IANA stands for the Internet Assigned Numbers Authority. IANA is currently a division of ICANN; ICANN is a non-profit corporation that manages the namespace of the Internet. IANA is currently located at the offices of ICANN (pictured below), which are situated in the Playa Vista neighborhood (Westside) of of Los Angeles, California, United States of America.
On the 18th of December, 2015, ICANN released a PDF documents establishing the current functions of IANA; which are as follows: 1) protocol assignments, 2) internet number resources, 3) root zone management. Therefore, IANA is responsible for assigning, managing and administrating the following:
1) Protocol assignments: IETF, with oversight provided by IAB, develop
Internet protocols, these protocols use parameters such as port numbers, PENs
and status codes.
2) Internet number resources: includes, Internet Protocol addresses (IPv4 and IPv6) and Autonomous System Numbers (ASNs).
3) Root zone management: manages the DNS Root Zone File, Root Zone Database, INT domain and ARPA top-level domains.
It is difficult to isolate a specific date when IANA was created as a formal organisation. The Internet evolved out of the protocols designed for ARPANET, and in 1972 Jon Postel and Vint Cerf began the process of creating a system of standard socket numbers for the hosts of ARPANET. This standardisation of network / protocol numbers would become the life's work of Jon Postel, who would become the principle head of the IANA function from 1972 to 1998.
What is clear however: is that while ARPANET expanded as a research network - the TCP/IP protocol suite was developed for it - that the IANA function operated on a fairly informal basis during the 1970's and 1980's. During this era IANA did not have a specific name, but there was always a group of individuals - headed by Jon Postel - that assigned numbers for ARPANET / Internet protocol related services. It was during the late 1980's - as the Internet began to evolve from it's academic ARPANET roots into a commercial backbone - that IANA was formally named and organised.
Some of the first RFC documents that specifically mention IANA are:
1) RFC 1083: (published December, 1988) Internet Activities Board published a Request for Comment document (1083) titled "IAB Official Protocol Standards" was probably the first document that made mention of IANA by name.
2) RFC 1060: (published March, 1990) Jon Postel and Joyce Reynolds published a Request for Comment document (1060) titled "Assigned Numbers" which was probably the first document to name IANA and give an expansive explanation of the IANA function. This document stated: "This RFC will be updated periodically, and in any case current information can be obtained from the Internet Assigned Numbers Authority (IANA). If you are developing a protocol or application that will require the use of a link, socket, port, protocol, etc., please contact the IANA to receive a number assignment."
RFC 1060 replaced RFC 1010 - both were titled "Assigned Numbers" and attempted to give an official status report on the numbers used in Internet protocols. RFC 1010 was published in 1987 by Jon Postel and Joyce Reynolds and made no mention of an organisation named IANA: therefore, I would speculate that the use of the name IANA began in 1988.
While the IANA function was initially related to standardising socket numbers, it's role expanded as the number of Internet services and their protocols expanded. IANA also began to administer the root zone of the Domain Name System (DNS); when this naming system was created 1983-1985. As the Internet expanded beyond the borders of the United States of America, IANA began to assign IP address blocks to regional registries who would assign IP addresses to network operators in their region. IANA also maintained it's role of assigning port and socket numbers to Internet services like the World Wide Web (HTTP application layer protocol).
Until 1998, IANA remained the exclusive 'domain' of the computer scientists who developed ARPANET; specifically Jon Postel, who helped install the first ARPANET node. ARPANET / Internet was primarily a research / educational network(s) in the 1970's / 1980's; therefore, it's importance was fairly minimal, and the funder of the project - various United States Government Departments - did not interfere with the scientists who developed and maintained it. Jon Postel and Joyce Reynolds were located at the University of Southern California (USC) Information Sciences Institute when managing the IANA function in the 1970's, 1980's and 1990's.
However, IANA would eventually come under stringent oversight by the United States Department of Commerce. This was due to Jon Postel, controversially, and on his own authority, 'hijacking' the Internet by instructing eight regional root nameservers to change the root zone server they 'pulled' addresses from. Such a unilateral action was no longer acceptable in an Internet largely supported by a commercial backbone and having growing civil and business importance. The United States Department of Commerce, in response to Jon Postel's 'hijacking', released a document named "A proposal to improve technical management of Internet names and addresses" which resulted in the creation of ICANN.
IANA became a department of ICANN in 1998, and IANA would henceforth be overseen and adhere to United States Department of Commerce policies. Jon Postel died of heart complications in 1998, and his era of IANA came to a close. Joyce Reynolds, his principle IANA collaborator, did continue to work for ICANN until 2001.
Since the late 1980's, the protocols of the Internet have been developed by the Internet Engineering Task Force (IETF); which is comprised of volunteers organised into working groups. Due to the creation of ICANN, ICANN had to get a agreement with IETF that the IANA function they now managed would still maintain it's role in assigning the numbers of Internet protocols that the IETF developed. In 2000, RFC 2860 was published by B. Carpenter (IAB), F. Baker (IETF), and M. Roberts (ICANN): titled "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority" it defined an agreement between IETF and IANA and the technical work carried out by IANA on behalf of the IETF.
From 1998-2017 (present day), IANA has remained a department of ICANN, and it's role has largely remained the same since it's inception in 1972. ICANN is a non-profit corporation, located in California, that was under contract to the United States Department of Commerce. On the 1st of October, 2016, ICANN and therefore IANA, was freed from U.S. government oversight, and has now transitioned to an international multi-stakeholder governance.