BT listening to us?!

Again actually calling them BT. I know, scary stuff :-)

So what have BT done right?

BT have a DLM (Dynamic Line Management) which tries to fine tune the settings on each broadband line to ensure it remains working at a good speed on a long term basis. The settings can be adjusted in many ways, and they are a trade off. Some settings can make a line more reliable against certain interference but also make the latency higher. Some settings can make the line faster but less reliable. There are a lot of settings.

Now, the DLM, taking care of all of these settings automatically, sounds like a good idea. Unfortunately it has its limits. In some cases the DLM makes matters a lot worse than simply picking some settings and leaving them. It is also impossible to properly tell the DLM what the customer wants - some people want the highest speed, but they know that the line will go off line at high speed every night and don't care as they are asleep! Some people must have a line that is reliable and really do not mind if it is set to only 500K if it works all the time. These are extremes, but especially with reliability the DLM itself causes resyncs and changes in the name of keeping the service reliable! In some cases the line characteristics mean the DLM cycles through different settings over a period of several weeks - thinking it can do better and then finding it cannot over and over again.

BT introduced some changes a while ago that allow the DLM to be slowed down - told not to make changes as often, or even told not to make any more changes. The issue there is that you get stuck with whatever settings you now have.

Now, on BE lines we have no DLM at all. We have direct control of the settings and we let customers tinker as needed. Our customers, or our support staff, can sort lines out if they are a problem and leave the settings where they work well.

So BT have finally listened to us and soon (December I think) we will have the controls to actually make changes to the settings and turn off the DLM on lines. We aim to expose the settings on the control pages so that customers can also make changes.

In most cases the DLM will do fine, and this won't affect most people - but those with iffy lines or special requirements will find this invaluable as a way to get their line working the way they want it.

So, well done BT for listening - I know it has taken a long time but looks like we may finally have something we have been asking for.

Now, can we have cheaper bandwidth please :-)


  1. Will BT allow the customer to specify the time frame to make the DLM adjustments?

  2. Well, my understanding is it will be done when you ask, or within a short time of that. So you specify the time by asking for the change at the time you want it to happen.

  3. Do this apply to 21CN only or FTTC/VDSL2 as well?

  4. Looks like 21CN and would only be ADSL not FTTC as the FTTC DLM is done within BT plc t/a Openreach, not BT plc t/a BT Wholesale.


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