Speed 4Mbps instead of 6Mbps, internet drops (DSL doesn't)

[#1]

Hello.
I've got another of those annoying problems that aren't bad enough for Plusnet to immediately spot, and aren't outside the so-called "acceptable" margin.  So perhaps the kind people in the community, and the new CRT, can help...?
My normal speed is around 6200kbps according to speedtest.net, and my "Current Line Speed" on the Plusnet portal is normally around 7 Mb.  For the past week or so, I've been getting around 3900kbps on speedtest.net and today my "Current Line Speed" is 4.1 Mb on the Plusnet portal data transfer speed page.  Also today the connection to the internet has dropped several times (the light on my Thomson ST546 router has gone out, leaving me unable to use the internet on my computer), but the DSL connection has remained according to the router settings page.
I tried turning the router off for 30 seconds and back on, with no improvement - it established a DSL connection, but not an internet connection.  And then, with my computer connected by ethernet, the router in the master test socket, no WiFi, no other background programs running etc, I turned the router off for 30 minutes.  When it was back on, I ran the BTW Performance Test:

Quote

Download speed achieved during the test was - 4.09 Mbps For your connection, the acceptable range of speeds is 1.2 Mbps-4 Mbps. IP Profile for your line is - 4.19 Mbps

My router stats show SN Margin Down 9.5 (normally 6.0 or less), Line attenuation down 49.0 (normally 48.0).
Any thoughts?

[#2]

Any noise on the phone line?

[#3]

No noise on the phone line in general, and I've just done a BT "Quiet Line Test" to confirm.

[#4]

Hi snozboz,
From what I can see with the non-intrusive testing (I didn't want to drop your connection again) it seems that you had a spike in errors on the 08/08/14 which spiralled across the rest of the month which means DLM kicked in to reign in the speeds. The testing hasn't flagged anything as a problem at the moment and it looks as thought the sync has improved a little (although the DLM hasn't picked this up yet) so it seems like it could be on the mend.
If you're happy for me to go ahead and run an intrusive test that will drop your session then let me know and I'll see if we can turn up anything more on this.

[#5]

Hi Adam.
Thank you very much for this.  Yes please, run your intrusive test.  The router is still in the master test socket, though my computer isn't plugged in to it with an ethernet cable.

[#6]

Morning snozboz,
I've just through the testing and so far I haven't been able to pick anything up other than the DLM updated this morning yet held steady at the 4191 mark as it has since the 14/08/14. Your actual sync speed is showing 5568 and you have consistencies in the profiles across the equipment so ideally we should see you sat around 4.9mbps at the moment.
Your connection is looking a little more stable after the events on the 21/08/14 (did anything noteworthy happen on this day with regards to new electrical equipment being introduced into the home?) so I would expect to see the service speeds return to normal of their own accord however if you haven't seen any change over the weekend I would suggest testing the connection with an alternate router and all other devices removed from the phone sockets if possible. Given that you're in the master/test socket I think that should rule everything else out.
<img src="http://community.plus.net/visualradius/generated/image14086969435714.png"/>

[#7]

Adam, thank you for your efforts so far.

Quote from: Adam

Your connection is looking a little more stable after the events on the 21/08/14 (did anything noteworthy happen on this day with regards to new electrical equipment being introduced into the home?)

Between 11.30am and 12noon on 21/08/14 (these times are exact), my vacuum cleaner was in use (used most weeks) and a steam cleaner (not used before) was also plugged in and used.  Apart from that, there were no new pieces of electrical equipment introduced nor were there any changes made to any electrical equipment during this month.

Quote from: Adam

if you haven't seen any change over the weekend I would suggest testing the connection with an alternate router and all other devices removed from the phone sockets if possible. Given that you're in the master/test socket I think that should rule everything else out.

I thought connecting to the master/test socket automatically meant that all other devices in phone sockets were disconnected?  Can such devices still cause an issue, even if the Master socket faceplate is off and the router is in the test socket?
BTW, I don't have any extension phone sockets - just a 1 bedroom flat - and normally just have a wired phone and the router plugged in to one microfilter in the one Master socket.
If it comes to it, I don't have an alternate router to try.  Does Plusnet still offer to send one out?

[#8]

Afternoon SnozBoz
Thanks for bearing with us over the bank holiday 
I've just been having a check over your connection and speeds. It looks like your line is much more stable than it had previously been but a profile on our end, which is used to manage your speeds to help with stability, hasn't been bumped back up to match your 6mbps profile.
I have now sorted this for you and over the course of the next few hours or so you should see some improvement.

[#9]

Thank you Jack.
I noticed that you had done this, which improved matters a bit, but things have got worse again (though not quite as bad as last Thursday - I haven't noticed any internet drops).  Since last Thursday, the vacuum cleaner and the steam cleaner have not been used.  However my speed is still not what it was (see my original post, and the following info).
I just did the following tests with my router in the Master/Test socket, and my computer using a wired ethernet connection.
http://www.speedtest.net
Download speed 4809kbps
https://portal.plus.net/my.html?action=data_transfer_speed
Current line speed 4.8 Mb
http://www.speedtest.btwholesale.com/
Download speed achieved during the test was - 4.91 Mbps
For your connection, the acceptable range of speeds is 2 Mbps-7.15 Mbps.
IP Profile for your line is - 4.82 Mbps
Thomson ST546 http://192.168.1.254/
Uptime: 1 day, 20:13:36
Modulation: G.992.3 annex A
Bandwidth (Up/Down) [kbps/kbps]: 444 / 5,469
Data Transferred (Sent/Received) [KB/KB]: 0.00 / 158.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 25.5 / 47.0
SN Margin (Up/Down) [dB]: 22.0 / 9.0
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 3 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 3 / 0
FEC Errors (Up/Down): 0 / 75,820
CRC Errors (Up/Down): 0 / 184
HEC Errors (Up/Down): 0 / 156
Any help would be appreciated.

[#10]

Hey snozboz,
I've been looking at your connection and running a few checks. In my opinion it looks like the recent errors on the line have caused the SNR to slightly increase on the line and its caused the profile to drop.
I've issued an SNR reset as the profile has actually been stuck at around 4.9MBps since the 24th. I'll check this again in about 20mins or so and see if this has made any difference.
Back in 20ish!
Dan

[#11]

Back again,
The line is looking 'better' now.
I've included a screenshot below. As you can see the sync has shot up (green) but the errors have increased (orange) which will probably mean the SNR will increase again over time. Its a matter of monitoring this for a few days to see if this happens. Though some errors aren't service affecting so we might be ok.
If the speeds drop again we will have to get an engineer out.
Let me know how it is over the next few days.
Dan

[#12]

Thanks Dan.
Speeds this morning are still not what they were by 1000kbps approx.  They are at least usable however.
Over the past few days, speeds dipped then rose again.  Before doing the tests (below), I turned the router off, waited 30 seconds, and turned it back on.  I noticed that before doing this, my router said my connection had only been up for 6 hours or so, and after doing this, my router reported a higher connection speed.
Tests done with Thomson ST546 router in Master/Test socket, computer connected by ethernet, no new electrical equipment, no other devices connected to the router, no other programs running etc.
http://www.speedtest.net/
Ping 42ms (normally in the 30s)
Upload speed 370kbps
Download speed 5363kbps (normally around 6200kbps)
https://portal.plus.net/my.html?action=data_transfer_speed
Current line speed: 6 Mb (normally around 7Mb)
http://www.speedtest.btwholesale.com/
Download speed achieved during the test was - 5.52 Mbps
For your connection, the acceptable range of speeds is 2 Mbps-7.15 Mbps.
IP Profile for your line is - 5.27 Mbps
Upload speed achieved during the test was - 0.24Mbps
Additional Information:
Upstream Rate IP profile on your line is - 0.45 Mbps
Thomson ST546 http://192.168.1.254/
Uptime: 0 days, 0:05:09
Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 444 / 6,283
Data Transferred (Sent/Received) [KB/KB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.5 / 0.0
Line Attenuation (Up/Down) [dB]: 26.0 / 48.5 (Down is normally 48.0)
SN Margin (Up/Down) [dB]: 23.0 / 9.0  (Down is normally 6 or less)
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 213
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0

[#13]

Hi,
The synch rate of 6.2Mbps at 9dB is a tad higher than the expectation of 5.9Mbps at 6dB for a 48dB attenuated line.  In other words the synch is higher than expectations.
The elevated SNRM is indicative of noise being picked up somewhere.  I would keep repeating the quiet line test - there might be an intermittent fault.
If you want to take a closer look at the line, you could go and download RouterStats.