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Massive speed fault

Justinian
Grafter
Posts: 59
Thanks: 8
Registered: 02-07-2013

Massive speed fault

Helo guys,

 

I am extremely curios how this is happening.

Most likely to some transient noise (error rate) which has long time disappeared I got the DLM setting the SNRM target to 13db as you can see bellow:

 

                Down            Up

SNR (dB):        13.9            6.2

Attn(dB):        19.4            0.0

Pwr(dBm):        12.7            7.4

 

But my biggest surprise came when I've actually ran a diagnostic to get the ACTUAL SNR on all the channels and looked over the noise distribution. While some of the channels are close to 6db but still under 6, there is not a single channel going over with the vast rest of the channels being close or even lower than 3db, nothing related to that 13db snrm target. (file attached)

 

As this has been going for some time please:

- set my SNRM target to 6 (fixed) forever and ignoring FEC/SES and whatever other error statistics (obviously misconfigured)

- set my inteleave to on ( to mitigate some of the eventual error frames)

While my gaming days are long gone I believe that interleave on, tcp error correction, VPN error correction are more than enough to deal with packet errors.

 

Max:    Upstream rate = 15030 Kbps, Downstream rate = 76256 Kbps

Bearer: 0, Upstream rate = 15060 Kbps, Downstream rate = 48998 Kbps

Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps

 

48Mbs link level speed instead of 76Mbs

while the true speed is:

 

speedtest-cli/speedtest.py 

Retrieving speedtest.net configuration...

Testing from PlusNet (xxxxxxx)...

Retrieving speedtest.net server list...

Selecting best server based on ping...

Hosted by Warwicknet Ltd. (Coventry) [45.57 km]: 19.495 ms

Testing download speed................................................................................

Download: 42.10 Mbit/s

Testing upload speed................................................................................................

Upload: 14.21 Mbit/s

 

Please correct these as soon as possible. I am happy to have an engineer come over if it is needed, however because the noise is transient I am pretty sure that the cause would be difficult to find.

Edit: mangle IP address

9 REPLIES
Plusnet Help Team
Plusnet Help Team
Posts: 6,859
Thanks: 1,945
Fixes: 348
Registered: 21-04-2017

Re: Massive speed fault

Hi there

 

We're not able to make any remote adjustments to the DLM on a fibre circuit I'm afraid.


Testing your line, your sync speed is slightly below your estimates...

 

Test Outcome Pass
Test Outcome Code GTC_FTTC_SERVICE_0003
Description No problem found, OAM test is not currently supported on this line.
Main Fault Location OK
Sync Status In Sync
Downstream Speed 46.9 Mbps
Upstream Speed 15.1 Mbps
Appointment Required N
Fault Report Advised N
NTE Power Status PowerOn
Voice Line Test Result Pass
Bridge Tap Not Detected
Radio Frequency Ingress Not Detected
Repetitive Electrical Impulse Noise Not Detected
Cross Talk Not Detected
Estimated Line Length In Metres 573.1
Upstream Rate Assessment Reasonable
Downstream Rate Assessment Reasonable
Interference Pattern Regular Interference Observed Daily
Service Impact No Impact Observed
Interference Duration Longest Occurrence ; 00:00 to 23:45
Interference Location Customer Premise
Interference Observed In Days 14
Home Wiring Problem Not Detected
Downstream Policing Discard Rate 0.0
Customer Traffic Level Upstream and Downstream Traffic Detected
Technology VDSL
Profile Name 0.128M-49M Downstream, Retransmission High - 0.128M-20M Upstream, Error Protection Off

 

Apart from that your connection is stable with a bit of instability around noon...

 

As the sync rate is resting below the estimates, I'd advise going through the checks here and if the problem remains then raise a fault to us here and we'll arrange an engineer visit.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
Justinian
Grafter
Posts: 59
Thanks: 8
Registered: 02-07-2013

Re: Massive speed fault

Thanks Gandalf, I've created the fault: 

#150363729

Plusnet Help Team
Plusnet Help Team
Posts: 6,859
Thanks: 1,945
Fixes: 348
Registered: 21-04-2017

Re: Massive speed fault

Thanks for raising the fault @Justinian

I've updated your fault ticket for you now.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
Browni
Aspiring Hero
Posts: 2,109
Thanks: 704
Fixes: 45
Registered: 02-03-2016

Re: Massive speed fault

Watch for a 'no fault found' charge.

Your line is currently banded at 49Mb hence the slow sync speed and DLM may remove that given time.

I must have been really bad in a previous life. This is my 3rd ISP in a row that uses lithium.
Now you lot are going to suffer because my current ISP doesn't run a forum Cheesy
Plusnet Help Team
Plusnet Help Team
Posts: 6,859
Thanks: 1,945
Fixes: 348
Registered: 21-04-2017

Re: Massive speed fault

Whilst the DLM may adjust the banding/profile, I don't believe this is affecting the sync rate as it is resting a few Mb below the banding.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
Browni
Aspiring Hero
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Registered: 02-03-2016

Re: Massive speed fault

2 Kbps below according to the OP's stats...

eta: hasn't this happened before where the GEA speed is reported as different from the router sync rate?

I must have been really bad in a previous life. This is my 3rd ISP in a row that uses lithium.
Now you lot are going to suffer because my current ISP doesn't run a forum Cheesy
Plusnet Help Team
Plusnet Help Team
Posts: 6,859
Thanks: 1,945
Fixes: 348
Registered: 21-04-2017

Re: Massive speed fault


Browni wrote:

eta: hasn't this happened before where the GEA speed is reported as different from the router sync rate?


I think I recall which thread you may be referring to, and I believe it was proven that the line speed from the GEA test is the actual sync rate. I'm can't remember what checks were done to prove it though. Undecided

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
RealAleMadrid
Seasoned Pro
Posts: 684
Thanks: 253
Fixes: 11
Registered: 07-07-2009

Re: Massive speed fault

Yes I remember seeing that before. The GEA test result knocks a bit of the actual sync speed. The Op should get a considerable increase in speed with the banding removed with the current SNRM at 13.9dB.

@Gandalf I am not convinced that the GEA is reporting the actual sync rate, I seem to recall the reported sync speed is lower if G.Inp (retransmissions) are active. You can't really say that the sync speed in the router stats is wrong, can you?

 

Anyway I need to start a new thread about a fault on my line.Sad

Community Veteran
Posts: 5,081
Thanks: 440
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Registered: 10-06-2010

Re: Massive speed fault


Gandalf wrote:

Browni wrote:

eta: hasn't this happened before where the GEA speed is reported as different from the router sync rate?


I think I recall which thread you may be referring to, and I believe it was proven that the line speed from the GEA test is the actual sync rate. I'm can't remember what checks were done to prove it though. Undecided


It'll be due to the "Retransmission High" profile. The "Downstream Speed 46.9 Mbps" from the test is obviously not the same as the 48,998 kbps from the modem, but the test must be reporting something different by design (probably some G.998.4 related number, possibly the ETR, taking into account the SHINERATIO_RTX).