Internet Connections

Introduction

For you to be here, you must have some access to the internet, but do you know much about your connection, choosing a connection, or what the difference between your's and your friend's connection is?

This page attempts to address some of these issues, so you can make an informed choice.

Speeds

Speed is the most important thing right? Well, in an uncontented (below) and unlimited world, speed is probably all it would come down to, these "limits" will be discussed later on, but let's discuss what speeds could be achieved by various connections.

An area of mass confusion, is what is MB what is mb? Well, the significance is in the case of the b/B! If the B is uppercase, that means byte, if the b is lowecase, that means bit, the difference being, their are 8 bits in a byte, so 1MB/sec is the same as 8mb/sec. Most speeds are advertised in their bit speed, i.e. 1mbps/256kbps, all with small bs, although some people, even ISPs, confuse the meaning.

This is the original method most of us used to connect to the internet. It's limited to below 56kbps because of what the line can handle. This technology works by converting digital signals from your computer into a signal for the phone line, using a modem, at the other end, it's converted back again.

This was the faster option available to many dialup users, with a guaranteed connection of 64 or 128, depending on the number of channels used. A line was typically split into 2 channels, and you would either use both for data, or one for data and the other for simultaneous voice.

DSL - Digital Subscriber Line

This category of technologies are currently the fastest available right now. DSL is the superset of many technologies, where data is transmitted down your normal copper line as digital signals, because voice uses a different frequency, you can do both at once, splitters at either end split the voice and the data into separate streams.

DSL technologies have a limit on the distance between the premises and your local telephone exchange, which is usually between 3KM and 5KM depending on the speed of the service you are applying for.

Often simply referred to as DSL in America, this method has a different upload and download speed, the download speed is usually much faster than upload, and is therefore ideal for the home user. It usually starts at about 256kbps rising all the way upto 8mbps in some areas, which in theory is the maximum.

Probably able to carry upto 25mbps downstream, this is a new technology being trialled in some areas.

This method has the same upload and download speed, and so therefore the maximum download must be lower. This is more common for business use, or dedicated gamers, as the speed with which you can send data is faster than that of normal ADSL.

This system uses a mixture of fibre optics, and coaxial cable to your home, not your existing phone line, therefore the technology must be available in your area.

This system uses radio technology, and a receiver based on your premises, depending on the technology, the receiver may be attached to your roof or inside the home. The speeds above were based on the UMTS TDD standards, in use by a UK wireless network (provided by Hong Kong).

Limits

Except for Dial-Up and ISDN, many of the above technologies have limits which can leave your speed much lower, and in theory, lower than dial up speeds!

Bandwidth Limits

The first of the limits is how much data you are allowed to download per day or per month. This is usually specified in GBs, and is common on cheaper services for 1GB a month, mid range services 15GBmth, or 1GBday, and unlimited on the premium services.

Contention

Contention is when you and other users are contending for the same line or server etc... for data. It is often expressed as a ratio, such as 50:1 meaning 50 people are sharing the same bandwidth.

Here we need a quick idea of how your data gets to your ISPs server:
1) Down your phone line to your exchange.
2) Your exchange into telcos network.
3) Your telcos network to ISP.

From your telephone line, to your exchange, there is just 1 user, yourself, here there is no contention, you can send and receive data at the fully specified level.

The telephone company will have many users on one exchange, and its at the exchange your data is split between voice and data. The data is then sent down a network cable from the exchange, into the telephone company's network. This is where the first contention comes in, the line may only be, for example, 4mbps. If your ISP says you can have 1mbps, with a 50:1 contention, then a maximum of 200 people may exist on this exchange, if they are keeping to their promise. This is not feasible, and the line is probably capable of a higher data rate, and there will be many lines, but the ratios still exist. If the ratio is anywhere near being met, the telephone company will most likely update the exchange.

From the telephone company's network, to your ISPs, there will be another contention, and this depends on the size of the bandwidth your ISP is willing to buy. This will usually not be a problem.

Contention on cable is usually between you and the fibre optic network, this depends on how many people are using the bandwidth in your area, for example, if the whole street is downloading a movie, it will slow down, as you're all on the same "cable".

Contention on a wireless system can take a few forms. Data must travel from your transmittor, the the local receiver, then from the local receiver, to the ISPs network.
The bandwidth is limited between your transmittor and the local receiver, but this can be improved by using multiple carriers at the receiver, the data is likely to travel from the receiver into the network by a normal network or fibre optic medium.