Seeking Diagnosis: ADSL Max: Automatic Reset of Hu...

Question

I’m hoping that the forum can suggest a diagnosis for an intermittent problem with my BT broadband link. I’ve been told in the past that my link uses ADSL Max. The problem has occurred before, though not for a couple of months, and not since an NTE5 and service-specific face plate were installed. I previously posted about this under the title “BT Hub3 - What Exactly Does 'Connection time' Mean?”.
The problem is that the Hub (specifically a Hub 3) performed an automatic reset (after the connection had been stable for almost 25 days), and on completion of the reset the upstream bit rate had fallen to a mere 160 kbit/s. The downstream bit rate had also fallen, but only slightly, and its value remained perfectly acceptable given the length of my phone line.
I’ve pasted below some statistics that I took from the hub manager, together with the date and time of their retrieval. Clearly the problem is correlated with, and probably caused by, a decline in the Noise Margin Up figure from 21.0 dB to 5.0 dB, and I’m interested in knowing whether this is symptomatic of a fault in BT’s network, or of any other obvious cause. I was actually talking on my phone line when the reset occurred, and I was alerted to it by crackling on the line.
Having identified the reduction in upstream bit rate I recovered the situation by unplugging the broadband cable and then plugging it in again a few moments later. I suspect that had I not done this the upstream bit rate would still be far too low. It is reasonable to expect that a low upstream bit rate would be corrected automatically, but my past experience is that this does not happen, and I’d be interested in knowing whether dynamic line management focuses exclusively on the downstream bit rate.
Thanks in anticipation.
170513 12:40
Connection time: 24 days, 19:50:17
Downstream 3,872 Kbps
Upstream 448 Kbps
Type: PPPoA
Modulation: G.992.1 Annex A
Latency: Fast
Noise Margin (Down/Up): 3.6 dB / 21.0 dB
Line attenuation (Down/Up): 53.0 dB / 31.5 dB
Output power (Down/Up): 19.3 dBm / 12.6 dBm
180513 14:23
Connection time: 0 day, 18:18:58
Downstream 3,616 Kbps
Upstream 160 Kbps
Type: PPPoA
Modulation: G.992.1 Annex A
Latency: Fast
Noise Margin (Down/Up): 6.0 dB / 5.0 dB
Line attenuation (Down/Up): 53.5 dB / 31.5 dB
Output power (Down/Up): 19.1 dBm / 12.1 dBm
180513 14:34
Connection time: 0 day, 00:01:10
Downstream 3,616 Kbps
Upstream 448 Kbps
Type: PPPoA
Modulation: G.992.1 Annex A
Latency: Fast
Noise Margin (Down/Up): 6.1 dB / 19.0 dB
Line attenuation (Down/Up): 53.0 dB / 31.5 dB
Output power (Down/Up): 18.8 dBm / 12.7 dBm
190513 09:22
Connection time: 0 day, 18:49:53
Downstream 3,616 Kbps
Upstream 448 Kbps
Type: PPPoA
Modulation: G.992.1 Annex A
Latency: Fast
Noise Margin (Down/Up): 5.4 dB / 19.0 dB
Line attenuation (Down/Up): 53.0 dB / 31.5 dB
Output power (Down/Up): 19.2 dBm / 12.7 dBm

Answer 1

Thanks.
Unfortunately, in order to monitor what is happening, I have been capturing screenshots of the Hub Manager connection stats daily, but have never clicked on 'More Details'. I'll have to start doing this, and - I fear - just hope that the problem recurs so that I can obtain more evidence