Huge decrease in download speed

vigor2820 · Feb 22, 2011, 13:22:15

Hi,

I'm hoping the forum might have some insights on a huge reduction in download speed that I've suffered over the past few weeks.

Before I migrated to IDNet a couple of months ago, I was enjoying speeds of around 16-17mbps, with no problems at all. After moving, I initially got around 15.5mbps, again with no problems at all (such as connections dropping). My IP profile according to the BT speedtester was at 21mbps at that point. I'm half a mile from the exchange.

One day I suddenly found everything had slowed to a crawl - 80kbps or thereabouts. Support went through the usual checks on my internal wiring etc., and ended up asking BTW to enable stability options and interleaving and a line retrain. However before that started my speed suddenly bounced up to 14mbps. Support said it had probably been a BT network issue that had been resolved.

So, all fine and good, except that my speed has since then, over the past 2 weeks, dropped gradually to around 7.5mbps and my IP profile is now listed as 8mbps! I'm surprised as I did leave the router on 24/7 during the retraining, and never had any connection trouble.

Support just say it's 'as expected on the circuit' and that the line may have 'degraded'. I find that logic hard accept - it calls for a big coincidence on the timing of the network problem and my line quickly losing half its speed capability. Support don't seem to see any reason to ask BTW to check things at the exchange or anything like that.

Does anyone know what might be going on here? Do lines suddenly 'degrade' like this, or is it unfortunate 'banding' or something?

If it helps, current stats from the router are as follows:

Up speed: 888888
Down speed: 9720000
SNRm: 10
Loop att: 24

I can't remove the faceplate on the master socket for testing as it's a double master for two lines and they don't have faceplates, but I have no extensions on the line at all and hard wired connections to the router.

Thanks for any thoughts!

Rik · Feb 22, 2011, 17:29:51

Hi and welcome to the forum.

Could you run a BT speed test and paste the results back here please? I'm wondering if you've been put on a banded profile.

Steve · Feb 22, 2011, 18:34:08

It's not far off the upper limit for that band of 9728

Sorry Vigor

vigor2820 · Feb 22, 2011, 19:13:21

Hi - many thanks for the kind welcome.

Here's the data from a BT speedtest I just did. Actually the speed looks a bit better on this (though it's still around 7.5mbps on speedtest.net). My SNRm has crept to to 11.

Thanks for any insights!

--------------------
Download speed achieved during the test was - 9077 Kbps
For your connection, the acceptable range of speedsis 2000-7150 Kbps.
Additional Information:
Your DSL Connection Rate :9720 Kbps(DOWN-STREAM), 888 Kbps(UP-STREAM)
IP Profile for your line is - 8000 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 19.0:24.4:56.61 (SBE:NBE:PBE)

Upload speed achieved during the test was - 575 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 888 Kbps
--------------------

Glenn · Feb 22, 2011, 19:18:24

I think Steve maybe on to something with the banded profile.

Rik · Feb 22, 2011, 19:23:16

That doesn't look like you're banded, the profile is correct for the sync speed. What appears to have happened, though, is that your target noise margin has been increased to give you stability, and with it, lower speed. The problem we have is that, once again, the BT tester is reporting a speed higher than the profile, which should never happen.

For your attenuation, I'd expect a much higher sync speed, which suggests that the quality of the line has degraded, eg a joint has corroded. Getting BT to fix this might be hard, though. Ask support whether they can reduce the stability measures and see what happens.

vigor2820 · Feb 23, 2011, 08:44:07

Thanks very much guys - appreciate that.

I'll do as you suggest.

vigor2820 · Feb 25, 2011, 10:44:52

A little update on this...

Support said they would ask BT to reduce the level of stability settings and that should have happened yesterday. However no change in speed as yet (I've just tried one reconnection).

Something that is really odd is that upon the last few reconnections (over the last week or so), my sync speeds have always been exactly 888888 kbps (up) and 9720000 (down). It used to be that every reconnection obtained slightly different speeds - and never such round numbers!

Does this hint at anything to anyone?

SNRm and Loop att remain at 10 and 24, respectively.

Rik · Feb 25, 2011, 10:46:42

I'd say it hints at a banded profile, but I don't think that's what you're on. Check with support.

Ray · Feb 25, 2011, 10:47:37

vigor2820 · Feb 25, 2011, 12:53:46

Thanks fellows. I'll give it a few days to see if the speed creeps up and if not enquire further about this...

vigor2820 · Feb 28, 2011, 16:07:25

There has been no increase in speed lately and stll connecting at those exact sync speed so I contacted support.

They say the line is banded, the router is reaching the top end of this banding and if the line maintains the connection and shows no errors then the banding will automatically update to allow higher connection speeds.

Should I just sit sight or is it better to ask that the banding is removed?

Thanks!

Rik · Feb 28, 2011, 16:13:45

Sit tight, if the banding is removed and things become unstable, you could be worse off.

vigor2820 · Feb 28, 2011, 16:18:58

OK - thanks for the quick response. I'll be really disappointed if it sticks at these awful speeds but fingers crossed it'll rise soon.

Rik · Feb 28, 2011, 16:26:48

Hopefully, it will, but BT are generally reluctant to have multiple goes at this sort of thing, so I feel it's better to hang on a while before asking and hoping nature will take its course.