Standardization of WiMax has been carried out and is still being carried out by three different entities: IEEE 802.16 WG, WiMax Forum and International Telecommunication Union (ITU).
The IEEE 802.16 WG was established in 1999. It has developed and published several versions of air-interface standards for wireless metropolitan area networks (Wireless MAN), with focus on the MAC and physical layer specifications. The WiMax forum was established in June 2001 by nine companies. Today it has hundreds of members, including most of the WiMax operators, component vendors and equipment vendors. It certifies products and equipment based on the IEEE 802.16 WG and European Telecommunications Standards Institute High Performance Metropolitan Area Networks (ETSI HiperMan). It can be said that the WiMax Forum is the equivalent to the WiFi Alliance for the WiMax side. WiMax Forum aims towards interoperability of WiMax devices and equipment and provides the certificate that a specific device meets the necessary requirements for that . ITU was established in 1865 in Paris as the International Telegraph Union and today constitutes a part of the United Nations (UN) for information and communication technology issues, based in Geneva, Switzerland. ITU gives recognition to WiMax standards developed by the IEEE 802.16 WG and the WiMax Forum, which allows spectrum owners to roll out WiMax easier in different countries and improves the international esteem of the technology .
The WiMax Forum extended the legacy 3-stage process of IEEE 802.16 WG to 6 stages in order to establish certified interoperability. This is illustrated in Figure 7.