Leased Lines – What are they?

Unlike the normal ‘broadband’ connections you hear about in the media, which are generic public internet connections (eg BT Infinity), a dedicated Leased line is just that. It is dedicated for you and only you. Here are the main points you should know about Leased Lines and we also list here the main differences between them and general broadband connections.


Leased Lines explained

Fast internet
Leased Lines – the main points


  1. These are dedicated connections to the internet for your use and yours alone
  2. Guaranteed and fixed speed – if you pay for 50Mb you get 50Mb. If you pay for 100Mb, you get 100Mb. You get the picture
  3. The speed is synchronous. It is the same both ways, up and down. So a 100Mb connection is 100Mb download and 100Mb upload. So you get some perspective on this, data typically travels around your internal computer network (ie from PC to PC, from PC to server etc, at 10 times this speed -1,000Mb also known as Gb or Gigabit)
  4. There is normally a Service Level Agreement or SLA. This is a guarantee from your service provider of a certain level of service (normally the % of time when the connection should be working/available – typically 99% or 99.something %). Along with this there is normally some sort of compensation payment available when the service falls below this target. Bear in mind that these targets typically have caviats which state that things outside of the service provider’s control do not count. A leased line can have problems just like any other connection although normally they tend to be less prone to issues (as most leased lines are delivered on direct fibre optic cable which is mostly underground and free from problems like wiring issues and interference – copper wires suffer from this alot).
  5. A leased line is normally delivered on fibre optic cabling (known as Fibre Ethernet). However, where there is no fibre or where budget is limited, it is often possible to get a copper-based connection EFM (Ethernet First Mile) or FTTC Ethernet. FTTC stands for ‘Fibre to The Cabinet. The connection is copper into your building and this runs to a nearby fibre cabinet where then connection is then Fibre back to the BT Exchange. We have a very helpful web pages that explains all the different types of internet connection you can get – see here – types of internet connections.
  6. Leased lines are normally offered with a back-up or failover. This can be a simple broadband connection (fibre broadband if possible). However, you might have a Fibre Ethernet Leased line (a direct fibre) with an ADSL Broadband back-up. But for added resiliency you might also have another ‘lesser leased line, such as an FTTC Ethernet or an EFM (Ethernet First Mile) connection. Or you could have a second Fibre Ethernet connection (effectively doubling your costs). Whatever back-up you have, the router that comes with your connection automatically handles the failover and deals with the IP address routing. If you want the absolute best failover, you would order a second Fibre Ethernet connection as a back-up and have it served from a different BT exchange to your local one or by a different route (or both). This is known and alternative and diverse routing.
  7. In previous years, an organisation with 2 or more sites used to have a connection which linked them together. Nowadays, you just have 2 connections to the internet and manage the connection yourself using routers and firewalls.
  8. A leased line, when delivered on fibre optic cabling, is normally delivered on either a 100Mb bearer or a 1Gb bearer. ‘Bearer’ is the term used for the physical connection. Naturally a 100Mb bearer can only support connections of up to 100Mb (in 5Mb increments). A Gb bearer can support speeds of greater than 100Mb (eg 200Mb, 300Mb etc). It is important to get the bearer right as there is a financial penalty for upgrading from a 100Mb bearer to a Gb bearer.
  9. A leased line is a managed connection in that it is normally monitored by the provider. So if it stops working they often know about it before you do. However, it is just a ‘pass-through’ connection to the internet. It is up to you or your IT support people to install and configure a firewall/router to provide security and other things like remote access, web filtering and bandwidth management
  10. It is worth pointing out that we have talked about Mb and Gb here. Actually, strictly speaking we are using the wrong terminology! A “100Mb” connection should really be described as a “100Mbps connection” – Mbps stands for Megabits per second. Also, people talk about ‘Megabits and Gigabits’ and ‘Megabytes and Gigabytes’. A ‘Bit’ is actually 1/8th of a ‘Byte’. Connection speeds are measured in Mbps and Gbps (Megabits/Gigabits per second). It is important to point out that file sizes are always shown in MB and GB (Megabytes and Gigabytes). In other words, to transfer/download a file of 1MB in one minute, you would need a speed of 8Mbps. Very often, IT providers and experts get this wrong and refer to Megabytes (MB) when they actually mean Megabits (Mb). Also, they often shorten it to ‘Meg’ and ‘Gig’. So the size of a file should always be referred to in Bytes and the speed should always be referred to in bits!
  11. Leased lines tend to take a while to install. A fibre ethernet can take 3 months or 60 working days (sometimes alot longer – ocassionally more quickly if there is already fibre in the building). Also, if there is no fibre directly in your premises, BT Openreach will need to get it installed. This could be as simple as extending the fibre from within your building (eg the basement) or it could be 10 kilometres of digging up roads and fields. The costs incurred here are called ECC’s (Excess Construction Costs) and are not to be confused with the ‘Installation’ cost. The only way to discover the ECC’s are by placing an order which results and a survey being completed. The ECC’s are then known and presented to the provider and in tunr to the customer, at which point they then either proceed or cancel.***Note at the time of writing this, the UK government covers up to £ 2,800 worth of ECC’s which means that, in around 85% of cases, there is no additional cost. We can inspect your site to determine if there is fibre in your premises or where the fibre is likely to be in terms of the closest fibre chamber in your road or area. EFM is copper based and takes around 35 days. FTTC Ethernet is copper-based and fibre from the cabinet. This takes 1 month – you also need a normal analogue PSTN phone line.
  12. In the majority of cases, it is normally BT Openreach which installs the fibre (this is known as a BT Tail). However, Virgin Media and Talk Talk are sometimes used as a cheaper alternative. The ‘tail’ merely refers to the local fibre run from your premises to the exchange, from where it then is connected to your providers network.
  13. These days it is very common for leased lines to be ‘converged’. This means that they simply have a small amount of bandwidth reserved for voice (SIP trunks or Hosted Telephony) with the rest of the bandwidth being available for normal internet and email. This converged connection is used as an alternative to ISDN which is more costly and out-of-date.


Broadband – so what does that actually mean?

Let us clear this up. Broadband is a much over-used term.

It was originally meant to mean a FAST connection. However, when people talk about it these days, they often mean ADSL (Asymmetric Subscriber Line) which is basically the products you hear about on TV (BT Infinity, SKY, Virgin Media, Talk Talk, Plusnet). So this tends to cost are little as £ 5 per month or as much as £ 60. It needs a normal phone line and home users all tend to have this type of connection.


Can a business work effectively using just broadband?

Yes but it depends.

How many users are using it? If it’s more than 10 then we would expect a business to have something better like a leased line (FTTC Ethernet, EFM or a Fibre Ethernet). Especially if they are using cloud-based services (such as Hosted Microsoft Exchange).


Why do we hear so much about Broadband in adverts?

Simple…… TV. Sky, Virgin Media and BT Retail want your TV business as that is where they make their money.

So why is ADSL so much cheaper than a Leased Line??


It’s not as good! Here is why:

ADSL is Asymmetrical. In other words, the upload is alot less than the download. This is OK but not great for things that need decent uploads (real-time stuff like Voice and Streaming TV and video). Admittedly fibre broadband is alot better than non-fibre (copper) as fibre tends to offer download speeds of up to 80Mbps and uploads of up to 20Mbps (you will never get 80 and 20 – more like 70 and 15/17. The speed you actually get will depend on the distance of your premises to the green cabinet in the street. Copper broadband offers speed of up to 24Mbps down and 2Mbps up. But you hardly ever see speeds of more than about 15Mps down and 1Mbps up. If you are a long way from the BT exchange, your speeds will be very slow or possibly you might not be in range at all! Then you have to consider having your own cable put in or use satellite or microwave technology (if available). Checkout www.samknows.co.uk to find out about your local exchange

It is a shared public internet connection. It is ‘contended’ meaning that you probably share it with up to 20 other broadband users!! Not great when all the kinds come back from school and hop on their Playstations and XBoxes! So the speed constantly varies.

It is copper. So it is not very resilient and it prone to weather conditions, interference from all sorts of other equipment and power, water ingress, rodent damage, BT engineers fiddling in boxes and poles and just plain old ‘old’ cabling. Furthermore, your single pair of copper wires might have 50 or so junction boxes on its path where is has to join up with hundreds of other pairs along telephone poles, fields, pavements, up and down walls etc etc. You get the picture! And who fixes this when it goes wrong? Good old BT Openreach.

It resides on a normal phone line – worth pointing out this bit – sometimes the fault is the DSL connection but most of the time it is the phone line itself. And your phone line and broadband provided might be different which makes fault finding more time-consuming and complicated.

It normally comes with a cheap router – no good for business use. It is worth paying for something reasonable like a Draytek router (with wi-fi of course). You will need to program this with your user name and password (quite easy if you are reasonably tech-savvy).


Can ADSL broadband be used for voice?

Yes. But only if it is a reasonable speed.

One phone call uses up to 100kbps (or 40kkps if your speed is slow and you cannot get anything better) so if you have a broadband with just a 500kbps upload, this can only support 5 simultaneous calls. Plus the speed varies so 5 calls may not always be possible – and you can forget about using this for general emailing and browsing – it should be dedicated for voice use only.

If you can get better speeds than this (the upload is the critical bit as that is the ‘bottleneck’) and , for example, Fibre Broadband is available, you can get (through us anyway – we cannot speak for other providers) a Converged Fibre Broadband which, like the leased lines mentioned above’ has a small amount of bandwidth reserved for Voice (SIP trunks or Hosted Telephony).

What can I get?

Call us now on 01233 527 100 and we will tell you within 2 or 3 minutes. You will need your address and postcode and, preferably, the number of a working analogue telephone line at the premises.

Ready to talk?

Contact us to learn how your organisation can begin moving to digital, or call us on 01233 527 100.

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