Leased Line vs DSL

It can be difficult to know whether your business needs a leased line or a DSL connection, so we’ve put together this page to help you determine which is right for you.

By the time you finish reading this article, you will have all the information you need to make the right decision for your company – so let’s dive right in.

What is DSL?

DSL (digital subscriber line) is the type of internet connection most people have in their homes. It’s delivered via the phone wall jack, similar to the old dial-up internet only through a different frequency – allowing you to use the internet and telephone at the same time.

It’s a cost-effective solution for many households across the UK, but often isn’t powerful enough for business use, as we’ll explore later.

What is a Leased Line?

A leased line is a private fibre cable that runs from your business to an exchange or network point of presence. Giving you a dedicated and uncontended connection to the internet or providing you with a site to site connection. 

This makes the connection incredibly fast and reliable, but often expensive to install (if you’d like to learn more about leased lines, click here).

DSL or Leased Lines?

Here we will now look into whether a leased line or DSL connection is best suited for your business.

Synchronous Upload/Download

DSL is not a synchronous connection, this means that you are not able to receive the same speeds on the upload as you are on the download. This can be a problem for some use cases that involve hosting servers or services using this connection type. A leased line is the same upload as download speed.

Speed

DSL is delivered via a copper telephone cable, these cables could have been installed for decades and will degrade over time. A leased line is most often a new or existing dedicated fibre cable which does not degrade to the same degree, therefore the speed or capacity of the fibre remains the same. A fibre cable also does not have the same distance limitations whereas the DSL line will. A dedicated fibre or fixed wireless leased line should always be faster than a traditional DSL circuit.

Installation

Because leased lines use physical fibre cables, installation can cost a considerable amount of money, and take a very long time. The construction that needs to take place to get fibre into your premises (known as ECC’s), can cost as much as £100,000 and take up to a year to get completed – depending on your location.

On the other hand, DSL uses your existing phone wall jack, so installation usually takes just 14 days.

Bandwidth

A fibre or fixed wireless leased line can often be installed with 1Gbps bearers, the bearer is the speed the line is capable of delivering. The new Openreach DSL service called G.Fast which is available only in very few places in the UK is theoretically capable of 1Gbps but you have to be within a very short distance to the cabinet or exchange building to achieve anywhere near these speeds and your supplier must have equipment capable of these speeds, in reality speeds of 100Mbps are more likely where this new service is available.

In comparison a leased line is most likely 1Gbps capable.  DSL circuits are built on shared infrastructure, this means you share your connection speeds with others therefore you can expect a variable service speed. Leased lines will not slow down during busy times of day, the promise from the provider will be that this does not happen and speeds remain constant.    

Reliability

A DSL line is delivered over a copper telephone cable, if this cable breaks your supplier (ISP) will have to arrange with BT Openreach to have it fixed, depending on the agreement between you, your ISP and BT Openreach, the fault could be fixed within hours, weeks or months. There is something called best endeavours, this means everyone does their best to get it fixed ASAP but there are no guarantees. A Leased line will come with a much tighter SLA (service level agreement), guaranteed fix times of up to 7 hours are not uncommon for leased lines. This represents a huge difference in service up time and guarantees compared to DSL circuits. 

Price

We have identified some very important differences above between the services, the last one is price. A dedicated leased line can cost from £300 per month for 100Mbps compared with from £25-35 for a limited DSL delivered service. You can expect a good service from both but they are very different and intended for different uses. A home user or small business may try to rely on a DSL service but they should do so knowing the differences and pitfalls above whereas a business or organisation who genuinely can’t be without an internet connection for long or needs ultra-reliable speeds needs to consider a leased line of some description.

Comparison Table

Main Differences Between Leased Line And DSL

The main difference between DSL and a leased line is the way you get the connection. DSL uses a phone jack that’s likely to already be installed in your premises, whereas a leased line needs physical fibre cables installed. This makes DSL a lot cheaper, but it also means you get a less powerful connection.

DSL is considerably slower, isn’t reliable enough for most businesses, but it’s fast to install and is very cheap to run on a monthly basis.

Leased lines are incomparably faster, far more reliable, but take a long time to install and cost more money per month.

Which Is Best?

Ultimately leased lines are far better in terms of performance, but that doesn’t mean they’re the right solution for you.

After reading through the information we shared above, you might find yourself needing a connection that’s somewhere between the two. In that case, it’s worth considering alternative connections for your business.

For example, microwave internet is a far better solution for most business owners, as it gives the same performance as a leased line but is a lot cheaper and faster to install.

Others that are working from home may find the unreliability or slowness of DSL forces them to invest in a leased line, however this is often not the case and there are other options available.

Further Reading

• What is Microwave Internet?
• You Don’t Need A Leased Line For Home