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Thanks to lower network costs, fiber to the home is becoming a feasible alternative to current broadband offerings, such as DSL and cable modem.

Fiber to the home offers the data rates of 10/100 Ethernet, scalable to Gigabit Ethernet or higher. It uses the Data Over Cable Service Interface Specification (DOCSIS) standard for security, and it's optimized for voice, data, and video.

Currently, two methods of deploying fiber to the home are preferred: a point-to-point network, and a passive optical network, or PON, which uses a point-to-multipoint architecture. ATM-based PON is described in ITU-T Recommendations G.983.1 and 983.3. Major carriers such as BellSouth helped write the specifications for PON and are advocating for its standardization and use.

Carry on With PON

With PON, providers passively split the signal to share the data rate among a maximum of 32 subscribers in a neighborhood. Several hundred homes are connected into optical line termination devices at the central office or head end.

Personal encryption for each subscriber ensures privacy; DOCSIS ensures cable modem security. Fixed network and exchange costs are spread out among all subscribers, thus reducing the cost-per-subscriber metric. The network has no outside-plant electronics, which reduces complexity and life-cycle costs and improves reliability. As a result, the economics are becoming attractive to service providers.

Point-to-Point

Point-to-point networks are also common. Enterprise LAN electronics can deliver services to single-family homes and multidwelling units. Using existing components and technology, standards bodies and equipment vendors are improving these networks so that they can carry the multiplicity of services subscribers want. Connecting subscribers directly to a centralized switch offers very high bandwidth capacity.

In either deployment, fiber provides the ultimate upgrade path. Data rates can scale from 1 megabit per second to 10 gigabits per second per home, without changing the fiber or outside-plant equipment (only the electronics--and, as a result, the software--changes). Fiber technology also provides the highest bandwidth, has a longer life expectancy than copper or coaxial cable, and is resistant to electromagnetic interference.

Once fiber reaches the home, it terminates at an optical network termination or an optical network unit located at or near the customer premises. An ONU is mounted indoors, or outdoors in a hardened, weatherproof box on the side of a home or building. ONTs service Ethernet networks inside homes. They convert the light signal from the fiber strand into an electrical signal.

A typical unit would have four 10/100 ports for Internet access; a video-on-demand port; and four plain-old telephone service ports, offering single party, voice grade, and caller ID services. The video-on-demand port would receive MPEG-format video, decompress it, and send it to a set-top box.