Header Compression for HTTP over QUIC
draft-ietf-quic-qcram-00

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QUIC                                                           C. Krasic
Internet-Draft                                               Google, Inc
Intended status: Standards Track                               M. Bishop
Expires: August 24, 2018                             Akamai Technologies
                                                        A. Frindell, Ed.
                                                                Facebook
                                                       February 20, 2018

                 Header Compression for HTTP over QUIC
                        draft-ietf-quic-qcram-00

Abstract

   The design of the core QUIC transport subsumes many HTTP/2 features,
   prominent among them stream multiplexing.  A key advantage of the
   QUIC transport is stream multiplexing free of head-of-line (HoL)
   blocking between streams.  In HTTP/2, multiplexed streams can suffer
   HoL blocking due to TCP.

   If HTTP/2's HPACK is used for header compression, HTTP/QUIC is still
   vulnerable to HoL blocking, because of HPACK's assumption of in-order
   delivery.  This draft defines QCRAM, a variation of HPACK and
   mechanisms in the HTTP/QUIC mapping that allow the flexibility to
   avoid header-compression-induced HoL blocking.

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
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   This Internet-Draft will expire on August 24, 2018.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Krasic, et al.           Expires August 24, 2018                [Page 1]
Internet-Draft                    QCRAM                    February 2018

   This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Head-of-Line Blocking in HPACK  . . . . . . . . . . . . .   3
     1.2.  Avoiding Head-of-Line Blocking in HTTP/QUIC . . . . . . .   3
   2.  HTTP over QUIC mapping extensions . . . . . . . . . . . . . .   4
     2.1.  HEADERS and PUSH_PROMISE  . . . . . . . . . . . . . . . .   4
     2.2.  HEADER_ACK  . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  HPACK extensions  . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Allowed Instructions  . . . . . . . . . . . . . . . . . .   5
     3.2.  Header Block Prefix . . . . . . . . . . . . . . . . . . .   5
     3.3.  Hybrid absolute-relative indexing . . . . . . . . . . . .   6
     3.4.  Preventing Eviction Races . . . . . . . . . . . . . . . .   7
       3.4.1.  Blocked Evictions . . . . . . . . . . . . . . . . . .   7
     3.5.  Refreshing Entries with Duplication . . . . . . . . . . .   8
   4.  Performance considerations  . . . . . . . . . . . . . . . . .   8
     4.1.  Speculative table updates . . . . . . . . . . . . . . . .   8
     4.2.  Additional state beyond HPACK.  . . . . . . . . . . . . .   8
       4.2.1.  Vulnerable Entries  . . . . . . . . . . . . . . . . .   8
       4.2.2.  Safe evictions  . . . . . . . . . . . . . . . . . . .   9
       4.2.3.  Decoder Blocking  . . . . . . . . . . . . . . . . . .   9
       4.2.4.  Fixed overhead. . . . . . . . . . . . . . . . . . . .   9
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  10
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   The QUIC transport protocol was designed from the outset to support
   HTTP semantics, and its design subsumes many of the features of
   HTTP/2.  QUIC's stream multiplexing comes into some conflict with