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Sudden change in achievable download speeds

dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Sudden change in achievable download speeds

Hello,

Can anyone make any useful suggestions based on the below: 

 

Plusnet website suggests: 

* Estimated line speed:80Mb (This may vary between 72Mb and 80Mb) - Checked on 2017-10-24 09:36:35

* Current line speed:65 Mb

 

Modem tells me: 

Status: UP
Line State: showtime_tc_sync [0x801]
Line Mode: G.993.2 (VDSL2)
Annex: B
Profile: 17a
Data Rate: 68.756 Mb/s / 20.000 Mb/s
Max. Attainable Data Rate (ATTNDR): 79.385 Mb/s / 22.082 Mb/s
Latency: 8.0 ms / 0.0 ms
Line Attenuation (LATN): 16.3 dB / 16.9 dB
Signal Attenuation (SATN): 16.3 dB / 16.7 dB
Noise Margin (SNR): 6 dB / 6.2 dB
Aggregate Transmit Power(ACTATP): 6 dB / 6.2 dB
Forward Error Correction Seconds (FECS): 103 / 88949
Errored seconds (ES): 0 / 2729
Severely Errored Seconds (SES): 0 / 39
Loss of Signal Seconds (LOSS): 0 / 202
Unavailable Seconds (UAS): 35 / 35
Header Error Code Errors (HEC): 0 / 0
Non Pre-emtive CRC errors (CRC_P): 0 / 0
Pre-emtive CRC errors (CRCP_P): 0 / 0
Line Uptime: 22m 20s
ATU-C System Vendor ID: Infineon 178.6
Power Management Mode: L0 - Synchronized

 

BT wholesale speedtest results range from 60Mbps to 35Mbps when run multiple times

 

My own periodic tests show that until about 11 days ago I was reliably getting the high 60s down, and about 20 up. This then suddenly changed to 50s down (up still steady at around 20) :

http://bbarker.duckdns.org/speed/index.php?interval=720

 

I have a ticket open, but nobody seems quite sure what is going on...suggestions welcome :-)  There seems to be a massive gap between "data rate" and "maximum data rate" - but I'm not sure on what metrics the latter is based...

12 REPLIES
dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Re: Sudden change in achievable download speeds

Another sustained speed drop to ~45Mbps down, whilst other router stats remain unchanged...

 

I managed to speak with phone support today, who were very polite, but were only able to suggest sending another OpenReach technician...

 

The first one found nothing wrong, and the line stats seem stable....not sure why the second one will do any better....

 

Hmmm......

 

 

 

 

 

 

Superuser
Superuser
Posts: 3,082
Thanks: 1,513
Fixes: 9
Registered: 10-04-2007

Re: Sudden change in achievable download speeds

Could be similar to a number of other capacity problems under investigation by PN and BT QA.  I'll tag @Gandalf to take a look at your case.

 

Superuser citation

This topic has been cited by one of the Superusers; the purpose of which is to provide a note for information which might help to focus continued discussion (but might not result in a staff response).


 

Plusnet Help Team
Plusnet Help Team
Posts: 7,163
Thanks: 2,029
Fixes: 359
Registered: 21-04-2017

Re: Sudden change in achievable download speeds

Welcome to the community forums @dbrb22

I've flagged this with the relevant people to further investigate. We'll let you know when we've got more info.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Re: Sudden change in achievable download speeds

Thanks. Fingers crossed....
The last open reach technician seemed to think the line was ok, and the changes (two now) seem quite sudden when they occur....

Is there still value in the planned visit next week? I have to be at home, which is tricky, so if the issue lies elsewhere I may try to cancel it....
Plusnet Help Team
Plusnet Help Team
Posts: 7,163
Thanks: 2,029
Fixes: 359
Registered: 21-04-2017

Re: Sudden change in achievable download speeds

At this stage, if another engineer visit will cause inconvenience to you I'm happy to cancel it?

Once we've investigated this*, if the problem still exists we can always rebook it in.

 

*I've included your account as part of a bigger picture we're looking at with regards to VLAN issues.

We should hopefully have more info next week.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Re: Sudden change in achievable download speeds

Thanks - yes, can we cancel for now?

Cheers,

Ben
Plusnet Help Team
Plusnet Help Team
Posts: 7,163
Thanks: 2,029
Fixes: 359
Registered: 21-04-2017

Re: Sudden change in achievable download speeds

Done. No problems Ben. I'll pick this back up Tuesday, as that'd be the earliest we'd have some form of update.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Re: Sudden change in achievable download speeds

Interesting - had a call from OpenReach today, very helpful guy. I'm not syncing at 76Mbps again - though my achievable download speeds are yet to shift from a fairly stable ~45....

Plusnet Help Team
Plusnet Help Team
Posts: 7,163
Thanks: 2,029
Fixes: 359
Registered: 21-04-2017

Re: Sudden change in achievable download speeds

It looks like we changed the speed profile on your account last night which would've likely been limiting your throughput.

What are your speeds like since then?

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Re: Sudden change in achievable download speeds

Good and bad :-)

 

My sync speed has remained stable at a respectable ~78Mbps down

My achievable speeds from scheduled test runs vary from ~72 down during the day to ~40 down in the evening

 

Interestingly, when this happens (see link in original post) it isn't a gradual tail off, but a sudden change...

Capacity issues? 

Superuser
Superuser
Posts: 3,082
Thanks: 1,513
Fixes: 9
Registered: 10-04-2007

Re: Sudden change in achievable download speeds

@MatthewWheeler  Can you pick this case up as part of @Gandalf ongoing investigations please.

dbrb22
Hooked
Posts: 7
Registered: 23-01-2018

Re: Sudden change in achievable download speeds

Not sure if someone has done something... but things have, for the moment, become a lot more stable:

http://bbarker.duckdns.org/speed/index.php?interval=168

download.png