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Versions: (draft-shade-quic-http2-mapping) 00 01 02 03 04 05 06 07 08

QUIC                                                      M. Bishop, Ed.
Internet-Draft                                                    Akamai
Intended status: Standards Track                        December 5, 2017
Expires: June 8, 2018


              Hypertext Transfer Protocol (HTTP) over QUIC
                        draft-ietf-quic-http-08

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 [1].

   Working Group information can be found at https://github.com/quicwg
   [2]; source code and issues list for this draft can be found at
   https://github.com/quicwg/base-drafts/labels/-http [3].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on June 8, 2018.







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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
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include 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  . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  QUIC Version Hints  . . . . . . . . . . . . . . . . . . .   4
   3.  Connection Establishment  . . . . . . . . . . . . . . . . . .   5
     3.1.  Draft Version Identification  . . . . . . . . . . . . . .   5
   4.  Stream Mapping and Usage  . . . . . . . . . . . . . . . . . .   6
     4.1.  Control Streams . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  HTTP Message Exchanges  . . . . . . . . . . . . . . . . .   7
       4.2.1.  Header Compression  . . . . . . . . . . . . . . . . .   8
       4.2.2.  The CONNECT Method  . . . . . . . . . . . . . . . . .   8
     4.3.  Request Prioritization  . . . . . . . . . . . . . . . . .   9
     4.4.  Server Push . . . . . . . . . . . . . . . . . . . . . . .  10
   5.  HTTP Framing Layer  . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Frame Layout  . . . . . . . . . . . . . . . . . . . . . .  11
     5.2.  Frame Definitions . . . . . . . . . . . . . . . . . . . .  12
       5.2.1.  DATA  . . . . . . . . . . . . . . . . . . . . . . . .  12
       5.2.2.  HEADERS . . . . . . . . . . . . . . . . . . . . . . .  12
       5.2.3.  PRIORITY  . . . . . . . . . . . . . . . . . . . . . .  12
       5.2.4.  CANCEL_PUSH . . . . . . . . . . . . . . . . . . . . .  14
       5.2.5.  SETTINGS  . . . . . . . . . . . . . . . . . . . . . .  15
       5.2.6.  PUSH_PROMISE  . . . . . . . . . . . . . . . . . . . .  17
       5.2.7.  GOAWAY  . . . . . . . . . . . . . . . . . . . . . . .  18
       5.2.8.  MAX_PUSH_ID . . . . . . . . . . . . . . . . . . . . .  21
   6.  Connection Management . . . . . . . . . . . . . . . . . . . .  22
   7.  Error Handling  . . . . . . . . . . . . . . . . . . . . . . .  22
     7.1.  HTTP/QUIC Error Codes . . . . . . . . . . . . . . . . . .  22
   8.  Considerations for Transitioning from HTTP/2  . . . . . . . .  24
     8.1.  Streams . . . . . . . . . . . . . . . . . . . . . . . . .  24
     8.2.  HTTP Frame Types  . . . . . . . . . . . . . . . . . . . .  24
     8.3.  HTTP/2 SETTINGS Parameters  . . . . . . . . . . . . . . .  26



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     8.4.  HTTP/2 Error Codes  . . . . . . . . . . . . . . . . . . .  27
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  28
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  28
     10.1.  Registration of HTTP/QUIC Identification String  . . . .  28
     10.2.  Registration of QUIC Version Hint Alt-Svc Parameter  . .  28
     10.3.  Frame Types  . . . . . . . . . . . . . . . . . . . . . .  29
     10.4.  Settings Parameters  . . . . . . . . . . . . . . . . . .  30
     10.5.  Error Codes  . . . . . . . . . . . . . . . . . . . . . .  31
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  34
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  34
     11.2.  Informative References . . . . . . . . . . . . . . . . .  35
     11.3.  URIs . . . . . . . . . . . . . . . . . . . . . . . . . .  35
   Appendix A.  Contributors . . . . . . . . . . . . . . . . . . . .  35
   Appendix B.  Change Log . . . . . . . . . . . . . . . . . . . . .  35
     B.1.  Since draft-ietf-quic-http-07 . . . . . . . . . . . . . .  35
     B.2.  Since draft-ietf-quic-http-06 . . . . . . . . . . . . . .  35
     B.3.  Since draft-ietf-quic-http-05 . . . . . . . . . . . . . .  36
     B.4.  Since draft-ietf-quic-http-04 . . . . . . . . . . . . . .  36
     B.5.  Since draft-ietf-quic-http-03 . . . . . . . . . . . . . .  36
     B.6.  Since draft-ietf-quic-http-02 . . . . . . . . . . . . . .  36
     B.7.  Since draft-ietf-quic-http-01 . . . . . . . . . . . . . .  36
     B.8.  Since draft-ietf-quic-http-00 . . . . . . . . . . . . . .  37
     B.9.  Since draft-shade-quic-http2-mapping-00 . . . . . . . . .  37
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  37

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

   Field definitions are given in Augmented Backus-Naur Form (ABNF), as
   defined in [RFC5234].



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   This document uses the variable-length integer encoding from
   [QUIC-TRANSPORT].

   Protocol elements called "frames" exist in both this document and
   [QUIC-TRANSPORT].  Where frames from [QUIC-TRANSPORT] are referenced,
   the frame name will be prefaced with "QUIC."  For example, "QUIC
   APPLICATION_CLOSE frames."  References without this preface refer to
   frames defined in Section 5.2.

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 50781 at the same
   hostname by including the following header in any response:

   Alt-Svc: hq=":50781"

   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.

   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.

   Servers MAY serve HTTP/QUIC on any UDP port.  Servers MUST use the
   same port across all IP addresses that serve a single domain, and
   SHOULD NOT change this port.

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



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   version 0x00000001 and the version rendered in ASCII as "Q034", it
   could specify the following header:

   Alt-Svc: hq=":49288";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 5.2.5) MUST be sent by each
   endpoint as the initial frame of their respective HTTP control stream
   (Stream ID 2 or 3, see Section 4).  The server MUST NOT send data on
   any other stream until the client's SETTINGS frame has been received.

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.



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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 the first client-initiated, bidirectional stream
   (Stream 0) for cryptographic operations.  HTTP over QUIC reserves the
   first unidirectional stream sent by either peer (Streams 2 and 3) for
   sending and receiving HTTP control frames.  This pair of
   unidirectional streams is analogous to HTTP/2's Stream 0.  The data
   sent on these streams is critical to the HTTP connection.  If either
   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 single client-initiated,
   bidirectional stream.  A bidirectional stream ensures that the
   response can be readily correlated with the request.  This means that
   the client's first request occurs on QUIC stream 4, with subsequent
   requests on stream 8, 12, and so on.

   Server push uses server-initiated, unidirectional streams.  Thus, the
   server's first push consumes stream 7 and subsequent pushes use
   stream 11, 15, and so on.

   These streams carry frames related to the request/response (see
   Section 5.2).  When a 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 7.1).  Streams which terminate
   abruptly may be reset at any point in the frame.

   Streams SHOULD be used sequentially, with no gaps.

   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 stream is closed in the appropriate direction.








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4.1.  Control Streams

   Since most connection-level concerns will be managed by QUIC, the
   primary use of Streams 2 and 3 will be for the SETTINGS frame when
   the connection opens and for PRIORITY frames subsequently.

   A pair of unidirectional streams is used rather than a single
   bidirectional stream.  This allows either peer to send data as soon
   they are able.  Depending on whether 0-RTT is enabled on the
   connection, either client or server might be able to send stream data
   first after the cryptographic handshake completes.

4.2.  HTTP Message Exchanges

   A client sends an HTTP request on a client-initiated, bidirectional
   QUIC stream.  A server sends an HTTP response on the same stream as
   the request.

   An HTTP message (request or response) consists of:

   1.  one header block (see Section 5.2.2) containing the message
       headers (see [RFC7230], Section 3.2),

   2.  the payload body (see [RFC7230], Section 3.3), sent as a series
       of DATA frames (see Section 5.2.1),

   3.  optionally, one header block 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 containing
   the message headers of informational (1xx) HTTP responses (see
   [RFC7230], Section 3.2 and [RFC7231], Section 6.2).

   PUSH_PROMISE frames MAY be interleaved with the frames of a response
   message indicating a pushed resource related to the response.  These
   PUSH_PROMISE frames are not part of the response, but carry the
   headers of a separate HTTP request message.  See Section 4.4 for more
   details.

   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
   following the body.  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
   discard any subsequent header blocks.



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   An HTTP request/response exchange fully consumes a QUIC stream.
   After sending a request, a client closes the stream for sending;
   after sending a response, the server closes the stream for sending
   and the QUIC stream is 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 triggering a QUIC STOP_SENDING with error code
   HTTP_EARLY_RESPONSE, sending a complete response, and cleanly closing
   its streams.  Clients MUST NOT discard complete responses as a result
   of having their request terminated abruptly, though clients can
   always discard responses at their discretion for other reasons.
   Servers MUST NOT abort a response in progress as a result of
   receiving a solicited RST_STREAM.

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
   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.
   QUIC anticipates moving to a modified version of HPACK without this
   assumption.  In the meantime, by fixing the size of the dynamic table
   at zero, HPACK can be used in an unordered environment.

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.




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   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.

   All DATA frames on the request stream correspond to data sent on the
   TCP connection.  Any DATA frame sent by the client is transmitted by
   the proxy to the TCP server; data received from the TCP server is
   packaged into DATA frames by the proxy.  Note that the size and
   number of TCP segments is not guaranteed to map predictably to the
   size and number of HTTP DATA or QUIC STREAM frames.

   The TCP connection can be closed by either peer.  When the client
   ends the request stream (that is, the receive stream at the proxy
   enters the "Data Recvd" state), 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 terminate the send stream that it sends to
   client.  TCP connections which remain half-closed in a single
   direction are not invalid, but are often handled poorly by servers,
   so clients SHOULD NOT cause send a STREAM frame with a FIN bit for
   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 7.1).  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.  Request Prioritization

   HTTP/QUIC uses the priority scheme described in [RFC7540],
   Section 5.3.  In this priority scheme, a given request can be
   designated as dependent upon another request, which expresses the
   preference that the latter stream (the "parent" request) be allocated
   resources before the former stream (the "dependent" request).  Taken
   together, the dependencies across all requests 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
   requests.

   HTTP/2 defines its priorities in terms of streams whereas HTTP over
   QUIC identifies requests.  The PRIORITY frame Section 5.2.3
   identifies a request either by identifying the stream that carries a
   request or by using a Push ID (Section 5.2.6).  Other than the means
   of identifying requests, the prioritization system is identical to
   that in HTTP/2.



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   Only a client can send PRIORITY frames.  A server MUST NOT send a
   PRIORITY frame.

4.4.  Server Push

   HTTP/QUIC supports server push as described in [RFC7540].  During
   connection establishment, the client enables server push by sending a
   MAX_PUSH_ID frame (see Section 5.2.8).  A server cannot use server
   push until it receives a MAX_PUSH_ID frame.

   As with server push for HTTP/2, the server initiates a server push by
   sending a PUSH_PROMISE frame that includes request header fields
   attributed to the request.  The PUSH_PROMISE frame is sent on the
   client-initiated, bidirectional stream that carried the request that
   generated the push.  This allows the server push to be associated
   with a request.  Ordering of a PUSH_PROMISE in relation to certain
   parts of the response is important (see Section 8.2.1 of [RFC7540]).

   Unlike HTTP/2, the PUSH_PROMISE does not reference a stream; when a
   server fulfills a promise, the stream that carries the stream headers
   references a Push ID.  This allows a server to fulfill promises in
   the order that best suits its needs.

   The server push response is conveyed on a push stream.  A push stream
   is a server-initiated, unidirectional stream.  A push stream includes
   a header (see Figure 1) that identifies the PUSH_PROMISE that it
   fulfills.  This header consists of a Push ID, encoded as a variable-
   length integer.  The Push ID identifies a server push (see
   Section 5.2.6).

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Push ID (i)                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 1: Push Stream Header

   A push stream always starts with a Push ID.  A client MUST treat
   receiving a push stream that contains a truncated variable-length
   integer as a connection error of type HTTP_MALFORMED_PUSH.

   A server SHOULD use Push IDs sequentially, starting at 0.  A client
   uses the MAX_PUSH_ID frame (Section 5.2.8) to limit the number of
   pushes that a server can promise.  A client MUST treat receipt of a
   push stream with a Push ID that is greater than the maximum Push ID
   as a connection error of type HTTP_MALFORMED_PUSH.




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   Each Push ID MUST only be used once in a push stream header.  If a
   push stream header includes a Push ID that was used in another push
   stream header, the client MUST treat this as a connection error of
   type HTTP_MALFORMED_PUSH.  The same Push ID can be used in multiple
   PUSH_PROMISE frames (see Section 5.2.6).

   After the push stream header, a push contains a response
   (Section 4.2), with response headers, a response body (if any)
   carried by DATA frames, then trailers (if any) carried by HEADERS
   frames.

   If a promised server push is not needed by the client, the client
   SHOULD send a CANCEL_PUSH frame; if the push stream is already open,
   a QUIC STOP_SENDING frame with an appropriate error code can be used
   instead (e.g., HTTP_PUSH_REFUSED, HTTP_PUSH_ALREADY_IN_CACHE; see
   Section 7).  This asks the server not to transfer the data and
   indicates that it will be discarded upon receipt.

5.  HTTP Framing Layer

   Frames are used on each stream.  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 8.2.

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 (i)                        ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Type (8)   |   Flags (8)   |       Frame Payload (*)     ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 2: HTTP/QUIC frame format

   A frame includes the following fields:

   Length:  A variable-length integer that describes the length of the
      Frame Payload.  This length does not include the frame header.

   Type:  An 8-bit type for the frame.

   Flags:  An 8-bit field containing flags.  The Type field determines
      the semantics of flags.




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   Frame Payload:  A payload, the semantics of which are determined by
      the Type field.

5.2.  Frame Definitions

5.2.1.  DATA

   DATA frames (type=0x0) convey arbitrary, variable-length sequences of
   octets associated with an HTTP request or response payload.

   The DATA frame defines no flags.

   DATA frames MUST be associated with an HTTP request or response.  If
   a DATA frame is received on either control stream, the recipient MUST
   respond with a connection error (Section 7) of type
   HTTP_WRONG_STREAM.

   DATA frames MUST contain a non-zero-length payload.  If a DATA frame
   is received with a payload length of zero, the recipient MUST respond
   with a stream error (Section 7) of type HTTP_MALFORMED_DATA.

5.2.2.  HEADERS

   The HEADERS frame (type=0x1) is used to carry a header block,
   compressed using HPACK Section 4.2.1.

   No flags are defined for the HEADERS frame.

   A HEADERS frame with any flags set MUST be treated as a connection
   error of type HTTP_MALFORMED_HEADERS.

5.2.3.  PRIORITY

   The PRIORITY (type=0x02) frame specifies the sender-advised priority
   of a stream and is substantially different in format from [RFC7540].
   In order to ensure that prioritization is processed in a consistent
   order, PRIORITY frames MUST be sent on the control stream.  A
   PRIORITY frame sent on any other stream MUST be treated as a
   HTTP_WRONG_STREAM error.

   The format has been modified to accommodate not being sent on a
   request stream, to allow for identification of server pushes, and the
   larger stream ID space of QUIC.  The semantics of the Stream
   Dependency, Weight, and E flag are otherwise the same as in HTTP/2.

   The flags defined are:





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   PUSH_PRIORITIZED (0x04):  Indicates that the Prioritized Stream is a
      server push rather than a request.

   PUSH_DEPENDENT (0x02):  Indicates a dependency on a server push.

   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 Request ID (i)                    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Stream Dependency ID (i)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Weight (8)  |
      +-+-+-+-+-+-+-+-+

                     Figure 3: PRIORITY frame payload

   The PRIORITY frame payload has the following fields:

   Prioritized Request ID:  A variable-length integer that identifies a
      request.  This contains the Stream ID of a request stream when the
      PUSH_PRIORITIZED flag is clear, or a Push ID when the
      PUSH_PRIORITIZED flag is set.

   Stream Dependency ID:  A variable-length integer that identifies a
      dependent request.  This contains the Stream ID of a request
      stream when the PUSH_DEPENDENT flag is clear, or a Push ID when
      the PUSH_DEPENDENT flag is set.  A request Stream ID of 0
      indicates a dependency on the root stream.  For details of
      dependencies, 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 identifies a request to prioritize, and a request
   upon which that request is dependent.  A Prioritized Request ID or
   Stream Dependency ID identifies a client-initiated request using the
   corresponding stream ID when the corresponding PUSH_PRIORITIZED or
   PUSH_DEPENDENT flag is not set.  Setting the PUSH_PRIORITIZED or
   PUSH_DEPENDENT flag causes the Prioritized Request ID or Stream
   Dependency ID (respectively) to identify a server push using a Push
   ID (see Section 5.2.6 for details).





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   A PRIORITY frame MAY identify a Stream Dependency ID using a Stream
   ID of 0; as in [RFC7540], this makes the request dependent on the
   root of the dependency tree.

   A PRIORITY frame MUST identify a client-initiated, bidirectional
   stream.  A server MUST treat receipt of PRIORITY frame with a Stream
   ID of any other type as a connection error of type
   HTTP_MALFORMED_PRIORITY.

   Stream ID 0 cannot be reprioritized.  A Prioritized Request ID that
   identifies Stream 0 MUST be treated as a connection error of type
   HTTP_MALFORMED_PRIORITY.

   A PRIORITY frame that does not reference a request MUST be treated as
   a HTTP_MALFORMED_PRIORITY error, unless it references Stream ID 0.  A
   PRIORITY that sets a PUSH_PRIORITIZED or PUSH_DEPENDENT flag, but
   then references a non-existent Push ID MUST be treated as a
   HTTP_MALFORMED_PRIORITY error.

   A PRIORITY frame MUST contain only the identified fields.  A PRIORITY
   frame that contains more or fewer fields, or a PRIORITY frame that
   includes a truncated integer encoding MUST be treated as a connection
   error of type HTTP_MALFORMED_PRIORITY.

5.2.4.  CANCEL_PUSH

   The CANCEL_PUSH frame (type=0x3) is used to request cancellation of
   server push prior to the push stream being created.  The CANCEL_PUSH
   frame identifies a server push request by Push ID (see Section 5.2.6)
   using a variable-length integer.

   When a server receives this frame, it aborts sending the response for
   the identified server push.  If the server has not yet started to
   send the server push, it can use the receipt of a CANCEL_PUSH frame
   to avoid opening a stream.  If the push stream has been opened by the
   server, the server SHOULD sent a QUIC RST_STREAM frame on those
   streams and cease transmission of the response.

   A server can send this frame to indicate that it won't be sending a
   response prior to creation of a push stream.  Once the push stream
   has been created, sending CANCEL_PUSH has no effect on the state of
   the push stream.  A QUIC RST_STREAM frame SHOULD be used instead to
   cancel transmission of the server push response.

   A CANCEL_PUSH frame is sent on the control stream.  Sending a
   CANCEL_PUSH frame on a stream other than the control stream MUST be
   treated as a stream error of type HTTP_WRONG_STREAM.




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   The CANCEL_PUSH frame has no defined flags.

   The CANCEL_PUSH frame carries a Push ID encoded as a variable-length
   integer.  The Push ID identifies the server push that is being
   cancelled (see Section 5.2.6).

   If the client receives a CANCEL_PUSH frame, that frame might identify
   a Push ID that has not yet been mentioned by a PUSH_PROMISE frame.

   A server MUST treat a CANCEL_PUSH frame payload does not contain
   exactly one variable-length integer as a connection error of type
   HTTP_MALFORMED_CANCEL_PUSH.

5.2.5.  SETTINGS

   The SETTINGS frame (type=0x4) conveys configuration parameters that
   affect how endpoints communicate, such as preferences and constraints
   on peer behavior, and is 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.)

   Different values for the same parameter can be advertised by each
   peer.  For example, a client might be willing to consume very large
   response headers, while servers are more cautious about request size.

   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.









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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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Identifier (16)       |            Length (i)       ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          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 either 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_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 7) of type HTTP_MALFORMED_SETTINGS.

5.2.5.1.  Integer encoding

   Settings which are integers use the QUIC variable-length integer
   encoding.

5.2.5.2.  Defined SETTINGS Parameters

   The following settings are defined in HTTP/QUIC:

   SETTINGS_HEADER_TABLE_SIZE (0x1):  An integer with a maximum value of
      2^30 - 1.  This value MUST be zero.

   SETTINGS_MAX_HEADER_LIST_SIZE (0x6):  An integer with a maximum value
      of 2^30 - 1



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5.2.5.3.  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
   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.

5.2.6.  PUSH_PROMISE

   The PUSH_PROMISE frame (type=0x05) is used to carry a request header
   set from server to client, as in HTTP/2.  The PUSH_PROMISE frame
   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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Push ID (i)                        ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Header Block (*)                      ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                   Figure 5: PUSH_PROMISE frame payload



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   The payload consists of:

   Push ID:  A variable-length integer that identifies the server push
      request.  A push ID is used in push stream header (Section 4.4),
      CANCEL_PUSH frames (Section 5.2.4), and PRIORITY frames
      (Section 5.2.3).

   Header Block:  HPACK-compressed request headers for the promised
      response.

   A server MUST NOT use a Push ID that is larger than the client has
   provided in a MAX_PUSH_ID frame (Section 5.2.8).  A client MUST treat
   receipt of a PUSH_PROMISE that contains a larger Push ID than the
   client has advertised as a connection error of type
   HTTP_MALFORMED_PUSH_PROMISE.

   A server MAY use the same Push ID in multiple PUSH_PROMISE frames.
   This allows the server to use the same server push in response to
   multiple concurrent requests.  Referencing the same server push
   ensures that a PUSH_PROMISE can be made in relation to every response
   in which server push might be needed without duplicating pushes.

   A server that uses the same Push ID in multiple PUSH_PROMISE frames
   MUST include the same header fields each time.  The octets of the
   header block MAY be different due to differing encoding, but the
   header fields and their values MUST be identical.  Note that ordering
   of header fields is significant.  A client MUST treat receipt of a
   PUSH_PROMISE with conflicting header field values for the same Push
   ID as a connection error of type HTTP_MALFORMED_PUSH_PROMISE.

   Allowing duplicate references to the same Push ID is primarily to
   reduce duplication caused by concurrent requests.  A server SHOULD
   avoid reusing a Push ID over a long period.  Clients are likely to
   consume server push responses and not retain them for reuse over
   time.  Clients that see a PUSH_PROMISE that uses a Push ID that they
   have since consumed and discarded are forced to ignore the
   PUSH_PROMISE.

5.2.7.  GOAWAY

   The GOAWAY frame (type=0x7) is used to initiate graceful shutdown of
   a connection by a server.  GOAWAY allows a server to stop accepting
   new requests while still finishing processing of previously received
   requests.  This enables administrative actions, like server
   maintenance.  GOAWAY by itself does not close a connection.






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   The GOAWAY frame does not define any flags, and the payload is a QUIC
   Stream ID for a client-initiated, bidirectional stream encoded as a
   variable-length integer.

   Clients do not need to send GOAWAY to initiate a graceful shutdown;
   they simply stop making new requests.  A server MUST treat receipt of
   a GOAWAY frame as a connection error (Section 7) of type
   HTTP_UNEXPECTED_GOAWAY.

   A client MUST treat receipt of a GOAWAY frame containing a Stream ID
   of any other type as a connection error of type
   HTTP_MALFORMED_GOAWAY.

   The GOAWAY frame applies to the connection, not a specific stream.
   An endpoint MUST treat a GOAWAY frame on a stream other than the
   control stream as a connection error (Section 7) of type
   HTTP_WRONG_STREAM.

   New client requests might already have been sent before the client
   receives the server's GOAWAY frame.  The GOAWAY frame contains the
   Stream ID of the last client-initiated request that was or might be
   processed in this connection, which enables client and server to
   agree on which requests were accepted prior to the connection
   shutdown.  This identifier MAY be lower than the stream limit
   identified by a QUIC MAX_STREAM_ID frame, and MAY be zero if no
   requests were processed.  Servers SHOULD NOT increase the
   MAX_STREAM_ID limit after sending a GOAWAY frame.

   Note:  In this context, "processed" means that some data from the
      stream was passed to some higher layer of software that might have
      taken some action as a result.

   Once sent, the server will refuse requests sent on streams with an
   identifier higher than the included last Stream ID.  Clients MUST NOT
   send new requests on the connection after receiving GOAWAY, although
   requests might already be in transit.  A new connection can be
   established for new requests.

   If the client has sent requests on streams with a higher Stream ID
   than indicated in the GOAWAY frame, those requests were not and will
   not be processed.  Endpoints SHOULD reset any streams above this ID
   with the error code HTTP_REQUEST_CANCELLED.  Servers MAY also reset
   streams below the indicated ID with HTTP_REQUEST_CANCELLED if the
   associated requests were not processed.  Servers MUST NOT use the
   HTTP_REQUEST_CANCELLED status for requests which were partially or
   fully processed.





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   The client can treat requests cancelled by the server as though they
   had never been sent at all, thereby allowing them to be retried later
   on a new connection.  If a stream is cancelled after receiving a
   complete response, the client MAY ignore the cancellation and use the
   response.  However, if a stream is cancelled after receiving a
   partial response, the response SHOULD NOT be used.  Automatically
   retrying such requests is not possible, unless this is otherwise
   permitted (e.g., idempotent actions like GET, PUT, or DELETE).
   Requests on Stream IDs less than or equal to the Stream ID in the
   GOAWAY frame might have been processed; their status cannot be known
   until they are completed successfully, reset individually, or the
   connection terminates.

   Servers SHOULD send a GOAWAY frame when the closing of a connection
   is known in advance, even if the advance notice is small, so that the
   remote peer can know whether a stream has been partially processed or
   not.  For example, if an HTTP client sends a POST at the same time
   that a server closes a QUIC connection, the client cannot know if the
   server started to process that POST request if the server does not
   send a GOAWAY frame to indicate what streams it might have acted on.

   For unexpected closures caused by error conditions, a QUIC
   CONNECTION_CLOSE or APPLICATION_CLOSE frame MUST be used.  However, a
   GOAWAY MAY be sent first to provide additional detail to clients and
   to allow the client to retry requests.  Including the GOAWAY frame in
   the same packet as the QUIC CONNECTION_CLOSE or APPLICATION_CLOSE
   frame improves the chances of the frame being received by clients.

   If a connection terminates without a GOAWAY frame, the last Stream ID
   is effectively the highest possible Stream ID (as determined by
   QUIC's MAX_STREAM_ID).

   An endpoint MAY send multiple GOAWAY frames if circumstances change.
   For instance, an endpoint that sends GOAWAY without an error code
   during graceful shutdown could subsequently encounter an error
   condition.  The last stream identifier from the last GOAWAY frame
   received indicates which streams could have been acted upon.  A
   server MUST NOT increase the value they send in the last Stream ID,
   since clients might already have retried unprocessed requests on
   another connection.

   A client that is unable to retry requests loses all requests that are
   in flight when the server closes the connection.  A server that is
   attempting to gracefully shut down a connection SHOULD send an
   initial GOAWAY frame with the last Stream ID set to the current value
   of QUIC's MAX_STREAM_ID and SHOULD NOT increase the MAX_STREAM_ID
   thereafter.  This signals to the client that a shutdown is imminent
   and that initiating further requests is prohibited.  After allowing



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   time for any in-flight requests (at least one round-trip time), the
   server MAY send another GOAWAY frame with an updated last Stream ID.
   This ensures that a connection can be cleanly shut down without
   losing requests.

   Once all requests on streams at or below the identified stream number
   have been completed or cancelled, and all promised server push
   responses associated with those requests have been completed or
   cancelled, the connection can be closed using an Immediate Close (see
   [QUIC-TRANSPORT]).  An endpoint that completes a graceful shutdown
   SHOULD use the QUIC APPLICATION_CLOSE frame with the HTTP_NO_ERROR
   code.

5.2.8.  MAX_PUSH_ID

   The MAX_PUSH_ID frame (type=0xD) is used by clients to control the
   number of server pushes that the server can initiate.  This sets the
   maximum value for a Push ID that the server can use in a PUSH_PROMISE
   frame.  Consequently, this also limits the number of push streams
   that the server can initiate in addition to the limit set by the QUIC
   MAX_STREAM_ID frame.

   The MAX_PUSH_ID frame is always sent on a control stream.  Receipt of
   a MAX_PUSH_ID frame on any other stream MUST be treated as a
   connection error of type HTTP_WRONG_STREAM.

   A server MUST NOT send a MAX_PUSH_ID frame.  A client MUST treat the
   receipt of a MAX_PUSH_ID frame as a connection error of type
   HTTP_MALFORMED_MAX_PUSH_ID.

   The maximum Push ID is unset when a connection is created, meaning
   that a server cannot push until it receives a MAX_PUSH_ID frame.  A
   client that wishes to manage the number of promised server pushes can
   increase the maximum Push ID by sending a MAX_PUSH_ID frame as the
   server fulfills or cancels server pushes.

   The MAX_PUSH_ID frame has no defined flags.

   The MAX_PUSH_ID frame carries a single variable-length integer that
   identifies the maximum value for a Push ID that the server can use
   (see Section 5.2.6).  A MAX_PUSH_ID frame cannot reduce the maximum
   Push ID; receipt of a MAX_PUSH_ID that contains a smaller value than
   previously received MUST be treated as a connection error of type
   HTTP_MALFORMED_MAX_PUSH_ID.

   A server MUST treat a MAX_PUSH_ID frame payload that does not contain
   a single variable-length integer as a connection error of type
   HTTP_MALFORMED_MAX_PUSH_ID.



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6.  Connection Management

   QUIC connections are persistent.  All of the considerations in
   Section 9.1 of [RFC7540] apply to the management of QUIC connections.

   HTTP clients are expected to use QUIC PING frames to keep connections
   open.  Servers SHOULD NOT use PING frames to keep a connection open.
   A client SHOULD NOT use PING frames for this purpose unless there are
   responses outstanding for requests or server pushes.  If the client
   is not expecting a response from the server, allowing an idle
   connection to time out (based on the idle_timeout transport
   parameter) is preferred over expending effort maintaining a
   connection that might not be needed.  A gateway MAY use PING to
   maintain connections in anticipation of need rather than incur the
   latency cost of connection establishment to servers.

7.  Error Handling

   QUIC allows the application to abruptly terminate (reset) 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].

   This section describes HTTP-specific error codes which can be used to
   express the cause of a connection or stream error.

7.1.  HTTP/QUIC Error Codes

   The following error codes are defined for use in QUIC RST_STREAM,
   STOP_SENDING, and CONNECTION_CLOSE frames when using HTTP/QUIC.

   STOPPING (0x00):  This value is reserved by the transport to be used
      in response to QUIC STOP_SENDING frames.

   HTTP_NO_ERROR (0x01):  No error.  This is used when the connection or
      stream needs to be closed, but there is no error to signal.

   HTTP_PUSH_REFUSED (0x02):  The server has attempted to push content
      which the client will not accept on this connection.

   HTTP_INTERNAL_ERROR (0x03):  An internal error has occurred in the
      HTTP stack.

   HTTP_PUSH_ALREADY_IN_CACHE (0x04):  The server has attempted to push
      content which the client has cached.

   HTTP_REQUEST_CANCELLED (0x05):  The client no longer needs the
      requested data.



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   HTTP_HPACK_DECOMPRESSION_FAILED (0x06):  HPACK failed to decompress a
      frame and cannot continue.

   HTTP_CONNECT_ERROR (0x07):  The connection established in response to
      a CONNECT request was reset or abnormally closed.

   HTTP_EXCESSIVE_LOAD (0x08):  The endpoint detected that its peer is
      exhibiting a behavior that might be generating excessive load.

   HTTP_VERSION_FALLBACK (0x09):  The requested operation cannot be
      served over HTTP/QUIC.  The peer should retry over HTTP/2.

   HTTP_MALFORMED_HEADERS (0x0A):  A HEADERS frame has been received
      with an invalid format.

   HTTP_MALFORMED_PRIORITY (0x0B):  A PRIORITY frame has been received
      with an invalid format.

   HTTP_MALFORMED_SETTINGS (0x0C):  A SETTINGS frame has been received
      with an invalid format.

   HTTP_MALFORMED_PUSH_PROMISE (0x0D):  A PUSH_PROMISE frame has been
      received with an invalid format.

   HTTP_MALFORMED_DATA (0x0E):  A DATA frame has been received with an
      invalid format.

   HTTP_INTERRUPTED_HEADERS (0x0F):  A HEADERS frame without the End
      Header Block flag was followed by a frame other than HEADERS.

   HTTP_WRONG_STREAM (0x10):  A frame was received on stream where it is
      not permitted.

   HTTP_MULTIPLE_SETTINGS (0x11):  More than one SETTINGS frame was
      received.

   HTTP_MALFORMED_PUSH (0x12):  A push stream header was malformed or
      included an invalid Push ID.

   HTTP_MALFORMED_MAX_PUSH_ID (0x13):  A MAX_PUSH_ID frame has been
      received with an invalid format.

   HTTP_UNEXPECTED_GOAWAY (0x14):  A GOAWAY frame has been received by a
      server.

   HTTP_MALFORMED_GOAWAY (0x15):  A GOAWAY frame was malformed or
      contained an invalid Stream ID.




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8.  Considerations for Transitioning from HTTP/2

   HTTP/QUIC is strongly informed by HTTP/2, and bears many
   similarities.  This section describes the approach taken to design
   HTTP/QUIC, points out important differences from HTTP/2, and
   describes how to map HTTP/2 extensions into HTTP/QUIC.

   HTTP/QUIC begins from the premise that HTTP/2 code reuse is a useful
   feature, but not a hard requirement.  HTTP/QUIC departs from HTTP/2
   primarily where necessary to accommodate the differences in behavior
   between QUIC and TCP (lack of ordering, support for streams).  We
   intend to avoid gratuitous changes which make it difficult or
   impossible to build extensions with the same semantics applicable to
   both protocols at once.

   These departures are noted in this section.

8.1.  Streams

   HTTP/QUIC permits use of a larger number of streams (2^62-1) then
   HTTP/2.  The considerations about exhaustion of stream identifier
   space apply, though the space is significantly larger such that it is
   likely that other limits in QUIC are reached first, such as the limit
   on the connection flow control window.

8.2.  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




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   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 control stream and the PRIORITY
   section is removed from the HEADERS frame.

   Frame type definitions in HTTP/QUIC often use the QUIC variable-
   length integer encoding.  In particular, Stream IDs use this
   encoding, which allow for a larger range of possible values than the
   encoding used in HTTP/2.  Redefinition of the encoding of extension
   frame types might be necessary if the encoding includes a Stream ID.

   Other than this issue, frame type HTTP/2 extensions are typically
   portable to QUIC simply by replacing Stream 0 in HTTP/2 with Stream 2
   or 3 in HTTP/QUIC.  HTTP/QUIC extensions will not assume ordering,
   but would not be harmed by ordering, and would be portable to HTTP/2
   in the same manner.

   Below is a listing of how each HTTP/2 frame type is mapped:

   DATA (0x0):  Padding is not defined in HTTP/QUIC frames.  See
      Section 5.2.1.

   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 5.2.2.

   PRIORITY (0x2):  As described above, the PRIORITY frame is sent on
      the control stream.  See Section 5.2.3.

   RST_STREAM (0x3):  RST_STREAM frames do not exist, since QUIC
      provides stream lifecycle management.  The same code point is used
      for the CANCEL_PUSH frame (Section 5.2.4).

   SETTINGS (0x4):  SETTINGS frames are sent only at the beginning of
      the connection.  See Section 5.2.5 and Section 8.3.

   PUSH_PROMISE (0x5):  The PUSH_PROMISE does not reference a stream;
      instead the push stream references the PUSH_PROMISE frame using a
      Push ID.  See Section 5.2.6.



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   PING (0x6):  PING frames do not exist, since QUIC provides equivalent
      functionality.

   GOAWAY (0x7):  GOAWAY is sent only from server to client and does not
      contain an error code.  See Section 5.2.7.

   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.

   Frame types defined by extensions to HTTP/2 need to be separately
   registered for HTTP/QUIC if still applicable.  The IDs of frames
   defined in [RFC7540] have been reserved for simplicity.  See
   Section 10.3.

8.3.  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.

   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 5.2.5.2.

   SETTINGS_ENABLE_PUSH:  This is removed in favor of the MAX_PUSH_ID
      which provides a more granular control over server push.

   SETTINGS_MAX_CONCURRENT_STREAMS:  QUIC controls the largest open
      Stream ID as part of its flow control logic.  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.




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   SETTINGS_MAX_HEADER_LIST_SIZE:  See Section 5.2.5.2.

   Settings need to be defined separately for HTTP/2 and HTTP/QUIC.  The
   IDs of settings defined in [RFC7540] have been reserved for
   simplicity.  See Section 10.4.

8.4.  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 the
   HTTP over QUIC error codes as follows:

   NO_ERROR (0x0):  HTTP_NO_ERROR in Section 7.1.

   PROTOCOL_ERROR (0x1):  No single mapping.  See new HTTP_MALFORMED_*
      error codes defined in Section 7.1.

   INTERNAL_ERROR (0x2):  HTTP_INTERNAL_ERROR in Section 7.1.

   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 7.1.

   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 7.1.

   COMPRESSION_ERROR (0x9):  HTTP_HPACK_DECOMPRESSION_FAILED in
      Section 7.1.

   CONNECT_ERROR (0xa):  HTTP_CONNECT_ERROR in Section 7.1.




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   ENHANCE_YOUR_CALM (0xb):  HTTP_EXCESSIVE_LOAD in Section 7.1.

   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 7.1.

   Error codes need to be defined for HTTP/2 and HTTP/QUIC separately.
   See Section 10.5.

9.  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.

10.  IANA Considerations

10.1.  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

10.2.  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






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10.3.  Frame Types

   This document establishes a registry for HTTP/QUIC frame type codes.
   The "HTTP/QUIC Frame Type" registry manages an 8-bit space.  The
   "HTTP/QUIC Frame Type" registry operates under either of the "IETF
   Review" or "IESG Approval" policies [RFC8126] for values between 0x00
   and 0xef, with values between 0xf0 and 0xff being reserved for
   Experimental Use.

   While this registry is separate from the "HTTP/2 Frame Type" registry
   defined in [RFC7540], it is preferable that the assignments parallel
   each other.  If an entry is present in only one registry, every
   effort SHOULD be made to avoid assigning the corresponding value to
   an unrelated operation.

   New entries in this registry require the following information:

   Frame Type:  A name or label for the frame type.

   Code:  The 8-bit code assigned to the frame type.

   Specification:  A reference to a specification that includes a
      description of the frame layout, its semantics, and flags that the
      frame type uses, including any parts of the frame that are
      conditionally present based on the value of flags.

   The entries in the following table are registered by this document.
























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                  +--------------+------+---------------+
                  | Frame Type   | Code | Specification |
                  +--------------+------+---------------+
                  | DATA         | 0x0  | Section 5.2.1 |
                  |              |      |               |
                  | HEADERS      | 0x1  | Section 5.2.2 |
                  |              |      |               |
                  | PRIORITY     | 0x2  | Section 5.2.3 |
                  |              |      |               |
                  | CANCEL_PUSH  | 0x3  | Section 5.2.4 |
                  |              |      |               |
                  | SETTINGS     | 0x4  | Section 5.2.5 |
                  |              |      |               |
                  | PUSH_PROMISE | 0x5  | Section 5.2.6 |
                  |              |      |               |
                  | Reserved     | 0x6  | N/A           |
                  |              |      |               |
                  | GOAWAY       | 0x7  | Section 5.2.7 |
                  |              |      |               |
                  | Reserved     | 0x8  | N/A           |
                  |              |      |               |
                  | Reserved     | 0x9  | N/A           |
                  |              |      |               |
                  | MAX_PUSH_ID  | 0xD  | Section 5.2.8 |
                  +--------------+------+---------------+

10.4.  Settings Parameters

   This document establishes a registry for HTTP/QUIC settings.  The
   "HTTP/QUIC Settings" registry manages a 16-bit space.  The "HTTP/QUIC
   Settings" registry operates under the "Expert Review" policy
   [RFC8126] for values in the range from 0x0000 to 0xefff, with values
   between and 0xf000 and 0xffff being reserved for Experimental Use.
   The designated experts are the same as those for the "HTTP/2
   Settings" registry defined in [RFC7540].

   While this registry is separate from the "HTTP/2 Settings" registry
   defined in [RFC7540], it is preferable that the assignments parallel
   each other.  If an entry is present in only one registry, every
   effort SHOULD be made to avoid assigning the corresponding value to
   an unrelated operation.

   New registrations are advised to provide the following information:

   Name:  A symbolic name for the setting.  Specifying a setting name is
      optional.

   Code:  The 16-bit code assigned to the setting.



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   Specification:  An optional reference to a specification that
      describes the use of the setting.

   The entries in the following table are registered by this document.

             +----------------------+------+-----------------+
             | Setting Name         | Code | Specification   |
             +----------------------+------+-----------------+
             | HEADER_TABLE_SIZE    | 0x1  | Section 5.2.5.2 |
             |                      |      |                 |
             | Reserved             | 0x2  | N/A             |
             |                      |      |                 |
             | Reserved             | 0x3  | N/A             |
             |                      |      |                 |
             | Reserved             | 0x4  | N/A             |
             |                      |      |                 |
             | Reserved             | 0x5  | N/A             |
             |                      |      |                 |
             | MAX_HEADER_LIST_SIZE | 0x6  | Section 5.2.5.2 |
             +----------------------+------+-----------------+

10.5.  Error Codes

   This document establishes a registry for HTTP/QUIC error codes.  The
   "HTTP/QUIC Error Code" registry manages a 16-bit space.  The "HTTP/
   QUIC Error Code" registry operates under the "Expert Review" policy
   [RFC8126].

   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 16-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   |             |                 |
   +-----------------------------+-----+-------------+-----------------+
   | STOPPING                    | 0x0 | Reserved by | [QUIC-TRANSPORT |
   |                             | 0   | QUIC        | ]               |
   |                             |     |             |                 |
   | HTTP_NO_ERROR               | 0x0 | No error    | Section 7.1     |
   |                             | 1   |             |                 |
   |                             |     |             |                 |
   | HTTP_PUSH_REFUSED           | 0x0 | Client      | Section 7.1     |
   |                             | 2   | refused     |                 |
   |                             |     | pushed      |                 |
   |                             |     | content     |                 |
   |                             |     |             |                 |
   | HTTP_INTERNAL_ERROR         | 0x0 | Internal    | Section 7.1     |
   |                             | 3   | error       |                 |
   |                             |     |             |                 |
   | HTTP_PUSH_ALREADY_IN_CACHE  | 0x0 | Pushed      | Section 7.1     |
   |                             | 4   | content     |                 |
   |                             |     | already     |                 |
   |                             |     | cached      |                 |
   |                             |     |             |                 |
   | HTTP_REQUEST_CANCELLED      | 0x0 | Data no     | Section 7.1     |
   |                             | 5   | longer      |                 |
   |                             |     | needed      |                 |
   |                             |     |             |                 |
   | HTTP_HPACK_DECOMPRESSION_FA | 0x0 | HPACK       | Section 7.1     |
   | ILED                        | 6   | cannot      |                 |
   |                             |     | continue    |                 |
   |                             |     |             |                 |
   | HTTP_CONNECT_ERROR          | 0x0 | TCP reset   | Section 7.1     |
   |                             | 7   | or error on |                 |
   |                             |     | CONNECT     |                 |
   |                             |     | request     |                 |
   |                             |     |             |                 |
   | HTTP_EXCESSIVE_LOAD         | 0x0 | Peer        | Section 7.1     |
   |                             | 8   | generating  |                 |
   |                             |     | excessive   |                 |
   |                             |     | load        |                 |
   |                             |     |             |                 |
   | HTTP_VERSION_FALLBACK       | 0x0 | Retry over  | Section 7.1     |
   |                             | 9   | HTTP/2      |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_HEADERS      | 0x0 | Invalid     | Section 7.1     |
   |                             | A   | HEADERS     |                 |
   |                             |     | frame       |                 |
   |                             |     |             |                 |



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   | HTTP_MALFORMED_PRIORITY     | 0x0 | Invalid     | Section 7.1     |
   |                             | B   | PRIORITY    |                 |
   |                             |     | frame       |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_SETTINGS     | 0x0 | Invalid     | Section 7.1     |
   |                             | C   | SETTINGS    |                 |
   |                             |     | frame       |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_PUSH_PROMISE | 0x0 | Invalid PUS | Section 7.1     |
   |                             | D   | H_PROMISE   |                 |
   |                             |     | frame       |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_DATA         | 0x0 | Invalid     | Section 7.1     |
   |                             | E   | DATA frame  |                 |
   |                             |     |             |                 |
   | HTTP_INTERRUPTED_HEADERS    | 0x0 | Incomplete  | Section 7.1     |
   |                             | F   | HEADERS     |                 |
   |                             |     | block       |                 |
   |                             |     |             |                 |
   | HTTP_WRONG_STREAM           | 0x1 | A frame was | Section 7.1     |
   |                             | 0   | sent on the |                 |
   |                             |     | wrong       |                 |
   |                             |     | stream      |                 |
   |                             |     |             |                 |
   | HTTP_MULTIPLE_SETTINGS      | 0x1 | Multiple    | Section 7.1     |
   |                             | 1   | SETTINGS    |                 |
   |                             |     | frames      |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_PUSH         | 0x1 | Invalid     | Section 7.1     |
   |                             | 2   | push stream |                 |
   |                             |     | header      |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_MAX_PUSH_ID  | 0x1 | Invalid     | Section 7.1     |
   |                             | 3   | MAX_PUSH_ID |                 |
   |                             |     | frame       |                 |
   |                             |     |             |                 |
   | HTTP_UNEXPECTED_GOAWAY      | 0x1 | A server    | Section 7.1     |
   |                             | 4   | received    |                 |
   |                             |     | GOAWAY      |                 |
   |                             |     |             |                 |
   | HTTP_MALFORMED_GOAWAY       | 0x1 | Invalid     | Section 7.1     |
   |                             | 5   | GOAWAY      |                 |
   |                             |     | frame       |                 |
   +-----------------------------+-----+-------------+-----------------+







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11.  References

11.1.  Normative References

   [QUIC-TRANSPORT]
              Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", draft-ietf-quic-
              transport-00 (work in progress), December 2017.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <https://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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [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,
              <https://www.rfc-editor.org/info/rfc7230>.

   [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,
              <https://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,
              <https://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,
              <https://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, <https://www.rfc-editor.org/info/rfc7838>.






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   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

11.2.  Informative References

   [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, <https://www.rfc-editor.org/info/rfc7301>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

11.3.  URIs

   [1] https://mailarchive.ietf.org/arch/search/?email_list=quic

   [2] https://github.com/quicwg

   [3] https://github.com/quicwg/base-drafts/labels/-http

Appendix A.  Contributors

   The original authors of this specification were Robbie Shade and Mike
   Warres.

   A substantial portion of Mike's contribution was supported by
   Microsoft during his employment there.

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-07

   o  Changes for integer encodings in QUIC (#595,#905)

B.2.  Since draft-ietf-quic-http-06

   o  Track changes in QUIC error code usage (#485)







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B.3.  Since draft-ietf-quic-http-05

   o  Made push ID sequential, add MAX_PUSH_ID, remove
      SETTINGS_ENABLE_PUSH (#709)

   o  Guidance about keep-alive and QUIC PINGs (#729)

   o  Expanded text on GOAWAY and cancellation (#757)

B.4.  Since draft-ietf-quic-http-04

   o  Cite RFC 5234 (#404)

   o  Return to a single stream per request (#245,#557)

   o  Use separate frame type and settings registries from HTTP/2 (#81)

   o  SETTINGS_ENABLE_PUSH instead of SETTINGS_DISABLE_PUSH (#477)

   o  Restored GOAWAY (#696)

   o  Identify server push using Push ID rather than a stream ID
      (#702,#281)

   o  DATA frames cannot be empty (#700)

B.5.  Since draft-ietf-quic-http-03

   None.

B.6.  Since draft-ietf-quic-http-02

   o  Track changes in transport draft

B.7.  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

      *  Settings can only occur in the SETTINGS frame a single time

      *  Boolean format updated





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   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.8.  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.9.  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)
   Akamai

   Email: mbishop@evequefou.be







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