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[Mark1]

Question:

Is there a fault threshold rate (FTR) applicable to the upstream, and if so how does it work in practice?

Background:

My connection has deteriorated in the last week from approx. 38 down 6.5 up to 35 down 2.6 up as a result of intermittent noise on the line during phone calls (HR Dis fault?). DLM has heavily interleaved and inp-eed downstream and increased noise margin on upstream (by banding?). Should the poor upstream speed alone trigger an automatic fault investigation?

[Chrysalis]

there is no FTR on FTTC, openreach scrapped it.

[Mark1]

there is no FTR on FTTC, openreach scrapped it.

Thank you. That makes it easier for BT!

[Mark1]

Presumably then, the following article is out of date:

http://www.ispreview.co.uk/index.php/2012/12/when-slow-speeds-become-a-fault-on-bts-fttc-superfast-broadband.html

[Mark1]

Apologies for such a basic question: Is the poor QLN in U0 band indicative of a fault? U0 attenuation is 4dB.

[ryant704]

No, the QLN graph is actually very healthy.

Though on your load BitLoading you have very little tones assigned in U1, this is where the problem lies with your connection.

It comes from interference, as you can see you have an INP of 8 on DS. I feel if the DLM applied some INP to the US this would fix the problem. But for your connection to run the best it can you will need an engineer to find and fix the noise source (Interference).

[Mark1]

Looking back through the stats, snr per tone in U1 hasn't changed. I believe DLM has reacted to drop outs and noise bursts through phone use by capping U0 and U1 instead of increasing INP or interleaving, hence the low bit loading.

[ryant704]

The SNR is there agreed but, the amount of bits assigned is not where it should be.

This from the interference and is very likely you line is banded as well.

[Chrysalis]

Presumably then, the following article is out of date:

http://www.ispreview.co.uk/index.php/2012/12/when-slow-speeds-become-a-fault-on-bts-fttc-superfast-broadband.html

The 25% applies but what I mean is it no longer each line has its own FTR rate identified over a 10 day period following installation, thats for adsl service sonly.

[Mark1]

The SNR is there agreed but, the amount of bits assigned is not where it should be.

You've lost me, I'm afraid. I have no idea where the bits should be.

[Mark1]

The 25% applies but what I mean is it no longer each line has its own FTR rate identified over a 10 day period following installation, thats for adsl service sonly.

In the article, Upstream FTR = 22.5% of downstream rate or 2Mbps. Is it still valid?

[ryant704]

Here is what your graph should look like roughly...

You can see my line, then I done a superb photoshop edit to show roughly how your connection should be.

[Mark1]

Many thanks for the explanation. I agree there is some loss to interference, I'm not sure it is recoverable however unless related to the phone fault.

[ryant704]

You have the spare US margin for it to be there, that's why I suggested your line is probably banded.

If you have a phone fault, you need to get that fixed first as that will affect your broadband.