The Broadband Revolution

In the early 1990s the Internet was the home of computer science students and academics. The Web boom was just a twinkle in the eye of a few telecommunications gurus, but they made one big mistake: they believed that the future lay in the mutant offspring of the telephone and the television, the ghastly named teleputer.

Convergence was the buzzword, and millions of dollars were pumped into the development of video on-demand systems and cable TV networks.

Then along came the World Wide Web and everything changed.

The only problem is that the modem has been too slow for anything serious, with little prospect for anything faster than the latest generation of 56,000bps systems.

But why have modem speeds slackened off, after years of speeds doubling every 18 months or so?

The problem with the modem is the local loop - the cabling between your home and the telephone exchange. The mix of copper cables and digital sampling systems gives this link a maximum on-line speed limit of 64Kps which is too slow for high-quality multimedia and interactive services. It's too expensive to rip up the streets and relay every link to every home, so the search for an alternative technology has gone back to the days of convergence.

The telephone line only accepts a narrow bandwidth of frequencies, and so is a narrowband service. In order to provide faster access we need broadband systems, devices that use a wide bandwidth connection to send as much data as possible as fast as possible.

Several different technologies are available to help connect you to the Internet much faster. These include ISDN (and Home Highway), ADSL (Asynchronous Digital Subscriber Line) and cable modems. Wireless technologies also offer an alternate approach to the always-on Internet.

Let's take a quick dash through the broadband future that is coming your way - and in some areas of the world may already have arrived.

The DSL revolution

What's causing most of the current hype is the approach of Digital Subscriber Line (DSL). This technology provides high-speed broadband access through your normal phone socket, and is currently under trial across the UK.

There are several different flavours of DSL, from ADSL to VDSL, but they all more or less do the same thing. The version of DSL we are likely to see in the UK is ADSL. The first generation of DSL systems were able to transmit data at the speeds required for MPEG 1 video, while letting a telephone conversation run in parallel.

As the technology developed, higher and higher data rates became possible. Now data can be delivered at anything up to 8Mbps, while you can transmit your own at speeds of up to 944Kps.

The next generation of DSL systems promise to be even faster, with VDSL offering a stupendous 54Mbps. Of course, you'll need to live next door to your telephone exchange to get that sort of performance, but it's still a long way from the 28,800bps modem.

Using DSL, a digital modem is able to use a standard telephone line to deliver far more data than you'd expect with a conventional modem.

DSL isn't a long distance technology because most of the world's long distance lines are not high-bandwidth fibre optic cables. Instead, it's designed to deliver high-speed data services over the existing copper local loop - which would be far too expensive for even BT to replace in one go.

The different flavours of DSL are often referred to as xDSL. For example in an ADSL system an ADSL modem links your home to a modified telephone exchange, enabling you to enjoy the benefits of an always-on high-speed data link at the same time as a normal telephone conversation, over the same twisted pair of copper wire.

ADSL is an asymmetric protocol, and is designed to deliver far more data than you send because it was originally designed to deliver video on demand over your phone line. Luckily, the development of the Web has meant that Internet usage is also asymmetric, with most users downloading far more Web pages than they upload, so you won't find this too much of a problem.

The speed you can get out of an ADSL connection depends on how close you are to your local telephone exchange, and it doesn't really work further than 18,000 feet away, so it's really only a service for cities and towns. However, that still covers most households on the UK.

Even that far from the exchange, speeds are still impressive: 1.5Mbps down the line from the exchange to you, equivalent to a US T1 high-speed connection. Connections back to the exchange are a lot slower and, depending on how the service has been set up, can be anything from 16Kbps to 640Kbps.

Recent developments in signal processing technology have increased the speed of ADSL systems to around 6Mbps. However, the current system on trial by BT suggests that the consumer service planned for March 2000 will be limited to a 512Kbps downstream connection and a 256Kbps upstream link.

How ADSL works

The key to ADSL systems has been the development of a new generation of signal processors. These are powerful integrated circuits designed to handle complex analog to digital conversions , as well as manipulating and analysing analogue signals. These enable an ADSL modem to directly convert a stream of digital data into a large number of separate analog channels, operating at many different frequencies and data rates to take advantage of all the available bandwidth of a telephone line.

This Discrete Multi-Tone (DMT) technology is designed to adapt to changes in your telephone line, due to temperature, or interference due to other calls and lines.

As well as dealing with interference, ADSL is a point-to-point technology; so all the available bandwidth is yours, unlike cable modems where you have to share with everyone else on your street. However, you will need to share any onward bandwidth from the exchange to the Internet and this could be contended at anything between 10:1 and 25:1, depending on how much you will be willing to pay!

As a result, every 512Kbps of onward bandwidth will be shared between 25 other people, so the service can reduce at busy times. Still beats a conventional modem...

ADSL systems can be expensive for telecoms companies to install because they require hardware modifications to both the exchange and your home telephone connection.

The modern chipset manufacturer Rockwell has come up with an alternative approach: Consumer DSL (CDSL), also known as DSL Lite. This uses more signal-processing hardware and software in the DSL modem and, as a result, your telephone connection doesn't need any expensive modifications.

A CDSL modem can be designed to offer a 56Kbps standard modem connection as well, so you could use it anywhere. As always when something is easier to use there's a catch, and CDSL modems will be limited to connection speeds of around 1 Mpbs. Even so, it's still a lot faster than your existing analogue modem.

Cable Modems

All across the UK, TV companies have been ripping up the streets, laying fibre optic and coaxial cables to the homes in their franchise areas.

While an extra 50 or so channels of TV programs or cheaper phone calls may be a good reason to have a cable connection, the design of the cable TV network hides one of the secrets of high speed Internet access.

The UK's cable TV systems aren't just one way pipes, pouring video into homes. The network equipment in street-side cabinets and buried under the pavements is designed to provide a return path to the cable companies network centres. Originally intended as part of any future teleputer network, these paths are the key to high-speed Internet access.

Calling a cable modem a modem is something of a misnomer. Like a telephone line modem, a cable modem modulates and demodulates signals, but that's where the similarities end because the cable modem is much more complex than the traditional device.

It's probably safer to compare a cable modem to a network card or a small router because a cable modem can be used to provide shared access to a small network of PCs, while handling encrypted data streams and authentication.

Cable modems have actually been around a while, with one of the first systems developed by First Pacific Networks initially tested in the UK in the early 1990s - though it was originally intended to be used as a means of delivering telephone calls over a cable TV network.

In the end, it proved cheaper for cable TV networks to use traditional technologies for their telephone services, but the prospect of high bandwidth Ethernet-style connections over a cable TV remained.

LANcity has produced a whole family of cable modem products. As well as a personal cable modem, designed for connection to a single PC, LANcity produces a workgroup system for a small home or business network of up to four PCs, and a multi-user system suitable for use in a large business or school. Its unique finned design makes the LANcity cable modems look like a Pentium processor's heat sink.

Like the Motorola system, a LANcity cable connects to your PC via a standard network card and a 10base Ethernet cable.

Based around the proprietary UniLINK protocol, the LANcity system offers a full duplex 10Mbps system. If you connect your PC to a LANcity cable modem, and if no one else is on line, you'll get as good a performance as your office's Ethernet LAN. You'll also be able to take advantage of a network that has been designed to prevent unauthorized access to your PC's data, as the LANcity modem will only forward IP packets to specific machines. This means that no one will be able to listen into your link to the cable TV head-end.

One of the key features of the LANcity system is its ability to use standard network management systems to provide network operators with a wide range of information about its network. It can also use this information to tune network behaviour for each individual cable modem, and to bill its subscribers if its not offering flat-rate access. It's not alone; other manufacturers producing cable modems include Hewlett Packard, Zenith and cable TV tuner manufacturers General Instrument and Scientific Atlanta.

However, at the moment, there still isn't a standard for cablemodem networks, so head-end equipment from one system won't work with cable modems from another.

Recent work by four of the largest cable TV networks in the US has lead to the development of an outline standard: DCOSIS (the Data Over Cable Service Interface Specification). As its acronym is almost as hard to remember as PCMCIA, the standard has become known as MCNS (the Multimedia Cable Network System, after the MCNS Partners, the group set up to govern the specification). The specification has been sent to the ITU, but the cable industry believes that MCNS will become the de facto standard by sheer force of market presence.

Most of the cable modem manufacturers will be producing MCNS-compliant systems within the next few months, though the current proprietary systems will remain around for a while. Some manufacturers like 3Com see MCNS as only part of its cable modem strategy, as it's designed for the home Web surfer. 3Com has developed a system based on the telecoms ATM protocol, and expect it to be used for business systems, where it will work together with the latest high-speed network technologies.

Teething Troubles

While the manufacturers and the cable companies are singing the praises of cable modems, there have been some teething troubles with American trials. Advertising has encouraged people to believe that they're going to get a 10Mbps Ethernet speed connection to the Internet, without telling them that the bandwidth is actually shared with anything up to 500 other users. Slow connections to the rest of the Internet have also created bottlenecks. With UK services limited to 512 Kbpsm, you will get a much better performance than a modem, but not as much as the initial cablemodem hype predicted.

A cable modem isn't just a modem, and it's much more complicated to install and run. Cable networks have found that supporting their cable modem customers has been more complicated than dial-up users. There have also been problems with the equipment used to handle the cable cable modem connections to the Internet, which hasn't been as reliable as the dial-up access routes used by the ISPs. However, a lot of the problems reported have been the result of teething problems - just like the free ISPs suffered from, as they struggled to cope with their sudden popularity. There's also the issue of security. With an ordinary modem, you connect to the Internet as and when you want. With a cable modem you've got a permanent connection to the Internet, so you'll need to be sure you're not sharing your hard-drive with everyone in your street!

The biggest cablemodem network in the US, @Home (now with relationships with both Excite and AT&T), has spent millions of dollars on building its own country wide network. With this it hopes to have its own bypass on the Information Superhighway. @Home also provides its own portal, which it makes faster by keeping local copies at all its cable TV partner's local connections. The same is likely to be true in the UK, with local caches used to reduce the effects of backbone congestion.

Leased Lines

The traditional way of connecting a network to the Internet permanently is a leased line. However, this can be expensive - a 64Kbps line will cost anything up to £6,000 for a year. Leased lines are provided by telecommunications providers, and provide a direct Internet connection into your home or office, connecting your computer systems to your ISP.

You can purchase managed leased lines, where an ISP provides and manages a router, or just the connectivity, where you can provide your own router - and system management skills. Routers are complex devices, so you're probably best purchasing a managed solution. Leased lines are the key to offering your own Internet services. They enable you to host Web servers, e-mail systems, FTP sites, streaming video and audio - anything that runs over the Internet. Of course, you'll need to consider security when connecting to the Internet through a leased line, and a Firewall is an essential part of any leased system.

As your requirements for bandwidth increase, you can add more connectivity. Starting out with 64Kbps over a copper you can go to 128Kbps, then to 256Kbps and up to 512Kps before needing to have a fibre optic connection. These can take sometime to be fitted, especially if you're outside central London, so if you're planning to buy a leased line, plan well ahead.

It's likely that cable modems and ADSL will force the process of leased lines to drop because customers who only need connectivity switch to using business ADSL connections. BT have already started to offer a starter system, at a much lower price - though this does mean that you'll need to share ongoing bandwidth at a 10:1 ratio. For around £3,000 a year, the NetStart service is likely to prove attractive to small business and better-off home users.

If you want a guaranteed high-speed connection, with complete control over what you connect to it, and what services you can offer, then a leased line is exactly what you'll need - at a price.

Wireless Connections

ISDN, Cable modems and ADSL aren't the only way of getting a high-speed Internet connection. The satellite TV networks and the mobile telephone companies have a few tricks up their sleeves.

In the US the first digital TV satellites have a hitchhiker. Direct PC satellite dishes don't receive video signals, they're part of a strange hybrid of the satellite and telephone systems.

Hughes Data Systems realised that the high bandwidth of a satellite link could be used as the return path of an Internet connection. Instead of data being pumped up and down the thin pipe of a modem connection, data requests are sent to a server at satellite ground station, with responses being beamed down to the home receiver at speeds of up to 6Mbps.

Astra, who runs the satellite systems for Sky, has teamed up with Hughes and Intel to bring a similar system to Europe in the next few months. As well as the hybrid modem-satellite system used in the US, Astra is planning to eventually use the home's PC satellite dish to transmit data at up to 400,000bps to their satellites. A two-way satellite data system is still a few years off, but will offer a high-quality, high-speed link when and wherever required.

However, this is a proprietary technology, and the number of information providers may be limited to those who pay for satellite data delivery.

The same technology is being used for interactive digital TV services, such as Sky's Open. This uses a telephone connection over a free phone line from the set-top box to request services and news pages, and a satellite connection to deliver them to your TV. However, the remote control may not be the best tool for accessing Internet-style services.

Internet in the Sky

Further down the line are the 'Internet in the Sky' plans of Teledesic. Using Bill Gates and cellular telephone mogul Bill McCaw's money, Teledesic will launch a network of over 800 low-earth orbit satellites, which will give everyone with one of its 18-inch dishes a 2Mbps two way connection to the Internet, It's not alone, as several other consortiums are planning satellite data networks.

Things are a bit slower over mobile phones. A standard GSM data connection is currently around 9,600bps, though 33.6kps connections are expected in the next year. Even Orange's much heralded pocket videophone will only be able to send very small images by using a proprietary compression technology. An alternative is a few years away, with the next generation of mobile telephone licenses only just about to be auctioned by the Government.

However, the mobile telephone industry has come up with an alternate means of connecting us to the Internet 24 hours a day - and this time, it's anywhere you can get a mobile phone signal. This is WAP.

The Wireless Application Protocol is a set of standards designed by the WAP form, a group of mobile telephone system developers (including Nokia, Motorola and Ericsson), to enable delivery of interactive applications over a digital mobile telephone service.

The entire WAP model is built around Internet standards, including TCP/IP, HTTP and XML, and the WAP Forum intends to make sure that this remains a single open specification - to stop different manufacturers from locking users into specific phones for specific networks.

Initially mobile phone access to the Internet will be for simple applications, as the WAP micro-browser isn't as sophisticated a tool as Internet Explorer 5.0. You'll use it to work with your bank account, or to read e-mail, or even to do a little on-line shopping. The limitations of WML aren't significant once you realise you don't need to see the pictures. And even so, the text WAP browser is likely to be a short-term solution. A next generation of WAP phones will have larger screens and keyboards, and will be much more like PDAs than the phones we're used to.

Motorola has put together a video showing how it sees the future of mobile Internet access. In it two schoolgirls use phones that look like a cross between a Palm PDA and a Nintendo GameBoy to send e-mail and pictures, as well as transferring notes and making phone calls. It takes a while to realise that they're using devices as powerful as today's PCs, but tucked away in their pockets. It may be years away, but the wireless future may be the real home for the always on, always connected computer.

So What Does it Mean for You?

There's a lot of cutting edge technology out there that's designed to help speed up the on-line world, and the race is on for which will be the first to reach home. While some of the promised speeds are likely to be beyond the initial consumer-level services, the delivered 512kpbs download speed is a substantial improvement over a 56kps modem that will only connect at around 44kps...

If you live in the country, you'll have to wait for a satellite Internet connection because the cable TV companies will be unlikely to run services outside large towns and cities, and the distance restriction of ADSL is going to keep it from your door. Wiring up the country with broadband cables and fibre optics is unlikely ever to be economical. If you do get a connection, your choice of service provider will be limited to your local cable franchise or one of a limited number of ADSL services, so you won't get to pick and choose the ISP that is best for you.

In the short and medium term, if you're lucky enough to live in a large city, then you may be able to have a high-speed connection within the next year for between £40 and £70 a month. It won't be as cheap as dialling up with a modem, but it will always be there, and if there's one thing that's been learnt from the US services and the UK trials, it will change your life.

If you don't use a Windows PC, you may find some problems. While NTL state in their FAQs that they will support non-Windows platforms like Linux and McOS, the same can't be said of services like like BT's ADSL - which initially required a specific specification of Windows PC for the trial. While it's not difficult for a network-savvy user to discover the DHCP server addresses, gateways and name servers, and so be able to configure their own system, they're unlikely to be supported if there are any problems.

The single PC requirements of most services will prevent small business or home workers from connecting networks to broadband connections - unless they are skilled enough to set up a small system as a router that uses non-standard IP addresses to mask a private network, and to provide firewall facilities.

Of course, there's one thing to remember: the future will be fast, but it'll never be fast enough. As faster and faster links become common, service providers and Web page designers will add more and more video and sound to their Web pages, so that you'll have more data to download in a vicious circle which will mean that you'll end up wanting a faster connection again!

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