In computing, a hextet, or a ''chomp'', is a sixteen-bit aggregation,
or four
nibble
In computing, a nibble, or spelled nybble to match byte, is a unit of information that is an aggregation of four- bits; half of a byte/ octet. The unit is alternatively called nyble, nybl, half-byte or tetrade. In networking or telecommuni ...
s. As a nibble typically is notated in hexadecimal format, a hextet consists of 4 hexadecimal digits. A hextet is the unofficial name for each of the 8 blocks in an
IPv6 address
An Internet Protocol version 6 address (IPv6 address) is a numeric label that is used to identify and locate a network interface of a computer or a Node (networking), network node participating in a computer network using IPv6. IP addresses are ...
.
A hextet is also referred to as a segment, in some documentation.
History
Bob Bemer
Robert William Bemer (February 8, 1920 – June 22, 2004) was a computer scientist best known for his work at IBM during the late 1950s and early 1960s.
Early life and education
Born in Sault Ste. Marie, Michigan, Bemer graduated from Cranbro ...
suggested the use of hextet for 16-bit groups in 2000.
In 2011 an
Internet Draft
An Internet Draft (I-D) is a document published by the Internet Engineering Task Force (IETF) containing preliminary technical specifications, results of networking-related research, or other technical information. Often, Internet Drafts are int ...
explored various alternatives for hextet such as ''quibble'', short for "quad nibble".
In response to this draft, author Trefor Davies suggested the use of the word ''chomp'' because it is in line with the current denominations ''bit'', ''nibble'', ''byte''.
''Hextet'' would more properly describe a 6-bit aggregation, whereas the exact term for 16 bits should be ''hexadectet'', directly related to the term
octet
Octet may refer to:
Music
* Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble
** String octet, a piece of music written for eight string instruments
*** Octet (Mendelssohn), 1825 compo ...
(for 8 bits). However, because it is harder to pronounce, the short form ''hextet'' is used—in analogy to how ''hex'' is commonly used as an abbreviation for ''
hexadecimal
Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbo ...
'' in computing. This usage of ''hex'' to mean 16 is also in line with the similar
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines.
The IEEE ...
1754 term ''
hexlet'' indicating 16 octets.
[ (NB. The standard defines doublets, quadlets, octlets and hexlets as 2, 4, 8 and 16 ]byte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable un ...
s, giving the numbers of bit
The bit is the most basic unit of information in computing and digital communication. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as ...
s (16, 32, 64 and 128) only as a secondary meaning.)
Although the word ''hextet'' is not officially recognized in the
IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster ...
documents, the word is used in technical literature on IPv6
published after the Internet Draft. Official IETF documents simply refer to them as ''pieces''.
Cisco
Cisco Systems, Inc. (using the trademark Cisco) is an American multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, s ...
sources generally use the term ''quartet'' as does IPv6.com,
a reference either to the four digit grouping or to the fact that it represents four nibbles; however, this term is also used by some to refer to a four-bit aggregation.
See also
*
Sextet
A sextet (or hexad) is a formation containing exactly six members. The former term is commonly associated with vocal ensembles (e.g. The King's Singers, Affabre Concinui) or musical instrument groups, but can be applied to any situation where six ...
(group of 6 bits)
*
Doublet (2 octets)
References
{{Information units
Units of information