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 Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  Name Systems and TCP/IP Name Registration and Name Resolution
           9  TCP/IP Name Systems: Host Tables and Domain Name System (DNS)
                9  TCP/IP Domain Name System (DNS)
                     9  DNS Name Registration, Public Administration, Zones and Authorities

Previous Topic/Section
DNS Name Registration, Public Administration, Zones and Authorities
Previous Page
Pages in Current Topic/Section
1
2
Next Page
DNS Organizational (Generic) Top Level Domains and Authorities
Next Topic/Section

DNS Hierarchical Authority Structure and the Distributed Name Database
(Page 2 of 2)

Lower-Level Authority Delegation

The process of authority delegation continues as we continue down the name space hierarchy. At each level the name space becomes more specific; if we use an organizational hierarchy, like the “.COM” top-level domain, we generally delegate authority for each second-level domain to the organization whose name it represents. So “IBM.COM” is managed by IBM, and so forth. Since IBM is huge, it may itself subdivide the authority structure further, but smaller organizations probably won't.

I want to point out explicitly that the authority hierarchy is complementary to the name hierarchy; they are not exactly the same. It is not necessary that there be a different authority for every level of the hierarchy. In many cases a single authority may manage a section of the name space that spans more than one level of the structure. For example, IANA manages the Internet root domain (“null”) and also the “.INT” top-level domain, but other TLDs are managed by other organizations. The name hierarchy is divided into zones of authority that reflect the hierarchy of authorities that manage parts of the name space.

It's also worth remembering that authority over a domain doesn't necessarily imply physical control. A domain can contain subdomains that are managed by organizations on different continents, and a single subdomain can contain named devices that are on different continents as well.

The DNS Distributed Name Database

Of course, with authority comes responsibility, and the main responsibility an authority has for a domain is registering names within the domain. When a name is registered, a set of data is created for it, which can then be used by internetwork devices to resolve the name into an address, or perform other functions. The set of all the data describing all DNS domains constitutes the DNS name database. Just as registration authority is distributed and hierarchical, this database too is distributed and hierarchical.

In other words, there is no single place where all DNS name information is stored. Instead, DNS servers carry resource records that describe the domains for which they have authority. As we'll see, the fact that this database is distributed has major implications on how name resolution is carried out.

Key Concept: The name space of the public Internet is managed by a hierarchy of authorities that is similar in structure to the hierarchical DNS name space, though not identical. The top of the hierarchy is centrally managed by IANA/ICANN, which delegates authority to other organizations for registering names in various other parts of the hierarchy. The information about name registrations is maintained in resource records stored in various locations, which form a distributed name database on the Internet.



Previous Topic/Section
DNS Name Registration, Public Administration, Zones and Authorities
Previous Page
Pages in Current Topic/Section
1
2
Next Page
DNS Organizational (Generic) Top Level Domains and Authorities
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.