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No Connection At All

As with all troubleshooting tasks the key is to narrow down the problem, discounting possible causes on the way. Before troubleshooting BroadBand problems you need to discount any home network or local computer setting issues. Use cables rather than wireless, try different computers to see if you get the same problems on both and try using different equipment (modems, routers, microfilters, telephones etc...).

When you have no connection at all the first thing that you must check is whether you can get a connection at the test socket inside the main master NTE5 socket. The reason for this is that the extension wiring in your house is your responsibility. If you can connect using the Test socket with no problems then technically the ISP has fulfilled it's part of the agreement. If you ask your ISP for a BT engineer to come out and he ends up fixing internal wiring to get your BroadBand working you will be charged and it's not cheap. If your problem is with internal wiring you should look through the page on Optimizing Your Wiring.

If things are not working at the test socket of the NTE5 the next step is to try and find where you are not connecting. What I mean by this is the problem could be to do with your home network or computer settings, a problem syncing with the exchange or a problem with the ISP.

So after setting the router up from the test socket you should try to ping the IP address of the router to make sure you can connect to this. If you can not then it would look like you are unable to connect to the Internet as you are not able to communicate with your router. In this circumstance you need to try without wireless connection and wireless security and trying different equipment to make sure something's not broken. More help on home networking issues can be found here.

When you can contact your router, you should try to access your routers web admin pages using a web browser. The web admin page will usually give some information as to what is going on and can be opened by typing the IP address of the router into the address bar of your web browser and entering the username and password if asked. You may also find the lights on the front of the router give good information too. There may be a light which tells you if you are connected to the exchange with a telephone or something similar above it and there may be light saying whether you are connected to the Internet, which usually has something like a world above it.

If you are unable to connect to the exchange you will usually find that the web admin page will display a message somewhere saying no connection or Sync. You will see no Sync Speed, Line Attenuation or SNR Margin. If you have lights on the front they may also display no connection with the exchange with, usually, a red light or no light on the indicator with a telephone above it. The symbol for this indicator may differ depending on modem / router. If this is the case it usually shows a line problem and this will need to be reported to your ISP so they can get a BT OpenReach engineer to check the line.

If you are connected with the exchange the router will show a Sync Speed, Line Attenuation and SNR Margin in the web admin page and, if applicable, the Exchange Sync light on the front of the router will be lit, usually green. If this is the case but you are still unable to connect you will usually see that the Internet light is not lit and should check the router logs through the web admin pages to see if they give any indication why you are not connecting. Most of the time, no matter how many times I've been told the BroadBand username and password are correct, it turns out the incorrect username and password have been entered into the router or they are wrong. You will need to check these with your ISP but will usually be on the welcome letter you receive when you first sign up giving you this information.

In this situation the router logs will usually say Authentication Denied or some similar message. You will need to make sure you have the correct connection details in the ADSL or WAN setup page. The information you usually need to provide, along with the most common settings used are shown below: -

If these settings are correct, you are Sync 'd with the exchange and you are still unable to authenticate your connection you must contact your ISP as there may be a problem with your account on their authentication servers.

Low Sync Despite Having A High SNR Margin

The way the BT Wholesale Max system works is that when your router Syncs with the exchange when it's turned on it will set its speed by giving all available SNR available up in return for more speed, minus the SNR Target Margin. Most ISP's set the Target Margin at 6dB but some ISP's initially set it higher to give a more stable line. What this means in effect is that every time your router Syncs the SNR Margin should be the SNR Target Margin, usually 6dB but can also be 9dB, 12dB or 15dB.

If you line gets noisier or quieter your SNR Margin will drift up and down from this number but if the SNR Margin starts to drop to around 2dB the router will start to be unable to differentiate the Signal due to too much Noise so will re-Sync back to a SNR Margin of the Target Margin which will cause a lower Sync rate.

If you have an ISP who prefers stability over speed your initial SNR Target Margin may have been set high by them to decrease the amount of support calls it has to deal with regarding unstable lines, this will obviously have an impact on your maximum Sync rate.

Also BT employ a Line Management System which will detect if your line re-Sync's a lot due to being unstable and will automatically increase your Target Margin until it reaches a level of stability. This is OK if you have a dodgy line as it will stabilize about a week or two after you first start using it, however if there is a thunderstorm one night or you have some power problems in your house this briefly emulates an unstable line (as for a while it is unstable) and your SNR Target Margin may get increased due to this.

If you have a low Sync with a lot of SNR available the first thing to do is re-Sync your router as if the Target Margin is 6dB it will re-Sync at 6dB and the excess will be used to increase your speed. You need to understand, though, that at different points of the day your line will pick up different amounts of Noise so this figure may wander up and down so if you have an unstable line the router will again re-Sync when the SNR Margin falls too low.

If your line has been set with a high Target Margin or your line has been unstable in the past, which will cause your Target Margin to increase, you need to make sure your line is stable enough to have a lower Target margin, after all what's the point of having the Target Margin lowered if this makes your line unstable and a couple of days later it has been automatically set to the higher figure again.

To make your line as stable as possible you first need to make sure that any action that caused the instability gets fixed, e.g. a broken electric boiler that emitted enough Noise to affect your telephone line, a phone plugged in without a microfilter or dodgy internal wiring. Sometimes this may not be possible as long lines from the telephone exchange will pick up Noise all along their way so will be just plain noisy lines but internal wiring can always be tweaked to minimize these effects and checking if phones or home equipment like monitors are affecting the stability of the line.

If your line does not re-Sync for two weeks then the BT Line Management System will reduce a high Target Margin by 3dB unless it has been manually set. This system seems to sometimes be a little temperamental and does not always work, if this is the case you need to contact your ISP's technical support department and ask for your SNR Target Margin to be reduced. This is where your choice of ISP may turn into a brick wall as some ISP's are particularly bad at explaining some of these aspects to their first line support staff and I have known people having to move ISP's to get to one that understands what this is about and be able to follow it through with BT Wholesale.

Low IP Profile Despite Higher Sync Rate

A lot of people on the BT Wholesale provided products don't seem to understand how the IP Profile system works. Your Sync Rate to the exchange determines what IP Profile you are put on and this is what determines you download rate. The Available IP Profiles and the Sync rates needed to achieve these rates are: -

So if your Sync rate is 2816Kbps you would be on a 2Mbps IP Profile which is a full ½Mbps slower than you are Sync 'd. This is because it is still 32Kbps short of the 2.5Mbps IP Profile.

Another quirk to the system which needs to be taken into account is your IP Profile is not based on what your Sync rate is now but it is based on your lowest Sync rate over the past three days. So if you are currently Sync 'd at 5696Kbps but your lowest Sync in the last three days was 2816Mbps your current IP Profile should be 2Mbps. There are reasons why the system needs to run like this, however it would be more helpful if the period was less than 3 days.

You will normally find that Noise is greater on your line during the night than it is during the day. If this has a big effect on your SNR you may find it beneficial to turn your router off when you finish using it at night as if it is off it will not need to re-Sync to a lower Sync.

My IP Profile Never Seems To Rise Despite A Higher Sync Rate

A lot of people have found that when changing from a legacy fixed Speed BroadBand Connection to BT's Rate Adaptive Max BroadBand packages that their IP Profile does not move up or down and stays at the same level of their their old fixed speed service even though their Sync has stayed consistently higher than this. This is known as a stuck IP Profile or Stuck BRAS Profile.

Sometimes a stuck IP Profile can be fixed by turning your router off for a couple of hours, or even better, leaving off one night. This sometimes kicks the Line Management System enough to wake it up and realize your Sync rate is moving and start the process of dynamically changing the IP Profile.

If this does not do the trick then again, it needs to be dealt with through your ISP, who should contact BT and request they give it a nudge. You will find that the same ISP's that cause problems getting Target Margins reset normally give similar problems when dealing with this for the same reasons.

MTU Issues

MTU stands for Maximum Transmission Unit and is the maximum size of a packet that can be routed from one segment to another. The MTU value that your network connection is set to is the size that your computer sends data packets out as. Your router and your network cards will have MTU values set to them and if your are using a modem it will usually be set in the Dial Up Networking option in Network Connections, through Control Panel.

Incorrect MTU settings can cause problems with download speeds being lower, sometimes considerably, than your sync rate (or IP Profile if on a BT Wholesale product), the inability to access certain web sites and choppiness of streamed media.

So if your computer is sending data packets out 1500 bytes big (Windows default) to a server in London and the data packets travel through a router with an MTU value of 1450 bytes, each packet will get split into two as it travels through the router because it is too large to travel through as a whole packet. This is what causes the slow download speeds and jittery media playback as the process of splitting the packets adds time and a few packets may get dropped in the process.

The reason an MTU value set too high may also stop you reaching certain sites is that some older routers are not capable of splitting the packets if they are too large so the packets just get dropped. Although the packets are usually re-transmitted, if the only route to the destination server is through routers which are unable to split the packets the data you are sending will never get to it's destination no matter how many times the packets are re-transmitted.

To set the MTU on your router you usually set it up through the ADSL or WAN section of your routers web admin pages. This is usually asked for on the same page as when you are giving the username and password of your BroadBand account when you first set our router up.

To change the MTU values on your PC network cards and modems you will need to download and install a program call Dr. TCP from BroadBandReports.com. This is a free Windows (Pre Vista only at present) utility and is very simple to use.

Dr TCP

To change the MTU value of your adapter, choose the adapter you want to set from the Adapter Settings list, alter the MTU value in the MaxMTU box click Apply and restart your computer. This process is reversible so as long as you note down the initial number from this box before you start tweaking the MTU value you can always put this number back in and things will be back the same as before you started.

If you are unable to access certain web sites the first step in the process of checking if a different MTU setting will help is to make sure that you set your routers MTU to the maximum size, this is usually 1500. This is because you want your computer to send the packets out at the correct size rather than your router splitting the packet to make it the correct size.

Next one by one, working down, try setting the MaxMTU setting of your network adapter to the following settings: -

After setting these values restart the computer and see if you still have the same problems. These are the usual values in use today for standard protocols so you should get some luck with one of these values.

Certain ISP's use different MTU settings to standard so it's always a good idea to check your ISP's support web site to see if their equipment uses specific values that you should also be using. Some have the annoying habit of saying you just need to set the MTU value on your router to their settings. As explained above this is not the best way forward although, as long as you do not have a really old router, it would allow you to connect to sites which you could previously not. It is best to set the router at the maximum and all your computers network adapters to use the specific values.

RWIN Issues

RWIN stands for TCP Receive Window and is what's used by TCP to ensure data delivery. The way it works is that its value, which represents bytes, is the total amount of data which the adapter can receive before it needs to send an acknowledge packet back to the sender.

If you are using a fast BroadBand connection you might find that your actual download speed is lower than your sync rate (or IP Profile if on a BT Wholesale provided product) if your RWIN value is set too low. This is because the network adapter will stop sending data when it gets to its RWIN value to wait for an acknowledgement which means your entire available bandwidth is not being used as efficiently as possible.

To maximize your RWIN value first make sure your MTU is correctly set. Then using Dr TCP set the value at a high value, for example 1000000 bytes. Next run the Tweaktester on BroadBandReports.com and you will be taken to a screen asking for some input which should be: -

After entering the required information click the recommend button and you will be taken to a screen showing an output similar to the one shown below. Open Dr. TCP and in the general settings section change the Tcp Receive Window to the value shown in the Receive Window (RWIN) box shown in the Tweaktester output.

Typical Tweaktester Output

Alternatively you can download a free tool from www.speedguide.net called TCPOptimizer. This tool will work out the best settings for your connection and set it appropriately. Just choose the network adapter, put in your connection speed (download sync rate if an LLU line or IP Profile if on a BT Wholesale provided product), put in your MTU value, select Optimal settings and click Apply changes. This program can also be used to maximize slow Wireless Network Connections.

TCPOptimizer

My BroadBand Will Only Connect When Making A Phone Call

At first glance a problem like this does not seem to make sense but it is quite common and is referred to as a High Resistance (HR) Fault. The fault may be intermittent and it may also be accompanied with a hissing noise on your telephone. This is to do with corrosion of the cables between your house and the telephone exchange.

External grade telephone cable is covered with a weatherproof jacket so that the weather can not effect the actual cable inside, however at some point the cable will need to join to another cable or junction box and when it does there will be a certain amount of the cable exposed.

Over time this cable will corrode and eventually completely give out but for a period before it does there will be just enough of the metal to provide a current through for the telephone signal but not for the BroadBand signal to travel through. The reason the BroadBand connection will suddenly come to life when the handset of a phone is lifted is the additional current provided by the telephone signal has an effect known as wetting the joint which gives the joint a little extra kick it needs to be able to carry the BroadBand signal through.

In the end the connection will end up giving up the ghost completely and the only option will be to arrange a BT engineer visit to sort the problem out if you want to have a working BroadBand connection and telephone line.

There are two paths which can be followed if you have a HR fault. If you are getting a hissing on your telephone you can arrange a BT engineer to sort out the hissing on the line through your telephone provider. Usually this will also sort out your BroadBand problems at the same time. If you are not getting any adverse effect on your telephone line then the problem must be reported to your ISP to arrange a BT engineer visit.

Whenever I Run Speed tests The Results From Different Speedtesters Vary Wildly

Speedtesters work by downloading a file / files to and from your computer and working out the time taken for the transfer of this data. You will then be given a download and upload speed for your connection. These upload and download figures can get biased by a number of different factors though. The main factor is usually the route taken from your computer to the specific speedtester being used. Many sites that offer speedtesters have peering arrangements with most of the major ISP's. This means that the route the data is taking between your ISP and the speedtester is as short as possible, and sometimes direct, which should give a more accurate figure of your connection speeds. However different peering arrangements can end up causing wildly different results from one speed test to another.

The next main consideration is that you do not have a definitive set speed as contention and congestion, from an ISP point of view, the speedtesters site point of view and from the wholesalers point of view, means that in all likely hood if you run 30 speed tests from the same site you would rarely get the exact same figure.

Also you need to look at how the speedtesters work. Some speedtesters will download only small files, others will use large files, some will use Java for it's back end programming and others will use different languages. All these things can have effects on how speedtesters carry out and report the results.

The last thing you need to consider is the actual figure being used to report the result. Is it Bits per second, Bytes per second, if it is Kilo Bits per second is this Kilo 1000 bits or 1024 bits. Make sure you understand that certain speedtesters will use their own set of denominations depending on how their programmer has been bought up to interpret these figures.

My Line Is Interleaved Which Is Causing High Ping Times, Why Is This?

Interleaving, along with error correction, is a process used to stabilize lines which may pick up random noise bursts by splitting the data sent, making sudden bursts of noise less likely to cause a complete re-transmit of data packets. More on how it works is explained here. Usually, Unless specifically requested by the ISP, Interleaving is initially set to Auto. In this situation Interleaving is actually off but if for some reason your line becomes unstable Interleaving will automatically be switched on. Some ISP's request that lines initially have their Interleave state switched on and you can request your ISP to have Interleaved set to off (disabled).

Because of the time taken to re-arrange the bytes and the time taken for the error correction process to work the time taken for the packets to get from the host to your computer will be longer. This will usually effect the Ping times (Latency) of your connection.

Nine times out of ten this is a good thing as it helps avoid re-transmits of data, however if you are using applications which require low latency connections, e.g. Gaming, VOIP, Streamed media etc..., then the speed of the packet transfer is more important than the fact that a few packets may get dropped. After all with games if you can get your packets to the game server quicker than your opponent, even if milliseconds, this could end up being the difference between winning and loosing. In these situations it is usually better to take a drop in speed, by having your Target Margin increased, to try to stabilize your line and then get your ISP to get Interleaving turned off.

You may also find situations where your line temporarily becomes unstable, e.g. if you are carrying out some internal telephone re-wiring or if you have a lightning storm or some other temporary random burst of noise. If this happens and your Interleave state is set to Auto this may trigger it to be turned on. If this is the case you will need to wait until conditions are again stable and request your ISP change the Interleave state of your connection.

We've Just Had A Thunderstorm And Now My Internet Connection Is Not Working

Thunder storms can cause problems with BroadBand connections and the old adage of unplugging the telephone when there is a storm is true not only for telephones but also for modems, routers and any other piece of equipment plugged into your telephone line, e.g. Sky boxes.

The worst effect a storm can have on a telephone line is when the lightning strikes close to where your telephone line runs. If this happens some of the current from the lightning strike can end up traveling down the line and completely frying the internal circuitry of the router / modem. In this situation as routers are so cheap nowadays the easiest option is normally just to buy a new router because the likely hood is that you are not going to get your router fixed, especially for less than the price of a new router.

The other effect a storm can have is to drop you IP Profile to an extremely low speed, which will mean an extremely low download rate. This can be caused by one of two things which happen, and can happen even if you are quite far away from the actual storm itself. The first problem you may encounter is a re-sync to a low sync rate due to the obvious increased amount of noise on your line from the lightning strikes. Although this may be annoying this is the best of the three scenarios a lightning storm can cause as after the storm has finished the line noise will return to normal and after three to four days your IP Profile will start to rise returning your download speeds to a more normal rate. This will only be experienced on BT Wholesale provided products.

The other way your download rate can be reduced by a storm is extremely annoying to get sorted out. If the systems keeping an eye on your line see a lot of quick re-syncs and fluctuating SNR figures caused by the lightning storm it may decide to increase your SNR Target Margin. If this happens and your Target Margin gets increased from 6dB to 15dB you will find that this has quite an impact on the highest possible sync rate you can now achieve. If this happens the only way out is to contact your ISP and ask them to get your line retrained or ask for your Target Margin to be reduced. This is not an easy task to achieve and I have heard of many people having to change ISP's just to get with a company which has a well trained customer support department that will be able to get a problem like this sorted.