PDF of this tutorialOverseeing the development of passive optical networks as part of fiber-optic backbones is the Full-Service Access Network (FSAN) Initiative. FSAN is a group of 20 telecommunications companies working collaboratively with equipment suppliers to agree on a common broadband access system for provisioning both broadband and narrowband services.
Since June 1995, the FSAN group has been working on the international initiative and recognizing that each member has differing needs, depending on regulatory, business, and structural environment in each country. FSAN is not a standards body, but rather submits specifications to standard bodies such as the International Telecommunications Union (ITU). Existing standards are incorporated where applicable. In October of 1998, the ITU adopted the G.983.1 broadband optical access system based on PON.
Members of the initiative throughout the process have intended to introduce elements of their results to appropriate standards bodies. On June 22, 1999, four FSAN members—NTT, British Telecom, BellSouth, and France Telecom—issued a common technical specification for ATM subscriber systems. Because each initiative member understood the need to develop future access networks, the group realized that industry-wide benefits could be achieved through adopting a common set of specifications. The consortium determined that the per-line cost of producing a full-service access network will decrease slowly with the production volume.
The group concluded that as volume increases, the development of new technologies will enable significant reductions in per-line equipment and installation costs. Fiber-based broadband networks could be cost-effective to deploy if their component part were built in bulk quantities for tens of millions of access lines, rather than according to today's typical 300,000-line system order.
The group's work has occurred in two phases. First, its task was to identify technical and economic barriers to the introduction of a broadband access network. It was determined that an ATM PON was the most promising technology to achieve large-scale, FSAN work deployment that could meet the evolving service needs of network users. The consortium felt that ATM PON was the best means of supporting a range of architectures such as FTTH, FTTB/C, and FTTH/CAB. Members have recognized that all operators require the same elements in their access network. The major differences come from the positioning of the optical network unit (ONT). All members see the need for a PON system. Second, the group's work was to devise a common set of specifications for full-service access networks. Six working teams—systems engineering/architecture; optical access networks; home network/network termination; operation, administration, and maintenance (OAM&P); VDSL; and component technology—undertook the development process.
