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!

Read offline with no ads or diagram watermarks!
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)

Previous Topic/Section
TCP/IP Exterior Gateway Protocol (EGP)
Previous Page
Pages in Current Topic/Section
1
Next Page
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
Next Topic/Section

TCP/IP Transport Layer Protocols

The first three layers of the OSI Reference Model—the physical layer, data link layer and network layer—are very important layers for understanding how networks function. The physical layer moves bits over wires; the data link layer moves frames on a network; the network layer moves datagrams on an internetwork. Taken as a whole, they are the parts of a protocol stack that are responsible for the actual “nuts and bolts” of getting data from one place to another.

Immediately above these we have the fourth layer of the OSI Reference Model: the transport layer, called the host-to-host transport layer in the TCP/IP model. This layer is interesting in that it resides in the very architectural center of the model. Accordingly, it represents an important transition point between the hardware-associated layers below it that do the “grunt work”, and the layers above that are more software-oriented and abstract.

Protocols running at the transport layer are charged with providing several important services to enable software applications in higher layers to work over an internetwork. They are typically responsible for allowing connections to be established and maintained between software services on possibly distant machines. Perhaps most importantly, they serve as the bridge between the needs of many higher-layer applications to send data in a reliable way without needing to worry about error correction, lost data or flow management, and network-layer protocols, which are often unreliable and unacknowledged. Transport layer protocols are often very tightly-tied to the network layer protocols directly below them, and designed specifically to take care of functions that they do not deal with.

In this section I describe transport layer protocols and related technologies used in the TCP/IP protocol There are two main protocols at this layer; the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). I also discuss how transport-layer addressing is done in TCP/IP in the form of ports and sockets.

Note: It may seem strange that I have only one subsection here, the one that covers TCP and UDP. This is a result of the fact that The TCP/IP Guide is excerpted from a larger networking reference.


Quick navigation to subsections and regular topics in this section



Previous Topic/Section
TCP/IP Exterior Gateway Protocol (EGP)
Previous Page
Pages in Current Topic/Section
1
Next Page
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
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.