The mysteries of broadband

[dickm]

Can one of you more IT-savvy folks explain something to me? As our house is entirely timber, we try to be careful not to leave electrical items running unnecessarily, and my computer is connected via one of those devices which switches off all the other items connected to it when the computer is switched off. This includes the router. A month or so back, the broadband connection became very unreliable, cutting off for minutes at a time. The John Lewis broadband helpline were moderately helpful, but said it was necessary to check all the relevant sockets, devices etc. within the house before they could call up BT to check the line. This was duly done, with no apparent result. Put everything back to original, and was about to ring the helpline when broadband miraculously reappeared and was completely stable until a couple of days ago, when it started failing again. Rang JL helpline and got a very rude and aggressive guy who looked at whatever readouts they have and said “well, it's your own fault as you've been turning your router off regularly”. I queried this, which made him even more aggressive, but he claimed it was to do with something called Dynamic Line Management. No mention of this appears in their literature, although apparently some other ISPs recommend keeping the router on permanently. Looking this up, I'm not much wiser, but it looks as if BT adjusts the speed of your connection depending how often it is used. Nothing about making it completely unreliable though.
Mysteriously, the connection became normal again almost as soon as I hung up with the rude guy. The router is now permanently on if we are in the house, and the connection seems stable, but am still puzzled about all this.
Any explanations comprehensible to an aged brain?

 

[tekno.mage]

Hmm - I just found this explaination of DLM online...

"DLM is Dynamic Line Management, a fully automated monitoring system which runs on broadband ADSL lines. The system runs 24/7 and is designed to help keep the line stable. It does this by applying different profiles to the line based on the current line conditions. The profiles will change the error correction and the speed of the line.

If the DLM detects errors, dropping connection or low sync rates it will lower the throughput of the line and/or increase the error correction on the line in order to help keep the line healthy. The profile will be updated within 75 minutes of the issue occurring.
The profile will then remain unchanged until the condition of the line improves and remains so for between 4 hours and 72 hours at which point the DLM will increase the profile accordingly. If at any time the condition re-occurs the timing is reset and it will take another 4 - 72 hours before it increases the profile."

Your router being powered off should be seen as a dropped connection and the DLM should either lower the speed or up the error correction rate of your line, but not cut it off completely! Either your ISP has set up their DLM wrong or you have another kind of problem....

I leave my router on all the time, and have occasionally experienced similar problems of broadband instablity as you - most recently when the really windy weather was happening and just after. I live somewhere very rural and don't get anything like "superfast" speeds due to the distance I am from the exchange, however the broadband is usually reliable if slow. I think my own probelms were caused by problems on, and work being done on, the BT network after the storms. What I find really weird is that sometimes on these sort of occasions I will have unreliable broadband and a working telephone landline, and sometimes a dead landline but working broadband - odd as they both come down the same copper cable to my house!

You do, of course, have a method of stabilising your broadband connection - ring up your ISP and moan as this seems to have worked every time so far!

 

[Lons]

Hi Dick

I'm far from being an expert but BT certainly do regulate the line though it's done automatically in most cases (I say most because though they deny, it@s widely believed do keep speeds slightly lower than possible to give themselves additional available bandwidth).

Basically, your connection is monitored and if detected that it's dropping regularly (switching off does that), it's assumed that your line is unstable and your speed is capped at a lower rate in your IP profile. This has happened to me several times and on each occasion I've had to phone India and get very insistant with the customer services people who read off a crib sheet.
My problems were caused by the electricity company having regular power interuptions.

It really shouldn't cause your broadband to cut off just lower your speed and I would have thought that the problem lies with BT if you're sure your router isn't faulty.

You can chech your connection and IP profile at http://speedtest.btwholesale.com/ but DO NOT follow the instructions to re-set your router as that just compounds the problems.

Bob

 

[Lons]

Forgot to add.

When you do the speed test just check the box to say you've done the resets etc (don't do them) and let it do the test then click further diagnostics, enter your phone number inc code and it will send to server. The results will show the capability of your line as well as your IP setting. I suggest you print that or write it down and if not satisfactory, complain like hell.

Bob

 

[SurreyHills]

Depending on how far you are from your local BT exchange typically determines 2 mains aspects of your Broadband service.
1) upload/download speeds - further away = slower
2) strength and clarity of the analogue to digital conversion - the ADSL technology used for UK broadband is an analogue one and not a true digital one. It relies on copper wires with digital to analogue converters at both ends (the exchange and your house) and the signal quality varies all the time. So when you start using the service the line speed may vary wildly and the "noise" on the line causes lots of errors and packets of data will need to be resent - I.e. An unstable connection and fluctuating line speed. In order to try and get to a happy equilibrium and make it more reliable BT use DLM to automatically monitor the traffic on the line to adjust it to an acceptable level. Normally this process takes a couple of days to settle down.

So if you keep turning off the router you are making a new Broadband connection each time it gets turned back on and this means you get assigned a new IP address which means there is no history about the quality of that connection and so the DLM process needs to start from scratch.

 

[Deejay]

Morning Dick

If you are happy with the broadband service you get now, it may be that you have a line fault, which could be intermittent.

If you have a dodgy connection on the line, it may cause errors on your broadband. If enough errors are seen at the exchange you might be disconnected, or your rate will drop. It will then slowly increase as said above. Finding the cause can be a nightmare.

Do you get any clicks or crackles on the telephone connection?

Try a quiet test and listen to the noise. Dial 17070 and choose option 2.

If you do get noise, it may be on your internal wiring, which is your responsibility. If Openreach come out and find it's on your kit, they will charge for the visit.

Cheers

Dave

 

[dickm]

Thanks, guys - at least I'm now better informed. THINK I understand what DLM is doing, but can't see why it's causing the problem. We are about 1/2 mile from the exchange, and for my useage, speed always seems adequate, though that's purely subjective. Surely if the DLM was just judging my usage and adjusting speed, then it would be noticeably slow, not just intermittently really flakey?

Will try deejay's suggestions,and am currently leaving the router on at least while we are in the house. But it may be significant that just after the last bad session, there were two BT Openreach vans outside our local exchange

 

[Racers]

Will try deejay's suggestions,and am currently leaving the router on at least while we are in the house. But it may be significant that just after the last bad session, there were two BT Openreach vans outside our local exchange

New packet of Hobnobs at the exchange, nothing else.

Pete

 

[MMUK]

Can you get fibre optic in your area? You won't have this problem then, even if you switch the router off

 

[dickm]

Can you get fibre optic in your area? You won't have this problem then, even if you switch the router off

In the wilds of north Aberdeenshire???? You have to be joking . Can't even get a decent mobile signal without walking 1/4 mile up the road, 'cos there's a bit of a hill in the 1/2 mile between us and the mast But maybe when we get independence............ (ducks and runs)