The Internet Assigned Numbers Authority®, often called IANA® for short, is the worldwide organization that assigns Internet addresses and maintains a database of numerical and text Internet addresses to help direct web users to the correct website. Functions performed by the Internet Assigned Numbers Authority are many, but include root zone management, top level domain database management, and IP and autonomous system numbers (ASN). The Internet Assigned Numbers Authority operates by a system of policies set by the Internet Corporation for Assigned Names and Numbers® (ICANN®).
A top level domain is the part of a domain name on the right-hand end of the domain name expression. This element of the domain can be one or two parts separated from the rest of the domain by a period often called a dot or stop. Common examples of top-level domains include .com, .co.uk, and .edu. A top-level domain is often connected to a country or type of organization such as a school or government office.
An ASN is a number assigned to certain types of networks, typically those with multiple routers that operate under the same network administrator using the same set of rules. These rules are generally called an interior gateway protocol (IGP). A type of network that might receive an assigned ASN is an Internet service provider (ISPs). When a user connects to an ISP using a router, she must often use a router compatible with the ASN assigned to the Internet service provider.
Even though a person browsing the web usually inputs a text address including a domain into the browser address bar, the addresses computers use to find each other are actually numerical addresses called IP address. Each computer and web server its own unique IP address through which other computers can find information stored on it. One of the responsibilities of the Internet Assigned Numbers Authority is to correlate IP addresses with the text addresses human users input to direct them to a website. The two types of IP addresses in use by the Internet Assigned Numbers Authority as of September 2010 are IP version 4 (IPv4) and IP version 6 (IPv6). The addresses used by IPv4 are 32 bit and bear the usual 220.127.116.11 arrangement, while IPv6 addresses are 128 bit and are usually arranged in hexadecimal strings that look like combinations of letters and numbers with colons.
Created in 1998, the related organization ICANN® is a non-profit corporation that sets rules for how identifying numbers like Internet protocol (IP) addresses are distributed. IANA® is the organization that carries out and enforces the protocol set forth by ICANN®. Both the Internet Assigned Numbers Authority and ICANN® help ensure that web numbering addresses are unique and on record where they can be used to accurately direct web traffic.