Header Compression for HTTP over QUIC
draft-krasic-quic-qcram-01

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QUIC                                                           C. Krasic
Internet-Draft                                                    Google
Intended status: Standards Track                           July 17, 2017
Expires: January 18, 2018

                 Header Compression for HTTP over QUIC
                       draft-krasic-quic-qcram-01

Abstract

   The design of the core QUIC transport and the mapping of HTTP
   semantics over it subsume many HTTP/2 features, prominent among them
   stream multiplexing and HTTP header compression.  A key advantage of
   the QUIC transport is that provides stream multiplexing free of HoL
   blocking between streams, while in HTTP/2 multiplexed streams can
   suffer HoL blocking primarily due to HTTP/2's layering above TCP.
   However, assuming HPACK is used for header compression, HTTP over
   QUIC is still vulnerable to HoL blocking, because of how HPACK
   exploits header redundancies between multiplexed HTTP transactions.
   This draft defines QCRAM, a variation of HPACK and mechanisms in the
   QUIC HTTP mapping that allow QUIC implementations the flexibility to
   avoid header-compression induced HoL blocking.

Status of This Memo

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   This Internet-Draft will expire on January 18, 2018.

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   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

Krasic                  Expires January 18, 2018                [Page 1]
Internet-Draft                    QCRAM                        July 2017

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  QCRAM overview  . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Example of HoL blocking . . . . . . . . . . . . . . . . .   3
     2.2.  How QCRAM avoids HoL blocking . . . . . . . . . . . . . .   4
       2.2.1.  Splitting writes from reads . . . . . . . . . . . . .   4
       2.2.2.  HPACK Fallback  . . . . . . . . . . . . . . . . . . .   5
       2.2.3.  Header Blocks, Fragments, Frames, Packets...  . . . .   5
   3.  HPACK extensions  . . . . . . . . . . . . . . . . . . . . . .   6
     3.1.  HPACK fallback  . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  QCRAM . . . . . . . . . . . . . . . . . . . . . . . . . .   6
       3.2.1.  Indexing  . . . . . . . . . . . . . . . . . . . . . .   7
       3.2.2.  HoL blocking logic  . . . . . . . . . . . . . . . . .   7
       3.2.3.  Table evictions . . . . . . . . . . . . . . . . . . .   8
       3.2.4.  Manditory De-duplication for equivilant entries . . .   8
   4.  HTTP Mapping changes  . . . . . . . . . . . . . . . . . . . .   8
     4.1.  Encode epoch  . . . . . . . . . . . . . . . . . . . . . .   9
     4.2.  Commit epoch  . . . . . . . . . . . . . . . . . . . . . .   9
     4.3.  Packet epoch  . . . . . . . . . . . . . . . . . . . . . .   9
   5.  Performance considerations  . . . . . . . . . . . . . . . . .   9
     5.1.  Memory footprint  . . . . . . . . . . . . . . . . . . . .  10
     5.2.  Table evictions . . . . . . . . . . . . . . . . . . . . .  10
     5.3.  Speculative table updates . . . . . . . . . . . . . . . .  10
     5.4.  Eliminating sequence numbers  . . . . . . . . . . . . . .  10
     5.5.  Fixed overhead. . . . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  11
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   The QUIC transport protocol was designed from the outset to support
   HTTP semantics, and its design subsumes most of the features of
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