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[Roxy]

In June/July we looked into fibre, and the estimator said we would achieve around 80/20 based on our telephone number. For the next two months we had a long winded FTTC install due to our fibre line being connected to the wrong cabinet. It took  eight engineers, lots of patience by myself and somewhere in the region of forty phone calls, three missed engineer appointments and five days off work.

After all that, unfortunately the speed we received was 42mbps, ten less than I estimated. In fact when the engineer was installing our package, he struggled to get 30mbps down. After two hours of fiddling in the cabinet(and claiming we were installed to a damaged port), he managed to increase it to 42 and then promptly left. Meanwhile next door(as in literally attached housing), they were getting 50 down. We're both on the same cabinet - only fibre customers in the village.

Couple of oddities :


• All engineers that visited our premises and the neighbours, gushed about how good our copper lines were.
• After six days, we both took a hit on our lines. We went from 42mbps sync down to 35 and they went from 50 down to 31. Both our pings rose from about 15ms to 35ms. Meanwhile the maximum data rate to cabinet is never below 44mbps for us and 52mbps for next door.
• The ISP has done multiple line 'checks' for our connections and found some undefined fault(Boost engineers booked for this weekend)
• Both our connections have about 24db line attenuation, yet we're 400m from the cabinet. My math tells me that's about 28-30% cable loss and our attenuation should be more around 19-22.
  

I believe that there's two issues here:

A) Faulty lines between our homes and the cabinet, not enough transmission power in the cabinet and unnecessary crosstalk is causing us to have higher attenuation and subsequently lower maximum rates as well as lower sync rates.
B) Our all-in-one VDSL routers are weak and keep dropping our sync. I suspect now DLM has prematurely gone into overdrive and made stabilising adjustments accordingly.

However as a result of these speed drops, our connections last about a day longer before resetting. In the furthering weeks, our connections have not improved. We still get disconnected at around 3am every few days, and resync at the same lowered speeds.

I've since purchased an ECI OR modem, hoping and praying it will keep the connection stable so DLM can try to repair it over time. We'll see what happens tomorrow with the engineer before I install the OR.

If anyone would like to comment about what I should or shouldn't say, request and demand of the boost engineer, please feel free.



EDIT: Here are our stats currently :

6. Data rate:   7484 / 37686
7. Maximum data rate:   7327 / 42983
8. Noise margin:    5.7/ 6.2
9. Line attenuation:    0.0 / 24.7

[boost]

That's quite some hassle!

You're definitely attached to an ECI cab?

Good luck!

[Black Sheep]

Whereabouts in the UK are you based, Roxy ??

[Roxy]

Hi Black,

We're in East Anglia>Norfolk>Diss>Palgrave area

And in twelve minutes from now, it will be the 5th engineer to not arrive for us. ;sigh; Like all things BT it's going to be another week before we might see another one.

That's quite some hassle!

You're definitely attached to an ECI cab?

Good luck!

I tried looking for it as I know where it should be, but all I could see was the old telecomms cabinet. It may be ECI it may not.

EDIT : Personal note - I'm also annoyed that the Home Hub 5 does not allow me to see any FEC/HEC/CRC errors or notes.

[kitz]

Have you been able to graph and monitor your SNRm?

[Roxy]

The only attention I've given to the SNRm is what the router tells me.

I sometimes get confused between SNR and SNR margin(?) but from my observations, throughout the day times it's settled on 6.0-6.1db for both upstream and downstream. When things get 'noisy' at night, it dips to around 5.7db up and 5.9 down.

EDIT: Just seen this today, worst so far across the board :

6. Data rate:   7484 / 37686
7. Maximum data rate:   7364 / 40163
8. Noise margin:    5.8 / 4.9
9. Line attenuation:    0.0 / 24.7


Finally got through to someone at BT, apparently the engineer did go to the cabinet today and the fault was 'too big for him to handle.' The way the indian woman said it did make me laugh. I retorted with 'what was he doing, fishing?'
Any ways, she ran over to the engineering department - and I believe she meant literally (which makes you wonder, if they're within close physical proximity, how come they never seem to communicate to one another?) - to resetup a new booking for Monday.

See my face now  another afternoon off of work because I want to be here to find out what exactly was going on, how it affected us, what the results were and etcetc.

[kitz]

The SNR Margin (Noise Margin as reported by the HH) can often tell a lot whats happening about your line.

As youre on BT, I assume you are currently using a HomeHub5.. and since you do appear to have some stats, you may be able to get routerstats to work with it

http://vwlowen.co.uk/RouterStatsHub/routerstatshub.htm

[VDSL2User]

@Roxy --- I was one of the initial HH4 testers and I told them way back that the lack
of line stats in terms of FEC, ES, CRC etc would make what could
be a half decent device into one that people want to move away from and reviewers
would mark down as a result.
Did they listen .... well of course not .... BT are bigger than customers
and always know best .... NOT
It would be a simple process as part of a software upgrade to HH4/HH5
to add the missing information as the chipset does create it but somehow
I don't see it happening.
Lets hope the supply of HG612 modems does not totally dry up or we may all
start to loose access to the stats in the future (The Billion 8800NL run in modem mode
is an alternate that may help in such a situation).

Hope you get your fault sorted out when the next engineer turns up with 'bigger tools' .....

[Roxy]

@Roxy --- I was one of the initial HH4 testers and I told them way back that the lack
of line stats in terms of FEC, ES, CRC etc would make what could
be a half decent device into one that people want to move away from and reviewers
would mark down as a result.
Did they listen .... well of course not .... BT are bigger than customers
and always know best .... NOT
It would be a simple process as part of a software upgrade to HH4/HH5
to add the missing information as the chipset does create it but somehow
I don't see it happening.
Lets hope the supply of HG612 modems does not totally dry up or we may all
start to loose access to the stats in the future (The Billion 8800NL run in modem mode
is an alternate that may help in such a situation).

Hope you get your fault sorted out when the next engineer turns up with 'bigger tools' .....

Thank you,

Yes, the more I speak to people about 'proper' routers the more the HH4 and 5 don't look so good as they once did.
Fortunately the engineer that started the job is supposed to be the on finishing. I guess continuity is a good thing in this case?

@Kitz

It does seem to connect and work. The graph is drawing something on each tab, albeit looks to be doing it slowly. Do I icon tray it and let it run all day?

[roseway]

It does seem to connect and work. The graph is drawing something on each tab, albeit looks to be doing it slowly. Do I icon tray it and let it run all day?

Yes, or at least for some hours. The SNR Margin (or Noise margin) graphs take samples at regular intervals and plot a new point for each sample. So it does take some time to get a meaningful graph. In the configuration you can change how frequently it samples, and what period of time is covered by a full page of the graphs.

[Roxy]

It does seem to connect and work. The graph is drawing something on each tab, albeit looks to be doing it slowly. Do I icon tray it and let it run all day?

Yes, or at least for some hours. The SNR Margin (or Noise margin) graphs take samples at regular intervals and plot a new point for each sample. So it does take some time to get a meaningful graph. In the configuration you can change how frequently it samples, and what period of time is covered by a full page of the graphs.

Thanks, I've seen that now, but I didn't get far before ....see attached.
I cannot be certain but the spikes/drop in Noise margin and connection speed happened right as I was trying to access my Linux torrents (http website searches and Bit Torrent client). I connected to my VPN and it resumed service/no slowdown. Probably just BT blocking P2P traffic.

Though curious is the noise margin would suffer just because I was surfing the web?


The transcending issue of my speed /sync drops is hopefully what the engineer will figure out.

[roseway]

I think what you're seeing there is not a series of big drops in the margin and speed, but simply the way routerstats reports the values when it's unable to get a sample of data. This is a known issue with some devices, and probably reflects the fact that the devices sometimes don't refresh their GUI quickly enough.

[Roxy]

I think what you're seeing there is not a series of big drops in the margin and speed, but simply the way routerstats reports the values when it's unable to get a sample of data. This is a known issue with some devices, and probably reflects the fact that the devices sometimes don't refresh their GUI quickly enough.

I tested it again by turning the VPN off and trying to do anything torrent related. Immediately web pages would hang, torrents died off or went really slow and generally the network was sluggish. The home hub stats /router stats went blank for those durations. When they came back, you see as in those graphs, drops in speed and margin. I know there's talk of BT still throttling over weekends at peak times, however last couple weekends I did not have this issue, it's recent as of this week.

See the last big dips, then fairly consistent while VPN is on.


EDIT: As of about ten in the evening, this torrent related behavior has stopped. I'll try it again tomorrow.
EDIT2: This thread isn't over. When I get my ECI modem installed and the cabinet issue is fixed, I hope to report that the OR modem is worth having for stability purposes.

[kitz]

As eric has already mentioned, the drops to 0 are when routerstats is unable to get a sample from the router.  It can happen if the PC is busy.
The HomeHub isnt the best of routers to get stats from but at least it does provide some basics and more importantly the SNRm.  Routerstatshub is about the only tool that will work with it.

What we are more looking for is the type of trend that we see towards the end of your second graph showing that the SNRm is actually moving..  atm its still moving within acceptable parameters, but its usually evenings when most lines will show bigger changes... and why the DLM may be kicking in. 

[Chrysalis]

Sorry for my idiocy but I Am confused by some of the original post.  So please if you can clarify.

Was your speed estimate 80/20? as you stated you was estimated that.
What made you estimate 52? or was that the actual isp estimate?
What do you mean by 'maximum data rate to cabinet'?

Now based on the info I understand.

24db attenuation for FTTC does indeed I reckon suggest around 400m, so it suggests something up with the cabling.

As a comparison on google maps I am about 200m from my cab, openreach support told me my line length is just above 400m (if I remember right I lost the email) and that has my modem reporting overall attenuation of 24db.

Can you post the pbparams that show attenuation for each seperate channel e.g. here is mine

                  VDSL Port Details               Upstream                Downstream
Attainable Net Data Rate:           30899 kbps              73372 kbps
Actual Aggregate Tx Power:             5.9 dBm               13.6 dBm
====================================================================================
        VDSL Band Status                U0              U1              U2     U3               U4              D1              D2              D3
  Line Attenuation(dB):  1.5     12.9    26.7     N/A     N/A    9.7     22.6   35.7
Signal Attenuation(dB):  1.5     12.8    26.6     N/A     N/A    12.2    22.4   35.7
                SNR Margin(dB):  11.9    13.4    12.9     N/A     N/A    6.4    6.4      6.4
                 TX Power(dBm): -4.6    -27.6    5.5      N/A     N/A    10.7   7.3      7.4

so my 3 downstream are 9.7     22.6   35.7
if yours is similiarly I would be very interested to see your hlog, snrm and bitloading graphs if you can get them as your line appears based on your attenuation and supposed 80/20 estimate to be way under performing.