What is the difference between dedicated and contended Internet?

Your business internet service is usually connected to the Internet via some sort of hard-wire connection. The easiest way to think about the above is whether on the way to the Internet, have any other users outside of your organisation also connected to it. If they have then you are in effect sharing the connection. Now as your service connects through a number of hardware switches and routers there is also higher capacity connectivity so sharing a connection doesn't matter. Let's for example assume you have a 100Mb connection in your office and the business next door to you also has an identical connection. Then if you are both being connected to the Internet over the same capacity connection then that connection is contended and at peak traffic usage you might only be able to get 50Mbps each. This is what is called a contended connection.

A dedicated connection means guaranteed bandwidth

If your business connection is described as "dedicated" then if you have paid for 100Mbps then this is what you will receive 100% of the time - your peak traffic usage you will always be able to upload and download this speed.

In contrast to a contended connection, the advertised speed is the maximum speed you will receive most of the time but at peak usage you may only be able to receive as low as 30% of the maximum speed.

The other major difference between the dedicated and contended is that contended connections tend to be asymmetrical i.e. the download speed is actually different to the upload. So for example if you are considering buying an FTTC service advertised as an 80mbps service then bear in mind that this is the maximum download speed you will receive and is actually based on your distance to the local green cabinet, usually at the end of your road. 

Here is an example of an FTTC upload / download speeds taken from a business internet router.

FTTC speeds taken from a router

 

This is different than “shared” connections, where the speed your company purchases is the maximum speed you will receive. (like at 2:00 AM). With shared connections, the actual speed is unpredictable and fluctuates throughout the day, depending on the ISP’s network traffic.

Throughput is what matters

In the above image the speed is not necessarily the rate at which you can send and receive data. This is just the bandwidth which your router can establish with the Internet provider's network? Imagine a water pipe of a certain diameter; think of this as the bandwidth. Then imagine how much water your supplier can send you through that pipe; this is the throughput. So imagine your peak water usage requires the pipe to pass through as much water as it can handle (i.e. the pipe would be full) but your supplier can only send you water at a rate which only half-fills that pipe. Well this is what throughput is. You can check throughput for your connection by using a speed test such as the one on our web site. Here is an example of a speed test for the FTTC service shown above:

Pretty close? Bear in mind that this speed test was taken at an off-peak time (well 6AM in the morning on a Sunday to be precise!).

In summary, despite having the same circuit speed, a 100Mbps dedicated Internet connection will always be faster than a 100Mbps inexpensive, shared Internet access connection!