A combination of difficult fiber rollout economics, rapid development of innovative technology, small DSLAMs and more capable home gateway CPE, and pressures from regulators and cable competitors is encouraging large telcos across the world to consider retaining copper access for the final drop into the subscriber's home, even if they have announced plans for fiber-to-the-home (FTTH). It's accepted that preserving copper in the ground and minimizing new network build (taking fiber to a cabinet, node or distribution point and using advanced DSL technologies) is cheaper and quicker than deploying FTTH. But telcos have difficult decisions to make that involve consideration of density of consumer broadband spend, quality of copper in the ground, loop lengths, and the technology roadmaps of their preferred access kit vendors.

It is natural to consider the capital expenditure required for different technologies -- the cost of civil work and engineer time being particularly significant -- and much focus is on the final few meters across the subscriber's yard and through the wall of the house. Telcos will also be concerned with the speed with which services can be launched on new networks: Competition in most broadband markets is intense and consumers know faster services are being introduced by many players.

A careful capex, time-to-market and revenue analysis may well result in a mixture of technologies being considered for different parts of an operator's network: perhaps fiber pulled to the home in affluent urban areas; vectored VDSL2 from cabinets/nodes as a lower-speed, lower-cost alternative in areas of lower demand density; and pair bonding, repeaters/regenerators and vectoring deployed to boost broadband speeds over longer lengths of copper where subscribers are far from the CO.

But it's important not to forget the opex consequences of such a strategy. Multiple technologies deployed through a network inevitably mean duplication of management systems -- simple networks are easier and cheaper to manage, requiring smaller NetOps departments, less reliant on the support of multiple vendors, or the knowledge of many specialist in-house engineers. There's also the requirement to maintain multiple networks over the long term, and also potentially very large electricity charges at every location where there is active equipment that cannot be line-powered.

This doesn't mean that advanced copper access technologies are not going to be a major part of most telcos' future broadband networks, but rather that the decisions on the choice of technologies must not be made on comparisons of rollout costs alone.

The Heavy Reading Insider report "Copper for Superfast Residential Broadband" looks at the key enhancements to DSL copper access -- focusing on bonding of copper pairs, vectoring, Phantom Mode and the emerging G.fast technology. It considers where, why and when each of these technologies might be deployed, and reviews the relevant portfolios of a number of the leading vendors of access equipment and solutions, summarizing and comparing their offers.

— Danny Dicks, Analyst, Heavy Reading Insider

"Copper for Superfast Residential Broadband," a 25-page report, is available as part of an annual subscription (12 monthly issues) to Heavy Reading Insider, priced at $1,595. This report is available for $900. To subscribe, please visit: www.heavyreading.com/insider.