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 Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)
      9  TCP/IP Internet Layer (OSI Network Layer) Protocols
           9  TCP/IP Routing Protocols (Gateway Protocols)
                9  TCP/IP Exterior Gateway/Routing Protocols (BGP and EGP)

Previous Topic/Section
TCP/IP Exterior Gateway/Routing Protocols (BGP and EGP)
Previous Page
Pages in Current Topic/Section
1
Next Page
BGP Fundamentals and General Operation
Next Topic/Section

TCP/IP Border Gateway Protocol (BGP/BGP-4)

Modern TCP/IP internetworks are comprised of autonomous systems (ASes) that are run independently. Each may use an interior routing protocol such as RIP, OSPF, IGRP or EIGRP to select routes between networks within the AS. To form larger internetworks, and especially the “mother of all internetworks”, the Internet, these autonomous systems must be connected together. This requires use of a consistent exterior routing protocol that all ASes can agree upon, and in today's TCP/IP that protocol is the Border Gateway Protocol (BGP).

In this section I describe the characteristics, general operation and detailed operation of the Border Gateway Protocol (BGP). The discussion is divided into two subsections. The first provides an overview and general look at the operation of BGP, including a discussion of key concepts such as topology, neighbor relationships, route determination and general messaging. The second gives a more detailed analysis of the different message types and how they are used, and describes the format of each message as well.

BGP is another in the rather large group of protocols and technologies that is so complex it would take dozens of topics to do justice. Therefore, I include here my somewhat standard disclaimer that you will find in this section only a relatively high-level look at BGP. You will need to refer to the BGP standards (described in the topic on BGP standards and versions) if you need more details.

Note: The current version of BGP is version 4, also called BGP-4. This is the only version widely used today, so unless otherwise indicated, assume BGP-4 wherever you see “BGP”.


Quick navigation to subsections and regular topics in this section



Previous Topic/Section
TCP/IP Exterior Gateway/Routing Protocols (BGP and EGP)
Previous Page
Pages in Current Topic/Section
1
Next Page
BGP Fundamentals and General 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.