Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 60
Address Allocation (The Internet Registry)

RFC 2050 describes the registry system for the distribution of globally unique Internet address space and registry options. This RFC is different from most others. Look in the upper–left corner and notice that the category is “Best Current Practice.” It represents an accurate representation of the current practice of the IP address registries.

The Internet Registry hierarchy was established in order to achieve address uniqueness, distribution of hierarchical distribution of global Internet addresses, and, most of all, produce a conservation of IPv4 Internet addressees. It consists of IANA, Regional IRs, and Local IRs.

The IANA is the Internet Assigned Numbers Authority, and it has overall authority for the number space used in the Internet. This number space includes port number, address, IP version numbers, and many other significant number assignments. Read RFC 1700 for a full description of the IANA.

The Regional IRs operate under the authority of IANA. They operate in large geographical areas such as continents. Currently, there are three defined: InterNIC, which serves North America; RIPE, which serves Europe; and APNIC, which serves the Asian Pacific region.

These IRs do not cover all areas. It is expected that each IR covers any area not specifically specified, but within its immediate area. Local IRs are established under the authority of the regional IR and IANA. They cover national dimensions.

Addresses are allocated to ISPs by regional registries, which in turn assign them to their customer base. ISPs that exchange routing information directly with other ISPs get their address allocation from their geographic IR. Other ISPs are referred to these ISPs for address assignment. In other words, if your address block has a reasonable chance of being propagated through the global Internet routing tables, then your address allocation will come from the IR. Otherwise, you will get your address assignment from your upstream ISP. Customers (commercial corporations) need not worry about this. They will get their address assignments from the ISP they sign up with. This is just a basic introduction to the IP addressing scheme.

Address Allocation (The Internet Registry)