP/QUIC uses a separate data
stream. See Section 4.
HEADERS (0x1): As described above, the PRIORITY region of HEADERS is
not supported. A separate PRIORITY frame MUST be used. Padding
is not defined in HTTP/QUIC frames. See Section 5.2.1.
PRIORITY (0x2): As described above, the PRIORITY frame is sent on
the connection control stream. See Section 5.2.2.
RST_STREAM (0x3): RST_STREAM frames do not exist, since QUIC
provides stream lifecycle management.
SETTINGS (0x4): SETTINGS frames are sent only at the beginning of
the connection. See Section 5.2.3 and Section 7.2.
PUSH_PROMISE (0x5): See Section 5.2.4.
PING (0x6): PING frames do not exist, since QUIC provides equivalent
functionality.
GOAWAY (0x7): GOAWAY frames do not exist, since QUIC provides
equivalent functionality.
WINDOW_UPDATE (0x8): WINDOW_UPDATE frames do not exist, since QUIC
provides flow control.
CONTINUATION (0x9): CONTINUATION frames do not exist; instead,
larger HEADERS/PUSH_PROMISE frames than HTTP/2 are permitted, and
HEADERS frames can be used in series.
The IANA registry of frame types has been updated in Section 9.3 to
include references to the definition for each frame type in HTTP/2
and in HTTP/QUIC. Frames not defined as available in HTTP/QUIC
SHOULD NOT be sent and SHOULD be ignored as unknown on receipt.
7.2. HTTP/2 SETTINGS Parameters
An important difference from HTTP/2 is that settings are sent once,
at the beginning of the connection, and thereafter cannot change.
This eliminates many corner cases around synchronization of changes.
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Some transport-level options that HTTP/2 specifies via the SETTINGS
frame are superseded by QUIC transport parameters in HTTP/QUIC. The
HTTP-level options that are retained in HTTP/QUIC have the same value
as in HTTP/2.
Below is a listing of how each HTTP/2 SETTINGS parameter is mapped:
SETTINGS_HEADER_TABLE_SIZE: See Section 5.2.3.2.
SETTINGS_ENABLE_PUSH: See SETTINGS_DISABLE_PUSH in Section 5.2.3.2.
SETTINGS_MAX_CONCURRENT_STREAMS: QUIC requires the maximum number of
incoming streams per connection to be specified in the initial
transport handshake. Specifying SETTINGS_MAX_CONCURRENT_STREAMS
in the SETTINGS frame is an error.
SETTINGS_INITIAL_WINDOW_SIZE: QUIC requires both stream and
connection flow control window sizes to be specified in the
initial transport handshake. Specifying
SETTINGS_INITIAL_WINDOW_SIZE in the SETTINGS frame is an error.
SETTINGS_MAX_FRAME_SIZE: This setting has no equivalent in HTTP/
QUIC. Specifying it in the SETTINGS frame is an error.
SETTINGS_MAX_HEADER_LIST_SIZE: See Section 5.2.3.2.
Settings defined by extensions to HTTP/2 MAY be expressed as integers
with a maximum value of 2^32-1, if they are applicable to HTTP/QUIC,
but SHOULD have a specification describing their usage. Fields for
this purpose have been added to the IANA registry in Section 9.4.
7.3. HTTP/2 Error Codes
QUIC has the same concepts of "stream" and "connection" errors that
HTTP/2 provides. However, because the error code space is shared
between multiple components, there is no direct portability of HTTP/2
error codes.
The HTTP/2 error codes defined in Section 7 of [RFC7540] map to QUIC
error codes as follows:
NO_ERROR (0x0): QUIC_NO_ERROR
PROTOCOL_ERROR (0x1): No single mapping. See new HTTP_MALFORMED_*
error codes defined in Section 6.1.
INTERNAL_ERROR (0x2) HTTP_INTERNAL_ERROR in Section 6.1.
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FLOW_CONTROL_ERROR (0x3): Not applicable, since QUIC handles flow
control. Would provoke a QUIC_FLOW_CONTROL_RECEIVED_TOO_MUCH_DATA
from the QUIC layer.
SETTINGS_TIMEOUT (0x4): Not applicable, since no acknowledgement of
SETTINGS is defined.
STREAM_CLOSED (0x5): Not applicable, since QUIC handles stream
management. Would provoke a QUIC_STREAM_DATA_AFTER_TERMINATION
from the QUIC layer.
FRAME_SIZE_ERROR (0x6) No single mapping. See new error codes
defined in Section 6.1.
REFUSED_STREAM (0x7): Not applicable, since QUIC handles stream
management. Would provoke a QUIC_TOO_MANY_OPEN_STREAMS from the
QUIC layer.
CANCEL (0x8): HTTP_REQUEST_CANCELLED in Section 6.1.
COMPRESSION_ERROR (0x9): HTTP_HPACK_DECOMPRESSION_FAILED in
Section 6.1.
CONNECT_ERROR (0xa): HTTP_CONNECT_ERROR in Section 6.1.
ENHANCE_YOUR_CALM (0xb): HTTP_EXCESSIVE_LOAD in Section 6.1.
INADEQUATE_SECURITY (0xc): Not applicable, since QUIC is assumed to
provide sufficient security on all connections.
HTTP_1_1_REQUIRED (0xd): HTTP_VERSION_FALLBACK in Section 6.1.
Error codes defined by HTTP/2 extensions need to be re-registered for
HTTP/QUIC if still applicable. See Section 9.5.
8. Security Considerations
The security considerations of HTTP over QUIC should be comparable to
those of HTTP/2.
The modified SETTINGS format contains nested length elements, which
could pose a security risk to an uncautious implementer. A SETTINGS
frame parser MUST ensure that the length of the frame exactly matches
the length of the settings it contains.
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9. IANA Considerations
9.1. Registration of HTTP/QUIC Identification String
This document creates a new registration for the identification of
HTTP/QUIC in the "Application Layer Protocol Negotiation (ALPN)
Protocol IDs" registry established in [RFC7301].
The "hq" string identifies HTTP/QUIC:
Protocol: HTTP over QUIC
Identification Sequence: 0x68 0x71 ("hq")
Specification: This document
9.2. Registration of QUIC Version Hint Alt-Svc Parameter
This document creates a new registration for version-negotiation
hints in the "Hypertext Transfer Protocol (HTTP) Alt-Svc Parameter"
registry established in [RFC7838].
Parameter: "quic"
Specification: This document, Section 2.1
9.3. Existing Frame Types
This document adds two new columns to the "HTTP/2 Frame Type"
registry defined in [RFC7540]:
Supported Protocols: Indicates which associated protocols use the
frame type. Values MUST be one of:
* "HTTP/2 only"
* "HTTP/QUIC only"
* "Both"
HTTP/QUIC Specification: Indicates where this frame's behavior over
QUIC is defined; required if the frame is supported over QUIC.
Values for existing registrations are assigned by this document:
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+---------------+---------------------+-------------------------+
| Frame Type | Supported Protocols | HTTP/QUIC Specification |
+---------------+---------------------+-------------------------+
| DATA | HTTP/2 only | N/A |
| | | |
| HEADERS | Both | Section 5.2.1 |
| | | |
| PRIORITY | Both | Section 5.2.2 |
| | | |
| RST_STREAM | HTTP/2 only | N/A |
| | | |
| SETTINGS | Both | Section 5.2.3 |
| | | |
| PUSH_PROMISE | Both | Section 5.2.4 |
| | | |
| PING | HTTP/2 only | N/A |
| | | |
| GOAWAY | HTTP/2 only | N/A |
| | | |
| WINDOW_UPDATE | HTTP/2 only | N/A |
| | | |
| CONTINUATION | HTTP/2 only | N/A |
+---------------+---------------------+-------------------------+
The "Specification" column is renamed to "HTTP/2 specification" and
is only required if the frame is supported over HTTP/2.
9.4. Settings Parameters
This document adds two new columns to the "HTTP/2 Settings" registry
defined in [RFC7540]:
Supported Protocols: Indicates which associated protocols use the
setting. Values MUST be one of:
* "HTTP/2 only"
* "HTTP/QUIC only"
* "Both"
HTTP/QUIC Specification: Indicates where this setting's behavior
over QUIC is defined; required if the frame is supported over
QUIC.
Values for existing registrations are assigned by this document:
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+-------------------------+------------------+----------------------+
| Setting Name | Supported | HTTP/QUIC |
| | Protocols | Specification |
+-------------------------+------------------+----------------------+
| HEADER_TABLE_SIZE | Both | Section 5.2.3.2 |
| | | |
| ENABLE_PUSH / | Both | Section 5.2.3.2 |
| DISABLE_PUSH | | |
| | | |
| MAX_CONCURRENT_STREAMS | HTTP/2 Only | N/A |
| | | |
| INITIAL_WINDOW_SIZE | HTTP/2 Only | N/A |
| | | |
| MAX_FRAME_SIZE | HTTP/2 Only | N/A |
| | | |
| MAX_HEADER_LIST_SIZE | Both | Section 5.2.3.2 |
+-------------------------+------------------+----------------------+
The "Specification" column is renamed to "HTTP/2 Specification" and
is only required if the setting is supported over HTTP/2.
9.5. Error Codes
This document establishes a registry for HTTP/QUIC error codes. The
"HTTP/QUIC Error Code" registry manages a 30-bit space. The "HTTP/
QUIC Error Code" registry operates under the "Expert Review" policy
[RFC5226].
Registrations for error codes are required to include a description
of the error code. An expert reviewer is advised to examine new
registrations for possible duplication with existing error codes.
Use of existing registrations is to be encouraged, but not mandated.
New registrations are advised to provide the following information:
Name: A name for the error code. Specifying an error code name is
optional.
Code: The 30-bit error code value.
Description: A brief description of the error code semantics, longer
if no detailed specification is provided.
Specification: An optional reference for a specification that
defines the error code.
The entries in the following table are registered by this document.
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+------------------------------+-----+--------------+---------------+
| Name | Cod | Description | Specification |
| | e | | |
+------------------------------+-----+--------------+---------------+
| HTTP_PUSH_REFUSED | 0x0 | Client | Section 6.1 |
| | 1 | refused | |
| | | pushed | |
| | | content | |
| | | | |
| HTTP_INTERNAL_ERROR | 0x0 | Internal | Section 6.1 |
| | 2 | error | |
| | | | |
| HTTP_PUSH_ALREADY_IN_CACHE | 0x0 | Pushed | Section 6.1 |
| | 3 | content | |
| | | already | |
| | | cached | |
| | | | |
| HTTP_REQUEST_CANCELLED | 0x0 | Data no | Section 6.1 |
| | 4 | longer | |
| | | needed | |
| | | | |
| HTTP_HPACK_DECOMPRESSION_FAI | 0x0 | HPACK cannot | Section 6.1 |
| LED | 5 | continue | |
| | | | |
| HTTP_CONNECT_ERROR | 0x0 | TCP reset or | Section 6.1 |
| | 6 | error on | |
| | | CONNECT | |
| | | request | |
| | | | |
| HTTP_EXCESSIVE_LOAD | 0x0 | Peer | Section 6.1 |
| | 7 | generating | |
| | | excessive | |
| | | load | |
| | | | |
| HTTP_VERSION_FALLBACK | 0x0 | Retry over | Section 6.1 |
| | 8 | HTTP/2 | |
| | | | |
| HTTP_MALFORMED_HEADERS | 0x0 | Invalid | Section 6.1 |
| | 9 | HEADERS | |
| | | frame | |
| | | | |
| HTTP_MALFORMED_PRIORITY | 0x0 | Invalid | Section 6.1 |
| | A | PRIORITY | |
| | | frame | |
| | | | |
| HTTP_MALFORMED_SETTINGS | 0x0 | Invalid | Section 6.1 |
| | B | SETTINGS | |
| | | frame | |
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| | | | |
| HTTP_MALFORMED_PUSH_PROMISE | 0x0 | Invalid | Section 6.1 |
| | C | PUSH_PROMISE | |
| | | frame | |
| | | | |
| HTTP_INTERRUPTED_HEADERS | 0x0 | Incomplete | Section 6.1 |
| | E | HEADERS | |
| | | block | |
| | | | |
| HTTP_SETTINGS_ON_WRONG_STREA | 0x0 | SETTINGS | Section 6.1 |
| M | F | frame on a | |
| | | request | |
| | | control | |
| | | stream | |
| | | | |
| HTTP_MULTIPLE_SETTINGS | 0x1 | Multiple | Section 6.1 |
| | 0 | SETTINGS | |
| | | frames | |
| | | | |
| HTTP_RST_CONTROL_STREAM | 0x1 | Message | Section 6.1 |
| | 1 | control | |
| | | stream was | |
| | | RST | |
+------------------------------+-----+--------------+---------------+
10. References
10.1. Normative References
[QUIC-TRANSPORT]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport".
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, DOI 10.17487/RFC0793, September 1981,
<http://www.rfc-editor.org/info/rfc793>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<http://www.rfc-editor.org/info/rfc7230>.
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[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<http://www.rfc-editor.org/info/rfc7231>.
[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
DOI 10.17487/RFC7540, May 2015,
<http://www.rfc-editor.org/info/rfc7540>.
[RFC7541] Peon, R. and H. Ruellan, "HPACK: Header Compression for
HTTP/2", RFC 7541, DOI 10.17487/RFC7541, May 2015,
<http://www.rfc-editor.org/info/rfc7541>.
[RFC7838] Nottingham, M., McManus, P., and J. Reschke, "HTTP
Alternative Services", RFC 7838, DOI 10.17487/RFC7838,
April 2016, <http://www.rfc-editor.org/info/rfc7838>.
10.2. Informative References
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <http://www.rfc-editor.org/info/rfc7301>.
Appendix A. Contributors
The original authors of this specification were Robbie Shade and Mike
Warres.
Appendix B. Change Log
*RFC Editor's Note:* Please remove this section prior to
publication of a final version of this document.
B.1. Since draft-ietf-quic-http-01:
o SETTINGS changes (#181):
* SETTINGS can be sent only once at the start of a connection; no
changes thereafter
* SETTINGS_ACK removed
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* Settings can only occur in the SETTINGS frame a single time
* Boolean format updated
o Alt-Svc parameter changed from "v" to "quic"; format updated
(#229)
o Closing the connection control stream or any message control
stream is a fatal error (#176)
o HPACK Sequence counter can wrap (#173)
o 0-RTT guidance added
o Guide to differences from HTTP/2 and porting HTTP/2 extensions
added (#127,#242)
B.2. Since draft-ietf-quic-http-00:
o Changed "HTTP/2-over-QUIC" to "HTTP/QUIC" throughout (#11,#29)
o Changed from using HTTP/2 framing within Stream 3 to new framing
format and two-stream-per-request model (#71,#72,#73)
o Adopted SETTINGS format from draft-bishop-httpbis-extended-
settings-01
o Reworked SETTINGS_ACK to account for indeterminate inter-stream
order (#75)
o Described CONNECT pseudo-method (#95)
o Updated ALPN token and Alt-Svc guidance (#13,#87)
o Application-layer-defined error codes (#19,#74)
B.3. Since draft-shade-quic-http2-mapping-00:
o Adopted as base for draft-ietf-quic-http.
o Updated authors/editors list.
Author's Address
Mike Bishop (editor)
Microsoft
Email: Michael.Bishop@microsoft.com
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