So what does it involve, and will it solve all our internet woes?
There's not much to the local loop. It's a pair of insulated copper wires that run from a telephone exchange to a customer. This is technology that Alexander Graham Bell would be at home with, designed to transmit the human voice and nothing more.
With modern tricks like digital subscriber line (DSL) technology, it is possible to do much more with these wires, but we're almost out of tricks. The problem with DSL is that it works best over a short distance and the faster it works the shorter the distance it works over.
Some people can't get standard DSL broadband because they're too far from an exchange. Even more will be deprived of the faster ADSL2+, which is about to take the nation by storm.
There are two solutions. FTTH enthusiasts say we should replace the local loop with shiny new fibre optic cable, which has none of the limitations of the old copper wires.
Others - including the Government and Chorus (the new Telecom business unit responsible for the local loop) - have a less radical plan: make the local loop shorter.
That's exactly what Chorus is doing with its "cabinetisation" project. Instead of the phone line running all the way to the exchange it will instead run to a roadside cabinet that is itself linked to the exchange with fibre. Then, with no customer more than 2.5km from a cabinet, everyone (well, around 80 per cent of homes) can enjoy ADSL2+.
This isn't the cop-out it seems. The ultimate goal is FTTH, but this way the fibre gradually spreads out from the exchange to engulf the local loop.
But even fast DSL won't be fast for long, and when the time comes that last 2.5km can be replaced with fibre, too.
Phone lines aren't the only way in. TelstraClear's hybrid fibre coaxial (HFC) networks in Christchurch and Wellington already offer the high speed and reliability Chorus is striving to achieve.
These networks are also organised so that fibre feeds several customers over copper cable, but the copper used here is more capable than that found in the conventional phone system.
TelstraClear customers in these areas can already access the internet at ADSL2+ speeds, and even higher speeds are possible. Because of this TelstraClear can afford to wait much longer before replacing that last stretch of copper with fibre.
This also tells us why FTTH is coming so slowly. Running fibre to every customer is a big job and there is little incentive to do so until the possibilities of existing copper are completely exhausted. The exception is new housing developments, where it makes sense to install fibre right from the start. Telecom is already trialling FTTH for new subdivisions.
Nevertheless, fibre is the way of the future for broadband internet access. The numbers say it all. The theoretical maximum speed for standard DSL is 12 megabits a second (Mbps) and ADSL2+ is 24Mbps.
Telecom's FTTH trial is starting at 30Mbps with the speed planned to rise to 100Mbps both to and from the customer. And that's just the beginning. At this speed many computers can happily share a single internet connection. Videoconferencing and HDTV on demand become feasible.
But don't get too excited - there's a catch. FTTH will eliminate what has been the chief bottleneck in internet access, but will expose us to other bottlenecks we've been shielded from.
FTTH is just an on-ramp to the information superhighway. Your data still has to navigate safely to its destination, competing with everyone else's data and avoiding the many spots where traffic jams can form. If your local exchange is congested, your ISP is overloaded, international connections are choked, or the server you're trying to contact is busy, performance suffers.
Some of these bottlenecks are already visible. Your broadband speed varies depending on how many of your neighbours are also online. Some websites crawl because they aren't geared to meet demand.
Big organisations such as Google and Microsoft do better, but only by scattering warehouses of servers around the main arteries of the internet.
If fibre was rolled to our doors tomorrow, the results would probably be disappointing. Some things wouldn't get any faster and, since higher speed would increase demand, some things might actually get slower.
FTTH will become essential as we demand more and more from the internet, but it's not a magic bullet. Without matching infrastructure across the entire internet, benefits will be patchy and, with control spread across the world, progress may not be smooth. Then again, what would you expect when you're rewiring the world?
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Quelle/Source: Stuff, 03.06.2008
