IP Address Management and Assignment Methods and Authorities
(Page 2 of 2)
The Original IP Address Authority: IANA
The Internet is of course the big IP internetwork, and requires this coordination task to be performed for millions of organizations worldwide. The job of managing IP address assignment on the Internet was originally carried out by a single organization: the Internet Assigned Number Authority (IANA). IANA was responsible for allocating IP addresses, along with other important centralized coordination functions such as managing universal parameters used for TCP/IP protocols. In the late 1990s, a new organization called the Internet Corporation for Assigned Names and Numbers (ICANN) was created. ICANN now oversees the IP address assignment task of IANA, as well as managing other tasks such as DNS name registration.
IP addresses were originally allocated directly to organizations. The original IP addressing scheme was based on classes, and so IANA would assign addresses in Class A, Class B and Class C blocks. Today, addressing is classless, using CIDRs hierarchical addressing scheme. IANA doesnt assign addresses directly, but rather delegates them to regional Internet registries (RIRs). These are APNIC, ARIN, LACNIC, and RIPE NCC. Each RIR can in turn delegate blocks of addresses to lower-level registries such as national Internet registries (NIRs) and local Internet registries (LIRs).
Eventually, blocks of addresses are obtained by Internet Service Providers (ISPs) for distribution to end-user organizations. Some of the ISPs customers are end-user organizations, but others are (smaller) ISPs themselves. They can in turn use or delegate the addresses in their blocks. This can continue for several stages in a hierarchical fashion. This arrangement helps ensure that IP addresses are assigned and used in the most efficient manner possible. See the section on CIDR for more information on how this works.
IANA, ICANN and the RIRs are responsible for more than just IP address allocation, though I have concentrated on IP addresses here for obvious reasons. For more general information on IANA, ICANN, APNIC, ARIN, LACNIC and RIPE NCC, try a can of alphabet soup or the topic on Internet registration authorities. J
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.