By Prof B.S. Chowdhry & Khalil-ur-Rehman Laghari
The major characteristics of a telecommunication system is unquestionably its information carrying capacity. The explosive growth of internet traffic, deregulation and the increasing demand of user/industry are putting pressure on our customers to increase the capacity of their network. The internet is getting more elaborate by the day. Web pages are swarming with animation, downloadable movies and music abound. The phone modems used by most people to get internet access have reached the limits of their performance, necessitating new technologies to allow users to surf the internet without having to wait minutes (or hours) for a page or file to download.

These new technologies are collectively known as broadband. They comprise a variety of different systems, but they all have one major goal: to increase the rate a user can send and receive data, and thus make the internet (and other online activities, like videoconferencing) easier and faster to use. . In this article, we'll explain a few of the more important bits of jargon, but for the most part, we'll concentrate on making sure that you know exactly what you need to choose the broadband service that's right for you.

If you access the net from home, you've probably been using what's known as a dial-up connection; in other words, you dial a telephone number on your computer, hear a series of weird sounds, and end up surfing the net about a minute later. Sometimes you get busy signals, or the connection speed suddenly drops to a snail's pace, or somebody in the house picks up the phone and cuts your connection right in the middle of an important download. Depending on your service provider, you might even have to carefully limit the amount of time you spend online, or else pay extra hourly fees.

The first advantage of broadband is that it generally avoids the hassles associated with dia-lup connections. With most forms of broadband, you can surf the 'net freely, without worrying about tying up your phone line or using up a precious allotment of hours.

The second and for many, the more important advantage of broadband is speed: lots of it. If you've sat around twiddling your thumbs while waiting for a web page to download, you know how annoying a slow connection is. With broadband, those aggravations are reduced or even eliminated. Not only will web surfing be faster in general, allowing you to hop from web page to web page almost as fast as you can click your mouse, but the speed of broadband opens up a host of other possibilities for both home and business users.

Streaming media are movies and music that can be viewed on your computer without first saving them to your hard drive, much like the way you've always been able to watch a television show without having to record it on a VCR first. Downloading a streaming video on a antenna; the signal can fade in and out, and even at its optimal performance, it's not the best. But a broadband connection, being fast and steady, can play streaming videos with much better video quality. Computer gamers can also play online against opponents around the world, without lag or slowdown, or the worry that a family member's important phone call will interrupt a vital shoot'em-up tournament.

Some broadband connections allow video conferencing. While video conferencing is now possible using multiple ISDN lines and costly equipment, the expense is far out of the budget of most small-business and home users. The speed and cost of broadband brings this once-rare capability within reach of the average consumer.

Broadband types

There exist five major categories of broadband service. Each one has its own advantages and disadvantages, and some are notably better overall than others. Here we cover each technology briefly:

Cable modem: Currently, the most popular form of broadband, cable modem service, uses the same cables that carry cable TV signals to carry data. You can get cable modem service as a stand-alone service or as an add-on to your current cable TV service. You can watch cable TV and use your cable broadband connection at the same time with no loss of quality. Cable modem system is easy to set up and maintain. This service is certainly agood choice for LAN setup with a small number of users.

The main disadvantage of the cable is that the speed of the system is dependent on the number of people who are online at the same time. It is to say that if a large number of people in your neighbourhood are using the services at the same time, your connection speed may drop considerably. Cable modem performance can undergo significant fluctuations. At its best, it's the fastest of all consumer-level broadband services; but at its worst, it's almost as slow as a dialup service.

DSL: It stands for Digital Subscriber Line. It's fast, reliable, and uses standard copper phone lines to carry data. You don't need a second phone line to use most consumer DSL services, and you can talk on your phone while using DSL connection to access the internet. There are many varieties, but the most important are ADSL and SDSL. ADSL (Asymmetric Digital Subscriber Line) is designed for residential and small-business use. Most home internet users receive (download) far more information from the internet than they send (upload). ADSL provides a higher download speed than upload speed; therefore, it is ideal for home internet users. In most cases, the upload speed of ADSL is still faster than a regular analog (phone) modem.

SDSL (Symmetric Digital Subscriber Line) is designed for business users who need to both upload and download large amounts of data, as in the case of video conferencing or running a web server.

The main disadvantage of DSL is that its speed is dependent on your physical distance from the phone company's nearest central switch known as a Central Office. The farther you are from the switch, the slower your average connection speed will be. Your home or business will have to pass a loop qualification test run by your phone company before you can have DSL installed. Also, DSL setup can be complex; in many cases, separate visits from the broadband provider and your phone company will be required.

DSL is a good choice if you're close to the phone company's central switch, the phone lines are up to the specifications, and you have a reliable high-speed connection. While it is not yet as widely available as cable modem service, DSL is often a viable alternative often preferable to cable modem.

Satellite: Satellite broadband uses a dish on your roof to send and receive data from satellites orbiting the Earth. The same dish may be used for satellite TV. The main advantage of satellite internet access over the other forms of broadband technology is its immediate availability. Thus, in places where cable modem, DSL and ISDN connections may be unavailable, you can still get a broadband connection, literally from out of the clear blue sky.

There are downsides, though. The performance of a satellite broadband connection is degraded by bad weather, local interference, or a misaligned dish. Also, because of the way the satellite data transfer works, satellite service is not well suited to applications that require constant transmission of small data packets; these include online gaming, web page hosting, video conferencing, and multiple small file downloads.

Some satellite providers who have not upgraded to two-way satellite communication equipment also require the use of a phone modem connection to send data to the broadband provider; this results in additional costs and slower speed. However, the monthly costs are usually reasonable, the equipment is often discounted or free, and most importantly, you can get satellite almost anywhere. Satellite isn't as fast or reliable as DSL or cable, but if it's your only choice, it's definitely better than dial-up.

ISDN: Integrated Services Digital Network is relatively old technology whose main advantages are wide availability and reliability. ISDN uses standard copper phone lines to transmit data. ISDN for the home user essentially splits your existing phone line into two channels, which can be used to make a phone call and surf the internet at 64kbps, or the channels can be combined for internet access at twice the speed of one channel at 128kbps.

ISDN is slower than the other newer forms of broadband. However, it is often the only choice for many users whose cable and phone companies haven't yet implemented local cable or DSL service.

ISDN also offers some advantages over satellite. For instance, ISDN is good for use by networked computers, online gamers, and web-page hosts; these are areas in which satellite's performance lags. ISDN lines are often used by businesses because their speed is reliable and constant. Its speed doesn't fluctuate as a result of bad weather, location, or cable modem activity in nearby buildings.

ISDN hardware is often complex and not easy for the novice to set up, and even basic ISDN service is more expensive than other forms of broadband. However, if neither cable nor DSL are available and suitable, ISDN is a viable, butexpensive alternative to get a broadband connection.

Wireless: Wireless broadband (also known as fixed wireless to distinguish it from the mobile wireless system used by some pagers and mobile phones) is a new technology that uses an antenna placed on or in your building to send and receive data. The data is transmitted via your city's wireless network, which consists of antenna towers placed three to five miles apart. No phone or copper wire is required for implementing this technology. It's the fastest internet connectivity solution in the world. It's speed can range from 64kbps to 100Mbps. It is bi-directional unlike satellite and eliminates the need for dedicated phone line, thereby reducing your cost while providing high speed data rate.

As you might have guessed, this means that if your home or building isn't in a city with wireless service, you won't be able to get fixed wireless broadband. Currently, fixed wireless broadband service is very limited; however, the service areas are expanding quickly. If you can get wireless, you're getting an excellent broadband connection. The connection speed is not limited by your distance from the wireless antenna or by the number of wireless users in your area. Wireless is a little more expensive than ADSL or cable, but the advantages are probably worth it.

Availability of service

Some broadband services aren't yet widely available. Since broadband systems use new technology, some providers haven't gotten around to implementing service in small towns and rural areas. If you live in a large metropolis, you have a good chance of having several choices for broadband service. In less-populated areas, you may be more limited, but even if you're alone out in the middle of a desert, you can still get a broadband connection via satellite.

Installation ease

Once it's working, broadband is refreshingly easy to use; in most cases, if your computer and modem are on, so is your internet connection. However, actually getting the broadband equipment set up can be difficult for casual computer users, and almost impossible for novices. Luckily, many providers lower or even waive the cost of a professional installation, but if you do find yourself having to install a network card (a small circuit board with a phone-jack-like plug) in your computer, you can always get help from your provider's technical support line. It's uncommon for a provider not to offer 24x7 support for users with problems; after all, an unhappy customer often becomes a competitor's customer.

Your computer doesn't need to be the latest and greatest to run broadband; most computers sold within the last five years should be quite capable of supporting a broadband connection. You will definitely want to check your system specifications, though, just to be sure. If you are not sure what the differences are between USB, PCI and a loaf of sliced bread, most broadband providers and support sites have customer service reps as well as quick online tutorials that will get you up to speed on the basic attributes of your computer.

Reliability

Current broadband systems are mostly "piggybacked" on existing technology; that is, they aren't so much a whole new car as they are a set of new tires on some old wheels. As such, they do sometimes run into problems related to the basic structure they're built on. Also, keep in mind that sometimes, popular websites can get bogged down, making even the fastest connection run like molasses. Still, broadband at its worst is still usually better than dial-up at its best.

Security issues

Broadband is relatively new technology, and like most new technologies, it brings along a whole new set of problems. These days, most information sent to and from your computer is encrypted using special security codes that make it very hard for someone to read your personal messages. However, even if someone can't intercept your love letters, they can use your broadband connection to break into your computer and play havoc with your files and even your hardware. This vulnerability is inherent to the always-on nature of many broadband systems, and has been a problem for businesses for some time.

However, don't let this scare you off, though; when properly set up and used, broadband is just as safe as talking to someone on the phone. Most businesses use a kind of software program called a firewall to protect their computers; much like a physical firewall, a computer firewall is a sturdy barrier against outside attack. Firewall software is available for home use, and in fact, many providers include or suggest specific firewalls when you install their software. Take some time to learn about security requirements and protection; a few hours during the learning stages can save you a lot of headaches later on.

As with any new product, competition is fierce. As more broadband choices become available, prices may drop, and more promotions and free extras will be offered. You'll have more providers to choose from, and you'll probably even be able to upgrade your current broadband service to something newer and better later on.

The growth of the internet demands high-speed connections. Many flashy web sites with complex graphics are designed with broadband connection speeds in mind. Consumers are demanding faster ways to get the data they need, whether it's for personal entertainment or for work. Broadband technologies are the best way to get the most mileage out of the information superhighway.-Dawn

Prof B. S. Chowdhry is chairman, department of electronic & telecommunication engineering, MUET, Jamshoro, and Khalil-ur-Rehman Laghari is a freelance writer doing a project on "wireless broadband networks" under the supervision of Prof Chowdhry.