ATM forum (ATMF)
The ATM Forum was founded in September 1991 by the companies Cisco, NET/Adaptive, Northern Telecom and US Sprint. In the meantime, the ATM Forum has about 800 members. The goal of the ATM Forum is not to leave the standardization of ATM to the International Telecommunication Union( ITU) alone, but to let industry suggestions flow into the design of the standards through close cooperation with the official standardization bodies
Furthermore, for those areas in which no standards have yet been defined, industry standards are to be created by specifications from the ATM Forum. This will enable companies to rapidly develop products, building on a quasi- standard. One of the first activities of the ATM Forum was the development of UNI 2.0, an enhanced specification of the ITU-UNI standard in June 1992.
ATM and SDH
The International Telecommunication Union (ITU) had initially defined only SDH-based transmission interfaces as the physical transmission method for ATM. In UNI 2.0, the corresponding recommendations for the transmission of ATM cells were extended to existing PDH lines(45 Mbit/s, 34 Mbit/s, etc.), and the 100 Mbit/s Transparent Asynchronous Transmitter/Receiver Interface was defined for the LAN area.
In 1994, the significantly expanded UNI 3.0 and UNI 3.1 specifications followed. For the first time, they defined transmission standards for local ATM networks, among other things. This also includes the standardized specification for the transmission of the ATM cell stream at transmission speeds of 25.6 Mbit/s ( ATM25 for short) or 155 Mbit/s.
Currently, the ATM Forum Technical Committee is divided into fourteen working groups: ATM signaling, Broadband Intercarrier Interface( B-ICI), Data Exchange Interface( DXI), LAN emulation, network load management, UTP-3(ATM on UTP cable Category 3), network management, interoperability of switching equipment, security aspects, service aspects of ATM, testing of ATM networks. Other discussion points include: Multiprotocol over ATM( MPoA), Residental Broadband (RBB) and LAN Emulation( LANE) or natural ATM API.
The ATM Forum had approximately 800 members at the beginning of 1996, including 220 voting members, 160 ATM users, and 410 ATM vendors and consultants. Decision-making within the ATM Forum is by a two-thirds majority of all full members.
In 1993, based on the ATM Forum, an ATM User Interest Group, the so-called Enterprise Network Users Roundtable, was founded. The aim of this group is to include universities as well as users in the process of developing standards.