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Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Jcdek
Grafter
Posts: 60
Thanks: 8
Registered: ‎07-09-2018

Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

I have some questions I hope somebody can help with on my Fibre 55/10.

1, I was under the impression that FTTC lines don't have a 10 day training period and that it only applied to ADSL line. The BT engineer visited today and told me I'd have to wait 10 days for th training period to end. Is this right?

2, I have had fibre for a few years now and been with Plusnet for over 2 now. I have had a rock solid connection for over a year now until suddenly out of the blue this week I started getting disconnects at various times of the day.
I called Plusnet who looked at the data and requested a BT engineer to visit. The BT engineer came today. He couldn't find any fault, couldn't explain what could have happened other than to say it may have been a glitch but after changing my faceplate and then performing a hard reset at the exchange I synced nearly 10mb less than I have been for over a year.
He assured me that I'd need to wait the 10 days training period and that the sync rate would almost certainly increase back to where I was originally (just under 49mb).
Currently my sync at 41mb with an SNR of 6db but I thought that the DLM would start at the max and then if needed reduce the sync to maintain the SNR. I said to the engineer that if the sync is at 41mb at an SNR of 6 (as set by the exchange) then surely my sync won't go up but he assured me it would. Is this correct?
The engineer called BT India to get them to perform the hard reset and also they discussed something about interleaving/fast path and were being asked if they wanted High or Low.....

3, Do I need to avoid reboots on the router? My line stats suggest I could sync higher than I am currently.

I hope somebody can enlighten me and if possible even better if a Plusnet expert could have a look at some of my settings.

Thanks in advance.

Moderator's note by Dick (Strat): Post released from Spam Filter.

23 REPLIES 23
Jcdek
Grafter
Posts: 60
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Thank you Strat (Mod). Thumbs_Up

Jcdek
Grafter
Posts: 60
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

BUMP.

Can anyone help?

I've just had another drop out. SNR solid until 7.04am then suddenly started varying from between 4 and 5.5 then dropped out. Resynced at 12mb (from 40+)

Gandalf
Community Gaffer
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Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Hi there and sorry for the delayed response.

Firstly welcome to our community forums.

1, I was under the impression that FTTC lines don't have a 10 day training period and that it only applied to ADSL line. The BT engineer visited today and told me I'd have to wait 10 days for th training period to end. Is this right?

 

While there isn't a training period for FTTC like there is on ADSL, after a line is reset or a new FTTC service is provisioned, it generally takes around 48 to 72 hours for the dynamic line management(DLM) software at the cabinet to work out the best line profile for your connection.

 

2, I have had fibre for a few years now and been with Plusnet for over 2 now. I have had a rock solid connection for over a year now until suddenly out of the blue this week I started getting disconnects at various times of the day.
I called Plusnet who looked at the data and requested a BT engineer to visit. The BT engineer came today. He couldn't find any fault, couldn't explain what could have happened other than to say it may have been a glitch but after changing my faceplate and then performing a hard reset at the exchange I synced nearly 10mb less than I have been for over a year.
He assured me that I'd need to wait the 10 days training period and that the sync rate would almost certainly increase back to where I was originally (just under 49mb).
Currently my sync at 41mb with an SNR of 6db but I thought that the DLM would start at the max and then if needed reduce the sync to maintain the SNR. I said to the engineer that if the sync is at 41mb at an SNR of 6 (as set by the exchange) then surely my sync won't go up but he assured me it would. Is this correct?
The engineer called BT India to get them to perform the hard reset and also they discussed something about interleaving/fast path and were being asked if they wanted High or Low.....

Sorry to hear that your speeds have dropped. 

From looking at the tests we did before the engineer visit, your sync rate was 19.1mbps and there wasn't any banding on the line either "0.128M-55M Downstream 3dB, Retransmission Low - 0.128M-10M Upstream, Error Protection Off"

After the engineer visit, your sync rate as you know is now higher at 44.1mbps and the banding is slightly different since the DLM reset they requested:  0.128M-55M Downstream 6dB, Interleaving Low - 0.128M-10M Upstream, Error Protection Off

The only difference is that you've gone from a 3dB profile to a 6dB one which I'd have expected that meant that your speeds would drop further, as a sync rate on 3dB is generally higher than on 6dB.

Interleaving(and retransmission) is a form of error correction which can help keep a connection stable, but it can also come at a price of sacrificing speed.

It sounds like there's either still an underlying intermittent issue out there, or changing the faceplate of your master socket had fixed the problem.

 

3, Do I need to avoid reboots on the router? My line stats suggest I could sync higher than I am currently.

I'd recommend avoiding rebooting your router frequently because a drop now and again is unlikely to trigger DLM to apply a negative change to your speeds/line. If you're interested in knowing more I'd have a read of the guides Here.

 

Assuming the drops since the engineer visit are due to rebooting the router, unfortunately as you're sync'ing within the estimates of your line of between 35mbps to 52.1mbps, and your connection seems to be stable so far, it's unlikely our suppliers will investigate this further.

image153650112048

 

However if your connection dropped by itself yesterday then I'd be inclined to look at arranging another engineer visit for further investigation. Feel free to let me know how it goes.

 

I hope somebody can enlighten me

I hope this helps.

 

and if possible even better if a Plusnet expert could have a look at some of my settings.

Here's a full copy of the KBD(Knowledge Based Diagnostics) test results I've run just now:

GEA Test Detail
Circuit ID NA Service ID BBEU00000000
 
 
Test Outcome Pass
Test Outcome Code GTC_FTTC_SERVICE_0000
Description GEA service test completed and no fault found .
Main Fault Location OK
Sync Status In Sync
Downstream Speed 44.1 Mbps
Upstream Speed 10.0 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 749.8
Upstream Rate Assessment Very Good
Downstream Rate Assessment Good
Interference Pattern Regular Interference Observed Daily
Service Impact No Impact Observed
Interference Duration Longest Occurrence From 14:15 to 17:00
Interference Location Customer Premise
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-55M Downstream 6dB, Interleaving Low - 0.128M-10M Upstream, Error Protection Off
Time Stamp 2018-09-07T14:30:00
Parameters MIN MAX AVG
Down Stream Line Rate 12.1 Mbps 44.1 Mbps 37.7 Mbps
Up Stream Line Rate 9.9 Mbps 9.9 Mbps 9.9 Mbps
Up Time 790.0 Sec 900.0 Sec 898.4 Sec
Retrains 0.0 5.0 0.0
Current and Last 15 Minute Bin Performance
Parameters Last Traffic Count(Upto 15 mins) Current Traffic Count(Upto 15 mins)
Start Time Stamp 2018-09-09T13:31:54Z 2018-09-09T13:46:54Z
Ingress Code Violation 1 0
Egress Code Violation 0 0
Errored Seconds 0 0
Severely Errored Seconds 0 0
Unavailable Seconds 0 0

 

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Plusnet
Jcdek
Grafter
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Many thanks for the reply.

In answer to your question the drop outs since the visit were not as a result of a router reboot.

Monitoring the line myself I see I have sporadic downstream SNR drops and this leads to the DSL connection dropping.

Can you please tell me what this information means form the KBD report?

Interference Duration Longest Occurrence From 14:15 to 17:00
Interference Location Customer Premise
Jcdek
Grafter
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Just to add, yesterday sync drop resulted in a resync at 12mb.

Just to clarify, I have had a stable connection at 46mb for about 1 1/2 years now (with Plusnet) with a constant SNR of 6db on both upstream and downstream. Until this week when suddenly the SNR drops started and I get disconnects.

Any idea what could cause the downstream alone SNR to suddenly drop from 6 to a point the sync drops?

Terranova667
Pro
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Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Interference can be a cause of the SNR to drop so low that a sync is triggered, If it is intereference it can be tough to nail down where the interference is especially if the interference is out side your home and casued by some one / something in your area.  

Jcdek
Grafter
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Thanks for the reply.

 

Any suggestions as to what to do about it?

 

Terranova667
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Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Well the first thing would be to determine whether the problem is down to interference or a fault, if plsunet / openreach rule out a fault being the issue then you can start to deal with interference. 

Jcdek
Grafter
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

@Gandalf

Could you please run some more tests and see if anything looks any different?
Can you also please tell me if possible what IP profile my line is set to?

I had a drop again just after midnight this morning and resynced at 14mb (from 44mb).
Downstream SNR dropped to zero and line disconnected. Currently SNR downstream is 17.5db whilst upstream remains at 8.

 

Jcdek
Grafter
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Thanks again for the reply.

Can you please tell me, would interference be only likely to affect my downstream as opposed to both upstream and downstream?

As it appears it is only my downstream that is dropping the line.

MasterOfReality
Plusnet Alumni (retired)
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Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Hi @Jcdek 

 

I've ran some more tests on our circuit.

 

For starters, here is you Visual RADIUS log for the last 7 days; 

 

 

I can see the drops you mention.  

 

A fresh KBD shows that your Sync has dropped - as you also pointed out.

 

Test OutcomePass

Test Outcome CodeGTC_FTTC_SERVICE_0000

DescriptionGEA service test completed and no fault found .

Main Fault LocationOK

Sync StatusIn Sync

Downstream Speed15.9 Mbps

Upstream Speed10.0 Mbps

Appointment RequiredN

Fault Report AdvisedN

NTE Power StatusPowerOn

Voice Line Test ResultPass

Bridge TapNot Detected

Repetitive Electrical Impulse NoiseNot Detected

Estimated Line Length In Metres749.8

Upstream Rate AssessmentVery Good

Downstream Rate AssessmentGood

Interference PatternRegular Interference Observed Daily

Service ImpactNo Impact Observed

Interference Duration Longest OccurrenceFrom 12:00 to 19:45

Interference LocationCustomer Premise

Home Wiring ProblemNot Detected

Downstream Policing Discard Rate0.0

Customer Traffic LevelUpstream and Downstream Traffic Detected

TechnologyVDSL

Profile Name0.128M-55M Downstream 6dB, Interleaving Low - 0.128M-10M Upstream, Error Protection Off

 

The same test also states "Problem Explanation: [NF507] No issues have been identified in the BTW network." 

 

As you can see from the above, you are syncing at about 15 d/l and 10 u/l - so you are correct in saying that your upload is not being affected.

 

You are syncing below your IP Profile (0.128M-55M), so it's safe to say that you are not being affected by any form of banding issue - therefore, we need to establish what is causing this reduction in sync. Can I please ask, are you currently set up in your Test Socket? If not, could you please do this for us, a guide on how to locate your test socket can be found here

 

Thanks,

MoR

Jcdek
Grafter
Posts: 60
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Thanks MoR for the reply,

I am not currently in the test socket however, BT when visited the other day replaced the faceplate and the home router is plugged directly into the master socket. There are no extensions in the house.

 

If you feel it absolutely necessary then I can remove the new faceplate to plug the router into the test socket. Please confirm.

 

Thanks again. Thumbs_Up

Waz
Plusnet Alumni (retired)
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Posts: 42
Registered: ‎18-06-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Hi @Jcdek,

 

Placing the connection into the test socket will help us identify where the problem rests. Please progress with removing the face plate and running the connection through the test socket. Completing this will help us validate the problem is not with your internal wiring or equipment if we were to progress with the booking of an engineer. Let us know how you get on.

Jcdek
Grafter
Posts: 60
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Registered: ‎07-09-2018

Re: Fibre Sudden strange disconnects, BT engineer visit, 10 day training period....

Thanks for the reply. @Waz

I have just plugged the router into the test socket. This does mean however I currently have no phone while this is happening so I would really appreciate an update as to when I can reconnect the phone. I have a poor reception here on mobile.