Zen Internet Support Forum

In order to help our customers diagnose the cause of slow speeds with their ADSL connection the following guide has been created.

Speed issues can be caused by a number of factors including:

 

• Equipment failure/fault at your premises.
• Third-party software using the upstream and/or downstream capacity of your ADSL connection (includes p2p, viruses or Internet applications).
• BT Exchange contention.
• Contention on the BT Central pipes which present your connection to Zen.
• Interference resulting in an intermittent connection or temporary low line speed.

The following page provides details of the Performance Thresholds provided by BT for the various ADSL services available:

http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10549

How to diagnose speed problems:

 

Step 1:

To ensure the problem is not related to a temporary problem with your computer or ADSL router/modem restart all your equipment. When restarted shut down any open applications and other computers on your network and proceed to step 2.

 

Step 2:

If you believe you are experiencing problems with your ADSL speed the next step after a restart is to confirm the speed you are experiencing. To do this you should close all open programs and switch off any other computers on your network. Once done use BT’s speed tester following the instructions in the Knowledge Base article here:

 

http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10383

 

Note the results – including the time of day and date. If your performance falls within the performance thresholds then BT would not accept a fault raised against your line.

 

If the results of the BT speed test show your IP profile of your line is below your DSL Connection rate it's likely you have experienced a low line rate event.  This could be caused by temporary interference (e.g. an unfiltered phone being plugged in or by an electrical storm) or by something more permanent.  You can determine if a low line rate event has been experienced by using the Line Data module available in the Customer Portal.  The following Knowledge Base article explains how:

 

 http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10593

 

If a low line rate event has occurred and the low speeds remain (with a low IP profile showing as the last update in the Customer Portal line data) after five days then you are likely experiencing an intermittent connection fault.  The following Knowledge Base articles provides advice on how to diagnose and resolve this type of fault:

 

http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10552 

 

When making changes to your wiring you should perform the BT speed test.  If the line rate has increased significantly then check again after 48 hours.  If only a small increase in speed has occurred it may take up to five days for your IP profile to change accordingly. 

 

If problems persist follow the instructions in step 9. 

 

Step 3:

If you are using a Wireless router ensure you have enabled encryption and Access Control lists. This will prevent anybody nearby “piggy-backing” on your connection – and therefore prevent them using your bandwidth.

 

Step 4:

Speed issues could be caused by a problem with your internal wiring setup. To eliminate this as a cause you should ensure your DSL filters are set up correctly. A brief overview of setting up DSL filters can be found here: http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10013

Alternatively you can test from the BT Master socket or BT Test socket and unplug all other telephony equipment (including Sky digital boxes, telephones, fax machines etc.). This would be a required step if a fault were to be raised with Zen. Once you are sure everything is set up correctly repeat the speed test process, and record the results.

 

Step 5:

If the BT Speed Test is below the minimum threshold rate possible for the service you receive (based on the IP profile recorded on the BT speed tester) you should repeat the Speed Test between 4 and 20 hours later. If it is still running below the minimum speed see step 9.

 

Step 6:

Viruses or other malware may be responsible for your poor speeds as they use your connection to propagate. If you are not already running Anti-virus and Firewall software install some, and then perform a full system scan for viruses. You should also check for Adware/Spyware.

 

Step 7:

If problems still persist, and no viruses or malware are present on your system, perform a traceroute to 212.23.6.100 and record the results.

 

Step 8:

If the speed problems are still present, and you have eliminated BT as the cause, you should perform speed tests at various points in the day. Once done follow the instructions in step 9.

 

Step 9:

 

If the problem continues then contact Technical Support for further advice - including your Zen ADSL username and/or order number. You must leave the router connected to a DSL Filter plugged into the BT Test socket (where available) when contacting support, and until the fault is resolved, in order to ensure diagnostics return accurate results for your service. 

When contacting Technical Support please advise of the time of day (or day of the week) and frequency of the problem experienced.  Include details of the tests you have performed and results.  Also please advise whether the equipment is connected to the BT Test socket, or if this will need to be arranged in order for diagnostics to be conducted.

Details for contacting Technical Support can be seen by clicking the Contact Us link on the left-hand-side of this page.

 

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Phil Long
Technical Support Manager - Zen Internet Ltd.