[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: (draft-rpeon-httpbis-header-compression) 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 7541

HTTPbis Working Group                                            R. Peon
Internet-Draft                                               Google, Inc
Intended status: Informational                                H. Ruellan
Expires: April 24, 2014                                        Canon CRF
                                                        October 21, 2013


                HPACK - Header Compression for HTTP/2.0
                draft-ietf-httpbis-header-compression-04

Abstract

   This document describes HPACK, a format adapted to efficiently
   represent HTTP header fields in the context of HTTP/2.0.

Editorial Note (To be removed by RFC Editor)

   Discussion of this draft takes place on the HTTPBIS working group
   mailing list (ietf-http-wg@w3.org), which is archived at
   <http://lists.w3.org/Archives/Public/ietf-http-wg/>.

   Working Group information and related documents can be found at
   <http://tools.ietf.org/wg/httpbis/> (Wiki) and
   <https://github.com/http2/http2-spec> (source code and issues
   tracker).

   The changes in this draft are summarized in Appendix A.1.

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 http://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 April 24, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the



Peon & Ruellan           Expires April 24, 2014                 [Page 1]


Internet-Draft                    HPACK                     October 2013


   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://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.








































Peon & Ruellan           Expires April 24, 2014                 [Page 2]


Internet-Draft                    HPACK                     October 2013


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1.  Outline  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Header Field Encoding  . . . . . . . . . . . . . . . . . . . .  5
     3.1.  Encoding Concepts  . . . . . . . . . . . . . . . . . . . .  5
       3.1.1.  Encoding Context . . . . . . . . . . . . . . . . . . .  5
       3.1.2.  Header Table . . . . . . . . . . . . . . . . . . . . .  6
       3.1.3.  Reference Set  . . . . . . . . . . . . . . . . . . . .  6
       3.1.4.  Header Field Representation  . . . . . . . . . . . . .  7
       3.1.5.  Header Field Emission  . . . . . . . . . . . . . . . .  8
     3.2.  Header Block Decoding  . . . . . . . . . . . . . . . . . .  8
       3.2.1.  Header Field Representation Processing . . . . . . . .  8
       3.2.2.  Reference Set Emission . . . . . . . . . . . . . . . .  9
       3.2.3.  Header Set Completion  . . . . . . . . . . . . . . . .  9
     3.3.  Header Table Management  . . . . . . . . . . . . . . . . .  9
       3.3.1.  Maximum Table Size . . . . . . . . . . . . . . . . . .  9
       3.3.2.  Entry Eviction When Header Table Size Changes  . . . . 10
       3.3.3.  Entry Eviction when Adding New Entries . . . . . . . . 10
   4.  Detailed Format  . . . . . . . . . . . . . . . . . . . . . . . 10
     4.1.  Low-level representations  . . . . . . . . . . . . . . . . 10
       4.1.1.  Integer representation . . . . . . . . . . . . . . . . 11
       4.1.2.  String Literal Representation  . . . . . . . . . . . . 13
     4.2.  Indexed Header Field Representation  . . . . . . . . . . . 14
     4.3.  Literal Header Field Representation  . . . . . . . . . . . 15
       4.3.1.  Literal Header Field without Indexing  . . . . . . . . 15
       4.3.2.  Literal Header Field with Incremental Indexing . . . . 16
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 18
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 18
   Appendix A.  Change Log (to be removed by RFC Editor before
                publication . . . . . . . . . . . . . . . . . . . . . 19
     A.1.  Since draft-ietf-httpbis-header-compression-03 . . . . . . 19
     A.2.  Since draft-ietf-httpbis-header-compression-02 . . . . . . 19
     A.3.  Since draft-ietf-httpbis-header-compression-01 . . . . . . 19
     A.4.  Since draft-ietf-httpbis-header-compression-01 . . . . . . 19
   Appendix B.  Static Table  . . . . . . . . . . . . . . . . . . . . 20
   Appendix C.  Huffman Codes For Requests  . . . . . . . . . . . . . 22
   Appendix D.  Huffman Codes for Responses . . . . . . . . . . . . . 28
   Appendix E.  Examples  . . . . . . . . . . . . . . . . . . . . . . 33
     E.1.  Request Decoding Example With Huffman  . . . . . . . . . . 33
     E.2.  Request Decoding Example Without Huffman . . . . . . . . . 38
     E.3.  Response Decoding Example With Huffman . . . . . . . . . . 43
     E.4.  Response Decoding Example Without Huffman  . . . . . . . . 51





Peon & Ruellan           Expires April 24, 2014                 [Page 3]


Internet-Draft                    HPACK                     October 2013


1.  Introduction

   This document describes HPACK, a format adapted to efficiently
   represent HTTP header fields in the context of HTTP/2.0 (see
   [HTTP2]).

2.  Overview

   In HTTP/1.X (see [HTTP-p1]), header fields are sent without any form
   of compression.  As web pages have grown to include dozens to
   hundreds of requests, the redundant header fields in these requests
   now pose a problem of measurable latency and unnecessary bandwidth
   (see [PERF1] and [PERF2]).

   SPDY [SPDY] initially addressed this redundancy by compressing header
   fields with Deflate, which proved very effective at eliminating the
   redundant header fields.  However, that aproach exposed a security
   risk as demonstrated by the CRIME [CRIME].

   In this document, we propose a new compressor for header fields which
   eliminates redundant header fields, is not vulnerable to CRIME style
   attacks, and which also has a bounded memory cost for use in
   constrained environments.

2.1.  Outline

   The HTTP header field encoding described in this document is based on
   a header table that map (name, value) pairs to index values.  Header
   tables are incrementally updated during the HTTP/2.0 session.

   The encoder is responsible for deciding which header fields to insert
   as new entries in the header table.  The decoder then does exactly
   what the encoder prescribes, ending in a state that exactly matches
   the encoder's state.  This enables decoders to remain simple and
   understand a wide variety of encoders.

   As two consecutive sets of header fields often have header fields in
   common, each set of header fields is coded as a difference from the
   previous set of header fields.  The goal is to only encode the
   changes (header fields present in one of the set and not in the
   other) between the two sets of header fields.

   Examples illustrating the use of these different mechanisms to
   represent header fields are available in Appendix E.







Peon & Ruellan           Expires April 24, 2014                 [Page 4]


Internet-Draft                    HPACK                     October 2013


3.  Header Field Encoding

3.1.  Encoding Concepts

   The encoding and decoding of header fields relies on some components
   and concepts:

   Header Field:  A key, value pair.  HPACK allows a header field value
      to be either a value as specified by HTTP/1.X (see [HTTP-p1]), or
      a NULL-separated ordered list of HTTP/1.X values.

   Header Table:  The header table (see Section 3.1.2) is a component
      used to associate stored header fields to index values.  The data
      stored in this table is in first-in, first-out order.

   Static Table:  The static table (see Appendix B) is a component used
      to associate static header fields to index values.  This data is
      ordered, read-only, always accessible, and may be shared amongst
      all encoding contexts.

   Reference Set:  The reference set (see Section 3.1.3) is a component
      containing an unordered set of references to entries in the header
      table or static table.  This is used for the differential encoding
      of a new header set.

   Header Set:  A header set is a potentially ordered group of header
      fields that are encoded jointly.  A complete set of key-value
      pairs contained in a HTTP request or response is a header set.

   Header Field Representation:  A header field can be represented in
      encoded form either as a literal or as an index (see
      Section 3.1.4).

   Header Block:  The entire set of encoded header field representations
      which, when decoded, yield a complete header set.

   Header Field Emission:  When decoding a set of header field
      representations, some operations emit a header field (see
      Section 3.1.5).  Emitted headers can be safely passed to the upper
      processing layers as part of the current Header Set.

3.1.1.  Encoding Context

   The set of mutable structures used within an encoding context include
   a header table and a reference set.  Everything else is either
   immutable or conceptual.

   Using HTTP, messages are exchanged between a client and a server in



Peon & Ruellan           Expires April 24, 2014                 [Page 5]


Internet-Draft                    HPACK                     October 2013


   both direction.  To keep the encoding of header fields in each
   direction independent from the other direction, there is one encoding
   context for each direction.

   The header fields contained in a PUSH_PROMISE frame sent by a server
   to a client are encoded within the same context as the header fields
   contained in the HEADERS frame corresponding to a response sent from
   the server to the client.

3.1.2.  Header Table

   A header table consists of a list of header fields maintained in
   first-in, first-out order.  The first and newest entry in a header
   table is always at index 0, and the oldest entry of a header table is
   at the index len(header table)-1.

   The header table is initially empty.

   There is typically no need for the header table to contain duplicate
   entries.  However, duplicate entries MUST NOT be treated as an error
   by a decoder.

   The encoder decides how to update the header table and as such can
   control how much memory is used by the header table.  To limit the
   memory requirements on the decoder side, the header table size is
   strictly bounded (see Section 3.3.1).

   The header table is updated during the processing of a set of header
   field representations (see header field representation processing
   (Section 3.2.1).

3.1.3.  Reference Set

   A reference set is an unordered set of references to entries either
   within the header table or the static table.

   The reference set is initially empty.

   The reference set is updated during the processing of a set of header
   field representations (see header field representation processing
   (Section 3.2.1).

   The reference set enables differential encoding, whereby only
   differences between the previous header set and the current header
   set need to be encoded.

   When an entry is evicted from the header table, if it was referenced
   from the reference set, its reference is removed from the reference



Peon & Ruellan           Expires April 24, 2014                 [Page 6]


Internet-Draft                    HPACK                     October 2013


   set.

3.1.4.  Header Field Representation

   An encoded header field can be represented either as a literal or as
   an index.

   Literal Representation:  A literal representation defines a new
      header field.  The header field name is represented either
      literally or as a reference to an entry of the header table.  The
      header field value is represented literally.

      Two different literal representations are provided:

      *  A literal representation that does not add the header field to
         the header table (see Section 4.3.1).

      *  A literal representation that adds the header field as a new
         entry at the beginning of the header table (see Section 4.3.2).

   Indexed Representation:  The indexed representation defines a header
      field as a reference to an entry in either the header table or the
      static table(see Section 4.2).


          <----------  Index Address Space ---------->
          <-- Header  Table -->  <-- Static  Table -->
          +---+-----------+---+  +---+-----------+---+
          | 0 |    ...    | k |  |k+1|    ...    | n |
          +---+-----------+---+  +---+-----------+---+
          ^                   |
          |                   V
   Insertion Point       Drop Point


                             Index Address Space

         Indices between 0 and len(header table)-1, inclusive, refer to
         elements in the header table, with index 0 referring to the
         beginning of the table.

         Indices between len(header table) and len(header table)+
         len(static table)-1, inclusive, refer to elements in the static
         table, where the index len(header table) refers to the first
         entry in the static table.






Peon & Ruellan           Expires April 24, 2014                 [Page 7]


Internet-Draft                    HPACK                     October 2013


         Any other indices MUST be treated as erroneous, and the
         compression context considered corrupt and unusable.

3.1.5.  Header Field Emission

   The emission of a header field is the process of passing that header
   field to the application, so that the application can process and
   react to header field data.

   By emitting header fields instead of emitting header sets, the
   decoder can be implemented in a streaming way, and as such must only
   keep in memory the header table and the reference set.  This bounds
   the amount of memory used by the decoder, even in presence of a very
   large set of header fields.  The management of memory for handling
   very large sets of header fields can therefore be deferred to the
   application.

   When a header field is a NULL-separated list of values, each value
   within the list MAY be emitted separately, with the same header field
   name, and the order of emission MUST be the order of appearance in
   the list.

3.2.  Header Block Decoding

   The processing of a header block to obtain a header set is defined in
   this section.  To ensure that the decoding will successfully produce
   a header set, a decoder MUST obey the following rules.

3.2.1.  Header Field Representation Processing

   All the header field representations contained in a header block are
   processed in the order in which they are presented, as specified
   below.

   An _indexed representation_ corresponding to an entry _present_ in
   the reference set entails the following actions:

   o  The reference to the entry is removed from the reference set.

   An _indexed representation_ corresponding to an entry _not present_
   in the reference set entails the following actions:

   o  If referencing an element of the static table:

      *  The header field corresponding to the referenced entry is
         emitted.





Peon & Ruellan           Expires April 24, 2014                 [Page 8]


Internet-Draft                    HPACK                     October 2013


      *  The referenced static entry is added to the header table.

      *  If the new entry fits within the header table, a reference to
         the header table entry is added to the reference set.

   o  If referencing an element of the header table:

      *  The header field corresponding to the referenced entry is
         emitted.

      *  The referenced header table entry is added to the header table.

   A _literal representation_ that is _not added_ to the header table
   entails the following action:

   o  The header field is emitted.

   A _literal representation_ that is _added_ to the header table
   entails the following actions:

   o  The header field is inserted at the beginning of the header table.

   o  A reference to the new entry is added to the reference set.

   o  The header field is emitted.

3.2.2.  Reference Set Emission

   Once all the representations contained in a header block have been
   processed, the header fields referenced in the reference set which
   have not previously been emitted during this processing are emitted.

3.2.3.  Header Set Completion

   Once all of the header field representations have been processed, and
   the remaining items in the reference set have been emitted, the
   header set is complete.

3.3.  Header Table Management

3.3.1.  Maximum Table Size

   To limit the memory requirements on the decoder side, the size of the
   the header table is bounded.  The size of the header table MUST stay
   lower than or equal to the value of the HTTP/2.0 setting
   SETTINGS_HEADER_TABLE_SIZE (see [HTTP2]).

   The size of the the header table is the sum of the size of its



Peon & Ruellan           Expires April 24, 2014                 [Page 9]


Internet-Draft                    HPACK                     October 2013


   entries.

   The size of an entry is the sum of its name's length in bytes (as
   defined in Section 4.1.2), of its value's length in bytes
   (Section 4.1.2) and of 32 bytes.

   The lengths are measured on the non-encoded entry name and entry
   value (for the case when a Huffman encoding is used to transmit
   string values).

   The 32 bytes are an accounting for the entry structure overhead.  For
   example, an entry structure using two 64-bits pointers to reference
   the name and the value and the entry, and two 64-bits integer for
   counting the number of references to these name and value would use
   32 bytes.

3.3.2.  Entry Eviction When Header Table Size Changes

   Whenever an entry is evicted from the header table, any reference to
   that entry contained by the reference set is removed.

   Whenever SETTINGS_HEADER_TABLE_SIZE is made smaller, entries are
   evicted from the end of the header table until the size of the header
   table is less than or equal to SETTINGS_HEADER_TABLE_SIZE.

   The eviction of an entry from the header table causes the index of
   the entries in the static table to be reduced by one.

3.3.3.  Entry Eviction when Adding New Entries

   Whenever a new entry is to be added to the table, any name referenced
   by the representation is cached, and then entries are evicted from
   the end of the header table until the size of the header table is
   less than or equal to SETTINGS_HEADER_TABLE_SIZE - new entry size, or
   until the table is empty.

   If the size of the new entry is less than or equal to
   SETTINGS_HEADER_TABLE_SIZE, that entry is added to the table.  It is
   not an error to attempt to add an entry that is larger than
   SETTINGS_HEADER_TABLE_SIZE.

4.  Detailed Format

4.1.  Low-level representations







Peon & Ruellan           Expires April 24, 2014                [Page 10]


Internet-Draft                    HPACK                     October 2013


4.1.1.  Integer representation

   Integers are used to represent name indexes, pair indexes or string
   lengths.  To allow for optimized processing, an integer
   representation always finishes at the end of a byte.

   An integer is represented in two parts: a prefix that fills the
   current byte and an optional list of bytes that are used if the
   integer value does not fit within the prefix.  The number of bits of
   the prefix (called N) is a parameter of the integer representation.

   The N-bit prefix allows filling the current byte.  If the value is
   small enough (strictly less than 2^N-1), it is encoded within the
   N-bit prefix.  Otherwise all the bits of the prefix are set to 1 and
   the value is encoded using an unsigned variable length integer [1]
   representation.  N is always between 1 and 8 bits.  An integer
   starting at a byte-boundary will have an 8-bit prefix.

   The algorithm to represent an integer I is as follows:

   If I < 2^N - 1, encode I on N bits
   Else
       encode 2^N - 1 on N bits
       I = I - (2^N - 1)
       While I >= 128
            Encode (I % 128 + 128) on 8 bits
            I = I / 128
       encode (I) on 8 bits

   This integer representation allows for values of indefinite size.  It
   is also possible for an encoder to send a large number of zero
   values, which can waste bytes and could be used to overflow integer
   values.  Excessively large integer encodings - in value or octet
   length - MUST be treated as a decoding error.  Different limits can
   be set for each of the different uses of integers, based on
   implementation constraints.

4.1.1.1.  Example 1: Encoding 10 using a 5-bit prefix

   The value 10 is to be encoded with a 5-bit prefix.

   o  10 is less than 31 (= 2^5 - 1) and is represented using the 5-bit
      prefix.


     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | X | X | X | 0 | 1 | 0 | 1 | 0 |   10 stored on 5 bits



Peon & Ruellan           Expires April 24, 2014                [Page 11]


Internet-Draft                    HPACK                     October 2013


   +---+---+---+---+---+---+---+---+

4.1.1.2.  Example 2: Encoding 1337 using a 5-bit prefix

   The value I=1337 is to be encoded with a 5-bit prefix.

      1337 is greater than 31 (= 2^5 - 1).



         The 5-bit prefix is filled with its max value (31).

      I = 1337 - (2^5 - 1) = 1306.



         I (1306) is greater than or equal to 128, the while loop body
         executes:



            I % 128 == 26

            26 + 128 == 154

            154 is encoded in 8 bits as: 10011010

            I is set to 10 (1306 / 128 == 10)

            I is no longer greater than or equal to 128, the while loop
            terminates.

         I, now 10, is encoded on 8 bits as: 00001010

      The process ends.


     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | X | X | X | 1 | 1 | 1 | 1 | 1 |  Prefix = 31, I = 1306
   | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 0 |  1306>=128, encode(154), I=1306/128
   | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 |  10<128, encode(10), done
   +---+---+---+---+---+---+---+---+








Peon & Ruellan           Expires April 24, 2014                [Page 12]


Internet-Draft                    HPACK                     October 2013


4.1.2.  String Literal Representation

   Header field names and header field values are encoded as sequences
   of bytes.  A header field name or a header field value is encoded in
   three parts:

   1.  One bit, H, indicating whether or not the bytes are huffman
       encoded.

   2.  The number of bytes required to hold the result of the next step,
       represented as a variable-length-quantity (Section 4.1.1),
       starting with a 7-bit prefix immediately following the first bit.

   3.  The encoded data of the string:

       1.  If H is true, then the the encoded string data is the bitwise
           concatenation of the canonical [CANON]huffman code [HUFF]
           corresponding to each character of the data, followed by
           between 0-7 bits of padding.

       2.  If H is false, then the encoded string is the bytes of the
           field value without modification.

   Padding is necessary when doing huffman encoding to ensure that the
   remaining bits between the actual end of the data and the next byte
   boundary are not misinterpreted as part of the input data.

   When padding for huffman encoding, use the bits from the EOS (end-of-
   string) entry in the Huffman table, starting with the MSB.  This
   entry is guaranteed to be at least 8 bits long.

   String literals sent in the client to server direction which use
   huffman encoding are encoded with the codes within the request
   huffman code table (Appendix C) (see Request Decoding With Huffman
   Example (Appendix E.3)).

   String literals sent in the server to client direction which use
   huffman encoding are encoded with the codes within the response
   huffman code table (Appendix D) (see Response Decoding With Huffman
   Example (Appendix E.3)).

   The EOS symbol is represented with value 256, and is used solely to
   signal the end of the huffman-encoded key data or the end of the
   huffman-encoded value data.  Given that only between 0-7 bits of the
   EOS symbol is included in any huffman-encoded string, and given that
   the EOS symbol is at least 8 bits long, it is expected that it should
   never be successfully decoded.




Peon & Ruellan           Expires April 24, 2014                [Page 13]


Internet-Draft                    HPACK                     October 2013


     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 1 |  Value Length Prefix (7)  |
   +---+---+---+---+---+---+---+---+
   |   Value Length (0-N bytes)    |
   +---+---+---+---+---+---+---+---+
   ...
   +---+---+---+---+---+---+---+---+
   | Huffman Encoded Data  |Padding|
   +---+---+---+---+---+---+---+---+

                   String Literal With Huffman Encoding


     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 |  Value Length Prefix (7)  |
   +---+---+---+---+---+---+---+---+
   |   Value Length (0-N bytes)    |
   +---+---+---+---+---+---+---+---+
   ...
   +---+---+---+---+---+---+---+---+
   |  Field Bytes Without Encoding |
   +---+---+---+---+---+---+---+---+

                  String Literal Without Huffman Encoding

4.2.  Indexed Header Field Representation

   An indexed header field representation either identifies an entry in
   the header table or static table.  The specified entry is emitted and
   a reference to that entry is added to the reference set if it is not
   currently in the reference set.  If it is present in the reference
   set then the reference is removed and the entry is not emitted.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 1 |        Index (7+)         |
   +---+---------------------------+

                           Indexed Header Field

   This representation starts with the '1' 1-bit pattern, followed by
   the index of the matching pair, represented as an integer with a
   7-bit prefix.






Peon & Ruellan           Expires April 24, 2014                [Page 14]


Internet-Draft                    HPACK                     October 2013


4.3.  Literal Header Field Representation

   Literal header field representations contain a literal header field
   value.  Header field names are either provided as a literal or by
   reference to an existing header table or static table entry.

   Literal representations all result in the emission of a header field
   when decoded.

4.3.1.  Literal Header Field without Indexing

   A literal header field without indexing causes the emission of a
   header field without altering the header table.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 |      Index (6+)       |
   +---+---+---+-------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

           Literal Header Field without Indexing - Indexed Name


     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 |           0           |
   +---+---+---+-------------------+
   |       Name Length (8+)        |
   +-------------------------------+
   |  Name String (Length octets)  |
   +-------------------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

             Literal Header Field without Indexing - New Name

   This representation starts with the '01' 2-bit pattern.

   If the header field name matches the header field name of a (name,
   value) pair stored in the Header Table or Static Table, the index of
   that entry, increased by one (index + 1), is represented as an
   integer with a 6-bit prefix.  Note that if the index is strictly
   below 63, only one byte is used for this representation.



Peon & Ruellan           Expires April 24, 2014                [Page 15]


Internet-Draft                    HPACK                     October 2013


   If the header field name does not match a header field name entry,
   the value 0 is represented on 6 bits followed by the header field
   name (Section 4.1.2).

   The header field name representation is followed by the header field
   value represented as a literal string as described in Section 4.1.2.

4.3.2.  Literal Header Field with Incremental Indexing

   A literal header field with incremental indexing adds a new entry to
   the header table.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 0 |      Index (6+)       |
   +---+---+---+-------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

             Literal Header Field with Incremental Indexing -
                               Indexed Name


     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 0 |           0           |
   +---+---+---+-------------------+
   |       Name Length (8+)        |
   +-------------------------------+
   |  Name String (Length octets)  |
   +-------------------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

             Literal Header Field with Incremental Indexing -
                                 New Name

   This representation starts with the '00' 2-bit pattern.

   If the header field name matches the header field name of a (name,
   value) pair stored in the header table or static table, the index of
   the pair increased by one (index + 1) is represented as an integer
   with a 6-bit prefix.




Peon & Ruellan           Expires April 24, 2014                [Page 16]


Internet-Draft                    HPACK                     October 2013


   If the header field name does not match a header field name entry,
   the value 0 is represented on 6 bits followed by the header field
   name (Section 4.1.2).

   The header field name representation is followed by the header field
   value represented as a literal string as described in Section 4.1.2.

5.  Security Considerations

   This compressor exists to solve security issues present in stream
   compressors such as DEFLATE whereby the compression context can be
   efficiently probed to reveal secrets.  A conformant implementation of
   this specification should be fairly safe against that kind of attack,
   as the reaping of any information from the compression context
   requires more work than guessing and verifying the plaintext data
   directly with the server.  As with any secret, however, the longer
   the length of the secret, the more difficult the secret is to guess.
   It is inadvisable to have short cookies that are relied upon to
   remain secret for any duration of time.

   A proper security-conscious implementation will also need to prevent
   timing attacks by ensuring that the amount of time it takes to do
   string comparisons is always a function of the total length of the
   strings, and not a function of the number of matched characters.

   A decoder needs to ensure that larger values or encodings of integers
   do not permit exploitation.  Decoders MUST limit the size of
   integers, both in value and encoded length, that it accepts (see
   Section 4.1.1).

   Another common security problem is when the remote endpoint
   successfully causes the local endpoint to exhaust its memory.  This
   compressor attempts to deal with the most obvious ways that this
   could occur by limiting both the peak and the steady-state amount of
   memory consumed in the compressor state, by providing ways for the
   application to consume/flush the emitted header fields in small
   chunks, and by considering overhead in the state size calculation.
   Implementors must still be careful in the creation of APIs to an
   implementation of this compressor by ensuring that header field keys
   and values are either emitted as a stream, or that the compression
   implementation have a limit on the maximum size of a key or value.
   Failure to implement these kinds of safeguards may still result in a
   scenario where the local endpoint exhausts its memory.

6.  References






Peon & Ruellan           Expires April 24, 2014                [Page 17]


Internet-Draft                    HPACK                     October 2013


6.1.  Normative References

   [HTTP-p1]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              draft-ietf-httpbis-p1-messaging-24 (work in progress),
              September 2013.

   [HTTP2]    Belshe, M., Peon, R., Thomson, M., and A. Melnikov,
              "Hypertext Transfer Protocol version 2.0",
              draft-ietf-httpbis-http2-06 (work in progress),
              August 2013.

6.2.  Informative References

   [CANON]    Schwartz, E. and B. Kallick, "Generating a canonical
              prefix encoding", Communications of the ACM Volume 7 Issue
              3, pp. 166-169, March 1964,
              <http://dl.acm.org/citation.cfm?id=363991>.

   [CRIME]    Rizzo, J. and T. Duong, "The Crime Attack",
              September 2012, <https://docs.google.com/a/twist.com/
              presentation/d/
              11eBmGiHbYcHR9gL5nDyZChu_-lCa2GizeuOfaLU2HOU/
              edit#slide=id.g1eb6c1b5_3_6>.

   [HUFF]     Huffman, D., "A Method for the Construction of Minimim
              Redundancy Codes", Proceedings of the Institute of Radio
              Engineers Volume 40, Number 9, pp. 1098-1101,
              September 1952, <http://ieeexplore.ieee.org/xpl/
              articleDetails.jsp?arnumber=4051119>.

   [PERF1]    Belshe, M., "IETF83: SPDY and What to Consider for
              HTTP/2.0", March 2012, <http://www.ietf.org/proceedings/
              83/slides/slides-83-httpbis-3>.

   [PERF2]    McManus, P., "SPDY: What I Like About You",
              September 2011, <http://bitsup.blogspot.com/2011/09/
              spdy-what-i-like-about-you.html>.

   [SPDY]     Belshe, M. and R. Peon, "SPDY Protocol",
              draft-mbelshe-httpbis-spdy-00 (work in progress),
              February 2012.

URIs

   [1]  <http://en.wikipedia.org/wiki/Variable-length_quantity>





Peon & Ruellan           Expires April 24, 2014                [Page 18]


Internet-Draft                    HPACK                     October 2013


Appendix A.  Change Log (to be removed by RFC Editor before publication

A.1.  Since draft-ietf-httpbis-header-compression-03

   o  A large number of editorial changes; changed the description of
      evicting/adding new entries.

   o  Removed substitution indexing

   o  Changed 'initial headers' to 'static headers', as per issue #258

   o  Merged 'request' and 'response' static headers, as per issue #259

   o  Changed text to indicate that new headers are added at index 0 and
      expire from the largest index, as per issue #233

A.2.  Since draft-ietf-httpbis-header-compression-02

   o  Corrected error in integer encoding pseudocode.

A.3.  Since draft-ietf-httpbis-header-compression-01

   o  Refactored of Header Encoding Section: split definitions and
      processing rule.

   o  Backward incompatible change: Updated reference set management as
      per issue #214.  This changes how the interaction between the
      reference set and eviction works.  This also changes the working
      of the reference set in some specific cases.

   o  Backward incompatible change: modified initial header list, as per
      issue #188.

   o  Added example of 32 bytes entry structure (issue #191).

   o  Added Header Set Completion section.  Reflowed some text.
      Clarified some writing which was akward.  Added text about
      duplicate header entry encoding.  Clarified some language w.r.t
      Header Set. Changed x-my-header to mynewheader.  Added text in the
      HeaderEmission section indicating that the application may also be
      able to free up memory more quickly.  Added information in
      Security Considerations section.

A.4.  Since draft-ietf-httpbis-header-compression-01

      Fixed bug/omission in integer representation algorithm.





Peon & Ruellan           Expires April 24, 2014                [Page 19]


Internet-Draft                    HPACK                     October 2013


      Changed the document title.

      Header matching text rewritten.

      Changed the definition of header emission.

      Changed the name of the setting which dictates how much memory the
      compression context should use.

      Removed "specific use cases" section

      Corrected erroneous statement about what index can be contained in
      one byte

      Added descriptions of opcodes

      Removed security claims from introduction.

Appendix B.  Static Table

   The static table consists of an unchangable ordered list of (name,
   value) pairs.  The first entry in the table is always represented by
   the index len(header table), and the last entry in the table is
   represented by the index len(header table)+len(static table)-1.

   [[anchor9: The ordering of these tables is currently arbitrary.  The
   tables in this section should be updated and ordered such that the
   table entries with the smallest indices are those which, based on a
   statistical analysis of the frequency of use weighted by size,
   achieve the largest decrease in bytes transmitted subject to HTTP 2.0
   header field rules (like removal of some header fields).  This set of
   header fields is currently very likely incomplete, and should be made
   complete.]]

   The following table lists the pre-defined header fields that make-up
   the static header table.

          +-------+-----------------------------+--------------+
          | Index | Header Name                 | Header Value |
          +-------+-----------------------------+--------------+
          | 0     | :authority                  |              |
          | 1     | :method                     | GET          |
          | 2     | :method                     | POST         |
          | 3     | :path                       | /            |
          | 4     | :path                       | /index.html  |
          | 5     | :scheme                     | http         |
          | 6     | :scheme                     | https        |
          | 7     | :status                     | 200          |



Peon & Ruellan           Expires April 24, 2014                [Page 20]


Internet-Draft                    HPACK                     October 2013


          | 8     | :status                     | 500          |
          | 9     | :status                     | 404          |
          | 10    | :status                     | 403          |
          | 11    | :status                     | 400          |
          | 12    | :status                     | 401          |
          | 13    | accept-charset              |              |
          | 14    | accept-encoding             |              |
          | 15    | accept-language             |              |
          | 16    | accept-ranges               |              |
          | 17    | accept                      |              |
          | 18    | access-control-allow-origin |              |
          | 19    | age                         |              |
          | 20    | allow                       |              |
          | 21    | authorization               |              |
          | 22    | cache-control               |              |
          | 23    | content-disposition         |              |
          | 24    | content-encoding            |              |
          | 25    | content-language            |              |
          | 26    | content-length              |              |
          | 27    | content-location            |              |
          | 28    | content-range               |              |
          | 29    | content-type                |              |
          | 30    | cookie                      |              |
          | 31    | date                        |              |
          | 32    | etag                        |              |
          | 33    | expect                      |              |
          | 34    | expires                     |              |
          | 35    | from                        |              |
          | 36    | if-match                    |              |
          | 37    | if-modified-since           |              |
          | 38    | if-none-match               |              |
          | 39    | if-range                    |              |
          | 40    | if-unmodified-since         |              |
          | 41    | last-modified               |              |
          | 42    | link                        |              |
          | 43    | location                    |              |
          | 44    | max-forwards                |              |
          | 45    | proxy-authenticate          |              |
          | 46    | proxy-authorization         |              |
          | 47    | range                       |              |
          | 48    | referer                     |              |
          | 49    | refresh                     |              |
          | 50    | retry-after                 |              |
          | 51    | server                      |              |
          | 52    | set-cookie                  |              |
          | 53    | strict-transport-security   |              |
          | 54    | transfer-encoding           |              |
          | 55    | user-agent                  |              |



Peon & Ruellan           Expires April 24, 2014                [Page 21]


Internet-Draft                    HPACK                     October 2013


          | 56    | vary                        |              |
          | 57    | via                         |              |
          | 58    | www-authenticate            |              |
          +-------+-----------------------------+--------------+

                       Table 1: Static Table Entries

   The table give the index of each entry in the static table.  The full
   index of each entry, to be used for encoding a reference to this
   entry, is computed by adding the number of entries in the header
   table to this index.

Appendix C.  Huffman Codes For Requests

   The following Huffman codes are used when encoding string literals in
   the client to server direction.

   [[anchor10: This table is out of date and needs updating.  In
   particular, EOS needs to be at least 7-bits long and currently is
   not.]]

                aligned                                  aligned
                 to                            len        to     len
                 MSB                            in        LSB     in
          sym    as bits                       bits      as hex  bits
         (  0) |11111111|11111111|11110111|010 [27]      7ffffba [27]
         (  1) |11111111|11111111|11110111|011 [27]      7ffffbb [27]
         (  2) |11111111|11111111|11110111|100 [27]      7ffffbc [27]
         (  3) |11111111|11111111|11110111|101 [27]      7ffffbd [27]
         (  4) |11111111|11111111|11110111|110 [27]      7ffffbe [27]
         (  5) |11111111|11111111|11110111|111 [27]      7ffffbf [27]
         (  6) |11111111|11111111|11111000|000 [27]      7ffffc0 [27]
         (  7) |11111111|11111111|11111000|001 [27]      7ffffc1 [27]
         (  8) |11111111|11111111|11111000|010 [27]      7ffffc2 [27]
         (  9) |11111111|11111111|11111000|011 [27]      7ffffc3 [27]
         ( 10) |11111111|11111111|11111000|100 [27]      7ffffc4 [27]
         ( 11) |11111111|11111111|11111000|101 [27]      7ffffc5 [27]
         ( 12) |11111111|11111111|11111000|110 [27]      7ffffc6 [27]
         ( 13) |11111111|11111111|11111000|111 [27]      7ffffc7 [27]
         ( 14) |11111111|11111111|11111001|000 [27]      7ffffc8 [27]
         ( 15) |11111111|11111111|11111001|001 [27]      7ffffc9 [27]
         ( 16) |11111111|11111111|11111001|010 [27]      7ffffca [27]
         ( 17) |11111111|11111111|11111001|011 [27]      7ffffcb [27]
         ( 18) |11111111|11111111|11111001|100 [27]      7ffffcc [27]
         ( 19) |11111111|11111111|11111001|101 [27]      7ffffcd [27]
         ( 20) |11111111|11111111|11111001|110 [27]      7ffffce [27]
         ( 21) |11111111|11111111|11111001|111 [27]      7ffffcf [27]
         ( 22) |11111111|11111111|11111010|000 [27]      7ffffd0 [27]



Peon & Ruellan           Expires April 24, 2014                [Page 22]


Internet-Draft                    HPACK                     October 2013


         ( 23) |11111111|11111111|11111010|001 [27]      7ffffd1 [27]
         ( 24) |11111111|11111111|11111010|010 [27]      7ffffd2 [27]
         ( 25) |11111111|11111111|11111010|011 [27]      7ffffd3 [27]
         ( 26) |11111111|11111111|11111010|100 [27]      7ffffd4 [27]
         ( 27) |11111111|11111111|11111010|101 [27]      7ffffd5 [27]
         ( 28) |11111111|11111111|11111010|110 [27]      7ffffd6 [27]
         ( 29) |11111111|11111111|11111010|111 [27]      7ffffd7 [27]
         ( 30) |11111111|11111111|11111011|000 [27]      7ffffd8 [27]
         ( 31) |11111111|11111111|11111011|001 [27]      7ffffd9 [27]
     ' ' ( 32) |11101000| [8]                                  e8 [8]
     '!' ( 33) |11111111|1100 [12]                           ffc [12]
     '"' ( 34) |11111111|111010 [14]                        3ffa [14]
     '#' ( 35) |11111111|1111100 [15]                       7ffc [15]
     '$' ( 36) |11111111|1111101 [15]                       7ffd [15]
     '%' ( 37) |100100 [6]                                     24 [6]
     '&' ( 38) |1101110 [7]                                    6e [7]
     ''' ( 39) |11111111|1111110 [15]                       7ffe [15]
     '(' ( 40) |11111111|010 [11]                            7fa [11]
     ')' ( 41) |11111111|011 [11]                            7fb [11]
     '*' ( 42) |11111110|10 [10]                             3fa [10]
     '+' ( 43) |11111111|100 [11]                            7fc [11]
     ',' ( 44) |11101001| [8]                                  e9 [8]
     '-' ( 45) |100101 [6]                                     25 [6]
     '.' ( 46) |00100 [5]                                       4 [5]
     '/' ( 47) |0000 [4]                                        0 [4]
     '0' ( 48) |00101 [5]                                       5 [5]
     '1' ( 49) |00110 [5]                                       6 [5]
     '2' ( 50) |00111 [5]                                       7 [5]
     '3' ( 51) |100110 [6]                                     26 [6]
     '4' ( 52) |100111 [6]                                     27 [6]
     '5' ( 53) |101000 [6]                                     28 [6]
     '6' ( 54) |101001 [6]                                     29 [6]
     '7' ( 55) |101010 [6]                                     2a [6]
     '8' ( 56) |101011 [6]                                     2b [6]
     '9' ( 57) |101100 [6]                                     2c [6]
     ':' ( 58) |11110110|0 [9]                                1ec [9]
     ';' ( 59) |11101010| [8]                                  ea [8]
     '<' ( 60) |11111111|11111111|10 [18]                  3fffe [18]
     '=' ( 61) |101101 [6]                                     2d [6]
     '>' ( 62) |11111111|11111110|0 [17]                   1fffc [17]
     '?' ( 63) |11110110|1 [9]                                1ed [9]
     '@' ( 64) |11111111|111011 [14]                        3ffb [14]
     'A' ( 65) |1101111 [7]                                    6f [7]
     'B' ( 66) |11101011| [8]                                  eb [8]
     'C' ( 67) |11101100| [8]                                  ec [8]
     'D' ( 68) |11101101| [8]                                  ed [8]
     'E' ( 69) |11101110| [8]                                  ee [8]
     'F' ( 70) |1110000 [7]                                    70 [7]



Peon & Ruellan           Expires April 24, 2014                [Page 23]


Internet-Draft                    HPACK                     October 2013


     'G' ( 71) |11110111|0 [9]                                1ee [9]
     'H' ( 72) |11110111|1 [9]                                1ef [9]
     'I' ( 73) |11111000|0 [9]                                1f0 [9]
     'J' ( 74) |11111000|1 [9]                                1f1 [9]
     'K' ( 75) |11111110|11 [10]                             3fb [10]
     'L' ( 76) |11111001|0 [9]                                1f2 [9]
     'M' ( 77) |11101111| [8]                                  ef [8]
     'N' ( 78) |11111001|1 [9]                                1f3 [9]
     'O' ( 79) |11111010|0 [9]                                1f4 [9]
     'P' ( 80) |11111010|1 [9]                                1f5 [9]
     'Q' ( 81) |11111011|0 [9]                                1f6 [9]
     'R' ( 82) |11111011|1 [9]                                1f7 [9]
     'S' ( 83) |11110000| [8]                                  f0 [8]
     'T' ( 84) |11110001| [8]                                  f1 [8]
     'U' ( 85) |11111100|0 [9]                                1f8 [9]
     'V' ( 86) |11111100|1 [9]                                1f9 [9]
     'W' ( 87) |11111101|0 [9]                                1fa [9]
     'X' ( 88) |11111101|1 [9]                                1fb [9]
     'Y' ( 89) |11111110|0 [9]                                1fc [9]
     'Z' ( 90) |11111111|00 [10]                             3fc [10]
     '[' ( 91) |11111111|111100 [14]                        3ffc [14]
     '\' ( 92) |11111111|11111111|11111011|010 [27]      7ffffda [27]
     ']' ( 93) |11111111|11100 [13]                         1ffc [13]
     '^' ( 94) |11111111|111101 [14]                        3ffd [14]
     '_' ( 95) |101110 [6]                                     2e [6]
     '`' ( 96) |11111111|11111111|110 [19]                 7fffe [19]
     'a' ( 97) |01000 [5]                                       8 [5]
     'b' ( 98) |101111 [6]                                     2f [6]
     'c' ( 99) |01001 [5]                                       9 [5]
     'd' (100) |110000 [6]                                     30 [6]
     'e' (101) |0001 [4]                                        1 [4]
     'f' (102) |110001 [6]                                     31 [6]
     'g' (103) |110010 [6]                                     32 [6]
     'h' (104) |110011 [6]                                     33 [6]
     'i' (105) |01010 [5]                                       a [5]
     'j' (106) |1110001 [7]                                    71 [7]
     'k' (107) |1110010 [7]                                    72 [7]
     'l' (108) |01011 [5]                                       b [5]
     'm' (109) |110100 [6]                                     34 [6]
     'n' (110) |01100 [5]                                       c [5]
     'o' (111) |01101 [5]                                       d [5]
     'p' (112) |01110 [5]                                       e [5]
     'q' (113) |11110010| [8]                                  f2 [8]
     'r' (114) |01111 [5]                                       f [5]
     's' (115) |10000 [5]                                      10 [5]
     't' (116) |10001 [5]                                      11 [5]
     'u' (117) |110101 [6]                                     35 [6]
     'v' (118) |1110011 [7]                                    73 [7]



Peon & Ruellan           Expires April 24, 2014                [Page 24]


Internet-Draft                    HPACK                     October 2013


     'w' (119) |110110 [6]                                     36 [6]
     'x' (120) |11110011| [8]                                  f3 [8]
     'y' (121) |11110100| [8]                                  f4 [8]
     'z' (122) |11110101| [8]                                  f5 [8]
     '{' (123) |11111111|11111110|1 [17]                   1fffd [17]
     '|' (124) |11111111|101 [11]                            7fd [11]
     '}' (125) |11111111|11111111|0 [17]                   1fffe [17]
     '~' (126) |11111111|1101 [12]                           ffd [12]
         (127) |11111111|11111111|11111011|011 [27]      7ffffdb [27]
         (128) |11111111|11111111|11111011|100 [27]      7ffffdc [27]
         (129) |11111111|11111111|11111011|101 [27]      7ffffdd [27]
         (130) |11111111|11111111|11111011|110 [27]      7ffffde [27]
         (131) |11111111|11111111|11111011|111 [27]      7ffffdf [27]
         (132) |11111111|11111111|11111100|000 [27]      7ffffe0 [27]
         (133) |11111111|11111111|11111100|001 [27]      7ffffe1 [27]
         (134) |11111111|11111111|11111100|010 [27]      7ffffe2 [27]
         (135) |11111111|11111111|11111100|011 [27]      7ffffe3 [27]
         (136) |11111111|11111111|11111100|100 [27]      7ffffe4 [27]
         (137) |11111111|11111111|11111100|101 [27]      7ffffe5 [27]
         (138) |11111111|11111111|11111100|110 [27]      7ffffe6 [27]
         (139) |11111111|11111111|11111100|111 [27]      7ffffe7 [27]
         (140) |11111111|11111111|11111101|000 [27]      7ffffe8 [27]
         (141) |11111111|11111111|11111101|001 [27]      7ffffe9 [27]
         (142) |11111111|11111111|11111101|010 [27]      7ffffea [27]
         (143) |11111111|11111111|11111101|011 [27]      7ffffeb [27]
         (144) |11111111|11111111|11111101|100 [27]      7ffffec [27]
         (145) |11111111|11111111|11111101|101 [27]      7ffffed [27]
         (146) |11111111|11111111|11111101|110 [27]      7ffffee [27]
         (147) |11111111|11111111|11111101|111 [27]      7ffffef [27]
         (148) |11111111|11111111|11111110|000 [27]      7fffff0 [27]
         (149) |11111111|11111111|11111110|001 [27]      7fffff1 [27]
         (150) |11111111|11111111|11111110|010 [27]      7fffff2 [27]
         (151) |11111111|11111111|11111110|011 [27]      7fffff3 [27]
         (152) |11111111|11111111|11111110|100 [27]      7fffff4 [27]
         (153) |11111111|11111111|11111110|101 [27]      7fffff5 [27]
         (154) |11111111|11111111|11111110|110 [27]      7fffff6 [27]
         (155) |11111111|11111111|11111110|111 [27]      7fffff7 [27]
         (156) |11111111|11111111|11111111|000 [27]      7fffff8 [27]
         (157) |11111111|11111111|11111111|001 [27]      7fffff9 [27]
         (158) |11111111|11111111|11111111|010 [27]      7fffffa [27]
         (159) |11111111|11111111|11111111|011 [27]      7fffffb [27]
         (160) |11111111|11111111|11111111|100 [27]      7fffffc [27]
         (161) |11111111|11111111|11111111|101 [27]      7fffffd [27]
         (162) |11111111|11111111|11111111|110 [27]      7fffffe [27]
         (163) |11111111|11111111|11111111|111 [27]      7ffffff [27]
         (164) |11111111|11111111|11100000|00 [26]       3ffff80 [26]
         (165) |11111111|11111111|11100000|01 [26]       3ffff81 [26]
         (166) |11111111|11111111|11100000|10 [26]       3ffff82 [26]



Peon & Ruellan           Expires April 24, 2014                [Page 25]


Internet-Draft                    HPACK                     October 2013


         (167) |11111111|11111111|11100000|11 [26]       3ffff83 [26]
         (168) |11111111|11111111|11100001|00 [26]       3ffff84 [26]
         (169) |11111111|11111111|11100001|01 [26]       3ffff85 [26]
         (170) |11111111|11111111|11100001|10 [26]       3ffff86 [26]
         (171) |11111111|11111111|11100001|11 [26]       3ffff87 [26]
         (172) |11111111|11111111|11100010|00 [26]       3ffff88 [26]
         (173) |11111111|11111111|11100010|01 [26]       3ffff89 [26]
         (174) |11111111|11111111|11100010|10 [26]       3ffff8a [26]
         (175) |11111111|11111111|11100010|11 [26]       3ffff8b [26]
         (176) |11111111|11111111|11100011|00 [26]       3ffff8c [26]
         (177) |11111111|11111111|11100011|01 [26]       3ffff8d [26]
         (178) |11111111|11111111|11100011|10 [26]       3ffff8e [26]
         (179) |11111111|11111111|11100011|11 [26]       3ffff8f [26]
         (180) |11111111|11111111|11100100|00 [26]       3ffff90 [26]
         (181) |11111111|11111111|11100100|01 [26]       3ffff91 [26]
         (182) |11111111|11111111|11100100|10 [26]       3ffff92 [26]
         (183) |11111111|11111111|11100100|11 [26]       3ffff93 [26]
         (184) |11111111|11111111|11100101|00 [26]       3ffff94 [26]
         (185) |11111111|11111111|11100101|01 [26]       3ffff95 [26]
         (186) |11111111|11111111|11100101|10 [26]       3ffff96 [26]
         (187) |11111111|11111111|11100101|11 [26]       3ffff97 [26]
         (188) |11111111|11111111|11100110|00 [26]       3ffff98 [26]
         (189) |11111111|11111111|11100110|01 [26]       3ffff99 [26]
         (190) |11111111|11111111|11100110|10 [26]       3ffff9a [26]
         (191) |11111111|11111111|11100110|11 [26]       3ffff9b [26]
         (192) |11111111|11111111|11100111|00 [26]       3ffff9c [26]
         (193) |11111111|11111111|11100111|01 [26]       3ffff9d [26]
         (194) |11111111|11111111|11100111|10 [26]       3ffff9e [26]
         (195) |11111111|11111111|11100111|11 [26]       3ffff9f [26]
         (196) |11111111|11111111|11101000|00 [26]       3ffffa0 [26]
         (197) |11111111|11111111|11101000|01 [26]       3ffffa1 [26]
         (198) |11111111|11111111|11101000|10 [26]       3ffffa2 [26]
         (199) |11111111|11111111|11101000|11 [26]       3ffffa3 [26]
         (200) |11111111|11111111|11101001|00 [26]       3ffffa4 [26]
         (201) |11111111|11111111|11101001|01 [26]       3ffffa5 [26]
         (202) |11111111|11111111|11101001|10 [26]       3ffffa6 [26]
         (203) |11111111|11111111|11101001|11 [26]       3ffffa7 [26]
         (204) |11111111|11111111|11101010|00 [26]       3ffffa8 [26]
         (205) |11111111|11111111|11101010|01 [26]       3ffffa9 [26]
         (206) |11111111|11111111|11101010|10 [26]       3ffffaa [26]
         (207) |11111111|11111111|11101010|11 [26]       3ffffab [26]
         (208) |11111111|11111111|11101011|00 [26]       3ffffac [26]
         (209) |11111111|11111111|11101011|01 [26]       3ffffad [26]
         (210) |11111111|11111111|11101011|10 [26]       3ffffae [26]
         (211) |11111111|11111111|11101011|11 [26]       3ffffaf [26]
         (212) |11111111|11111111|11101100|00 [26]       3ffffb0 [26]
         (213) |11111111|11111111|11101100|01 [26]       3ffffb1 [26]
         (214) |11111111|11111111|11101100|10 [26]       3ffffb2 [26]



Peon & Ruellan           Expires April 24, 2014                [Page 26]


Internet-Draft                    HPACK                     October 2013


         (215) |11111111|11111111|11101100|11 [26]       3ffffb3 [26]
         (216) |11111111|11111111|11101101|00 [26]       3ffffb4 [26]
         (217) |11111111|11111111|11101101|01 [26]       3ffffb5 [26]
         (218) |11111111|11111111|11101101|10 [26]       3ffffb6 [26]
         (219) |11111111|11111111|11101101|11 [26]       3ffffb7 [26]
         (220) |11111111|11111111|11101110|00 [26]       3ffffb8 [26]
         (221) |11111111|11111111|11101110|01 [26]       3ffffb9 [26]
         (222) |11111111|11111111|11101110|10 [26]       3ffffba [26]
         (223) |11111111|11111111|11101110|11 [26]       3ffffbb [26]
         (224) |11111111|11111111|11101111|00 [26]       3ffffbc [26]
         (225) |11111111|11111111|11101111|01 [26]       3ffffbd [26]
         (226) |11111111|11111111|11101111|10 [26]       3ffffbe [26]
         (227) |11111111|11111111|11101111|11 [26]       3ffffbf [26]
         (228) |11111111|11111111|11110000|00 [26]       3ffffc0 [26]
         (229) |11111111|11111111|11110000|01 [26]       3ffffc1 [26]
         (230) |11111111|11111111|11110000|10 [26]       3ffffc2 [26]
         (231) |11111111|11111111|11110000|11 [26]       3ffffc3 [26]
         (232) |11111111|11111111|11110001|00 [26]       3ffffc4 [26]
         (233) |11111111|11111111|11110001|01 [26]       3ffffc5 [26]
         (234) |11111111|11111111|11110001|10 [26]       3ffffc6 [26]
         (235) |11111111|11111111|11110001|11 [26]       3ffffc7 [26]
         (236) |11111111|11111111|11110010|00 [26]       3ffffc8 [26]
         (237) |11111111|11111111|11110010|01 [26]       3ffffc9 [26]
         (238) |11111111|11111111|11110010|10 [26]       3ffffca [26]
         (239) |11111111|11111111|11110010|11 [26]       3ffffcb [26]
         (240) |11111111|11111111|11110011|00 [26]       3ffffcc [26]
         (241) |11111111|11111111|11110011|01 [26]       3ffffcd [26]
         (242) |11111111|11111111|11110011|10 [26]       3ffffce [26]
         (243) |11111111|11111111|11110011|11 [26]       3ffffcf [26]
         (244) |11111111|11111111|11110100|00 [26]       3ffffd0 [26]
         (245) |11111111|11111111|11110100|01 [26]       3ffffd1 [26]
         (246) |11111111|11111111|11110100|10 [26]       3ffffd2 [26]
         (247) |11111111|11111111|11110100|11 [26]       3ffffd3 [26]
         (248) |11111111|11111111|11110101|00 [26]       3ffffd4 [26]
         (249) |11111111|11111111|11110101|01 [26]       3ffffd5 [26]
         (250) |11111111|11111111|11110101|10 [26]       3ffffd6 [26]
         (251) |11111111|11111111|11110101|11 [26]       3ffffd7 [26]
         (252) |11111111|11111111|11110110|00 [26]       3ffffd8 [26]
         (253) |11111111|11111111|11110110|01 [26]       3ffffd9 [26]
         (254) |11111111|11111111|11110110|10 [26]       3ffffda [26]
         (255) |11111111|11111111|11110110|11 [26]       3ffffdb [26]
     EOS (256) |11111111|11111111|11110111|00 [26]       3ffffdc [26]









Peon & Ruellan           Expires April 24, 2014                [Page 27]


Internet-Draft                    HPACK                     October 2013


Appendix D.  Huffman Codes for Responses

   The following Huffman codes are used when encoding string literals in
   the server to client direction.

   [[anchor11: This table is out of date and needs updating.  In
   particular, EOS needs to be at least 7-bits long and currently is
   not.]]


                aligned                                  aligned
                 to                           len         to     len
                 MSB                           in         LSB     in
          sym    as bits                      bits       as hex  bits
         (  0) |11111111|11111111|11011110|0 [25]        1ffffbc [25]
         (  1) |11111111|11111111|11011110|1 [25]        1ffffbd [25]
         (  2) |11111111|11111111|11011111|0 [25]        1ffffbe [25]
         (  3) |11111111|11111111|11011111|1 [25]        1ffffbf [25]
         (  4) |11111111|11111111|11100000|0 [25]        1ffffc0 [25]
         (  5) |11111111|11111111|11100000|1 [25]        1ffffc1 [25]
         (  6) |11111111|11111111|11100001|0 [25]        1ffffc2 [25]
         (  7) |11111111|11111111|11100001|1 [25]        1ffffc3 [25]
         (  8) |11111111|11111111|11100010|0 [25]        1ffffc4 [25]
         (  9) |11111111|11111111|11100010|1 [25]        1ffffc5 [25]
         ( 10) |11111111|11111111|11100011|0 [25]        1ffffc6 [25]
         ( 11) |11111111|11111111|11100011|1 [25]        1ffffc7 [25]
         ( 12) |11111111|11111111|11100100|0 [25]        1ffffc8 [25]
         ( 13) |11111111|11111111|11100100|1 [25]        1ffffc9 [25]
         ( 14) |11111111|11111111|11100101|0 [25]        1ffffca [25]
         ( 15) |11111111|11111111|11100101|1 [25]        1ffffcb [25]
         ( 16) |11111111|11111111|11100110|0 [25]        1ffffcc [25]
         ( 17) |11111111|11111111|11100110|1 [25]        1ffffcd [25]
         ( 18) |11111111|11111111|11100111|0 [25]        1ffffce [25]
         ( 19) |11111111|11111111|11100111|1 [25]        1ffffcf [25]
         ( 20) |11111111|11111111|11101000|0 [25]        1ffffd0 [25]
         ( 21) |11111111|11111111|11101000|1 [25]        1ffffd1 [25]
         ( 22) |11111111|11111111|11101001|0 [25]        1ffffd2 [25]
         ( 23) |11111111|11111111|11101001|1 [25]        1ffffd3 [25]
         ( 24) |11111111|11111111|11101010|0 [25]        1ffffd4 [25]
         ( 25) |11111111|11111111|11101010|1 [25]        1ffffd5 [25]
         ( 26) |11111111|11111111|11101011|0 [25]        1ffffd6 [25]
         ( 27) |11111111|11111111|11101011|1 [25]        1ffffd7 [25]
         ( 28) |11111111|11111111|11101100|0 [25]        1ffffd8 [25]
         ( 29) |11111111|11111111|11101100|1 [25]        1ffffd9 [25]
         ( 30) |11111111|11111111|11101101|0 [25]        1ffffda [25]
         ( 31) |11111111|11111111|11101101|1 [25]        1ffffdb [25]
     ' ' ( 32) |0000 [4]                                        0 [4]
     '!' ( 33) |11111111|1010 [12]                           ffa [12]



Peon & Ruellan           Expires April 24, 2014                [Page 28]


Internet-Draft                    HPACK                     October 2013


     '"' ( 34) |1101010 [7]                                    6a [7]
     '#' ( 35) |11111111|11010 [13]                         1ffa [13]
     '$' ( 36) |11111111|111100 [14]                        3ffc [14]
     '%' ( 37) |11110110|0 [9]                                1ec [9]
     '&' ( 38) |11111110|00 [10]                             3f8 [10]
     ''' ( 39) |11111111|11011 [13]                         1ffb [13]
     '(' ( 40) |11110110|1 [9]                                1ed [9]
     ')' ( 41) |11110111|0 [9]                                1ee [9]
     '*' ( 42) |11111111|1011 [12]                           ffb [12]
     '+' ( 43) |11111111|010 [11]                            7fa [11]
     ',' ( 44) |100010 [6]                                     22 [6]
     '-' ( 45) |100011 [6]                                     23 [6]
     '.' ( 46) |100100 [6]                                     24 [6]
     '/' ( 47) |1101011 [7]                                    6b [7]
     '0' ( 48) |0001 [4]                                        1 [4]
     '1' ( 49) |0010 [4]                                        2 [4]
     '2' ( 50) |0011 [4]                                        3 [4]
     '3' ( 51) |01000 [5]                                       8 [5]
     '4' ( 52) |01001 [5]                                       9 [5]
     '5' ( 53) |01010 [5]                                       a [5]
     '6' ( 54) |100101 [6]                                     25 [6]
     '7' ( 55) |100110 [6]                                     26 [6]
     '8' ( 56) |01011 [5]                                       b [5]
     '9' ( 57) |01100 [5]                                       c [5]
     ':' ( 58) |01101 [5]                                       d [5]
     ';' ( 59) |11110111|1 [9]                                1ef [9]
     '<' ( 60) |11111111|11111010| [16]                     fffa [16]
     '=' ( 61) |1101100 [7]                                    6c [7]
     '>' ( 62) |11111111|11100 [13]                         1ffc [13]
     '?' ( 63) |11111111|1100 [12]                           ffc [12]
     '@' ( 64) |11111111|11111011| [16]                     fffb [16]
     'A' ( 65) |1101101 [7]                                    6d [7]
     'B' ( 66) |11101010| [8]                                  ea [8]
     'C' ( 67) |11101011| [8]                                  eb [8]
     'D' ( 68) |11101100| [8]                                  ec [8]
     'E' ( 69) |11101101| [8]                                  ed [8]
     'F' ( 70) |11101110| [8]                                  ee [8]
     'G' ( 71) |100111 [6]                                     27 [6]
     'H' ( 72) |11111000|0 [9]                                1f0 [9]
     'I' ( 73) |11101111| [8]                                  ef [8]
     'J' ( 74) |11110000| [8]                                  f0 [8]
     'K' ( 75) |11111110|01 [10]                             3f9 [10]
     'L' ( 76) |11111000|1 [9]                                1f1 [9]
     'M' ( 77) |101000 [6]                                     28 [6]
     'N' ( 78) |11110001| [8]                                  f1 [8]
     'O' ( 79) |11110010| [8]                                  f2 [8]
     'P' ( 80) |11111001|0 [9]                                1f2 [9]
     'Q' ( 81) |11111110|10 [10]                             3fa [10]



Peon & Ruellan           Expires April 24, 2014                [Page 29]


Internet-Draft                    HPACK                     October 2013


     'R' ( 82) |11111001|1 [9]                                1f3 [9]
     'S' ( 83) |101001 [6]                                     29 [6]
     'T' ( 84) |01110 [5]                                       e [5]
     'U' ( 85) |11111010|0 [9]                                1f4 [9]
     'V' ( 86) |11111010|1 [9]                                1f5 [9]
     'W' ( 87) |11110011| [8]                                  f3 [8]
     'X' ( 88) |11111110|11 [10]                             3fb [10]
     'Y' ( 89) |11111011|0 [9]                                1f6 [9]
     'Z' ( 90) |11111111|00 [10]                             3fc [10]
     '[' ( 91) |11111111|011 [11]                            7fb [11]
     '\' ( 92) |11111111|11101 [13]                         1ffd [13]
     ']' ( 93) |11111111|100 [11]                            7fc [11]
     '^' ( 94) |11111111|1111100 [15]                       7ffc [15]
     '_' ( 95) |11111011|1 [9]                                1f7 [9]
     '`' ( 96) |11111111|11111111|0 [17]                   1fffe [17]
     'a' ( 97) |01111 [5]                                       f [5]
     'b' ( 98) |1101110 [7]                                    6e [7]
     'c' ( 99) |101010 [6]                                     2a [6]
     'd' (100) |101011 [6]                                     2b [6]
     'e' (101) |10000 [5]                                      10 [5]
     'f' (102) |1101111 [7]                                    6f [7]
     'g' (103) |1110000 [7]                                    70 [7]
     'h' (104) |1110001 [7]                                    71 [7]
     'i' (105) |101100 [6]                                     2c [6]
     'j' (106) |11111100|0 [9]                                1f8 [9]
     'k' (107) |11111100|1 [9]                                1f9 [9]
     'l' (108) |1110010 [7]                                    72 [7]
     'm' (109) |101101 [6]                                     2d [6]
     'n' (110) |101110 [6]                                     2e [6]
     'o' (111) |101111 [6]                                     2f [6]
     'p' (112) |110000 [6]                                     30 [6]
     'q' (113) |11111101|0 [9]                                1fa [9]
     'r' (114) |110001 [6]                                     31 [6]
     's' (115) |110010 [6]                                     32 [6]
     't' (116) |110011 [6]                                     33 [6]
     'u' (117) |110100 [6]                                     34 [6]
     'v' (118) |1110011 [7]                                    73 [7]
     'w' (119) |11110100| [8]                                  f4 [8]
     'x' (120) |1110100 [7]                                    74 [7]
     'y' (121) |11110101| [8]                                  f5 [8]
     'z' (122) |11111101|1 [9]                                1fb [9]
     '{' (123) |11111111|11111100| [16]                     fffc [16]
     '|' (124) |11111111|111101 [14]                        3ffd [14]
     '}' (125) |11111111|11111101| [16]                     fffd [16]
     '~' (126) |11111111|11111110| [16]                     fffe [16]
         (127) |11111111|11111111|11101110|0 [25]        1ffffdc [25]
         (128) |11111111|11111111|11101110|1 [25]        1ffffdd [25]
         (129) |11111111|11111111|11101111|0 [25]        1ffffde [25]



Peon & Ruellan           Expires April 24, 2014                [Page 30]


Internet-Draft                    HPACK                     October 2013


         (130) |11111111|11111111|11101111|1 [25]        1ffffdf [25]
         (131) |11111111|11111111|11110000|0 [25]        1ffffe0 [25]
         (132) |11111111|11111111|11110000|1 [25]        1ffffe1 [25]
         (133) |11111111|11111111|11110001|0 [25]        1ffffe2 [25]
         (134) |11111111|11111111|11110001|1 [25]        1ffffe3 [25]
         (135) |11111111|11111111|11110010|0 [25]        1ffffe4 [25]
         (136) |11111111|11111111|11110010|1 [25]        1ffffe5 [25]
         (137) |11111111|11111111|11110011|0 [25]        1ffffe6 [25]
         (138) |11111111|11111111|11110011|1 [25]        1ffffe7 [25]
         (139) |11111111|11111111|11110100|0 [25]        1ffffe8 [25]
         (140) |11111111|11111111|11110100|1 [25]        1ffffe9 [25]
         (141) |11111111|11111111|11110101|0 [25]        1ffffea [25]
         (142) |11111111|11111111|11110101|1 [25]        1ffffeb [25]
         (143) |11111111|11111111|11110110|0 [25]        1ffffec [25]
         (144) |11111111|11111111|11110110|1 [25]        1ffffed [25]
         (145) |11111111|11111111|11110111|0 [25]        1ffffee [25]
         (146) |11111111|11111111|11110111|1 [25]        1ffffef [25]
         (147) |11111111|11111111|11111000|0 [25]        1fffff0 [25]
         (148) |11111111|11111111|11111000|1 [25]        1fffff1 [25]
         (149) |11111111|11111111|11111001|0 [25]        1fffff2 [25]
         (150) |11111111|11111111|11111001|1 [25]        1fffff3 [25]
         (151) |11111111|11111111|11111010|0 [25]        1fffff4 [25]
         (152) |11111111|11111111|11111010|1 [25]        1fffff5 [25]
         (153) |11111111|11111111|11111011|0 [25]        1fffff6 [25]
         (154) |11111111|11111111|11111011|1 [25]        1fffff7 [25]
         (155) |11111111|11111111|11111100|0 [25]        1fffff8 [25]
         (156) |11111111|11111111|11111100|1 [25]        1fffff9 [25]
         (157) |11111111|11111111|11111101|0 [25]        1fffffa [25]
         (158) |11111111|11111111|11111101|1 [25]        1fffffb [25]
         (159) |11111111|11111111|11111110|0 [25]        1fffffc [25]
         (160) |11111111|11111111|11111110|1 [25]        1fffffd [25]
         (161) |11111111|11111111|11111111|0 [25]        1fffffe [25]
         (162) |11111111|11111111|11111111|1 [25]        1ffffff [25]
         (163) |11111111|11111111|10000000| [24]          ffff80 [24]
         (164) |11111111|11111111|10000001| [24]          ffff81 [24]
         (165) |11111111|11111111|10000010| [24]          ffff82 [24]
         (166) |11111111|11111111|10000011| [24]          ffff83 [24]
         (167) |11111111|11111111|10000100| [24]          ffff84 [24]
         (168) |11111111|11111111|10000101| [24]          ffff85 [24]
         (169) |11111111|11111111|10000110| [24]          ffff86 [24]
         (170) |11111111|11111111|10000111| [24]          ffff87 [24]
         (171) |11111111|11111111|10001000| [24]          ffff88 [24]
         (172) |11111111|11111111|10001001| [24]          ffff89 [24]
         (173) |11111111|11111111|10001010| [24]          ffff8a [24]
         (174) |11111111|11111111|10001011| [24]          ffff8b [24]
         (175) |11111111|11111111|10001100| [24]          ffff8c [24]
         (176) |11111111|11111111|10001101| [24]          ffff8d [24]
         (177) |11111111|11111111|10001110| [24]          ffff8e [24]



Peon & Ruellan           Expires April 24, 2014                [Page 31]


Internet-Draft                    HPACK                     October 2013


         (178) |11111111|11111111|10001111| [24]          ffff8f [24]
         (179) |11111111|11111111|10010000| [24]          ffff90 [24]
         (180) |11111111|11111111|10010001| [24]          ffff91 [24]
         (181) |11111111|11111111|10010010| [24]          ffff92 [24]
         (182) |11111111|11111111|10010011| [24]          ffff93 [24]
         (183) |11111111|11111111|10010100| [24]          ffff94 [24]
         (184) |11111111|11111111|10010101| [24]          ffff95 [24]
         (185) |11111111|11111111|10010110| [24]          ffff96 [24]
         (186) |11111111|11111111|10010111| [24]          ffff97 [24]
         (187) |11111111|11111111|10011000| [24]          ffff98 [24]
         (188) |11111111|11111111|10011001| [24]          ffff99 [24]
         (189) |11111111|11111111|10011010| [24]          ffff9a [24]
         (190) |11111111|11111111|10011011| [24]          ffff9b [24]
         (191) |11111111|11111111|10011100| [24]          ffff9c [24]
         (192) |11111111|11111111|10011101| [24]          ffff9d [24]
         (193) |11111111|11111111|10011110| [24]          ffff9e [24]
         (194) |11111111|11111111|10011111| [24]          ffff9f [24]
         (195) |11111111|11111111|10100000| [24]          ffffa0 [24]
         (196) |11111111|11111111|10100001| [24]          ffffa1 [24]
         (197) |11111111|11111111|10100010| [24]          ffffa2 [24]
         (198) |11111111|11111111|10100011| [24]          ffffa3 [24]
         (199) |11111111|11111111|10100100| [24]          ffffa4 [24]
         (200) |11111111|11111111|10100101| [24]          ffffa5 [24]
         (201) |11111111|11111111|10100110| [24]          ffffa6 [24]
         (202) |11111111|11111111|10100111| [24]          ffffa7 [24]
         (203) |11111111|11111111|10101000| [24]          ffffa8 [24]
         (204) |11111111|11111111|10101001| [24]          ffffa9 [24]
         (205) |11111111|11111111|10101010| [24]          ffffaa [24]
         (206) |11111111|11111111|10101011| [24]          ffffab [24]
         (207) |11111111|11111111|10101100| [24]          ffffac [24]
         (208) |11111111|11111111|10101101| [24]          ffffad [24]
         (209) |11111111|11111111|10101110| [24]          ffffae [24]
         (210) |11111111|11111111|10101111| [24]          ffffaf [24]
         (211) |11111111|11111111|10110000| [24]          ffffb0 [24]
         (212) |11111111|11111111|10110001| [24]          ffffb1 [24]
         (213) |11111111|11111111|10110010| [24]          ffffb2 [24]
         (214) |11111111|11111111|10110011| [24]          ffffb3 [24]
         (215) |11111111|11111111|10110100| [24]          ffffb4 [24]
         (216) |11111111|11111111|10110101| [24]          ffffb5 [24]
         (217) |11111111|11111111|10110110| [24]          ffffb6 [24]
         (218) |11111111|11111111|10110111| [24]          ffffb7 [24]
         (219) |11111111|11111111|10111000| [24]          ffffb8 [24]
         (220) |11111111|11111111|10111001| [24]          ffffb9 [24]
         (221) |11111111|11111111|10111010| [24]          ffffba [24]
         (222) |11111111|11111111|10111011| [24]          ffffbb [24]
         (223) |11111111|11111111|10111100| [24]          ffffbc [24]
         (224) |11111111|11111111|10111101| [24]          ffffbd [24]
         (225) |11111111|11111111|10111110| [24]          ffffbe [24]



Peon & Ruellan           Expires April 24, 2014                [Page 32]


Internet-Draft                    HPACK                     October 2013


         (226) |11111111|11111111|10111111| [24]          ffffbf [24]
         (227) |11111111|11111111|11000000| [24]          ffffc0 [24]
         (228) |11111111|11111111|11000001| [24]          ffffc1 [24]
         (229) |11111111|11111111|11000010| [24]          ffffc2 [24]
         (230) |11111111|11111111|11000011| [24]          ffffc3 [24]
         (231) |11111111|11111111|11000100| [24]          ffffc4 [24]
         (232) |11111111|11111111|11000101| [24]          ffffc5 [24]
         (233) |11111111|11111111|11000110| [24]          ffffc6 [24]
         (234) |11111111|11111111|11000111| [24]          ffffc7 [24]
         (235) |11111111|11111111|11001000| [24]          ffffc8 [24]
         (236) |11111111|11111111|11001001| [24]          ffffc9 [24]
         (237) |11111111|11111111|11001010| [24]          ffffca [24]
         (238) |11111111|11111111|11001011| [24]          ffffcb [24]
         (239) |11111111|11111111|11001100| [24]          ffffcc [24]
         (240) |11111111|11111111|11001101| [24]          ffffcd [24]
         (241) |11111111|11111111|11001110| [24]          ffffce [24]
         (242) |11111111|11111111|11001111| [24]          ffffcf [24]
         (243) |11111111|11111111|11010000| [24]          ffffd0 [24]
         (244) |11111111|11111111|11010001| [24]          ffffd1 [24]
         (245) |11111111|11111111|11010010| [24]          ffffd2 [24]
         (246) |11111111|11111111|11010011| [24]          ffffd3 [24]
         (247) |11111111|11111111|11010100| [24]          ffffd4 [24]
         (248) |11111111|11111111|11010101| [24]          ffffd5 [24]
         (249) |11111111|11111111|11010110| [24]          ffffd6 [24]
         (250) |11111111|11111111|11010111| [24]          ffffd7 [24]
         (251) |11111111|11111111|11011000| [24]          ffffd8 [24]
         (252) |11111111|11111111|11011001| [24]          ffffd9 [24]
         (253) |11111111|11111111|11011010| [24]          ffffda [24]
         (254) |11111111|11111111|11011011| [24]          ffffdb [24]
         (255) |11111111|11111111|11011100| [24]          ffffdc [24]
     EOS (256) |11111111|11111111|11011101| [24]          ffffdd [24]


Appendix E.  Examples

   A number of examples are worked through here, for both requests and
   responses, and with and without huffman coding.

E.1.  Request Decoding Example With Huffman



   # Header set to be encoded
   :method: GET
   :scheme: http
   :path: /
   :authority: www.foo.com




Peon & Ruellan           Expires April 24, 2014                [Page 33]


Internet-Draft                    HPACK                     October 2013


   # Hexdump of encoded data which will be decoded
   02 84 f7 77 78 ff 07 83 ce 31 77 06 81 0f 04 88 | ...wx....1w.....
   db 6d 89 8b 5a 44 b7 4f                         | .m..ZD.O

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:
           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "84"
           decoded: 4
       value_data:
           is_huffman_encoded: 1
           encoded: "f77778ff"
           decoded: "GET"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '07'
       name_index:
           encoded: "07"
           decoded: 7
       value_data_length:
           encoded: "83"
           decoded: 3
       value_data:
           is_huffman_encoded: 1
           encoded: "ce3177"
           decoded: "http"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '06'
       name_index:
           encoded: "06"
           decoded: 6
       value_data_length:
           encoded: "81"
           decoded: 1
       value_data:
           is_huffman_encoded: 1
           encoded: "0f"
           decoded: "/"

   LITERAL_INCREMENTAL_OPCODE:



Peon & Ruellan           Expires April 24, 2014                [Page 34]


Internet-Draft                    HPACK                     October 2013


           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '04'
       name_index:
           encoded: "04"
           decoded: 4
       value_data_length:
           encoded: "88"
           decoded: 8
       value_data:
           is_huffman_encoded: 1
           encoded: "db6d898b5a44b74f"
           decoded: "www.foo.com"


   # Decoded header set
   :authority: www.foo.com
   :method: GET
   :path: /
   :scheme: http

   #########################

   # Header set to be encoded
   :method: GET
   :scheme: https
   :path: /
   :authority: www.bar.com
   cache-control: no-cache

   # Hexdump of encoded data which will be decoded
   03 84 ce 31 74 3f 02 88 db 6d 89 7a 1e 44 b7 4f | ...1t?...m.z.D.O
   1d 86 63 65 4a 13 98 ff 83 85                   | ..ceJ.....

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '03'
       name_index:
           encoded: "03"
           decoded: 3
       value_data_length:
           encoded: "84"
           decoded: 4
       value_data:
           is_huffman_encoded: 1
           encoded: "ce31743f"
           decoded: "https"




Peon & Ruellan           Expires April 24, 2014                [Page 35]


Internet-Draft                    HPACK                     October 2013


   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:
           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "88"
           decoded: 8
       value_data:
           is_huffman_encoded: 1
           encoded: "db6d897a1e44b74f"
           decoded: "www.bar.com"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '1d'
       name_index:
           encoded: "1d"
           decoded: 29
       value_data_length:
           encoded: "86"
           decoded: 6
       value_data:
           is_huffman_encoded: 1
           encoded: "63654a1398ff"
           decoded: "no-cache"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '83'
       entry_index:
           encoded: "83"
           decoded: 3

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '85'
       entry_index:
           encoded: "85"
           decoded: 5


   # Decoded header set
   :authority: www.bar.com
   :method: GET
   :path: /
   :scheme: https



Peon & Ruellan           Expires April 24, 2014                [Page 36]


Internet-Draft                    HPACK                     October 2013


   cache-control: no-cache

   #########################

   # Header set to be encoded
   :method: GET
   :scheme: https
   :path: /custom-path.css
   :authority: www.bar.com
   custom-key: custom-value

   # Hexdump of encoded data which will be decoded
   05 8b 04 eb 08 b7 49 5c 88 e6 44 c2 1f 00 88 4e | ......I\..D....N
   b0 8b 74 97 90 fa 7f 89 4e b0 8b 74 97 9a 17 a8 | ..t.....N..t....
   ff 82 86                                        | ...

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '05'
       name_index:
           encoded: "05"
           decoded: 5
       value_data_length:
           encoded: "8b"
           decoded: 11
       value_data:
           is_huffman_encoded: 1
           encoded: "04eb08b7495c88e644c21f"
           decoded: "/custom-path.css"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '00'
       name_index:
           encoded: "00"
           decoded: 0
       name_data_length:
           encoded: "88"
           decoded: 8
       name_data:
           is_huffman_encoded: 1
           encoded: "4eb08b749790fa7f"
           decoded: "custom-key"
       value_data_length:
           encoded: "89"
           decoded: 9
       value_data:



Peon & Ruellan           Expires April 24, 2014                [Page 37]


Internet-Draft                    HPACK                     October 2013


           is_huffman_encoded: 1
           encoded: "4eb08b74979a17a8ff"
           decoded: "custom-value"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '82'
       entry_index:
           encoded: "82"
           decoded: 2

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '86'
       entry_index:
           encoded: "86"
           decoded: 6


   # Decoded header set
   :authority: www.bar.com
   :method: GET
   :path: /custom-path.css
   :scheme: https
   custom-key: custom-value

   #########################


E.2.  Request Decoding Example Without Huffman



   # Header set to be encoded
   :method: GET
   :scheme: http
   :path: /
   :authority: www.foo.com

   # Hexdump of encoded data which will be decoded
   02 03 47 45 54 07 04 68 74 74 70 06 01 2f 04 0b | ..GET..http../..
   77 77 77 2e 66 6f 6f 2e 63 6f 6d                | www.foo.com

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:



Peon & Ruellan           Expires April 24, 2014                [Page 38]


Internet-Draft                    HPACK                     October 2013


           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "03"
           decoded: 3
       value_data:
           is_huffman_encoded: 0
           encoded: "474554"
           decoded: "GET"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '07'
       name_index:
           encoded: "07"
           decoded: 7
       value_data_length:
           encoded: "04"
           decoded: 4
       value_data:
           is_huffman_encoded: 0
           encoded: "68747470"
           decoded: "http"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '06'
       name_index:
           encoded: "06"
           decoded: 6
       value_data_length:
           encoded: "01"
           decoded: 1
       value_data:
           is_huffman_encoded: 0
           encoded: "2f"
           decoded: "/"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '04'
       name_index:
           encoded: "04"
           decoded: 4
       value_data_length:
           encoded: "0b"
           decoded: 11
       value_data:



Peon & Ruellan           Expires April 24, 2014                [Page 39]


Internet-Draft                    HPACK                     October 2013


           is_huffman_encoded: 0
           encoded: "7777772e666f6f2e636f6d"
           decoded: "www.foo.com"


   # Decoded header set
   :authority: www.foo.com
   :method: GET
   :path: /
   :scheme: http

   #########################

   # Header set to be encoded
   :method: GET
   :scheme: https
   :path: /
   :authority: www.bar.com
   cache-control: no-cache

   # Hexdump of encoded data which will be decoded
   03 05 68 74 74 70 73 02 0b 77 77 77 2e 62 61 72 | ..https..www.bar
   2e 63 6f 6d 1d 08 6e 6f 2d 63 61 63 68 65 83 85 | .com..no-cache..

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '03'
       name_index:
           encoded: "03"
           decoded: 3
       value_data_length:
           encoded: "05"
           decoded: 5
       value_data:
           is_huffman_encoded: 0
           encoded: "6874747073"
           decoded: "https"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:
           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "0b"
           decoded: 11



Peon & Ruellan           Expires April 24, 2014                [Page 40]


Internet-Draft                    HPACK                     October 2013


       value_data:
           is_huffman_encoded: 0
           encoded: "7777772e6261722e636f6d"
           decoded: "www.bar.com"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '1d'
       name_index:
           encoded: "1d"
           decoded: 29
       value_data_length:
           encoded: "08"
           decoded: 8
       value_data:
           is_huffman_encoded: 0
           encoded: "6e6f2d6361636865"
           decoded: "no-cache"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '83'
       entry_index:
           encoded: "83"
           decoded: 3

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '85'
       entry_index:
           encoded: "85"
           decoded: 5


   # Decoded header set
   :authority: www.bar.com
   :method: GET
   :path: /
   :scheme: https
   cache-control: no-cache

   #########################

   # Header set to be encoded
   :method: GET
   :scheme: https
   :path: /custom-path.css
   :authority: www.bar.com



Peon & Ruellan           Expires April 24, 2014                [Page 41]


Internet-Draft                    HPACK                     October 2013


   custom-key: custom-value

   # Hexdump of encoded data which will be decoded
   05 10 2f 63 75 73 74 6f 6d 2d 70 61 74 68 2e 63 | ../custom-path.c
   73 73 00 0a 63 75 73 74 6f 6d 2d 6b 65 79 0c 63 | ss..custom-key.c
   75 73 74 6f 6d 2d 76 61 6c 75 65 82 86          | ustom-value..

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '05'
       name_index:
           encoded: "05"
           decoded: 5
       value_data_length:
           encoded: "10"
           decoded: 16
       value_data:
           is_huffman_encoded: 0
           encoded: "2f637573746f6d2d706174682e637373"
           decoded: "/custom-path.css"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '00'
       name_index:
           encoded: "00"
           decoded: 0
       name_data_length:
           encoded: "0a"
           decoded: 10
       name_data:
           is_huffman_encoded: 0
           encoded: "637573746f6d2d6b6579"
           decoded: "custom-key"
       value_data_length:
           encoded: "0c"
           decoded: 12
       value_data:
           is_huffman_encoded: 0
           encoded: "637573746f6d2d76616c7565"
           decoded: "custom-value"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '82'
       entry_index:
           encoded: "82"



Peon & Ruellan           Expires April 24, 2014                [Page 42]


Internet-Draft                    HPACK                     October 2013


           decoded: 2

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '86'
       entry_index:
           encoded: "86"
           decoded: 6


   # Decoded header set
   :authority: www.bar.com
   :method: GET
   :path: /custom-path.css
   :scheme: https
   custom-key: custom-value

   #########################


E.3.  Response Decoding Example With Huffman



# Header set to be encoded
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

# Hexdump of encoded data which will be decoded
08 82 40 9f 18 86 c3 1b 39 bf 38 7f 22 92 a2 fb | ..@.....9.8."...
a2 03 20 f2 eb cc 0c 49 00 62 d2 43 4c 82 7a 1d | .. ....I.b.CL.z.
2f 91 68 71 cf 3c 32 6e bd 7e 9e 9e 92 6e 7e 32 | /.hq.<2n.~...n~2
55 7d bf                                        | U}.

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '08'
    name_index:
        encoded: "08"
        decoded: 8
    value_data_length:
        encoded: "82"
        decoded: 2
    value_data:
        is_huffman_encoded: 1



Peon & Ruellan           Expires April 24, 2014                [Page 43]


Internet-Draft                    HPACK                     October 2013


        encoded: "409f"
        decoded: "302"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '18'
    name_index:
        encoded: "18"
        decoded: 24
    value_data_length:
        encoded: "86"
        decoded: 6
    value_data:
        is_huffman_encoded: 1
        encoded: "c31b39bf387f"
        decoded: "private"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '22'
    name_index:
        encoded: "22"
        decoded: 34
    value_data_length:
        encoded: "92"
        decoded: 18
    value_data:
        is_huffman_encoded: 1
        encoded: "a2fba20320f2ebcc0c490062d2434c827a1d"
        decoded: "Mon, 21 OCt 2013 20:13:21 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '2f'
    name_index:
        encoded: "2f"
        decoded: 47
    value_data_length:
        encoded: "91"
        decoded: 17
    value_data:
        is_huffman_encoded: 1
        encoded: "6871cf3c326ebd7e9e9e926e7e32557dbf"
        decoded: ": https://www.bar.com"


# Decoded header set
:status: 302



Peon & Ruellan           Expires April 24, 2014                [Page 44]


Internet-Draft                    HPACK                     October 2013


cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
04 82 31 1f 03 92 a2 fb a2 03 20 f2 eb cc 0c 49 | ..1....... ....I
00 62 d2 43 4c c2 7a 1d 03 90 e3 9e 78 64 dd 7a | .b.CL.z.....xd.z
fd 3d 3d 24 dc fc 64 aa fb 7f 20 84 e1 fb b3 0f | .==$..d... .....
3d ff ee 02 df 7d fb 36 ed db b7 6e dd bb 76 ed | =....}.6...n..v.
db b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 | ..n..v...n..v...
6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd | n..v...n..v...n.
bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 | .v...n..v...n..v
ed db b7 6e dd bb 7e 3b 69 ec f0 fe 7e 1f d7 f3 | ...n..~;i...~...
d5 fe 7f 7e 5f d7 9f 6f 97 cb bf e9 b7 fb fe bc | ...~_..o........
fb 7c bb fe 9b 7f bf 8f 87 f3 f0 fe bc fc bb 7b | .|.............{
fe 9b 7e 3f d7 9f 6f 97 7f d3 6f f7 f1 fe bb 7e | ..~?..o...o....~
9b 7f bf 8f c7 f9 f0 db 4f 67 f5 e7 db e5 f4 ef | ........Og......
db fd f8 91 a1 3f 1d b4 f6 78 7f 3f 0f eb f9 ea | .....?...x.?....
ff 3f bf 2f eb cf b7 cb e5 df f4 db fd ff 5e 7d | .?./..........^}
be 5d ff 4d bf df c7 c3 f9 f8 7f 5e 7e 5d bd ff | .].M.......^~]..
4d bf 1f eb cf b7 cb bf e9 b7 fb f8 ff 5d bf 4d | M............].M
bf df c7 e3 fc f8 6d a7 b3 fa f3 ed f2 fa 77 ed | ......m.......w.
fe fc 48 d0 9f 8e da 7b 3c 3f 9f 87 f5 fc f5 7f | ..H....{<?......
9f df 97 f5 e7 db e5 f2 ef fa 6d fe ff af 3e df | ..........m...>.
2e ff a6 df ef e3 e1 fc fc 3f af 3f 2e de ff a6 | .........?.?....
df 8f f5 e7 db e5 df f4 db fd fc 7f ae df a6 df | ................
ef e3 f1 fe 7c 36 d3 d9 fd 79 f6 f9 7d 3b f6 ff | ....|6...y..};..
7e 24 68 4f c7 6d 3d 9e 1f cf c3 fa fe 7a bf cf | ~$hO.m=......z..
ef cb fa f3 ed f2 f9 77 fd 36 ff 7f d7 9f 6f 97 | .......w.6....o.
7f d3 6f f7 f1 f0 fe 7e 1f d7 9f 97 6f 7f d3 6f | ..o....~....o..o
c7 fa f3 ed f2 ef fa 6d fe fe 3f d7 6f d3 6f f7 | .......m..?.o.o.
f1 f8 ff 3e 1b 69 ec fe bc fb 7c be 9d fb 7f bf | ...>.i....|.....



Peon & Ruellan           Expires April 24, 2014                [Page 45]


Internet-Draft                    HPACK                     October 2013


12 34 27 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f | .4'..?....?....?
cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf | ....?....?....?.
f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 | ...?....?....?..
fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc | ..?....?....?...
ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff | .?....?....?....
3f cf f3 fc ff 3f cf f3 fc ff 3f cf f0 8d 09 0b | ?....?....?.....
5f d2 37 f0 86 c4 4a 23 ef 0e 70 c7 2b 2f bb 61 | _.7...J#..p.+/.a
7f 85 86 88                                     | ....

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "82"
        decoded: 2
    value_data:
        is_huffman_encoded: 1
        encoded: "311f"
        decoded: "200"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "92"
        decoded: 18
    value_data:
        is_huffman_encoded: 1
        encoded: "a2fba20320f2ebcc0c490062d2434cc27a1d"
        decoded: "Mon, 21 OCt 2013 20:13:22 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "90"
        decoded: 16
    value_data:



Peon & Ruellan           Expires April 24, 2014                [Page 46]


Internet-Draft                    HPACK                     October 2013


        is_huffman_encoded: 1
        encoded: "e39e7864dd7afd3d3d24dcfc64aafb7f"
        decoded: "https://www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '20'
    name_index:
        encoded: "20"
        decoded: 32
    value_data_length:
        encoded: "84"
        decoded: 4
    value_data:
        is_huffman_encoded: 1
        encoded: "e1fbb30f"
        decoded: "gzip"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '3d'
    name_index:
        encoded: "3d"
        decoded: 61
    value_data_length:
        encoded: "ffee02"
        decoded: 493
    value_data:
        is_huffman_encoded: 1
        encoded: "df7dfb36eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76edd\
bb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddb\
b76eddbb7e3b69ecf0fe7e1fd7f3d5fe7f7e5fd79f6f97cbbfe9b7fbfebcfb7cbbfe9b7\
fbf8f87f3f0febcfcbb7bfe9b7e3fd79f6f977fd36ff7f1febb7e9b7fbf8fc7f9f0db4f\
67f5e7dbe5f4efdbfdf891a13f1db4f6787f3f0febf9eaff3fbf2febcfb7cbe5dff4dbf\
dff5e7dbe5dff4dbfdfc7c3f9f87f5e7e5dbdff4dbf1febcfb7cbbfe9b7fbf8ff5dbf4d\
bfdfc7e3fcf86da7b3faf3edf2fa77edfefc48d09f8eda7b3c3f9f87f5fcf57f9fdf97f\
5e7dbe5f2effa6dfeffaf3edf2effa6dfefe3e1fcfc3faf3f2edeffa6df8ff5e7dbe5df\
f4dbfdfc7faedfa6dfefe3f1fe7c36d3d9fd79f6f97d3bf6ff7e24684fc76d3d9e1fcfc\
3fafe7abfcfefcbfaf3edf2f977fd36ff7fd79f6f977fd36ff7f1f0fe7e1fd79f976f7f\
d36fc7faf3edf2effa6dfefe3fd76fd36ff7f1f8ff3e1b69ecfebcfb7cbe9dfb7fbf123\
427fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcf\
f3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff\
3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff08d090b5fd237f086c44a23ef0e70c7\
2b2fbb617f"
        decoded: "foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\



Peon & Ruellan           Expires April 24, 2014                [Page 47]


Internet-Draft                    HPACK                     October 2013


IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '88'
    entry_index:
        encoded: "88"
        decoded: 8


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com



Peon & Ruellan           Expires April 24, 2014                [Page 48]


Internet-Draft                    HPACK                     October 2013


content-encoding: gzip
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
01 ff ee 02 df 7d fb 3f cf f3 fc ff 3f cf f3 fc | .....}.?....?...
ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff | .?....?....?....
3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f | ?....?....?....?
cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf | ....?....?....?.
f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 | ...?....?....?..
fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc | ..?....?....?...
ff 3e 3b 69 ec f0 fe 7e 1f d7 f3 d5 fe 7f 7e 5f | .>;i...~......~_
d7 9f 6f 97 cb bf e9 b7 fb fe bc fb 7c bb fe 9b | ..o.........|...
7f bf 8f 87 f3 f0 fe bc fc bb 7b fe 9b 7e 3f d7 | ..........{..~?.
9f 6f 97 7f d3 6f f7 f1 fe bb 7e 9b 7f bf 8f c7 | .o...o....~.....
f9 f0 db 4f 67 f5 e7 db e5 f4 ef db fd f8 91 a1 | ...Og...........
3f 1d b4 f6 78 7f 3f 0f eb f9 ea ff 3f bf 2f eb | ?...x.?.....?./.
cf b7 cb e5 df f4 db fd ff 5e 7d be 5d ff 4d bf | .........^}.].M.
df c7 c3 f9 f8 7f 5e 7e 5d bd ff 4d bf 1f eb cf | ......^~]..M....
b7 cb bf e9 b7 fb f8 ff 5d bf 4d bf df c7 e3 fc | ........].M.....
f8 6d a7 b3 fa f3 ed f2 fa 77 ed fe fc 48 d0 9f | .m.......w...H..
8e da 7b 3c 3f 9f 87 f5 fc f5 7f 9f df 97 f5 e7 | ..{<?...........
db e5 f2 ef fa 6d fe ff af 3e df 2e ff a6 df ef | .....m...>......
e3 e1 fc fc 3f af 3f 2e de ff a6 df 8f f5 e7 db | ....?.?.........
e5 df f4 db fd fc 7f ae df a6 df ef e3 f1 fe 7c | ...............|
36 d3 d9 fd 79 f6 f9 7d 3b f6 ff 7e 24 68 4f c7 | 6...y..};..~$hO.
6d 3d 9e 1f cf c3 fa fe 7a bf cf ef cb fa f3 ed | m=......z.......
f2 f9 77 fd 36 ff 7f d7 9f 6f 97 7f d3 6f f7 f1 | ..w.6....o...o..
f0 fe 7e 1f d7 9f 97 6f 7f d3 6f c7 fa f3 ed f2 | ..~....o..o.....
ef fa 6d fe fe 3f d7 6f d3 6f f7 f1 f8 ff 3e 1b | ..m..?.o.o....>.
69 ec fe bc fb 7c be 9d fb 7f bf 12 34 27 6e dd | i....|......4'n.
bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 | .v...n..v...n..v
ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db | ...n..v...n..v..
b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 6e | .n..v...n..v...n
dd bb 76 ed db b7 6e dd bb 76 ed db b4 8d 09 0b | ..v...n..v......
5f d2 37 f0 86 c4 4a 23 ef 0e 70 c7 2b 2f bb 61 | _.7...J#..p.+/.a
7f 81                                           | ..

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '01'
    name_index:



Peon & Ruellan           Expires April 24, 2014                [Page 49]


Internet-Draft                    HPACK                     October 2013


        encoded: "01"
        decoded: 1
    value_data_length:
        encoded: "ffee02"
        decoded: 493
    value_data:
        is_huffman_encoded: 1
        encoded: "df7dfb3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3f\
cff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fc\
ff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3e3b69ecf\
0fe7e1fd7f3d5fe7f7e5fd79f6f97cbbfe9b7fbfebcfb7cbbfe9b7fbf8f87f3f0febcfc\
bb7bfe9b7e3fd79f6f977fd36ff7f1febb7e9b7fbf8fc7f9f0db4f67f5e7dbe5f4efdbf\
df891a13f1db4f6787f3f0febf9eaff3fbf2febcfb7cbe5dff4dbfdff5e7dbe5dff4dbf\
dfc7c3f9f87f5e7e5dbdff4dbf1febcfb7cbbfe9b7fbf8ff5dbf4dbfdfc7e3fcf86da7b\
3faf3edf2fa77edfefc48d09f8eda7b3c3f9f87f5fcf57f9fdf97f5e7dbe5f2effa6dfe\
ffaf3edf2effa6dfefe3e1fcfc3faf3f2edeffa6df8ff5e7dbe5dff4dbfdfc7faedfa6d\
fefe3f1fe7c36d3d9fd79f6f97d3bf6ff7e24684fc76d3d9e1fcfc3fafe7abfcfefcbfa\
f3edf2f977fd36ff7fd79f6f977fd36ff7f1f0fe7e1fd79f976f7fd36fc7faf3edf2eff\
a6dfefe3fd76fd36ff7f1f8ff3e1b69ecfebcfb7cbe9dfb7fbf1234276eddbb76eddbb7\
6eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76\
eddbb76eddbb76eddbb76eddbb76eddbb76eddbb48d090b5fd237f086c44a23ef0e70c7\
2b2fbb617f"
        decoded: "foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '81'
    entry_index:
        encoded: "81"
        decoded: 1


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\



Peon & Ruellan           Expires April 24, 2014                [Page 50]


Internet-Draft                    HPACK                     October 2013


XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

#########################


E.4.  Response Decoding Example Without Huffman



# Header set to be encoded
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

# Hexdump of encoded data which will be decoded
08 03 33 30 32 18 07 70 72 69 76 61 74 65 22 1d | ..302..private".
4d 6f 6e 2c 20 32 31 20 4f 43 74 20 32 30 31 33 | Mon, 21 OCt 2013
20 32 30 3a 31 33 3a 32 31 20 47 4d 54 2f 15 3a |  20:13:21 GMT/.:
20 68 74 74 70 73 3a 2f 2f 77 77 77 2e 62 61 72 |  https://www.bar
2e 63 6f 6d                                     | .com

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '08'
    name_index:
        encoded: "08"
        decoded: 8
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "333032"
        decoded: "302"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '18'
    name_index:
        encoded: "18"
        decoded: 24
    value_data_length:
        encoded: "07"



Peon & Ruellan           Expires April 24, 2014                [Page 51]


Internet-Draft                    HPACK                     October 2013


        decoded: 7
    value_data:
        is_huffman_encoded: 0
        encoded: "70726976617465"
        decoded: "private"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '22'
    name_index:
        encoded: "22"
        decoded: 34
    value_data_length:
        encoded: "1d"
        decoded: 29
    value_data:
        is_huffman_encoded: 0
        encoded: "4d6f6e2c203231204f437420323031332032303a31333a3231204\
74d54"
        decoded: "Mon, 21 OCt 2013 20:13:21 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '2f'
    name_index:
        encoded: "2f"
        decoded: 47
    value_data_length:
        encoded: "15"
        decoded: 21
    value_data:
        is_huffman_encoded: 0
        encoded: "3a2068747470733a2f2f7777772e6261722e636f6d"
        decoded: ": https://www.bar.com"


# Decoded header set
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT



Peon & Ruellan           Expires April 24, 2014                [Page 52]


Internet-Draft                    HPACK                     October 2013


location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
04 03 32 30 30 03 1d 4d 6f 6e 2c 20 32 31 20 4f | ..200..Mon, 21 O
43 74 20 32 30 31 33 20 32 30 3a 31 33 3a 32 32 | Ct 2013 20:13:22
20 47 4d 54 03 13 68 74 74 70 73 3a 2f 2f 77 77 |  GMT..https://ww
77 2e 62 61 72 2e 63 6f 6d 20 04 67 7a 69 70 3d | w.bar.com .gzip=
7f e1 02 66 6f 6f 3d 41 41 41 41 41 41 41 41 41 | ...foo=AAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 4c | AAAAAAAAAAAAAAAL
41 53 44 4a 4b 48 51 4b 42 5a 58 4f 51 57 45 4f | ASDJKHQKBZXOQWEO
50 49 55 41 58 51 57 45 4f 49 55 41 58 4c 4a 4b | PIUAXQWEOIUAXLJK
48 51 57 4f 45 49 55 41 4c 51 57 45 4f 49 55 41 | HQWOEIUALQWEOIUA
58 4c 51 45 55 41 58 4c 4c 4b 4a 41 53 44 51 57 | XLQEUAXLLKJASDQW
45 4f 55 49 41 58 4e 31 32 33 34 4c 41 53 44 4a | EOUIAXN1234LASDJ
4b 48 51 4b 42 5a 58 4f 51 57 45 4f 50 49 55 41 | KHQKBZXOQWEOPIUA
58 51 57 45 4f 49 55 41 58 4c 4a 4b 48 51 57 4f | XQWEOIUAXLJKHQWO
45 49 55 41 4c 51 57 45 4f 49 55 41 58 4c 51 45 | EIUALQWEOIUAXLQE
55 41 58 4c 4c 4b 4a 41 53 44 51 57 45 4f 55 49 | UAXLLKJASDQWEOUI
41 58 4e 31 32 33 34 4c 41 53 44 4a 4b 48 51 4b | AXN1234LASDJKHQK
42 5a 58 4f 51 57 45 4f 50 49 55 41 58 51 57 45 | BZXOQWEOPIUAXQWE
4f 49 55 41 58 4c 4a 4b 48 51 57 4f 45 49 55 41 | OIUAXLJKHQWOEIUA
4c 51 57 45 4f 49 55 41 58 4c 51 45 55 41 58 4c | LQWEOIUAXLQEUAXL
4c 4b 4a 41 53 44 51 57 45 4f 55 49 41 58 4e 31 | LKJASDQWEOUIAXN1
32 33 34 4c 41 53 44 4a 4b 48 51 4b 42 5a 58 4f | 234LASDJKHQKBZXO
51 57 45 4f 50 49 55 41 58 51 57 45 4f 49 55 41 | QWEOPIUAXQWEOIUA
58 4c 4a 4b 48 51 57 4f 45 49 55 41 4c 51 57 45 | XLJKHQWOEIUALQWE
4f 49 55 41 58 4c 51 45 55 41 58 4c 4c 4b 4a 41 | OIUAXLQEUAXLLKJA
53 44 51 57 45 4f 55 49 41 58 4e 31 32 33 34 5a | SDQWEOUIAXN1234Z
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 31 32 33 34 20 6d 61 78 2d | ZZZZZZZ1234 max-
61 67 65 3d 33 36 30 30 3b 20 76 65 72 73 69 6f | age=3600; versio
6e 3d 31 85 86 88                               | n=1...

# Decoded opcodes



Peon & Ruellan           Expires April 24, 2014                [Page 53]


Internet-Draft                    HPACK                     October 2013


LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "323030"
        decoded: "200"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "1d"
        decoded: 29
    value_data:
        is_huffman_encoded: 0
        encoded: "4d6f6e2c203231204f437420323031332032303a31333a3232204\
74d54"
        decoded: "Mon, 21 OCt 2013 20:13:22 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "13"
        decoded: 19
    value_data:
        is_huffman_encoded: 0
        encoded: "68747470733a2f2f7777772e6261722e636f6d"
        decoded: "https://www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '20'
    name_index:
        encoded: "20"



Peon & Ruellan           Expires April 24, 2014                [Page 54]


Internet-Draft                    HPACK                     October 2013


        decoded: 32
    value_data_length:
        encoded: "04"
        decoded: 4
    value_data:
        is_huffman_encoded: 0
        encoded: "677a6970"
        decoded: "gzip"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '3d'
    name_index:
        encoded: "3d"
        decoded: 61
    value_data_length:
        encoded: "7fe102"
        decoded: 480
    value_data:
        is_huffman_encoded: 0
        encoded: "666f6f3d414141414141414141414141414141414141414141414\
14141414141414141414141414141414141414141414141414141414141414141414141\
41414141414141414141414141414c4153444a4b48514b425a584f5157454f504955415\
85157454f495541584c4a4b4851574f454955414c5157454f495541584c51455541584c\
4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a584f5157454\
f50495541585157454f495541584c4a4b4851574f454955414c5157454f495541584c51\
455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a5\
84f5157454f50495541585157454f495541584c4a4b4851574f454955414c5157454f49\
5541584c51455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b4\
8514b425a584f5157454f50495541585157454f495541584c4a4b4851574f454955414c\
5157454f495541584c51455541584c4c4b4a4153445157454f554941584e313233345a5\
a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a\
5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a3\
1323334206d61782d6167653d333630303b2076657273696f6e3d31"
        decoded: "foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"



Peon & Ruellan           Expires April 24, 2014                [Page 55]


Internet-Draft                    HPACK                     October 2013


        decoded: 5

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '88'
    entry_index:
        encoded: "88"
        decoded: 8


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded



Peon & Ruellan           Expires April 24, 2014                [Page 56]


Internet-Draft                    HPACK                     October 2013


01 7f e1 02 66 6f 6f 3d 5a 5a 5a 5a 5a 5a 5a 5a | ....foo=ZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
4c 41 53 44 4a 4b 48 51 4b 42 5a 58 4f 51 57 45 | LASDJKHQKBZXOQWE
4f 50 49 55 41 58 51 57 45 4f 49 55 41 58 4c 4a | OPIUAXQWEOIUAXLJ
4b 48 51 57 4f 45 49 55 41 4c 51 57 45 4f 49 55 | KHQWOEIUALQWEOIU
41 58 4c 51 45 55 41 58 4c 4c 4b 4a 41 53 44 51 | AXLQEUAXLLKJASDQ
57 45 4f 55 49 41 58 4e 31 32 33 34 4c 41 53 44 | WEOUIAXN1234LASD
4a 4b 48 51 4b 42 5a 58 4f 51 57 45 4f 50 49 55 | JKHQKBZXOQWEOPIU
41 58 51 57 45 4f 49 55 41 58 4c 4a 4b 48 51 57 | AXQWEOIUAXLJKHQW
4f 45 49 55 41 4c 51 57 45 4f 49 55 41 58 4c 51 | OEIUALQWEOIUAXLQ
45 55 41 58 4c 4c 4b 4a 41 53 44 51 57 45 4f 55 | EUAXLLKJASDQWEOU
49 41 58 4e 31 32 33 34 4c 41 53 44 4a 4b 48 51 | IAXN1234LASDJKHQ
4b 42 5a 58 4f 51 57 45 4f 50 49 55 41 58 51 57 | KBZXOQWEOPIUAXQW
45 4f 49 55 41 58 4c 4a 4b 48 51 57 4f 45 49 55 | EOIUAXLJKHQWOEIU
41 4c 51 57 45 4f 49 55 41 58 4c 51 45 55 41 58 | ALQWEOIUAXLQEUAX
4c 4c 4b 4a 41 53 44 51 57 45 4f 55 49 41 58 4e | LLKJASDQWEOUIAXN
31 32 33 34 4c 41 53 44 4a 4b 48 51 4b 42 5a 58 | 1234LASDJKHQKBZX
4f 51 57 45 4f 50 49 55 41 58 51 57 45 4f 49 55 | OQWEOPIUAXQWEOIU
41 58 4c 4a 4b 48 51 57 4f 45 49 55 41 4c 51 57 | AXLJKHQWOEIUALQW
45 4f 49 55 41 58 4c 51 45 55 41 58 4c 4c 4b 4a | EOIUAXLQEUAXLLKJ
41 53 44 51 57 45 4f 55 49 41 58 4e 31 32 33 34 | ASDQWEOUIAXN1234
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 31 32 33 34 20 6d 61 78 | AAAAAAAA1234 max
2d 61 67 65 3d 33 36 30 30 3b 20 76 65 72 73 69 | -age=3600; versi
6f 6e 3d 31 81                                  | on=1.

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '01'
    name_index:
        encoded: "01"
        decoded: 1
    value_data_length:
        encoded: "7fe102"
        decoded: 480
    value_data:
        is_huffman_encoded: 0
        encoded: "666f6f3d5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5\
a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a\
5a5a5a5a5a5a5a5a5a5a5a5a5a5a4c4153444a4b48514b425a584f5157454f504955415\
85157454f495541584c4a4b4851574f454955414c5157454f495541584c51455541584c\



Peon & Ruellan           Expires April 24, 2014                [Page 57]


Internet-Draft                    HPACK                     October 2013


4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a584f5157454\
f50495541585157454f495541584c4a4b4851574f454955414c5157454f495541584c51\
455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a5\
84f5157454f50495541585157454f495541584c4a4b4851574f454955414c5157454f49\
5541584c51455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b4\
8514b425a584f5157454f50495541585157454f495541584c4a4b4851574f454955414c\
5157454f495541584c51455541584c4c4b4a4153445157454f554941584e31323334414\
14141414141414141414141414141414141414141414141414141414141414141414141\
41414141414141414141414141414141414141414141414141414141414141414141413\
1323334206d61782d6167653d333630303b2076657273696f6e3d31"
        decoded: "foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '81'
    entry_index:
        encoded: "81"
        decoded: 1


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

#########################









Peon & Ruellan           Expires April 24, 2014                [Page 58]


Internet-Draft                    HPACK                     October 2013


Authors' Addresses

   Roberto Peon
   Google, Inc

   EMail: fenix@google.com


   Herve Ruellan
   Canon CRF

   EMail: herve.ruellan@crf.canon.fr







































Peon & Ruellan           Expires April 24, 2014                [Page 59]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/