Gentlefolk,
Thank you all for your very valuable replies.
The first point I was trying to highlight is that for those unaware on poorly performing asymmetric services, the lock-up result of heavy upload usage with e.g. cloud computing facilities, is very baffling and believing all difficulties emanate with the network infrastructure was quite definitely wrong in this case.
Isolating the real cause takes super-human effort and dogged persistence particularly with BT Retail call centres.
This person is highly mobile from Yorkshire to London to Taunton so a cloud solution is the most convenient method and the end user is now aware of the pitfalls.
Once the problem was understood it was then easier to discover a solution but care is needed if you select another work-around which just hides but does not cure the problem.
I agree the band plan on difficult lines is seriously skewed towards download when having some user-configurable compromise would be a far better solution.
In this case it was an ECI Cabinet on a noisy line of around 2 km and where, annoyingly, the end user across the road obtains over 22 Mbps download sync speed.
Here are the pbParams and part of the line status from the unlocked Huawei HG612 modem where we expected and observed a very big "hole" in the download bit loading graph.
Max: Upstream rate = 479 Kbps, Downstream rate = 19548 Kbps
Bearer: 0, Upstream rate = 495 Kbps, Downstream rate = 14999 Kbps
Discovery Phase (Initial) Band Plan
US: (6,31) (882,1193) (1984,2770)
DS: (33,857) (1218,1959) (2795,4083)
Medley Phase (Final) Band Plan
US: (6,31)
DS: (67,770)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 479 kbps 19548 kbps
Actual Aggregate Tx Power: 5.2 dBm 5.2 dBm
=====================================================================================
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 8.3 67.4 65.6 N/A N/A 28.5 N/A N/A
Signal Attenuation(dB): 8.2 N/A N/A N/A N/A 37.3 N/A N/A
SNR Margin(dB): 5.2 N/A N/A N/A N/A 7.4 N/A N/A
TX Power(dBm): 5.2 N/A N/A N/A N/A 10.7 N/A N/A
# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 488 Kbps, Downstream rate = 19548 Kbps
Bearer: 0, Upstream rate = 495 Kbps, Downstream rate = 14999 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 7.4 5.6
Attn(dB): 28.5 0.0
Pwr(dBm): 5.2 5.2
VDSL2 framing
Bearer 0
MSGc: 42 33
B: 31 82
M: 1 1
T: 64 4
R: 10 16
S: 0.0677 5.3333
L: 4960 153
D: 481 7
I: 42 102
N: 42 102
Finally I am aware of persisting with voice calls but there is often some value in recording a chat part of which is shown below:-
Raja Bordoloi: Hello. I'm Raja Bordoloi.Thanks for that information, I'll check it and get back to you in a moment.
Mr FRUSTRATED: Hello Raja Bordoloi
Raja Bordoloi: Hello Mr FRUSTRATED
Mr FRUSTRATED: I am Walter Willcox helping (remotely) Mr FRUSTRATED who can't get a reliable broadband connection
Raja Bordoloi: I am sorry to hear about the issue you are facing with your broadband connection . I will try my best to help you today.
Raja Bordoloi: Before that Can you just confirm a few bits of information so I can look into your account please?
• Are you the account holder?
• Your full name?
• Your telephone number?
• Your address and postcode?
Mr FRUSTRATED: No I am NOT the account holder as I have just explained. My name is Walter G M Willcox acting with authority for Mr FRUSTRATED on 01xxxxxxxxx BT A/c No. GBxxxxxxxx at yyyy yyyy yyyy TA4 1AN.
Raja Bordoloi: Thanks for that information.