Increase Broadband Speed Guide
This guide helps you get the very best from your existing ADSL broadband connection. The vast majority of broadband connections in the UK use ADSL technology, where broadband signals are sent along copper wires between your premises and the BT exchange, alongside voice telephony signals.
Background to your ADSL broadband service
When ADSL broadband services were first introduced by BT, a limited set of services were available. Customers were provided with one of a number of services with fixed maximum downlink speeds (0.25Mbps, 0.5Mbps, 1Mbps or 2Mbps). The choice of service was made by BT, based upon its conservative opinion of the quality of your line. Many households were provided with 1Mbps or less, even if the phone line was able to sustain higher data rates.
In March 2006, BT introduced its MaxDSL service in the UK, which is what we still have now. Rather than having speeds determined by BT’s out-of-date and inaccurate centrally-held database, your connection speed is now determined automatically by the quality of your particular line. Since line quality can vary over time, measurement equipment has been installed in each exchange. This continuously monitors your line’s performance and adjusts the connection speed accordingly. This process is called Digital Line Management (DLM).
As we will show, there are a number of actions that you can take to improve the quality of your line and adjust how the BT exchange equipment measures the quality of your line. In many cases, these will substantially increase your connection speed.
First of all, baseline your connection speed and throughput
Before trying to implement improvements, we recommend that you achieve a good understanding of your current broadband performance and speed. This will help you gauge how much of an improvement you have made. There are two numbers that you should find out, for both the downlink (data transferred from the Internet to you) and the uplink (data that is transferred from you to the Internet):
- the connection speed of your broadband connection (sometimes called the ‘sync speed’)
- the actual throughput of your broadband connection (which may be significantly less than the sync speed). This is the actual speed of your line.
View your connection speeds by accessing your modem
The connection speeds are the downlink and uplink rates at which your modem connects (synchronises) to the BT exchange, and are set by equipment in the exchange. These speeds are negotiated between your ADSL modem/router and the equipment in the exchange (called the DSLAM).
The exchange equipment sets the downlink connection speed so that the signal level that the modem receives from the exchange is higher than any noise on your line by a set margin, which is called the target signal-to-noise ratio (SNR) margin. When your broadband line is first switched on by BT, the target SNR margin for the downlink is set at a default level (6dB), and then the line is continuously monitored using BT’s Digital Line Management.
If your line experiences poor performance, or drops out, then the exchange equipment will increase the downlink target SNR margin over time, in steps, up to a maximum of 18 dB, with the aim of stabilising your line. While a higher target SNR margin can make an unreliable line more reliable, the huge downside is that there is a corresponding drop in the downlink connection speed with every increase in target SNR margin. So, if you are experiencing relatively slow speeds, this may be because you have a high target SNR margin set on your line. As will be discussed later, there are things you can do to address this.
For most basic BT-based ADSL services (based on BT’s IP Stream Max service), the uplink connection speed is set at 448kbps, and you cannot increase the uplink connection speed by tweaking. BT does offer a more expensive, enhanced ADSL service targeted at business users, which provides an enhanced uplink connection speed of 832kbps. This is called the IP Stream Max Premium service. Many ISPs can offer this premium service if you would like to increase your uplink speed (for example, if you regularly upload large image files to the Internet). However, for most popular services (such as Web browsing and iPlayer), the downlink speed is more important.
Most ADSL modems/routers provide information on the sync speeds of their connections, and you will need to find out how to access this information from your particular modem/router instruction book (or search for it online).
Here is the display for the Billion 7800N, which is currently our favourite modem. It shows that, at the time this image was captured, we had a connection speed of about 5.4Mbps on the downlink and 832kbps on the uplink.
Measure your real throughputs with an accurate online speed test
In practice, the actual speeds that you achieve with your broadband connection (e.g. for downloading files) will be lower than the connection speeds. The best way to gauge the real throughputs that your broadband service delivers is to run a reliable online speed test.
We are cautious of many online tests, because they often provide inaccurate numbers. However, we have found that the following sites provide reasonably accurate throughput assessments. Rather than doing a one-off test, we recommend that you perform a number of tests on different days and at different times so you can get a good feel for any differences, if they exist. Make sure that no-one else in your house is using your connection when you run the test.
Here is the output of the test for my broadband service. You may be disappointed to discover that your actual throughputs are substantially lower than the connection speeds shown by your modem/router, as they are here. Remember that my downlink connection speed was about 5.4Mbps.
Your actual throughputs may be much lower than your connection speeds due to a number of factors:
- BT constrains the maximum downlink throughput of each line, using what it terms the ‘IP/bRAS Profile’.
- If a line drops regularly and experiences significant fluctuations in connection rate each time the modem connects, BT does not increase the IP profile immediately after the modem syncs at a higher speed (and it can take many days of constant connection before it is adjusted upwards).
- Depending on your broadband package and choice of ISP, your particular ISP may apply what is termed ‘traffic shaping’ at busy times. Many ISPs deliberately reduce speeds to reduce their costs.
The combined effect of these three factors can mean that your downlink throughput, as measured by online speed tests, is dramatically lower than your modem downlink connection speed.
Although we do not wish to make this article overly complex, here is a table that shows how BT limits the throughput of an ADSL line, according to the connection speed. So, if you have a downlink connection speed of just under 5664kbps, for example, your maximum throughput will only be 4.5Mbps – more than 1Mbps less.
|Sync speed from||to||Maximum throughput speed|
|5696kbps||6208 kbps||5 Mbps|
Table 1. How BT sets the maximum throughput according to connection speed
If your line experiences drop-outs, your IP/bRAS Profile does not automatically increase if you resync at a higher speed. If your line experiences significant interference at certain times of the day, which causes your ADSL line to drop, then your modem may connect at a much lower sync speed than normal. Any drop in sync speed is quickly followed by a drop in the IP/bRAS Profile. However, if the modem then resyncs at a much higher speed, then the IP/bRAS Profile is not increased, typically for a period of 48 to 72 hours (and sometimes longer).
Finally, as the profit margins of ISPs have become tighter and the amount of broadband traffic has increased (e.g. with the rapid adoption of Internet applications such as BBC iPlayer), many ISPs have resorted to deliberately reducing speeds at peak times. Thankfully not all ISPs do this, but it is vital to choose the right ISP to maximise your speeds.
So now that you have a good baseline for your current broadband performance, you can implement improvements and assess the difference they make to your broadband connection. Here are our top tips to increase broadband speed.
Seven tips to increase broadband speed
Here are seven actions that we recommend, which can make a significant difference to your broadband speeds:
1. Ensure you have an NTE5 BT mastersocket
Check that BT has previously installed an NTE5 mastersocket in your property, like the one shown in the image on the left. BT-installed NTE5s have a little BT logo in the top left of the unit. The NTE5 marks the point at which BT’s telephone cable enters your property. BT Openreach has total responsibility for the telephone network to your property and your NTE5. However, the wiring going from the NTE5 into your property is your responsibility.
Consumers are are not permitted to tamper with the core part of the NTE5. However, you are perfectly free to unscrew the face plate (the front bottom part of the NTE5), for example, to connect extension wiring. Possessing an NTE5 allows you to replace the existing faceplate with a special ADSL faceplate (as described below).
BT has been installing NTE5s for many years, although some older houses may not have one. In the unlikely event that you do not currently have an NTE5 installed, you can ask BT to install one for you. BT may charge you for this. A cheaper alternative is to fit your own NTE5-style box next to the BT mastersocket as an extension.
2. Fit an ADSL faceplate (also termed a ‘filtered faceplate’)
If you make only one tweak, please may it be this! Simply remove the standard faceplate on the NTE5 BT mastersocket and replace it with an ADSL faceplate. In most cases, this makes a dramatic difference and it’s cheap! This is probably one of the biggest ‘secrets’ in the broadband industry. As described in our ADSL faceplate page, there is substantial evidence that shows that filtered faceplates can dramatically increase broadband speeds, and yet the vast majority of consumers are not aware of their benefits and do not use them. This is a wasted opportunity.
When most people set up their broadband, they go round their house and plug in microfilters (which were provided with the modem or by the ISP) in all phone extension sockets as well as the BT mastersocket. Doing this can involve a significant number of broadband filters (which can look unsightly), and it’s essential that there is a filter plugged in to every single phone socket, including the one used for Sky’s Digibox (if you have one). You don’t need to do this, and there is a better, cheaper solution.
All you need to do is unscrew the standard faceplate on the BT mastersocket, and fit an ADSL faceplate. This simply fits over your BT socket. It is totally legal and supported by BT.
All this device does is separate your broadband signal from the rest of your house telephone wiring, reducing interference and noise.
An extra benefit of this faceplate is that, since ADSL filtering is now taking place at the BT mastersocket, there’s absolutely no need to put any filters on your telephone sockets throughout your property. A truly elegant solution.
To make it easy for you, you can buy a high quality ADSL faceplate through Amazon on the left at a great price! The small commission we receive will help fund this broadband information site, and you will get the same great price from Amazon. Thank you for your support.
3. Make sure your modem is located next to your BT mastersocket
Ideally, you should place your modem next to your BT mastersocket, wherever your mastersocket is located in your property, and connect your modem to the mastersocket using a short cable.
We have seen many interesting wiring set-ups in homes! Please resist the temptation of connecting your modem to an extension socket rather than the main BT mastersocket, or connecting your modem to the BT mastersocket using a long extension cable. These will significantly reduce your broadband speeds, and make your connection more susceptible to noise and interference.
If you really want to locate your PC in a different room to the BT master socket, we strongly advise that you use a high-quality wireless (WiFi) router/ modem (such as the Billion 7800N) and connect your PC to it wirelessly. This may provide you with increased flexibility while maximising your broadband speed.
4. Choose the right ISP
Many people consider that ISPs are all much the same, and that it is better to stick with BT, since it has provided telephone services for many years and so must be the best.
ISPs are certainly not all the same! It’s unwise just to stay with BT due to apathy or because you think that BT is the best. The reality is that BT Broadband’s services are generally not the best, in terms of performance or customer service. It’s now very easy to change ISP, without losing your connection, so we strongly recommend that you consider moving to one of the better providers.
As discussed on our Which ISP page, there are two important attributes of an ISP when it comes to maximising your broadband speed. These are:
- excellent customer service
- the absence of traffic shaping.
You may have an undiagnosed fault on your line that significantly reduces your broadband speed, or you may suffer from such a fault in the future. Excellent customer service from your ISP is essential so that you’re able to diagnose if you have a fault and get this fixed easily and swiftly, without spending all of your life talking to a call centre in India!
Some broadband customers connected to busy telephone exchanges suffer from exchange congestion, which also reduces their broadband speeds. However, added to this is ‘traffic shaping’, which is a relatively recent phenomenon that affects many more people. Traffic shaping is the deliberate reduction in broadband speeds by ISPs at peak times, aimed at reducing their costs. It is amazing how quickly traffic shaping has become endemic among ISPs and yet most broadband users are completely unaware that this is being done to them. Many ISPs (including BT Broadband) apply traffic shaping.
Fortunately, there are a few ISPs remaining that do not apply traffic shaping. One of our current favourites among ISPs is Xilo. As confirmed by the independent ISPreview league table, Xilo provides fantastic performance and customer service, and pricing is very good for a quality provider. With an ISP such as Xilo, you should find that online speed tests deliver the fastest throughputs possible for your line at all times, including peak periods.
5. Tweak the SNR target margin, if your modem supports this
Users of BT-based ADSL services are at the mercy of BT’s Digital Line Management. Intended to help maintain a stable connection, Digital Line Management can often cause more harm than good by artificially reducing downlink connection speeds. When a broadband connection is first made live, the BT exchange equipment attempts to set up a connection with a default 6dB target SNR margin. For a number of reasons (such as line drops due to thunderstorms or increased errors on the line due to radio interference), the exchange equipment can increase the target SNR margin, up to a maximum of 18dB. As the target SNR margin is raised, so downlink connection speeds are substantially reduced. Once a high target SNR margin has been set by the BT exchange equipment, it can take weeks or months for this to be reduced, and sometimes you are stuck with a high SNR target margin.
Rather than putting up with the target SNR margin that the BT exchange equipment sets for your line, some modems allow you to tweak the target SNR margin setting to a lower value and, hence, substantially increase downlink connection speeds.
Tweaking of your SNR target margin is covered in more detail on our dedicated SNR tweak page. All modems are different, and many modems do not allow you to change the target SNR margin. If you are considering a new modem, we would recommend that you purchase one that has the ability to adjust the target SNR margin.
Bear in mind that reducing the target SNR margin on some lines may cause the broadband signal to drop more often, so you have to balance the increased speed with reliability. For many, the compromise may be perfectly acceptable and the line may not drop, even with low SNR margin, for weeks or indeed months.
We are fans of SNR margin tweaking, as it can make a huge difference to downlink speeds. Many broadband users find that a high-quality modem can hold its connection for several weeks at a time with an SNR margin of about 3dB. However, bear in mind that your line may be different. If you find that your line becomes unstable at low target SNR margins, you can simply increase the margin until it becomes stable.
6. Consider replacing your existing modem/router with a more robust model
When most people purchase their broadband modem/router, they probably think that all modems perform in a similar fashion, and that the differences between them come down to aesthetics, features (for example, whether or not WiFi is supported) and price. This could not be further from the truth.
We have rigorously tested many different broadband modems over the years, and we are constantly amazed by how different they are in terms of the speeds that they connect at and, in particular, their abilities to maintain their broadband connections. If your modem is relatively old, or you suffer from regular disconnections on your line, there may be significant benefits in upgrading, particularly if your current modem does not support target SNR margin tweaking.
Recently we helped a young family, living in rural Cambridgeshire, which was suffering frequent broadband disconnections, so that they were unable to access the Internet during the evenings and weekends. After having several visits from BT Openreach engineers, they were are the end of their tethers. We found that simply replacing their Belkin modem with a more robust model had a dramatic effect, and their line suddenly became stable.
Some of the very latest modems (using a chip from Broadcom) incorporate advanced technology that reduces the impact of impulse noise on a line. Broadcom claims that its technology provides a ten-fold improvement in noise resilience.
We are often asked to provide a recommendation for a broadband modem. As described in more detail on our dedicated Which Router page, our favourite router/modem currently is the Billion BiPAC 7800N. While it may not be the most attractive modem in existence, it has a killer set of capabilities, which include:
- the latest Broadcom impulse noise protection
- comprehensive tweaking of the target SNR margin
- Gigabit routing
- 802.11n WiFi capability, using two radio channels to deliver WiFi speeds of up to 300Mbps
- three external antennas to deliver excellent WiFi range
- advanced content filtering, so you can control if and when particular applications (such as Facebook and iPlayer) are used in your house (and on which computers).
Although the Billion 7800N is not the cheapest modem around, its feature set and great performance, even on the most challenging lines, make it excellent value for money.
If you would like to purchase the Billion 7800N, please consider doing so through the Amazon link to the left. The small commission generated will help contribute towards the costs of running this information site, while you will still pay the same low price. Thank you!
7. Get a second line, which may be surprisingly affordable
When you have applied all the previous broadband speed enhancement techniques to a single ADSL line, you could consider getting an extra line. With the increasing availability of Local Loop Unbundled (LLU) services (e.g. TalkTalk), using more than a single ADSL connection is now affordable with the right choice of supplier. Not only can multiple connections speed up Internet access, it can provide much-valued resilience – so that you are not disconnected from the Internet if a single line goes down (which is particularly important for businesses).
With the increased availability of low-cost LLU services, the cost of two ADSL connections may be little different from maintaining a single line with BT, for example. By using more than one ADSL line, you have the option of using lower-priced ADSL connections with smaller usage allowances (by spreading usage across multiple connections).
For more information, please read our dedicated Multiple ADSL Connections to Increase Broadband Speed page. With the Sharedband service, you can easily aggregate bandwidth (download and upload) from multiple ADSL lines from any ISP.
Please get in touch!
We hope that our article has helped you get the most from your broadband connection, whatever the quality of your BT line. If we have been of some help, please get in touch to let us know. We would love to hear from you about your broadband experiences. Please email us at firstname.lastname@example.org.