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Progressively degrading ADSL download speed

tactilis
Dabbler
Posts: 14
Registered: ‎03-01-2013

Progressively degrading ADSL download speed

Hi DCT, can you help please?
My next door neighbour is who also with Plusnet, is connected to the same exchange as me and also uses a TG582n. He gets a consistent download speed of over 4Mbps: http://www.thinkbroadband.com/speedtest/results.html?id=141322821616078790743
However, I currently get only 1.8 - 1.9 Mbps: http://www.thinkbroadband.com/speedtest/results.html?id=141321705317968098117

The attached graph shows that over the past 18 months my download speed has degraded progressively from >3.5Mbps down to 2.5 - 2.75Mbps.
Then, in the past 2 months we have had some intermittent disconnects caused by repeated powercuts during thunderstorms. This has caused my download speed to drop to 1.8 – 1.9 Mbps, however in this time my neighbour’s speed has remained at > 4Mbps.
Our routers are both connected to the master socket with NTE5 faceplates.
My TG582n stats are currently:

[tt]Uptime: 3 days, 0:28:50
DSL Type: ITU-T G.992.3
Bandwidth (Up/Down) [kbps/kbps]: 440 / 2.268
Data Transferred (Sent/Received) [MB/GB]: 430,71 / 1,99
Output Power (Up/Down) [dBm]: 12,7 / 0,0
Line Attenuation (Up/Down) [dB]: 29,7 / 50,0
SN Margin (Up/Down) [dB]: 17,7 / 6,9
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 2 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 66 / 0
FEC Errors (Up/Down): 621 / 722.621
CRC Errors (Up/Down): 6 / 211
HEC Errors (Up/Down): 1 / 765[/tt]
From the BT speedtester I get:

[tt]Download speed achieved during the test was - 1.98 Mbps
For your connection, the acceptable range of speeds is 0.8 Mbps-2 Mbps.
IP Profile for your line is - 2 Mbps
Upload speed achieved during the test was - 0.33Mbps
Upstream Rate IP profile on your line is - 0.45 Mbps[/tt]
Questions and DCT assistance requested please:

  • Why do I get consistently lower download speed then my neighbour?

  • Why has my speed progressively degraded over the past 18 months?

  • What can be done to improve my speed?

  • What can be done to make my connection speed more resilient to disconnects, as my neighbour’s appears to be?

Thank you




16 REPLIES
Cruise85
Grafter
Posts: 105
Registered: ‎05-08-2014

Re: Progressively degrading ADSL download speed

Hi  tactilis
Sorry to hear about the issue in regards to your connection speeds
I have run several tests on the lin ethis afternoon, and thus far have been unable to locate any problems in relation to the speed of the line. I do however accept that the current line speed is showing at 2.5mb, which is lower than the speeds your neighbour may be achieving
There may be reasons behind this, however your line is currently running above the estimate given to us by Openreach, and as such does not fall below their fault parameters. Ypu can see the confirmation of this through the link below
http://www.dslchecker.bt.com/adsl/adslchecker.welcome
I have however requested that your line be reset to see if this will have any positive impact on your connection.
Hope this helps
Regards
Matt
Superuser
Superuser
Posts: 13,043
Thanks: 4,332
Fixes: 26
Registered: ‎22-08-2007

Re: Progressively degrading ADSL download speed

Matt,
The line might be within BT's very conservative estimates, but the synch speed is well shy of what might be expected on a 50dB attenuated line.

Hi Tactilis,
Welcome to the forums.
To answer your question about differences between you and your neighbour, there could be numerous causes, from a different quality in the line to they taking a different route (e-side) from the cabinet to the exchange.
Do both lines report similar attenuation and SNRM?
Is your phone line quiet?  Dial 17070 option 2.  Do it frequently and keep an ear on phone call quality.
If there is an intermittent bad joint on the line (frequently the cause if issues like this) the best that can be said is it was not detectable on the day the engineer called.
It would be useful to get router stats installed and monitoring SNRM 24x7 to rule out REIN.
tactilis
Dabbler
Posts: 14
Registered: ‎03-01-2013

Re: Progressively degrading ADSL download speed

Quote from: Cruise85
Your line is currently running above the estimate given to us by Openreach, and as such does not fall below their fault parameters.
I have however requested that your line be reset to see if this will have any positive impact on your connection.

Thank you Matt.
However, the point is not just that my line is worse than my neighbour's but that mine used to be much better than it is now. It has degraded over the past 18 months as can clearly be seen in the graph attached to my original post.
The line reset you requested has occured but has made no difference to the sync speed.
Quote from: Townman
The line might be within BT's very conservative estimates, but the synch speed is well shy of what might be expected on a 50dB attenuated line.

Indeed.
Quote from: Townman
Do both lines report similar attenuation and SNRM?

I now have my neighbour's TG582n stats. The attached PDF shows a side by side comparison of my router stats with my neighbour's, with the major differences highlighted.
His attenuation is actually slightly higher than mine!
My SNRM is significantly higher.
I note that my DSL Type is G.992.3 (ADSL2) and his is G.992.5 (ADSL2+). Why is this? Is this significant?
He has many more FEC, CRC and HEC errors than me and yet retains a solid connection at a much higher speed.

Quote from: Townman
Is your phone line quiet?  Dial 17070 option 2.  Do it frequently and keep an ear on phone call quality.

It seems to be quiet and call quality is good. I'll monitor this.
Quote from: Townman
If there is an intermittent bad joint on the line (frequently the cause if issues like this) the best that can be said is it was not detectable on the day the engineer called.

No engineer has been involved thus far.
Quote from: Townman
It would be useful to get router stats installed and monitoring SNRM 24x7 to rule out REIN.

Thanks. Will do.
Aled
Dabbler
Posts: 20
Registered: ‎24-07-2014

Re: Progressively degrading ADSL download speed

Hi tactilis,
You make a compelling case!
I've raised <a href="https://www.plus.net/wizard/?p=view_question&id=93182958">Ticket: 93182958</a> on your account and will do a little more digging for you when I'm in tomorrow. I also want to have a look at what happened after Matt's reset as it's a little odd that it went straight back to where it was - it may not have gone through properly.
Thanks,
Aled
Community Veteran
Posts: 5,223
Thanks: 494
Fixes: 22
Registered: ‎10-06-2010

Re: Progressively degrading ADSL download speed

It's perfectly expected that a DLM reset here will achieve nothing. The SNR margin isn't particularly high so that's not holding back the speed. Of course the plusnet staff should be able to see all the DLM data so might have more insight. Or perhaps they should read the ccSNR_Best_Practice_Guide.
I've always thought the BTWholesale speed estimate is partly based on the line's current performance - a long time ago it used to amusingly tell me that I couldn't get broadband (that was before I disconnected the bell wires). Isn't there the Fault Threshold Rate that has more significance for acceptance of speed faults?
Mayfly
Pro
Posts: 1,227
Thanks: 135
Fixes: 1
Registered: ‎04-06-2009

Re: Progressively degrading ADSL download speed

I dare say there could be a number of reasons but I had the same symptoms 5 years ago. Gradual decay of speed - PN would reset, alls well for a week or two then degrade again. After 2 mths  of increase/decrease with no obvious fault after going through the fault checker BT came and changed my master socket. No problems since.
Cruise85
Grafter
Posts: 105
Registered: ‎05-08-2014

Re: Progressively degrading ADSL download speed

Hi all
@Tactilis  I can see that Aled has taken a bit of a personal ownership on this one to try and get to the bottom of the issue
He's in the office this afternoon so I'll ask him to pick it up then. In regards to the Line reset, if this hasn't helped then it may need to looked into further and if needed it may require a similar outcome to Mayfly , where we arrange an engineer to attend
I will let Aled pick this up when he gets in, as I don't want to be treading on his toes if he's dealing with it.
Regards
Matt
Community Veteran
Posts: 19,102
Thanks: 443
Fixes: 21
Registered: ‎31-08-2007

Re: Progressively degrading ADSL download speed

Hi tactilis,
as I started reading your thread, my thoughts turned to "internal wiring" and I see ejs also picked upon this possibility (mention of the bellwire in the context of BT speed estimates - quite correctly).
Well done for the pdf comparison, that immediately led me to a couple more thoughts, so a few questions to follow and checks for you to do.
But first, just a quick mention of Routerstats, I would start with Routerstats Lite as it's Plug and Play without complex setup problems and only go to the full RouterStats if the situation merits it. (Download the zipped versions and install in your root directory - not Program Files)
Ok, Quiet Line Test already mentioned - keep an ear on it. It's also probable that your line is speed banded - likely due to drops/reboots and errors, but whether the line reset actually occurred and removed any banding will need CRT to check.
Whether or not it has, resolving an further issues/causes of the low speed would be best before any further reset action on the line is taken. ejs rightly mentioned the FTR. I've seen cases where lines have been fully reset under "faulty" conditions resulting in a lower FTR and hence defeating the whole object of the FTR in the first place.
OK, questions and checks.
Do you have a Master Socket like the one on the left?
Do you have any extension phone sockets, and where are you currently plugged in?
Do all your Microfilters look like this?
Are you using any extension leads either between a socket and filter, or between a filter and the Modem/Router?
If you have extension sockets, can you have a look at the wiring behind one of them (not the master or the one you have the Modem/Router connected to at this time) and tell us the colour of the wires and terminal numbers they are connected to?
In future, if you wish do do anything involving loss of sync (even a reboot situation), use the following Disconnect method -
Log in to the Modem/Router, in the Internet box, click Disconnect to drop the PPP Internet session (this is not the sync), wait about a minute and then power down the Modem/Router. After about another minute you can unplug it from the line.
Do whatever is needed, but stay offline for at least 10 minutes. When you re-connect and power up, Login to the Modem/Router and click Connect to establish a new PPP session.
Don't do this more than 5 times in an hour, then leave it for the rest of the day. This method is to help stop the Exchange DLM from thinking your sync loss was a dropped connection.
(Anyone with a modem/router that doesn't have an interface for you to drop the PPP session, should just pull the power plug and wait a minute or two before unplugging from the line).
One further point, especially applicable to long lines, you will get very small differences in sync speed every time you sync, so just because you get a marginally better sync speed in one situation, it doesn't necessarily mean that situation is better than another situation.
PS. You can do a Disconnect & Connect (without a power down) to Gateway hop.
HTH, I'll keep an eye open for your answers.
Edit: Do you have a (any) spare filters?
Aled
Dabbler
Posts: 20
Registered: ‎24-07-2014

Re: Progressively degrading ADSL download speed

Hi tactilis,
As I suspected, the reset Matt placed failed so I placed another one this afternoon. There was a banding on the line so your synch has jumped straight up to 5.6mbps and I've spoken to BT Wholesale who say that your line rate will increase later this afternoon. You can re-establish the connection this evening and should connect at a higher rate.
I'll keep my ticket open, and will have a look at you connection on Monday, but let us know how you get on.
Thanks,
Aled
tactilis
Dabbler
Posts: 14
Registered: ‎03-01-2013

Re: Progressively degrading ADSL download speed

Hi Aled (and Matt for your earlier involvement)
Thank you for invistigating my low line speed. After the resets today (there appeared to be two about 15 minutes apart) the sync speed has, as you say, jumped to 5.6Mbps. The TBB speedtester now gives 4.71Mbps http://www.thinkbroadband.com/speedtest/results.html?id=141356372625687586132
My stats are now:

[tt]Uptime: 0 days, 1:34:33
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 440 / 5.691
Data Transferred (Sent/Received) [MB/GB]: 812,45 / 1,99
Output Power (Up/Down) [dBm]: 12,7 / 0,0
Line Attenuation (Up/Down) [dB]: 29,8 / 53,0
SN Margin (Up/Down) [dB]: 17,4 / 6,1
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 26 / 0
Loss of Signal (Local/Remote): 5 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 315 / 0
FEC Errors (Up/Down): 0 / 4.510
CRC Errors (Up/Down): 0 / 4
HEC Errors (Up/Down): 0 / 3[/tt]
I am very happy with the improvement in download speed (assuming it persists). I do notice however that my neighbour has an upload sync speed of 1,012kbps vs. my 440kbps and that this is reflected in his higher 0.8Mbps TBB speed test result. For my education please, what determines the upload sync speed and is there a tradeoff that can be made between download and upload speeds?
Thank you Anotherone (and the other people who replied) for your investigation suggestions. I now have Routerstats running 24x7 and will monitor the line to see whether it again degrades over time. Note that I used the wrong terminology in describing my master socket as an NTE5. From the info you have provided I see it is actually an ADSL Faceplate, hence no microfilters are used on the extension sockets.
Quote from: Anotherone
In future, if you wish do do anything involving loss of sync (even a reboot situation), use the following Disconnect method...

All noted. Thank you.

LukeS
Grafter
Posts: 203
Registered: ‎09-05-2014

Re: Progressively degrading ADSL download speed

Hi tactilis,
When your order was placed it's likely that a 448Kps upstream cap will have been selected. I've now placed an order to remove it and it should complete on Monday.
Superuser
Superuser
Posts: 13,043
Thanks: 4,332
Fixes: 26
Registered: ‎22-08-2007

Re: Progressively degrading ADSL download speed

Quote from: tactilis
I do notice however that my neighbour has an upload sync speed of 1,012kbps vs. my 440kbps and that this is reflected in his higher 0.8Mbps TBB speed test result. For my education please, what determines the upload sync speed and is there a tradeoff that can be made between download and upload speeds?

Hi tactills,
Good to see that you have attained some level of improvement - I hope it stays - though running routerstats will inform of what is happening with the SNRM, thereby indicating is there is a reason for the repeated fall off in speeds.
To answer your specific question - depending on how the line is configured through BT Wholesale's ordering system (think of something with sharp edges which cuts the fingers of users - which has US 440kbps set as the default) determines what US you end up with.  Sadly when making manual changes to user's lines it is all too easy to forget to change the US.
On 21CN there is no trade-off between US and DS when uncapping the US.
Kevin
Community Veteran
Posts: 19,102
Thanks: 443
Fixes: 21
Registered: ‎31-08-2007

Re: Progressively degrading ADSL download speed

There is a trade-off between upstream and downstream on the Annex M variant, but this is not available on Residential Plusnet Products. Only a few specialist providers offer Annex M for residential customers.
Aled
Dabbler
Posts: 20
Registered: ‎24-07-2014

Re: Progressively degrading ADSL download speed

Hi tactilis,
Your connection is looking good and has maintained speed and connection over the weekend. Luke's order is due to complete by tomorrow morning, so let us know how you get on.
Aled