Steady line speed suddenly dropped by 50%??

Hi,

We have a long line and slow but steady speed (around 2meg) for the last 4 or 5 years. Over the weekend, the modem lost sync and would only re-sync at well under 1 meg. Not good at all as we rely on the line for business.

I'm a bit off the pace as far as ADSL is concerned but I suspect this may be something to do with BRAS profile which now looks stuck. Is there anything we can do to force the line to re-train please? We've tried rebooting the router a fair few times but no joy.

We are due FTTC in March but we need a steady connection until then as we run a design business from home.

Any guidance (simple speak please!) appreciated. For info we have checked all the wiring, spitter and even a spare modem - same result.

Thanks for your help,
Dave

Could be RFI noise on the line. Can you post router stats - sync speed, SNRM, Attenuation?
Have you recently installed anything new - sky box, phone, microwave etc?
What does speedtester.bt.com say about your speeds and profile?

Hi,

This is the limited info from the router (cheap Belkin N150)

Noise Margin 14 11
Output power(dBm) 12 15
Attenuation(dB) 57 31

Getting 800 down, 400 up at the moment.

Speed Tester gives an IP profile of 705, 800 down, 416 up and 625/326 for the test.

Our download has always been 2.5 x these figures?? We haven't installed any new kit so the problem must be external?

Is this a BRAS issue do you think? Very odd and inconvenient!!

Thanks
Dave

Are those stats taken from the test socket inside the master?

BRAS is the IP profile, the modem is connecting slower than one would expect, 3Meg should be possible.

Has it been unstable? And how long after switching on the modem were those figures taken?

In reply to a post by spon:

We've tried rebooting the router a fair few times but no joy.

Bit late now I'm afraid, but that could have made things worse, by jacking up the sync-time noise margin. We would need the stats taken immediately after a reconnection to know what it is now set at, but the "system's" way of correcting it is Case 4 on this page.

It is possible however that you could get your ISP to do an SNRM reset. They now have this facility but some ISPs don't seem keen on it. Let's see the stats first, straight after a day-time reconnection, preferably using the test socket as mentioned by BatBoy.

Hi Folks and thanks for your help.

The stats are still similar this morning. They are from the normal socket altho we have tried a complete new extension cable up to the router to eliminate that. So all the wiring/splitter has been tried and we've tried a new router but no joy. We have a steady connection - just less than half speed!

Some of the on-line references suggest that it may fix itself in 10 - 12 days? Is this correct please as we can soldier on slowly if necessary. In this period, is it best to avoid any re-boots of the router? I say this as it has an "auto heal" setting where it re-boots once per week in the middle of the night.

Thanks for your help
Dave

The stats don't usually change dramatically over time during a connection, except the noise margin will vary by a few dB. To give you the best advice we need to see stats taken in the same way as before, but immediately after a reconnection.

Re your auto-night-time reboot of the router, that should be unnecessary, and is highly likely to cost several hundred kbps compared to a daytime reconnection. Why do you feel a daily night-time reboot is a good idea?

Please can you describe your cabling. Is it:-

Computer >> short ethernet cable >> router >> ADSL cable >> splitter >> phone extension cable >> phone socket; or

Computer >> long ethernet cable >> router >> ADSL cable >> splitter >> phone socket.

I ask because some people would call a long ethernet cable an extension cable.

Yes, the system is for a high noise margin setting in the DLM to reduce by 3dB every 10-14 days. This can be prevented by a noisy line or one with lots of in-use errors that get dealt with one way or anither without losing the connection, or it can just fail for no known reason.

Hi,

Just rebooted. Stats on router are:

Downstream Upstream
Data rate(Kbps) 896 480
Noise Margin 14 10
Output power(dBm) 0 16
Attenuation(dB) 57 31

Stats on BT tester are:

Download speedachieved during the test was - 694 Kbps
For your connection, the acceptable range of speeds is 400-1000 Kbps.
Additional Information:
Your DSL Connection Rate :896 Kbps(DOWN-STREAM), 480 Kbps(UP-STREAM)
IP Profile for your line is - 790 Kbps

Upload speed achieved during the test was - 352 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 480 Kbps

Our config is socket > long telephone extension > splitter > short telephone cable > router > short ethernet cables to 2 x PCs (+ wireless)

The auto re-boot option is just the default in the router.

So a slight improvement (96 kbps) on yesterday but still way down on what we got for years (around 1.8 -> 2megs)

Thanks
Dave

You would 9 times out of 10 get better and more stable results by plugging the filter into the socket directly. The long extension lead will be subject to picking up RF and other nasties and will just hamper your connection more often than not.

It would be a good idea to test the router in the test socket on the master socket and post up your router stats here right afterwards.

See this for more info:- http://www.kitz.co.uk/adsl/socket.htm