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 TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Network Interface / Internet "Layer Connection" Protocols

TCP/IP Network Interface / Internet "Layer Connection" Protocols 1 Address Resolution Concepts and Issues

Communication on an internetwork is accomplished by sending data at layer three using a network layer address, but the actual transmission of that data occurs at layer two using a data link layer address. This means that every device with a fully-specified networking protocol stack will have both a layer two and a layer three address. It is necessary to define some way of being able to link these addresses together. Usually, this is done by taking a network layer address and determining what data link layer address goes with it. This process is called address resolution.

In this section I look at the problem of address resolution at both a conceptual and practical level, with a focus on how it is done in the important TCP/IP protocol suite. I begin with a section that overviews address resolution in general terms and describes the issues involved in the process. I then describe the TCP/IP Address Resolution Protocol (ARP), probably the best-known and most commonly used address resolution technique. I also provide a brief overview of how address resolution is done for multicast addresses in IP, and the method used in the new IP version 6.

TCP/IP Network Interface / Internet "Layer Connection" Protocols 1 Address Resolution Concepts and Issues