One document matched: draft-snell-httpbis-bohe-04.xml
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<rfc category="info" ipr="trust200811" docName="draft-snell-httpbis-bohe-04">
<front>
<title abbrev="application/merge-patch">
HTTP/2.0 Discussion: Stored Header Encoding
</title>
<author initials="J.M." surname="Snell" fullname="James M Snell">
<address>
<email>jasnell@gmail.com</email>
</address>
</author>
<date month="April" year="2013" />
<keyword>I-D</keyword>
<keyword>http</keyword>
<keyword>spdy</keyword>
<abstract>
<t>This memo describes a proposed alternative encoding for
headers that combines the best concepts from the proposed
Delta and HeaderDiff options with the typed value codecs
introduced by previous versions of this draft.</t>
</abstract>
</front>
<middle>
<section title="Stored Header Encoding">
<t>The Stored Header Encoding is an alternative "binary header encoding" for
HTTP/2.0 that combines the best elements from three other proposed encodings,
including:</t>
<t><list style="symbols">
<t>The "Header Delta Compression" scheme proposed by Roberto Peon in
http://tools.ietf.org/html/draft-rpeon-httpbis-header-compression-03</t>
<t>The "Header Diff" encoding proposed by Herve Reullan, Jun Fujisawa,
Romain Bellessort, and Youenn Fablet in
http://tools.ietf.org/html/draft-ruellan-headerdiff-00</t>
<t>The "Binary Optimized Header Encoding" proposed by James Snell (me) in
http://tools.ietf.org/html/draft-snell-httpbis-bohe-03</t>
</list></t>
<t>The Stored Header Encoding seeks to find an elegant, efficient and simple
marriage of the best concepts from each of these separate proposals.</t>
</section>
<section title="State Model">
<t>The compressor and decompressor each maintain a cache of header value pairs.
There is a static cache, prepopulated by the specification, and a dynamic
cache, populated through the compression and decompression process. Each
cache contains a maximum of 128 individual key+value pairs. </t>
<t>Each item in the index is referenced by an 8-bit identifier. The most
significant bit identifies whether an item from the static or dynamic
cache is being referenced. Note: the Nil byte (0x00) is a valid identifier
for the dynamic cache.</t>
<figure><artwork>
0xxxxxxx -- Dynamic Cache
1xxxxxxx -- Static Cache
</artwork></figure>
<t>The dynamic cache is managed in a "least recently written" style, that is, as
the cache fills to capacity in both number of entries and maximum stored byte
size, the least recently written items are dropped and those index positions
are reused.</t>
<t>Index positions from the dynamic cache are assigned in "encounter order",
beginning from 0x00 and increasing monotonically to 0x7F. That is to say, the
positions are assigned in precisely the same order that they are serialized,
and thereby encountered by the decompressor upon reading and processing the
block.</t>
<t>Each item in the store consists of a Header Name and a Value. The Name is a
lower-case ISO-8859-1 character sequence. The Value is either a UTF-8 string,
a number, a Timestamp or an arbitrary sequence of binary octets. </t>
<t>The available size of the stored compression state can be capped by the
decompressor. Each stored value contributes to the accumulated size of the
storage state. As new key+value pairs are assigned positions in the dynamic
cache, the least-recently assigned items must be removed if necessary to free
up the required space. </t>
<t>The size of string values is measured by the number of UTF-8
bytes required for the character sequence.</t>
<t>The size of number and timestamp values are measured by the number of
unsigned variable length integer (uvarint) encoded bytes it takes to represent
the value (see the section of value types below).</t>
<t>The size of raw binary values is measured by the number of octets.</t>
<t>Header names DO NOT contribute to the stored state size of the compressor;
only the size of the value is considered. Duplicate values MUST be counted
individually.</t>
</section>
<section title="Header Serialization">
<t>Headers are serialized into four typed header groups, each represented by a
two-bit identifier.</t>
<figure><artwork>
00 -- Index Header Group
01 -- Index Range Header Group
10 -- Cloned Index Header Group
11 -- Literal Header Group
</artwork></figure>
<t>The Cloned Index (10) and Literal (11) header group types have an additional
"ephemeral" property that indicates whether or not the group affects the
compression state. </t>
<t>Each header group contains a single 8-bit prefix and up to 32 distinct header
instances. </t>
<figure><preamble>Wire Format</preamble><artwork><![CDATA[
header-block = *(index-header-group /
index-range-header-group /
cloned-index-header-group /
literal-header-group)
; Header Group Prefix = 8 bits ...
; First two bits = header-group-type
; Third bit = ephemeral flag
; Final five bits = instance counter
;
index-header-group-type = 00
index-range-group-type = 01
cloned-index-group-type = 10
literal-group-type = 11
count = 5bit
index-header-prefix = index-header-group-type
unset count ; 000xxxxx
index-range-header-prefix = index-header-group-type
unset count ; 010xxxxx
cloned-index-header-prefix = cloned-index-group-type
bit count ; 10?xxxxx
literal-header-prefix = literal-group-type
bit count ; 11?xxxxx
; Cache Index Identifier = 8 bits ...
; 0xxxxxxx = Dynamic Cache Identifier
; 1xxxxxxx = Static Cache Identifier
cache-index = %x00-FF
; Index Header Group
index-header-group = index-header-prefix
1*32cache-index
; Index-Range Header Group
; Contains a pair of cache-index values, second MUST
; me strictly higher in value than the first...
index-range-header-group = index-range-header-prefix
1*32(cache-index cache-index)
; Cloned-Index Header Group
cloned-index-header-group = cloned-index-header-prefix
1*32(cache-index value)
; Literal Header Group
literal-header-group = literal-header-prefix
1*32(name value)
value = text-value /
number-value /
timestamp-value /
binary-value
text-value-type = 00 ; two bits
number-value-type = 01
timestamp-value-type = 10
binary-value-type = 11
text-value-prefix = text-value-type
unset count ; 000xxxxx
number-value-prefix = number-value-type
unset count ; 010xxxxx
timestamp-value-prefix = timestamp-value-type
unset count ; 100xxxxx
binary-value-prefix = binary-value-type
unset count ; 110xxxxx
text-value = text-value-prefix *32string
number-value = number-value-type *32uvarint
timestamp-value = timestamp-value-prefix *32uvarint
binary-value = binary-value-prefix uvarint *OCTET
uvarint = *uvarint-continuation uvarint-final
uvarint-continuation = %x80-FF
uvarint-final = %x00-7F
name = 1*tchar
tchar = "!" / "#" / "$" / "%" / "&" /
"'" / "*" / "+" / "-" / "." /
"^" / "_" / "`" / "|" / "~"
/ DIGIT / ALPHA
string = uvarint *(HUFFMAN-ENCODED-CHAR)
HUFFMAN-EOF
padding-to-nearest-byte;
padding-to-nearest-byte = *7unset
bit = set / unset
unset = 0
set = 1
]]></artwork></figure>
<section title="Header Group Prefix">
<t>The Header Group Prefix is a single octet that provides three distinct
pieces of information:</t>
<figure><artwork>
00 0 00000
</artwork></figure>
<t>The first two most significant bits of the header group prefix identify the
group type.</t>
<t>The next bit is the "ephemeral flag" and is used only for Cloned
and Literal group types. This bit indicates whether or not the group alters
the stored compression state.</t>
<t>The remaining five bits specify the number of header instances in the group,
with 00000 indicating that the group contains 1 instance and 11111 contains 32.
A header group MUST contain at least one instance.</t>
<t>The remaining serialization of the header group depends entirely on the
group type.</t>
</section>
<section title="Index Header Group">
<t>The serialization of the Index Header Group consists of the Header Group Prefix
and up to 32 additional octets, each referencing a single 8-bit storage index
identifier for items in either the Static or Dynamic Cache.</t>
<figure><preamble>For instance</preamble><artwork>
00000000 00000000 = References item #0 from
the dynamic cache
00000001 00000000 10000000 = References item #0 from the
dynamic cache and item #0
from the static cache
</artwork></figure>
<t>Index Header Groups do not affect the stored compression state. If an Index
Header Group references a header index that has not yet been allocated, the
deserialization MUST terminate with an error. This likely means that the
compression state has become out of sync and needs to be reestablished.</t>
</section>
<section title="Index Range Header Group">
<t>The serialization of the Index Range Header Group consists of the Header Group
Prefix and up to 32 additional 2-octet (16 bits) pairs of 8-bit storage index
identifiers. Each pair specifies a sequential range of adjacent ranges. </t>
<figure><preamble>For instance:</preamble><artwork>
01000000 00000000 00000100 = References items #0-#4 from
the dynamic cache.
(five distinct items total)
</artwork></figure>
<t>A range MAY span dynamic and static index values. Index values are treated
as unsigned byte values, so indices from the static cache are numerically
greater than dynamic cache values.. e.g.</t>
<figure><artwork>
01000000 01111111 10000001 = References item #127 from the
dynamic cache, and items #0
and #1 from the static cache.
</artwork></figure>
<t>Index Range Header Groups do not affect the stored compression state. If a
range references a header index that has not yet been allocated, the
deserialization MUST terminate with an error. This likely means that the
compression state has become out of sync and needs to be reestablished.</t>
</section>
<section title="Cloned Index Header Group">
<t>The serialization of the Cloned Index Header Group consists of the Header Group
Prefix and up to 32 Index+Value pairs. Each Index+Value pair consists of a
leading 8-bit storage index of an existing stored header followed by a new
serialized value. The serialization of the value depends on the value type
(see discussion of Value serialization below).</t>
<t>The Cloned Header Group affects the stored compression state if, and only if,
the "ephemeral" flag in the Header Group Prefix is NOT set. If the header
group is not marked as being ephemeral, then the specified value is stored in
the next available storage index using the key name from the referenced storage
index.</t>
<t>For instance, assume the dynamic cache currently contains an item at index #1
with key name "foo" and value "bar", the following causes a new item to be
added to the storage with key name "foo" and value "baz":</t>
<figure><artwork>
10000000 00000001 00000000 00000100
10111000 01001111 10110101 00100000
</artwork></figure>
<t>An explanation of the value syntax is given a bit later.</t>
<t>If a Cloned Header Group references a header index that has not yet been
allocated, the deserialization MUST terminate with an error. This likely
means that the compression state has become out of sync and needs to be
reestablished.</t>
</section>
<section title="Literal Header Group">
<t>The serialization of the Literal Header Group consists of the Header Group
Prefix and up to 32 Name+Value pairs. Each Name+Value pair consists of a
length-prefixed sequence of ASCII bytes specifying the Header Name
followed by the serialized value. The serialization of the value depends
on the value type. The length prefix is encoded as an unsigned variable
length integer (uvarint). The length prefix SHOULD NOT be longer than five
octets and SHOULD NOT specify a value larger than 0xFFFF. </t>
<t>The Literal Heaer Group affects the stored compression state if, and only if,
the "ephemeral" flag in the Header Group Prefix is NOT set. If the header
group is not marked as being ephemeral, then the specified key name and value
is stored in the next available storage index.</t>
<figure><preamble>For instance:</preamble><artwork>
11000000 00000011 01100110 01101111
01101111 00000000 00000010 10111000
01000100 11010010
</artwork></figure>
<t>Stores a new header with name "foo" and value "baz" in the dynamic cache.</t>
<t>Each Header Group consists of up to 32 distinct Header Instances. If a
particular serialization block contains more than 32 intances of a given
type, then multiple instances of the Header Group Type can be included in
the serialized block. For instance, if a given message contains 33 index
references, the serialized block may contain two separate Index Header Groups.
While this is allowed, it is expected to be rare.</t>
</section>
</section>
<section title="Header Values">
<t>Header Values can be one of four types, each identified by a
two-bit identifier.</t>
<t><list style="symbols">
<t>00 -- UTF-8 Text</t>
<t>01 -- Numeric</t>
<t>10 -- Timetamp</t>
<t>11 -- Raw Binary Octets</t>
</list></t>
<t>An individual value MAY consist of up to 32 distinct discreet "value instances".
A value with multiple instances is considered, for all intensive purposes, to
be a single value.</t>
<t>Each serialized value is preceded by an 8-bit Value Prefix.</t>
<figure><artwork>
00 0 00000
</artwork></figure>
<t>The first two most significant bits specifies the value type.</t>
<t>The third significant bit is a reserved flag. Future iterations of this specification
might make use of this bit.</t>
<t>The final five least-significant bits specify the number of discreet instances
in the value. 00000 indicates that one instance is included, 11111 indicates
that 32 instances are included. The value MUST contain at least one instance.</t>
<t>The remaining serialization depends entirely on the type.</t>
<section title="UTF-8 Text Values">
<t>UTF-8 Text is encoded as a length-prefixed sequence of Huffman-encoded UTF-8
octets. The length prefix is encoded as an unsigned variable-length integer
specifying the number of octets after applying the Huffman-encoding.</t>
</section>
<section title="Numeric Values">
<t>Numeric values are encoded as unsigned variable-length integers (uvarint) of
up to a maximum of 10-octets. Unsigned values larger than 64-bits (0xFFFFFFFF)
MUST NOT be used. Negative values cannot be represented using this syntax.
The uvarint syntax is described below.</t>
</section>
<section title="Timestamp Values">
<t>Timestamp values are encoded as unsigned variable-length integers specifying
the number of seconds that have passed since the standard Epoch. The syntax
is identical that used for Numeric Values. Dates prior to the epoch cannot
be represented using this syntax.</t>
</section>
<section title="Raw Binary Octet Values">
<t>Binary values are encoded as a length prefixed sequence of arbitrary octets.
The length prefix is encoded as an unsigned variable length integer.</t>
</section>
<section title="Unsigned Variable Length Integer Syntax">
<t>The uvarint syntax is identical to that used by Google's protobufs. They
are serialized with the least-significant bytes first in batches of 7-bits,
with the most significant bit per byte reserved as a continuation bit. Values
less than or equal to 127 are serialized using at most one byte; values less
than or equal to 16383 are serialized using at most two bytes; values less
than or equal to 2097151 are serialized using at most three bytes. </t>
<figure><artwork><![CDATA[
def uvarint(num):
return [] if num = 0
ret = []
while(num != 0):
m = num >>> 7 ; unsigned shift left 7 bits
ret.push (byte)((num & ~0x80) | ( m > 0 ? 0x80 : 0x00 ));
num = m;
return ret;
]]></artwork></figure>
<t>For example, the binary representation of the 32-bit integer 217 is:</t>
<figure><artwork>
00000000 00000000 00000000 11011001
</artwork></figure>
<t>The variable length encoding is:</t>
<figure><artwork>
11011001 00000001
</artwork></figure>
<t>The binary representation of the 32-bit integer 1386210052 is:</t>
<figure><artwork>
01010010 10011111 11100011 00000100
</artwork></figure>
<t>The variable length encoding is:</t>
<figure><artwork>
10000100 11000110 11111111 10010100 00000101
</artwork></figure>
</section>
<section title="Huffman Coding">
<t>All UTF-8 text values are compressed using a modified static huffman code.
"Modified" because the encoded version may contain compact-representations
of raw, arbitrary UTF-8 bytes that are not covered by the static huffman
code table.</t>
<t>There are two huffman tables in use, one for HTTP Requests and another for
HTTP Responses, each covers UTF-8 codepoints strictly less than 128 as well
the fifty possible UTF-8 leading octets.</t>
<t>The encoded result MUST end with a specific terminal sequence of bits
called the "HUFFMAN_EOF". Currently, the HUFFMAN_EOF is the same for both
the Request and Response tables, but that could change if the tables are
regenerated. Currently, the HUFFMAN_EOF sequence is 101001.</t>
<t>Codepoints >= 128 are handled by first taking the leading octet of the UTF-8
representation and serializing it's associated huffman code from the table
to the output stream, then, depending on the octets value, serializing the
six least significant bits from each of the remaining trailing octets.</t>
<t>For instance, the UTF-8 character U+00D4 (LATIN CAPITAL LETTER O WITH
CIRCUMFLEX), with UTF-8 representation of C394 (hex) is encoded as:</t>
<figure><artwork>
11000100 01010010 10010000
</artwork></figure>
<t>The first 8-bits represents the huffman-table prefix, the first six most
significant bytes of the second octet are taken directly from the six least
significant bits of the second UTF-8 byte (0x94). Following those six bits
are the six bits of the HUFFMAN_EOF 101001, followed by four unset padding
bits.</t>
<t>The number of raw UTF-8 bits to write depends on the value of the leading
octet. If the value is between 0xC2 and 0xDF (inclusive), six bits from the
second continuation byte is encoded. If the value is between 0xE0 and 0xEF
(inclusive), six bits from the second and third continuation bytes are
encoded. If the value is between 0xF0 and 0xF4 (inclusive), six bits from
the second, third and fourth continuation bytes are encoded. UTF-8 codepoints
that require greater than four bytes to encode cannot be represented.</t>
</section>
</section>
<section title="Security Considerations">
<t>TBD</t>
</section>
</middle>
<back>
<references title="Normative References">
&rfc2119;
</references>
<section title="Huffman Tables">
<figure><preamble>Request Table</preamble><artwork><![CDATA[
( 0) |11111111|11111111|11111111|0 [25] 1fffffe [25]
( 1) |11111111|11111111|11111111|1 [25] 1ffffff [25]
( 2) |11111111|11111111|11100000 [24] ffffe0 [24]
( 3) |11111111|11111111|11100001 [24] ffffe1 [24]
( 4) |11111111|11111111|11100010 [24] ffffe2 [24]
( 5) |11111111|11111111|11100011 [24] ffffe3 [24]
( 6) |11111111|11111111|11100100 [24] ffffe4 [24]
( 7) |11111111|11111111|11100101 [24] ffffe5 [24]
( 8) |11111111|11111111|11100110 [24] ffffe6 [24]
( 9) |11111111|11111111|11100111 [24] ffffe7 [24]
( 10) |11111111|11111111|11101000 [24] ffffe8 [24]
( 11) |11111111|11111111|11101001 [24] ffffe9 [24]
( 12) |11111111|11111111|11101010 [24] ffffea [24]
( 13) |11111111|11111111|11101011 [24] ffffeb [24]
( 14) |11111111|11111111|11101100 [24] ffffec [24]
( 15) |11111111|11111111|11101101 [24] ffffed [24]
( 16) |11111111|11111111|11101110 [24] ffffee [24]
( 17) |11111111|11111111|11101111 [24] ffffef [24]
( 18) |11111111|11111111|11110000 [24] fffff0 [24]
( 19) |11111111|11111111|11110001 [24] fffff1 [24]
( 20) |11111111|11111111|11110010 [24] fffff2 [24]
( 21) |11111111|11111111|11110011 [24] fffff3 [24]
( 22) |11111111|11111111|11110100 [24] fffff4 [24]
( 23) |11111111|11111111|11110101 [24] fffff5 [24]
( 24) |11111111|11111111|11110110 [24] fffff6 [24]
( 25) |11111111|11111111|11110111 [24] fffff7 [24]
( 26) |11111111|11111111|11111000 [24] fffff8 [24]
( 27) |11111111|11111111|11111001 [24] fffff9 [24]
( 28) |11111111|11111111|11111010 [24] fffffa [24]
( 29) |11111111|11111111|11111011 [24] fffffb [24]
( 30) |11111111|11111111|11111100 [24] fffffc [24]
( 31) |11111111|11111111|11111101 [24] fffffd [24]
' ' ( 32) |11111111|0110 [12] ff6 [12]
'!' ( 33) |11111111|0111 [12] ff7 [12]
'"' ( 34) |11111111|111010 [14] 3ffa [14]
'#' ( 35) |11111111|1111100 [15] 7ffc [15]
'$' ( 36) |11111111|1111101 [15] 7ffd [15]
'%' ( 37) |011000 [6] 18 [6]
'&' ( 38) |1010100 [7] 54 [7]
''' ( 39) |11111111|1111110 [15] 7ffe [15]
'(' ( 40) |11111111|1000 [12] ff8 [12]
')' ( 41) |11111111|1001 [12] ff9 [12]
'*' ( 42) |11111111|1010 [12] ffa [12]
'+' ( 43) |11111111|1011 [12] ffb [12]
',' ( 44) |11111011|10 [10] 3ee [10]
'-' ( 45) |011001 [6] 19 [6]
'.' ( 46) |00010 [5] 2 [5]
'/' ( 47) |00011 [5] 3 [5]
'0' ( 48) |011010 [6] 1a [6]
'1' ( 49) |011011 [6] 1b [6]
'2' ( 50) |011100 [6] 1c [6]
'3' ( 51) |011101 [6] 1d [6]
'4' ( 52) |1010101 [7] 55 [7]
'5' ( 53) |1010110 [7] 56 [7]
'6' ( 54) |1010111 [7] 57 [7]
'7' ( 55) |1011000 [7] 58 [7]
'8' ( 56) |1011001 [7] 59 [7]
'9' ( 57) |1011010 [7] 5a [7]
':' ( 58) |011110 [6] 1e [6]
';' ( 59) |11111011|11 [10] 3ef [10]
'<' ( 60) |11111111|11111111|10 [18] 3fffe [18]
'=' ( 61) |011111 [6] 1f [6]
'>' ( 62) |11111111|11111110|0 [17] 1fffc [17]
'?' ( 63) |11110110|0 [9] 1ec [9]
'@' ( 64) |11111111|11100 [13] 1ffc [13]
'A' ( 65) |10111010 [8] ba [8]
'B' ( 66) |11110110|1 [9] 1ed [9]
'C' ( 67) |10111011 [8] bb [8]
'D' ( 68) |10111100 [8] bc [8]
'E' ( 69) |11110111|0 [9] 1ee [9]
'F' ( 70) |10111101 [8] bd [8]
'G' ( 71) |11111100|00 [10] 3f0 [10]
'H' ( 72) |11111100|01 [10] 3f1 [10]
'I' ( 73) |11110111|1 [9] 1ef [9]
'J' ( 74) |11111100|10 [10] 3f2 [10]
'K' ( 75) |11111111|010 [11] 7fa [11]
'L' ( 76) |11111100|11 [10] 3f3 [10]
'M' ( 77) |11111000|0 [9] 1f0 [9]
'N' ( 78) |11111101|00 [10] 3f4 [10]
'O' ( 79) |11111101|01 [10] 3f5 [10]
'P' ( 80) |11111000|1 [9] 1f1 [9]
'Q' ( 81) |11111101|10 [10] 3f6 [10]
'R' ( 82) |11111001|0 [9] 1f2 [9]
'S' ( 83) |11111001|1 [9] 1f3 [9]
'T' ( 84) |11111010|0 [9] 1f4 [9]
'U' ( 85) |11111101|11 [10] 3f7 [10]
'V' ( 86) |11111110|00 [10] 3f8 [10]
'W' ( 87) |11111110|01 [10] 3f9 [10]
'X' ( 88) |11111110|10 [10] 3fa [10]
'Y' ( 89) |11111110|11 [10] 3fb [10]
'Z' ( 90) |11111111|00 [10] 3fc [10]
'[' ( 91) |11111111|111011 [14] 3ffb [14]
'\' ( 92) |11111111|11111111|11111110 [24] fffffe [24]
']' ( 93) |11111111|111100 [14] 3ffc [14]
'^' ( 94) |11111111|111101 [14] 3ffd [14]
'_' ( 95) |1011011 [7] 5b [7]
'`' ( 96) |11111111|11111111|110 [19] 7fffe [19]
'a' ( 97) |00100 [5] 4 [5]
'b' ( 98) |1011100 [7] 5c [7]
'c' ( 99) |00101 [5] 5 [5]
'd' (100) |100000 [6] 20 [6]
'e' (101) |0000 [4] 0 [4]
'f' (102) |100001 [6] 21 [6]
'g' (103) |100010 [6] 22 [6]
'h' (104) |100011 [6] 23 [6]
'i' (105) |00110 [5] 6 [5]
'j' (106) |10111110 [8] be [8]
'k' (107) |10111111 [8] bf [8]
'l' (108) |100100 [6] 24 [6]
'm' (109) |100101 [6] 25 [6]
'n' (110) |100110 [6] 26 [6]
'o' (111) |00111 [5] 7 [5]
'p' (112) |01000 [5] 8 [5]
'q' (113) |11111010|1 [9] 1f5 [9]
'r' (114) |01001 [5] 9 [5]
's' (115) |01010 [5] a [5]
't' (116) |01011 [5] b [5]
'u' (117) |100111 [6] 27 [6]
'v' (118) |11000000 [8] c0 [8]
'w' (119) |101000 [6] 28 [6]
'x' (120) |11000001 [8] c1 [8]
'y' (121) |11000010 [8] c2 [8]
'z' (122) |11111011|0 [9] 1f6 [9]
'{' (123) |11111111|11111110|1 [17] 1fffd [17]
'|' (124) |11111111|1100 [12] ffc [12]
'}' (125) |11111111|11111111|0 [17] 1fffe [17]
'~' (126) |11111111|1101 [12] ffd [12]
(127) |101001 [6] 29 [6]
(0xC2) |11000011 [8] c3 [8]
(0xC3) |11000100 [8] c4 [8]
(0xC4) |11000101 [8] c5 [8]
(0xC5) |11000110 [8] c6 [8]
(0xC6) |11000111 [8] c7 [8]
(0xC7) |11001000 [8] c8 [8]
(0xC8) |11001001 [8] c9 [8]
(0xC9) |11001010 [8] ca [8]
(0xCA) |11001011 [8] cb [8]
(0xCB) |11001100 [8] cc [8]
(0xCC) |11001101 [8] cd [8]
(0xCD) |11001110 [8] ce [8]
(0xCE) |11001111 [8] cf [8]
(0xCF) |11010000 [8] d0 [8]
(0xD0) |11010001 [8] d1 [8]
(0xD1) |11010010 [8] d2 [8]
(0xD2) |11010011 [8] d3 [8]
(0xD3) |11010100 [8] d4 [8]
(0xD4) |11010101 [8] d5 [8]
(0xD5) |11010110 [8] d6 [8]
(0xD6) |11010111 [8] d7 [8]
(0xD7) |11011000 [8] d8 [8]
(0xD8) |11011001 [8] d9 [8]
(0xD9) |11011010 [8] da [8]
(0xDA) |11011011 [8] db [8]
(0xDB) |11011100 [8] dc [8]
(0xDC) |11011101 [8] dd [8]
(0xDD) |11011110 [8] de [8]
(0xDE) |11011111 [8] df [8]
(0xDF) |11100000 [8] e0 [8]
(0xE0) |11100001 [8] e1 [8]
(0xE1) |11100010 [8] e2 [8]
(0xE2) |11100011 [8] e3 [8]
(0xE3) |11100100 [8] e4 [8]
(0xE4) |11100101 [8] e5 [8]
(0xE5) |11100110 [8] e6 [8]
(0xE6) |11100111 [8] e7 [8]
(0xE7) |11101000 [8] e8 [8]
(0xE8) |11101001 [8] e9 [8]
(0xE9) |11101010 [8] ea [8]
(0xEA) |11101011 [8] eb [8]
(0xEB) |11101100 [8] ec [8]
(0xEC) |11101101 [8] ed [8]
(0xED) |11101110 [8] ee [8]
(0xEE) |11101111 [8] ef [8]
(0xEF) |11110000 [8] f0 [8]
(0xF0) |11110001 [8] f1 [8]
(0xF1) |11110010 [8] f2 [8]
(0xF2) |11110011 [8] f3 [8]
(0xF3) |11110100 [8] f4 [8]
(0xF4) |11110101 [8] f5 [8]
]]></artwork></figure>
<figure><preamble>Response Table:</preamble><artwork><![CDATA[
( 0) |11111111|11111111|11111111|0 [25] 1fffffe [25]
( 1) |11111111|11111111|11111111|1 [25] 1ffffff [25]
( 2) |11111111|11111111|11100000 [24] ffffe0 [24]
( 3) |11111111|11111111|11100001 [24] ffffe1 [24]
( 4) |11111111|11111111|11100010 [24] ffffe2 [24]
( 5) |11111111|11111111|11100011 [24] ffffe3 [24]
( 6) |11111111|11111111|11100100 [24] ffffe4 [24]
( 7) |11111111|11111111|11100101 [24] ffffe5 [24]
( 8) |11111111|11111111|11100110 [24] ffffe6 [24]
( 9) |11111111|11111111|11100111 [24] ffffe7 [24]
( 10) |11111111|11111111|11101000 [24] ffffe8 [24]
( 11) |11111111|11111111|11101001 [24] ffffe9 [24]
( 12) |11111111|11111111|11101010 [24] ffffea [24]
( 13) |11111111|11111111|11101011 [24] ffffeb [24]
( 14) |11111111|11111111|11101100 [24] ffffec [24]
( 15) |11111111|11111111|11101101 [24] ffffed [24]
( 16) |11111111|11111111|11101110 [24] ffffee [24]
( 17) |11111111|11111111|11101111 [24] ffffef [24]
( 18) |11111111|11111111|11110000 [24] fffff0 [24]
( 19) |11111111|11111111|11110001 [24] fffff1 [24]
( 20) |11111111|11111111|11110010 [24] fffff2 [24]
( 21) |11111111|11111111|11110011 [24] fffff3 [24]
( 22) |11111111|11111111|11110100 [24] fffff4 [24]
( 23) |11111111|11111111|11110101 [24] fffff5 [24]
( 24) |11111111|11111111|11110110 [24] fffff6 [24]
( 25) |11111111|11111111|11110111 [24] fffff7 [24]
( 26) |11111111|11111111|11111000 [24] fffff8 [24]
( 27) |11111111|11111111|11111001 [24] fffff9 [24]
( 28) |11111111|11111111|11111010 [24] fffffa [24]
( 29) |11111111|11111111|11111011 [24] fffffb [24]
( 30) |11111111|11111111|11111100 [24] fffffc [24]
( 31) |11111111|11111111|11111101 [24] fffffd [24]
' ' ( 32) |11111111|0110 [12] ff6 [12]
'!' ( 33) |11111111|0111 [12] ff7 [12]
'"' ( 34) |11111111|111010 [14] 3ffa [14]
'#' ( 35) |11111111|1111100 [15] 7ffc [15]
'$' ( 36) |11111111|1111101 [15] 7ffd [15]
'%' ( 37) |011000 [6] 18 [6]
'&' ( 38) |1010100 [7] 54 [7]
''' ( 39) |11111111|1111110 [15] 7ffe [15]
'(' ( 40) |11111111|1000 [12] ff8 [12]
')' ( 41) |11111111|1001 [12] ff9 [12]
'*' ( 42) |11111111|1010 [12] ffa [12]
'+' ( 43) |11111111|1011 [12] ffb [12]
',' ( 44) |11111011|10 [10] 3ee [10]
'-' ( 45) |011001 [6] 19 [6]
'.' ( 46) |00010 [5] 2 [5]
'/' ( 47) |00011 [5] 3 [5]
'0' ( 48) |011010 [6] 1a [6]
'1' ( 49) |011011 [6] 1b [6]
'2' ( 50) |011100 [6] 1c [6]
'3' ( 51) |011101 [6] 1d [6]
'4' ( 52) |1010101 [7] 55 [7]
'5' ( 53) |1010110 [7] 56 [7]
'6' ( 54) |1010111 [7] 57 [7]
'7' ( 55) |1011000 [7] 58 [7]
'8' ( 56) |1011001 [7] 59 [7]
'9' ( 57) |1011010 [7] 5a [7]
':' ( 58) |011110 [6] 1e [6]
';' ( 59) |11111011|11 [10] 3ef [10]
'<' ( 60) |11111111|11111111|10 [18] 3fffe [18]
'=' ( 61) |011111 [6] 1f [6]
'>' ( 62) |11111111|11111110|0 [17] 1fffc [17]
'?' ( 63) |11110110|0 [9] 1ec [9]
'@' ( 64) |11111111|11100 [13] 1ffc [13]
'A' ( 65) |10111010 [8] ba [8]
'B' ( 66) |11110110|1 [9] 1ed [9]
'C' ( 67) |10111011 [8] bb [8]
'D' ( 68) |10111100 [8] bc [8]
'E' ( 69) |11110111|0 [9] 1ee [9]
'F' ( 70) |10111101 [8] bd [8]
'G' ( 71) |11111100|00 [10] 3f0 [10]
'H' ( 72) |11111100|01 [10] 3f1 [10]
'I' ( 73) |11110111|1 [9] 1ef [9]
'J' ( 74) |11111100|10 [10] 3f2 [10]
'K' ( 75) |11111111|010 [11] 7fa [11]
'L' ( 76) |11111100|11 [10] 3f3 [10]
'M' ( 77) |11111000|0 [9] 1f0 [9]
'N' ( 78) |11111101|00 [10] 3f4 [10]
'O' ( 79) |11111101|01 [10] 3f5 [10]
'P' ( 80) |11111000|1 [9] 1f1 [9]
'Q' ( 81) |11111101|10 [10] 3f6 [10]
'R' ( 82) |11111001|0 [9] 1f2 [9]
'S' ( 83) |11111001|1 [9] 1f3 [9]
'T' ( 84) |11111010|0 [9] 1f4 [9]
'U' ( 85) |11111101|11 [10] 3f7 [10]
'V' ( 86) |11111110|00 [10] 3f8 [10]
'W' ( 87) |11111110|01 [10] 3f9 [10]
'X' ( 88) |11111110|10 [10] 3fa [10]
'Y' ( 89) |11111110|11 [10] 3fb [10]
'Z' ( 90) |11111111|00 [10] 3fc [10]
'[' ( 91) |11111111|111011 [14] 3ffb [14]
'\' ( 92) |11111111|11111111|11111110 [24] fffffe [24]
']' ( 93) |11111111|111100 [14] 3ffc [14]
'^' ( 94) |11111111|111101 [14] 3ffd [14]
'_' ( 95) |1011011 [7] 5b [7]
'`' ( 96) |11111111|11111111|110 [19] 7fffe [19]
'a' ( 97) |00100 [5] 4 [5]
'b' ( 98) |1011100 [7] 5c [7]
'c' ( 99) |00101 [5] 5 [5]
'd' (100) |100000 [6] 20 [6]
'e' (101) |0000 [4] 0 [4]
'f' (102) |100001 [6] 21 [6]
'g' (103) |100010 [6] 22 [6]
'h' (104) |100011 [6] 23 [6]
'i' (105) |00110 [5] 6 [5]
'j' (106) |10111110 [8] be [8]
'k' (107) |10111111 [8] bf [8]
'l' (108) |100100 [6] 24 [6]
'm' (109) |100101 [6] 25 [6]
'n' (110) |100110 [6] 26 [6]
'o' (111) |00111 [5] 7 [5]
'p' (112) |01000 [5] 8 [5]
'q' (113) |11111010|1 [9] 1f5 [9]
'r' (114) |01001 [5] 9 [5]
's' (115) |01010 [5] a [5]
't' (116) |01011 [5] b [5]
'u' (117) |100111 [6] 27 [6]
'v' (118) |11000000 [8] c0 [8]
'w' (119) |101000 [6] 28 [6]
'x' (120) |11000001 [8] c1 [8]
'y' (121) |11000010 [8] c2 [8]
'z' (122) |11111011|0 [9] 1f6 [9]
'{' (123) |11111111|11111110|1 [17] 1fffd [17]
'|' (124) |11111111|1100 [12] ffc [12]
'}' (125) |11111111|11111111|0 [17] 1fffe [17]
'~' (126) |11111111|1101 [12] ffd [12]
(127) |101001 [6] 29 [6]
(0xC2) |11000011 [8] c3 [8]
(0xC3) |11000100 [8] c4 [8]
(0xC4) |11000101 [8] c5 [8]
(0xC5) |11000110 [8] c6 [8]
(0xC6) |11000111 [8] c7 [8]
(0xC7) |11001000 [8] c8 [8]
(0xC8) |11001001 [8] c9 [8]
(0xC9) |11001010 [8] ca [8]
(0xCA) |11001011 [8] cb [8]
(0xCB) |11001100 [8] cc [8]
(0xCC) |11001101 [8] cd [8]
(0xCD) |11001110 [8] ce [8]
(0xCE) |11001111 [8] cf [8]
(0xCF) |11010000 [8] d0 [8]
(0xD0) |11010001 [8] d1 [8]
(0xD1) |11010010 [8] d2 [8]
(0xD2) |11010011 [8] d3 [8]
(0xD3) |11010100 [8] d4 [8]
(0xD4) |11010101 [8] d5 [8]
(0xD5) |11010110 [8] d6 [8]
(0xD6) |11010111 [8] d7 [8]
(0xD7) |11011000 [8] d8 [8]
(0xD8) |11011001 [8] d9 [8]
(0xD9) |11011010 [8] da [8]
(0xDA) |11011011 [8] db [8]
(0xDB) |11011100 [8] dc [8]
(0xDC) |11011101 [8] dd [8]
(0xDD) |11011110 [8] de [8]
(0xDE) |11011111 [8] df [8]
(0xDF) |11100000 [8] e0 [8]
(0xE0) |11100001 [8] e1 [8]
(0xE1) |11100010 [8] e2 [8]
(0xE2) |11100011 [8] e3 [8]
(0xE3) |11100100 [8] e4 [8]
(0xE4) |11100101 [8] e5 [8]
(0xE5) |11100110 [8] e6 [8]
(0xE6) |11100111 [8] e7 [8]
(0xE7) |11101000 [8] e8 [8]
(0xE8) |11101001 [8] e9 [8]
(0xE9) |11101010 [8] ea [8]
(0xEA) |11101011 [8] eb [8]
(0xEB) |11101100 [8] ec [8]
(0xEC) |11101101 [8] ed [8]
(0xED) |11101110 [8] ee [8]
(0xEE) |11101111 [8] ef [8]
(0xEF) |11110000 [8] f0 [8]
(0xF0) |11110001 [8] f1 [8]
(0xF1) |11110010 [8] f2 [8]
(0xF2) |11110011 [8] f3 [8]
(0xF3) |11110100 [8] f4 [8]
(0xF4) |11110101 [8] f5 [8]
]]></artwork></figure>
</section>
<section title="Static Storage Cache">
<figure><artwork><![CDATA[
0x80 "date" = NIL
0x81 ":scheme" = "https"
0x82 ":scheme" = "http"
0x83 ":scheme" = "ftp"
0x84 ":method" = "get"
0x85 ":method" = "post"
0x86 ":method" = "put"
0x87 ":method" = "delete"
0x88 ":method" = "options"
0x89 ":method" = "patch"
0x8A ":method" = "connect"
0x8B ":path" = "/"
0x8C ":host" = NIL
0x8D "cookie" = NIL
0x8E ":status" = 100
0x8F ":status" = 101
0x90 ":status" = 102
0x91 ":status" = 200
0x92 ":status" = 201
0x93 ":status" = 202
0x94 ":status" = 203
0x95 ":status" = 204
0x96 ":status" = 205
0x97 ":status" = 206
0x98 ":status" = 207
0x99 ":status" = 208
0x9A ":status" = 300
0x9B ":status" = 301
0x9C ":status" = 302
0x9D ":status" = 303
0x9E ":status" = 304
0x9F ":status" = 305
0xA0 ":status" = 307
0xA1 ":status" = 308
0xA2 ":status" = 400
0xA3 ":status" = 401
0xA4 ":status" = 402
0xA5 ":status" = 403
0xA6 ":status" = 404
0xA7 ":status" = 405
0xA8 ":status" = 406
0xA9 ":status" = 407
0xAA ":status" = 408
0xAB ":status" = 409
0xAC ":status" = 410
0xAD ":status" = 411
0xAE ":status" = 412
0xAF ":status" = 413
0xB0 ":status" = 414
0xB1 ":status" = 415
0xB2 ":status" = 416
0xB3 ":status" = 417
0xB4 ":status" = 500
0xB5 ":status" = 501
0xB6 ":status" = 502
0xB7 ":status" = 503
0xB8 ":status" = 504
0xB9 ":status" = 505
0xBA ":status-text" = "OK"
0xBB ":version" = "1.1"
0xBC "accept" = NIL
0xBD "accept-charset" = NIL
0xBE "accept-encoding" = NIL
0xBF "accept-language" = NIL
0xC0 "accept-ranges" = NIL
0xC1 "allow" = NIL
0xC2 "authorization" = NIL
0xC3 "cache-control" = NIL
0xC4 "content-base" = NIL
0xC5 "content-encoding" = NIL
0xC6 "content-length" = NIL
0xC7 "content-location" = NIL
0xC8 "content-md5" = NIL
0xC9 "content-range" = NIL
0xCA "content-type" = NIL
0xCB "content-disposition" = NIL
0xCC "content-language" = NIL
0xCD "etag" = NIL
0xCE "expect" = NIL
0xCF "expires" = NIL
0xD0 "from" = NIL
0xD1 "if-match" = NIL
0xD2 "if-modified-since" = NIL
0xD3 "if-none-match" = NIL
0xD4 "if-range" = NIL
0xD5 "if-unmodified-since" = NIL
0xD6 "last-modified" = NIL
0xD7 "location" = NIL
0xD8 "max-forwards" = NIL
0xD9 "origin" = NIL
0xDA "pragma" = NIL
0xDB "proxy-authenticate" = NIL
0xDC "proxy-authorization" = NIL
0xDD "range" = NIL
0xDE "referer" = NIL
0xDF "retry-after" = NIL
0xE0 "server" = NIL
0xE1 "set-cookie" = NIL
0xE2 "status" = NIL
0xE3 "te" = NIL
0xE4 "trailer" = NIL
0xE5 "transfer-encoding" = NIL
0xE6 "upgrade" = NIL
0xE7 "user-agent" = NIL
0xE8 "vary" = NIL
0xE9 "via" = NIL
0xEA "warning" = NIL
0xEB "www-authenticate" = NIL
0xEC "access-control-allow-origin" = NIL
0xED "get-dictionary" = NIL
0xEE "p3p" = NIL
0xEF "link" = NIL
0xF0 "prefer" = NIL
0xF1 "preference-applied" = NIL
0xF2 "accept-patch" = NIL
0xF3 NIL
0xF4 NIL
0xF5 NIL
0xF6 NIL
0xF7 NIL
0xF8 NIL
0xF9 NIL
0xFA NIL
0xFB NIL
0xFC NIL
0xFD NIL
0xFE NIL
0xFF NIL
]]></artwork></figure>
</section>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 05:38:37 |