QPACK: Header Compression for HTTP over QUIC
draft-ietf-quic-qpack-00
QUIC C. Krasic
Internet-Draft Google, Inc
Intended status: Standards Track M. Bishop
Expires: November 24, 2018 Akamai Technologies
A. Frindell, Ed.
Facebook
May 23, 2018
QPACK: Header Compression for HTTP over QUIC
draft-ietf-quic-qpack-00
Abstract
This specification defines QPACK, a compression format for
efficiently representing HTTP header fields, to be used in HTTP over
QUIC. This is a variation of HPACK header compression that seeks to
reduce head-of-line blocking.
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/-qpack [3].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 24, 2018.
Krasic, et al. Expires November 24, 2018 [Page 1]
Internet-Draft QPACK May 2018
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Head-of-Line Blocking in HPACK . . . . . . . . . . . . . 3
1.2. Avoiding Head-of-Line Blocking in HTTP/QUIC . . . . . . . 4
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 5
2.1. Notational Conventions . . . . . . . . . . . . . . . . . 5
3. Wire Format . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Primitives . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Indexing . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. QPACK Encoder Stream . . . . . . . . . . . . . . . . . . 8
3.3.1. Insert With Name Reference . . . . . . . . . . . . . 8
3.3.2. Insert Without Name Reference . . . . . . . . . . . . 9
3.3.3. Duplicate . . . . . . . . . . . . . . . . . . . . . . 9
3.3.4. Dynamic Table Size Update . . . . . . . . . . . . . . 10
3.4. QPACK Decoder Stream . . . . . . . . . . . . . . . . . . 10
3.4.1. Table State Synchronize . . . . . . . . . . . . . . . 11
3.4.2. Header Acknowledgement . . . . . . . . . . . . . . . 11
3.5. Request and Push Streams . . . . . . . . . . . . . . . . 11
3.5.1. Header Data Prefix . . . . . . . . . . . . . . . . . 12
3.5.2. Instructions . . . . . . . . . . . . . . . . . . . . 12
4. Encoding Strategies . . . . . . . . . . . . . . . . . . . . . 15
4.1. Single pass encoding . . . . . . . . . . . . . . . . . . 15
4.2. Preventing Eviction Races . . . . . . . . . . . . . . . . 15
4.3. Reference Tracking . . . . . . . . . . . . . . . . . . . 15
4.3.1. Blocked Eviction . . . . . . . . . . . . . . . . . . 16
4.3.2. Blocked Decoding . . . . . . . . . . . . . . . . . . 16
4.4. Speculative table updates . . . . . . . . . . . . . . . . 16
4.5. Sample One Pass Encoding Algorithm . . . . . . . . . . . 17
5. Security Considerations . . . . . . . . . . . . . . . . . . . 18
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
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