Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Enjoy The TCP/IP Guide? Get the complete PDF!
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Protocol Suite and Architecture

Previous Topic/Section
TCP/IP Protocol Suite and Architecture
Previous Page
Pages in Current Topic/Section
1
2
3
Next Page
TCP/IP Services and Client/Server Operation
Next Topic/Section

TCP/IP Overview and History
(Page 2 of 3)

Modern TCP/IP Development and the Creation of TCP/IP Architecture

Testing and development of TCP continued for several years. In March 1977, version 2 of TCP was documented. In August 1977, a significant turning point came in TCP/IP’s development. Jon Postel, one of the most important pioneers of the Internet and TCP/IP, published a set of comments on the state of TCP. In that document (known as Internet Engineering Note number 2, or IEN 2), he provided what I consider superb evidence that reference models and layers aren't just for textbooks, and really are important to understand:

We are screwing up in our design of internet protocols by violating the principle of layering. Specifically we are trying to use TCP to do two things: serve as a host level end to end protocol, and to serve as an internet packaging and routing protocol. These two things should be provided in a layered and modular way. I suggest that a new distinct internetwork protocol is needed, and that TCP be used strictly as a host level end to end protocol.

-- Jon Postel, IEN 2, 1977

What Postel was essentially saying was that the version of TCP created in the mid-1970s was trying to do too much. Specifically, it was encompassing both layer three and layer four activities (in terms of OSI Reference Model layer numbers). His vision was prophetic, because we now know that having TCP handle all of these activities would have indeed led to problems down the road.

Postel's observation led to the creation of TCP/IP architecture, and the splitting of TCP into TCP at the transport layer and IP at the network layer; thus the name “TCP/IP”. (As an aside, it's interesting, given this history, that sometimes the entire TCP/IP suite is called just “IP”, even though TCP came first.) The process of dividing TCP into two portions began in version 3 of TCP, written in 1978. The first formal standard for the versions of IP and TCP used in modern networks (version 4) were created in 1980. This is why the first “real” version of IP is version 4 and not version 1. TCP/IP quickly became the standard protocol set for running the ARPAnet. In the 1980s, more and more machines and networks were connected to the evolving ARPAnet using TCP/IP protocols, and the TCP/IP Internet was born.

Key Concept: TCP/IP was initially developed in the 1970s as part of an effort to define a set of technologies to operate the fledgling Internet. The name “TCP/IP” came about when the original Transmission Control Program (TCP) was split into the Transmission Control Protocol (TCP) and Internet Protocol (IP). The first modern versions of these two key protocols were documented in 1980 as TCP version 4 and IP version 4.



Previous Topic/Section
TCP/IP Protocol Suite and Architecture
Previous Page
Pages in Current Topic/Section
1
2
3
Next Page
TCP/IP Services and Client/Server Operation
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.