5 Common Causes of a Slow Broadband Connection
1. DSL filters can be installed to prevent interference from normal voice calls.
DSL modems use the telephone line to connect to the service provider, however, they use a different frequency range to the human voice that is transmitted at 4KHZ and below. This 4KHZ band is also known as the base band. Avoiding the base band, DSL modems use the broad band frequencies which are in the 4KHZ to 4MHZ range allowing them to provide higher bandwidth and to work simultaneously with normal telephone voice calls. Interference between the base band and the broad band frequencies can affect DSL connection performance. DSL filter(s) can be installed in order to prevent interference between the home telephone(s) and the DSL service. An easy way to check whether noise is being generated by other devices is to temporarily unplug the telephone(s) and fax. If this corrects the problem with the DSL then it is a confirmation that you need filters to prevent noise from those external devices.
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2. The distance to the exchange affects the DSL connection speed
Another common problem experienced by DSL broadband users is one of attenuation. Attenuation is a term used to describe the reduction in signal strength. As distance increases so does attenuation and as the level of attenuation increases the speed that you will ultimately receive from the DSL service decreases. This is one of the reasons why service providers cannot guarantee DSL speeds at the time of subscription.
It is true, however, that attenuation should be reasonably constant given that the distance between your home and the service provider’s exchange doesn’t change. But some users experience different levels of performance during different time periods throughout the day. So what causes varying degrees slow modem problems?
3. Electrical components in the vicinity of the phone line can cause noise on the line
Another cause of slow broadband connections is SNR (Signal to Noise) ratios. Noise caused by electromagnetic interference from electrical devices degrades the signal strength. This in turn causes performance problems with the broadband connection. Generally speaking, evenings are the worst time for line noise because many people are home using electrical equipment such as televisions and air conditioners. There is little a user can do about a high SNR , however, the phone company can be contacted for a line test to be done. In many cases components leading into the home can be replaced to help reduce noise.
4. Other users in your area may share some of the bandwidth
Another possible contributor to slow modem response may be backhaul oversubscription by the service provider. Backhaul oversubscription means that the connection between the exchange and the core provider network has insufficient capacity to carry all the DSL subscribers together at full load. This may seem a troublesome strategy at first, but it helps to keep DSL line costs down for all users. In addition, the probability of all users requiring capacity at the same time is very low.
The contention ratio is the definition that service providers use to describe the number of users that will be sharing a backhaul service. The lower the contention the lower the chances that you will share infrastructure with other users. For example a contention of 20:1 is better than 50:1. Some business class DSL services offer a contention as high as 1:1 which means that the line will be guaranteed all the provisioned bandwidth between the modem and the core network.
5. Your Modem Brand and Model
Don't worry, I am not going to try to sell you any modems. In fact I am not even going to mention vendors because there will be a time lapse between my writing this page and you reading it. For that reason I have no way of knowing which models are the best at the time you visit this page. What I can tell you is that I have personally experienced performance increases when I have upgraded my own modems. Don't be fooled into thinking the most expensive modems are the best - sometimes they are more expensive because they have more features. As a general guide, the big names are usually quite good, do your research and make sure that you get right down to make and model in your search.
The reason upgraded models may perform better is because they may have better connections and signal strength than older modems. I recently experienced this very fix when I replaced a friend's modem on exactly the same line and provider. The Internet connected at a faster rate and the only thing we changed was the modem.
Sometimes upgrading the firmware on a modem will also help with performance issues. Check the vendor documentation to find out what issues newer versions of firmware address.
