Header Compression for HTTP/QUIC
draft-bishop-quic-http-and-qpack-07

Document Type Active Internet-Draft (individual)
Last updated 2017-12-15
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
QUIC Working Group                                             M. Bishop
Internet-Draft                                                    Akamai
Intended status: Standards Track                       December 14, 2017
Expires: June 17, 2018

                    Header Compression for HTTP/QUIC
                  draft-bishop-quic-http-and-qpack-07

Abstract

   HTTP/2 [RFC7540] uses HPACK [RFC7541] for header compression.
   However, HPACK relies on the in-order message-based semantics of the
   HTTP/2 framing layer in order to function.  Messages can only be
   successfully decoded if processed by the decoder in the same order as
   generated by the encoder.  This draft refines HPACK to loosen the
   ordering requirements for use over QUIC [I-D.ietf-quic-transport].

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 17, 2018.

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

Bishop                    Expires June 17, 2018                 [Page 1]
Internet-Draft                    QPACK                    December 2017

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  QPACK - Concepts  . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Changes to Static and Dynamic Tables  . . . . . . . . . .   4
       2.1.1.  Dynamic Table State Synchronization . . . . . . . . .   4
     2.2.  Encoding Constraints  . . . . . . . . . . . . . . . . . .   6
       2.2.1.  Permitted References  . . . . . . . . . . . . . . . .   6
       2.2.2.  Header Table Size . . . . . . . . . . . . . . . . . .   6
   3.  Wire Format . . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.1.  Feedback Stream . . . . . . . . . . . . . . . . . . . . .   8
       3.1.1.  HEADERS_DONE  . . . . . . . . . . . . . . . . . . . .   8
       3.1.2.  ACK_FLUSH . . . . . . . . . . . . . . . . . . . . . .   8
       3.1.3.  DROP  . . . . . . . . . . . . . . . . . . . . . . . .   9
       3.1.4.  ACK_DROP  . . . . . . . . . . . . . . . . . . . . . .   9
     3.2.  Checkpoint Streams  . . . . . . . . . . . . . . . . . . .  10
       3.2.1.  INSERT  . . . . . . . . . . . . . . . . . . . . . . .  10
       3.2.2.  TOUCH . . . . . . . . . . . . . . . . . . . . . . . .  12
     3.3.  Request Streams . . . . . . . . . . . . . . . . . . . . .  12
       3.3.1.  Indexed Header Field Representation . . . . . . . . .  13
       3.3.2.  Literal Header Field Representation . . . . . . . . .  13
   4.  Use in HTTP/QUIC  . . . . . . . . . . . . . . . . . . . . . .  14
     4.1.  SETTING_QPACK_BLOCKING_PERMITTED  . . . . . . . . . . . .  15
     4.2.  SETTING_QPACK_INITIAL_CHECKPOINT  . . . . . . . . . . . .  15
   5.  Implementation trade-offs . . . . . . . . . . . . . . . . . .  15
     5.1.  Compression Efficiency versus Blocking Avoidance  . . . .  16
     5.2.  Timely State Transitions versus Decoder Complexity  . . .  16
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
     7.1.  Settings  . . . . . . . . . . . . . . . . . . . . . . . .  17
     7.2.  Errors  . . . . . . . . . . . . . . . . . . . . . . . . .  18
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  18
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  18
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  19
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  19

1.  Introduction

   HPACK has a number of features that were intended to provide
Show full document text