When we talk about the word “Octet” it actually has several meanings. Of which there are octets in music, engineering and chemistry. But the one that I am talking about pertains to computing. The word’s root “octo” means eight. There are eight bits inside of an octet. So in a way you could say that an octet is the same as 8-bit and if you think about it a megabyte is also called a mega-octet. But the difference between a byte and octet is the number of digits in an octet is 8.“Computer networking standards almost exclusively use "octet". It is prominently used in Request for Comments (RFCs) published by the Internet Engineering Task Force.” (http://en.academic.ru/dic.nsf/enwiki/2060979) An octet commonly is used in a numeric value form, although it can be used in a variety of ways like hexadecimal, decimal, and other number systems. It can also be used as a string which uses only letters instead of numbers.“The OCTET STRING type is used to specify octets of binary or textual information. There is no limit to the maximum number of octets in a value of this type specified in SMI v1.”( http://www.webnms.com/net-snmp/help/developing_management_applications/datatypes/smi_datatypes/octetstring_datatype.html) Octets are use in across the internet and even on your home network. “Octets most commonly refers to any of the four bytes of an IPv4 address. In dotted-decimal notation, an IP address appears as follows - [ octet ] . [ octet ] . [ octet ] . [ octet ] “ (http://compnetworking.about.com/od/workingwithipaddresses/g/bldef_octet.htm) Each one of the octet in a IP address should and do add up to a total of 256, that being a number anywhere between 0 and 255. So as you can see this complicated use of a combination of numbers can provide many different possibilities.
You can actually identify, based upon the first or the last octet whether it represents a “Net” or a “Host/Node”. A “Net” is always contained in the first octete while a “Node/Host” is always contained in the last. So just by looking at computer or a device on the internet or network we kind of can tell what type of a system it is and what it does. As you can see this important when looking at “Class A” networks. “In the “classful” IP addressing scheme, a Class A network contains addresses for about 16 million network interfaces; a Class B about 65,000; and a Class C, 254.” (http://www.tcpipguide.com/free/t_IPAddressClassABandCNetworkandHostCapacities.htm)
If we take a look at other aspects of computing we can see pretty much the same thing, for instance, file compression. One popular form of file compression is MIME attachment.“A MIME attachment with the content type "application/octet-stream" is a binary file. Typically, it will be an application or a document that must be opened in an application, such as a spreadsheet or word processor.”( http://kb.iu.edu/data/agtj.html) In order for file compression to work both the sender and the receiver must use the same type of compression. The algorithms on both ends have to be the same meaning each octet in the algorithms should line up.
