Overview
Many companies are finding their experience on-line frustrating because they are relying on slow and unreliable dial-up connections. Installing a faster connection will make it possible to exploit the full potential of the net for trading, learning and research. This factsheet provides the necessary background information you need before choosing which type of connection to install.

What is Broadband
The speed with which data can move through any link in a network is called the ‘Bandwidth’. Bandwidth is measure of maximum traffic capacity measured in data bits transmitted per sec. We talk about ‘narrowband’ where there is less capacity, and ‘Broadband’ where there is more. As with road traffic, it is possible to share capacity, so that if a number of users share a given bandwidth their individual bandwidth is reduced. The dividing line between broadband and narrowband is drawn differently by different people, but in this factsheet we will define Broadband as any connection over 256 Kbits/sec – so that we include medium bandwidth connections with ‘always on’ potential such as ASDL as well as the ‘true’ broadband of over 2Mbits/sec.

For comparison – most people today connect to the Internet over a phone line, typically using a modem with a speed of 28.8 or 56 kilobits per second.

Not Just Speed...
The important advantage of most broadband connections, apart from speed , is the fact that there is a continuous connection. This means that there is no need to wait for your computer to dial the service before you are on-line. Once established, the connection is far less likely to ‘drop out’. For these reasons, if you need to use your business connection for anything beyond the infrequent e-mail or looking up train times then broadband is a must. This kind of connection is unsuitable for anything other than e-mail and browsing.

Recent Developments
Until this year, the most common way in which higher bandwidth and broadband services have been supplied is via dedicated high bandwidth cable connections to the internet ‘backbone’. These leased line connections were only affordable for larger businesses. However in the last two years two new methods of getting a faster connection via the phone subscriber network have been developed – ISDN and then ADSL.

The services have been slow to arrive because service providers were waiting for BT to make its local network available to other companies. However both services are now widely available in London. Even more recently some of the cable networks supplying cable TV have offered a permanent modem connection via cable. There is also the possibility of satellite or wireless connection, but as this factsheet is primarily targetted at businesses in London where leased line, DSL and ISDN are the main options.

Leased lines
Leased lines are permanent telecommunications links supplied by network operators to users. They provide capacity dedicated to the user’s exclusive use. Leased lines are used by large businesses and some SMEs to carry high volumes of voice and data traffic, for example financial institutions use them for data traffic between different branches. Internet Service Providers use leased lines to connect to the Internet and to offer high speed Internet access to business consumers.

Leased lines are reliable dedicated internet connections. They are offered at various speeds from T1 (256Kbps to 1.5Mbps) to T3 (3Mbps up to 45Mbps). OC-3 connections can range from 60Mbps to 155Mbps. For most businesses a T1 connection is the most likely and most cost effective solution. It is only if you are hosting your own server, or dealing with a large quantity of e-mail or shared data, that more than 1.5Mbps would be required.

Leased Line not only provides capacity, it also provides a better quality of service than dial-up connections as it does not suffer from dial delays, line noise, packet loss problems, or contention.

Frame Relay is a particular type of leased line connection which offers a high speed connection but in burstable amounts meaning your ISP will offer a minimum connection speed plus allow higher speed access for short periods of time. The computer data is broken down into packets or ‘frames of data’ and then sent to their destination where the reverse is performed.

Another type of access which you may come across is ‘ATM’ (Asynchronous Transfer Mode). This is used for larger companies who require high-speed, high-bandwidth capacity for real-time voice and video, as well as general data bits.

SMDS (switched Multi-Megabyte Data Service) is a third type of service offered by BT. It offers speeds from 0.2Mbits/sec to 25Mbits/sec. Like Frame Relay and ATM is can only be offered in certain areas.

ADSL
DSL – Digital Subscriber Line – is a method of adapting ordinary telephone lines for faster data access. It is delivered down a single copper telephone line that has been split in two – one for voice use and one for data. There are two types – Asymmetric and Symmetric (ADSL and SDSL), but ADSL is more widely available. ADSL enables a copper line to send a large quantity of data (eg a television picture) down the line and a small quantity (eg. a telephone call) in the opposite direction. It was designed for the consumer, but now widely used by business, as SDSL is not widely available.

It is obviously more suitable for those that need to access the net for information and purchasing rather than for web hosting. The disadvantage of DSL is that it downgrades with distance, meaning a user must be within 4km of the telephone exchange in order to get it. The closer you are, the faster the service.

ADSL is capable of working at speeds of up to 8Mbps to the user and 1Mbps in the other direction, but for economic reasons most telcos provide only a fraction of this. Speed falls off rapidly over distance from the exchange. The download speeds available commercially for ADSL are 512k, 1MB and 2MB. Upload speeds are a maximum of 256k regardless of the download speed.

ADSL has the huge advantage that it runs over an infrastructure that's already installed and near universal in scope. Using ordinary telephone lines (you must have a BT line to subscribe), DSL is much faster than ISDN and costs far less than a leased line connection such as a T-1.
However ADSL is a contended service, meaning you share the available bandwidth with a number of other users. This means that the amount of bandwidth available to you will depend on the number of users online at any given time. For business use, the contention ratio is likely to be around 20:1 (up to 19 other users sharing your bandwidth) whereas for home use it could be as high as 50:1.

Cable
Cable Modem is potentially the cheapest method of connection, if available.

A Cable Modem connection is offered by a local cable television company and is a high speed internet connection equivalent to some leased lines. The connection is always on and the cable company charges a monthly fee for subscription to the service. Unlike ADSL which is a phone technology, Cable Modems use the fibre optic network of the cable companies therefore is only available where the optical network is in the street.

Cable TV companies work by providing a private radio spectrum to your home nearly a gigahertz wide. With enough bandwidth for hundreds of television channels, it's a relatively simple idea to reserve one channel for computer data. Cable modems work as miniature TV broadcast and reception stations, receiving data from one sliver of a shared TV channel and transmitting it on another. A cable TV channel is capable of delivering around 30Mbps, but most cable companies share this between the fifty or so people who share the local repeater which provides a street with TV services, capping each user at 512kbps (Home) and 1Mbps (business).

In the London Area the cable companies are TeleWest or NTL.. At the present time (November 2001) they have widespread availability of cable modem for home use, but restrictions for business use. NTL are at present rolling out programs for business in Hertfordshire and Surrey.Telewest (via Blue Yonder) have package deals for business which include cable modem and business e-mail.

ISDN
ISDN is not in the broadband range, but is concluded for comparison, as it is the most widely-available offering. Depending on your ISP you will probably be on a pay-as-you-go-tariff, so you will be dialling up for each session. If you pay a flat rate you can leave your connection on, but the service provider has the right to disconnect at their discretion, so it is difficult to get a truly ‘always-on’ service. Companies usually offer two speeds of ISDN, a 64Kbps connection, recommended for smaller organisations, and a 128Kbps connection for more flexibility and more capacity.

For internet access, ISDN is superior to a standard phone connection because data, graphics, sound and video can be downloaded at a much faster rate.

For telecommuting, ISDN can be used to connect a home PC to a network much cheaper than a dedicated line.

However ISDN is not suitable for BtoB trading, heavy e-mail use, on-line training, or any transaction-based e-commerce.

Cost Comparisons
With leased line, cable modem or ADSL, the rental is fixed and there are no call charges . This in itself means that if you are using the internet for business already, updating to broadband can be justifiable in cost savings alone.

Leased line is the most expensive option, but it is dificult to quote costs because they are dependent on location and bandwidth. The good news is that the rental is cheaper in London.
If investment in a leased line is justified it will usually be worthwhile buying additional bandwidth rather than the minimum, because often extra bandwidth can be purchased for a small amount in comparison with the base cost.

Leased line costs are due to fall in 2002 because OFTEL are forcing BT to drop its costs for the BT part of the service – the ‘BT Tail’ which connects the business to the ISP’s nearest POP. (Point of Presence).

Installation Costs
ISDN, ADSL and cable modem requires a modem (which costs around £150 to £250 to have installed). Leased Line installation needs routers and cabling and the installation charge is slightly greater.

Firewalls
A firewall is a software package which monitors incoming and outgoing messages from the internet and prevents unauthorised access in either direction. Firewall software is often provided as part of your server software, but may be an additional cost, in which case it is like to be a significant cost, depending on whether the support is outsourced.

If you have an 'always on' connection it is recommended you have a firewall installed to protect your network.

The risk is further increased if you are hosting your own web site, or extranet site. This means that you have an external IP address on which anyone on the net can reach you. A firewall then becomes essential.