Saturday, April 12, 2008

Fibre to the home

More Fiber in Their Future: Cable Industry Developing Standards for FTTP

Eventually, every house will have a fiber connection - and who doesn't need more fiber? Increasingly, that's the long-term view of many in the telecom industry. The question for cable operators, who use a mix of fiber and coaxial cable to distribute their voice, video and data services, is how to get there while also supporting the existing base of legacy technologies, including, most prominently, DOCSIS, which is the standard that defines the operation of broadband IP data services.

The cable industry took a step in defining what fiber optics will look like in the network this week with the announcement that its main standards body - the Society of Cable Telecommunications Engineers (SCTE) - is pursuing a standard that will effectively be the equivalent of fiber to the premises (FTTP) for cable networks.

The SCTE Engineering Committee - which is accredited by the American National Standards Institute (ANSI) - will focus on defining a technology it calls "RF over Glass" (RFoG). It has also been referred to as "Cable PON." The committee approved the RFoG program in late 2007, and relevant subcommittees have begun meeting to start crafting a standard that is expected to significantly improve overall cable network capacity.

The move comes at a time when cable operators are under pressure to increase the capacity in their networks to support not only ultrahigh-speed broadband to compete against fiber to the home (FTTH) services being deployed by telco and other carrier competitors, but also a future where everything on demand and massive amounts of high-definition programming, over-the-top and peer-to-peer video, and other bandwidth-laden applications and services are the norm.

SCTE is undertaking development of a suite of technical standards to support wider use of optical fiber in the cable plant, while also supporting the coexistence of current legacy technologies over cable's hybrid fiber-coaxial (HFC) system architecture, where voice, video and data share the same spectrum. Any new standard must deal with DOCSIS, which is the standard for IP data services.

An SCTE "interface" subcommittee will examine key issues of RFoG, including performance issues of existing outside plant equipment such as splitters and couplers; specifications for fiber-optic passive filters and gateway RF levels; environmental requirements for gateways; and issues and practices dealing with "midsplit" cable equipment and system operations. This last one is interesting, as it deals with rearranging the spectral capacity of the cable's limited upstream path.

What vendors will benefit in the carrier network infrastructure space from this potential migration to fiber? The usual suspects include Cisco, Motorola and Arris, of course. However, some other smaller players that already offer products in this segment, such as Wave7 Optics, Aurora Networks, Calix and Alloptic, have been in this space as well. The RFoG standards initiative could also open a door to a more significant presence for Alcatel-Lucent in the cable market as well, which it has targeted as a new opportunity area.

In addition to external network equipment, the RFoG standards work will also help ensure interoperability with existing digital set-tops and DOCSIS modems/VoIP eMTAs, as well as integrated gateways' seamless operation on any FTTP-type architecture that emerges. A number of cable operators are already implementing deep fiber architectures in "greenfield" build-outs, and a number are also moving to FTTP already in their primary networks. In some higher-end markets, home builders are asking for FTTH connections as a way to increase the value of their properties to upscale buyers. As a general rule, home builders enter into nonexclusive agreements with TV and broadband service providers, but often provide incentives, such as subsidization, for running fiber connections to their developments.

From the time a new cable standard is initiated to the time of market implementation can be as long as five years, so if cable is to think about what its networks are going to look like by 2013 and beyond, the work must start now.

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