FTTC for Dummies
Believe it or not, broadband ADSL has been around since 2000. But what is the latest incarnation, how does it differ from the previous services and is it actually any good?
DSL (Digital Subscriber Line) services deliver data using high frequency transmission bands over analogue telephone lines. DSL revolutionized internet access as it was cheaper and faster than analogue and ISDN dial up. The genius was that it utilized copper line infrastructure that all businesses and homes already had installed. The first services were fixed at 1Mbps or 2Mbps downstream and together with the routers of the time were distinctly flakey.
Since then ADSL Max, ADSL Max Premium, ADSL2 and ADSL2+ were launched. Each had better exchange equipment and thus speeds and reliability improved. The transport mechanism from the local telephone exchange to the ISP also went through various upgrades which meant that data throughput increased (i.e. contention was lowered).
The problem with all of these services was that the speed and reliability decreased as the copper line length to the exchange increased. The latest ADSL2+ service with a maximum download speed of 24Mbps, dropped off the quickest of all. Meaning that up to a third of users didn’t get any improvement. Effectively circular bands of achievable speed could be drawn around the exchange.
Then came FTTC (Fibre To The Cabinet) ADSL, or Infinity as BT Retail brand it. Firstly this had much improved maximum speeds. There are two variants – 40Mbps down and 10Mbps up or 80Mbps down and 20Mbps up. Secondly, and certainly the biggest difference was as the name implies – fibre is used from the exchange to the green street cabinets. Therefore instead of a radius of decreasing speed around an exchange, speeds are only dependant on how close you are to the nearest street cabinet.
And that was where this service was so markedly, and in my opinion so brilliantly different. Customers who had almost given up on the internet could get superfast broadband. The Openreach implementation costs were acceptable as the cabinet to premises connection was still just a copper analogue line. Even the transport network from the exchange to the ISPs was improved and significantly cheaper to move lots of data across.
So are there any down sides to FTTC?
Naturally the government claimed to be doing this to improve Britain, make the world a better place etc. etc. This meant that areas where votes came from were picked first for cabinet upgrades, rather than business areas in towns and cities. In fact many areas in London still have no availability, effectively polarising the market between ADSL2+ users (the “have nots”) and leased line users (the “haves”). There are also cabinets that can never be upgraded to incorporate the new FTTC equipment due to size restrictions. I’m not sure whether it’s an urban myth, but apparently a middle class, home counties area campaigned to have smaller, less imposing cabinets as part of the normal Openreach replacement program. Only to find these were too small for FTTC equipment and that they were then at the back of the queue for upgrades. Another problem is that FTTC is still reliant on an analogue line and some of this infrastructure is over 60 years old. And maybe it’s just me becoming more intolerant, but the Openreach PSTN engineers or their contractors seem to be less competent these days.
One notable point about FTTC is that Openreach are the only cabinet and exchange equipment provider. So unlike other DSL services in the past, none of the other ISPs or carriers have their own equipment. It’s one big happy family of infighting, different branding and price wars.
So in summary; FTTC has revolutionised the UK internet delivery sector in a good way. It is affordable, reliable, does what it says and availability is improving all the time. Digital WWW love supplying FTTC! It even gives business users access to a hybrid FTTC ADSL / Ethernet leased line service. But that is another subject altogether…..