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 Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  Name Systems and TCP/IP Name Registration and Name Resolution
           9  Name System Issues, Concepts and Techniques

Previous Topic/Section
Name Resolution Techniques and Functional Elements of A Name Resolution System
Previous Page
Pages in Current Topic/Section
1
2
Next Page
TCP/IP Name Systems: Host Tables and Domain Name System (DNS)
Next Topic/Section

Efficiency, Reliability and Other Name Resolution Issues and Features
(Page 2 of 2)

Reliability Considerations

The main concern with name resolution after efficiency is reliability. As I said earlier in the section, having a name system isn't strictly necessary for the computers, but it's very important for the users, especially on a large network like the Internet. While having a single central place that maintains all information about a name system may make administration simpler, it creates a dangerous “single point of failure”. If anything happens to the device storing the information, the entire name system fails.

Modern name systems employ redundancies to prevent having the entire system rely on any particular device for resolution. A typical approach in a client/server system is to have multiple servers in different locations (or attached to different networks) that can respond to name resolution requests.

Key Concept: Since name resolution is the part of a name system that is used most often, it is here that we must pay careful attention to implementation issues. The two most important ones are efficiency and reliability. Efficiency is essential due to the many thousands or millions of resolutions performed every day on a large system; reliability is a consideration because users of the name system quickly come to rely on it and we must make sure it is robust.


Other Considerations

An optional feature in some name resolution systems is load balancing. When properly implemented, load balancing allows a single name to map to more than one underlying address. This allows requests sent to a particular “virtual” device to actually be directed to a number of different actual physical devices, spreading the load over multiple machines. A common use of this feature is for very popular, heavily-trafficked Web sites.

Finally, while name resolution is obviously designed to allow names to be mapped into addresses, there are cases where we may wish to go in the other direction: given a numeric address, find the name that goes with it. This process, called reverse resolution, is analogous to having a phone number and trying to find the name of the person or company to which it belongs. Just as we can't easily find the name matching a phone number using a conventional phone book (we'd have to scan every page looking for the number), reverse resolution requires special support on the part of the name system. This is especially true if the name system data is distributed over many servers.

 


Previous Topic/Section
Name Resolution Techniques and Functional Elements of A Name Resolution System
Previous Page
Pages in Current Topic/Section
1
2
Next Page
TCP/IP Name Systems: Host Tables and Domain Name System (DNS)
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.