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FTTC - Massive drop in sync speed

KevinG
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Registered: 05-11-2008

FTTC - Massive drop in sync speed

I posted this on TBB this morning but no response as yet, so probably better here:
I know about the recent problems with peak time performance and latency and had experienced some of this myself last week, but this seems to be unrelated.
Ever since I got FTTC I have synced at between the mid 60s and low 70s Mbps, although the periods in the 70s have been fairly short-lived. This is fine, I am 450m from the cabinet and beating my estimated speed. I just got back from a weekend away (router and modem left switched on) and, after running a speed test to check the peak-time performance issue and getting a lowish speed, I found that my modem had re-synced at 40492/11783. This has never happened before and worried me somewhat. The SNR was 15.9 and max attainable 74036. My IP profile was 39.19, which is correct for the sync speed and my Plusnet line speed 64.2Mbps as it hadn't caught up yet.
So, I thought, reboot the modem and see what happens. It resynced at 60613/19556, which is much better and I thought I could live with that for now, in the hope that it would increase in time. The SNR was 6.3 and max attainable 78768. Speed tests in the mid to high 50s confirmed that all was reasonably well.
BUT ... I get up this morning and find I am synced at 39999/9997, which is highly suspicious. SNR is 11.8 and max attainable 78192/28880. Now this looks to me as though either I have been erroneously regraded to the 40/10 product or some sort of banding has been applied. Does anyone have an opinion on this? I can obviously go through the official support channels but I thought I'd put this out here first as I'm a bit pushed for time. I may reboot the modem again, if I do I'll edit the post.
Incidentally, the Plusnet line speed is still 64.2 and the IP profile is 58.23, which almost matches yesterday's evening's recorded sync speed of 60613 (it's actually slightly lower than it should be).
(Edit: No change after modem reboot, as expected, though obviously my IP profile will now have changed as I've had to start a new session.)
12 REPLIES
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
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Registered: 13-07-2012

Re: FTTC - Massive drop in sync speed

Hi there,
I've had a look over your connection and your line profile has been set to 40/10, this may have been due to recent events on your line. You're still on the 80/20 product and haven't been regraded.
To resolve this can you run through the fault wizard at http://faults.plus.net and we can then look at getting your line reset.
Chris
KevinG
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Re: FTTC - Massive drop in sync speed

Hi Chris, I have done this, question ID is 66637883.
KevinG
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Re: FTTC - Massive drop in sync speed

Just received this update:
Quote
I have tested your connection today and found a fault on your line. I have now raised your fault to our suppliers to investigate your fault further we should now have a further update in the next 24 hours.
KevinG
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Re: FTTC - Massive drop in sync speed

Thanks for the call Chris, looking forward to engineer visit on Friday morning  Smiley
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
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Registered: 13-07-2012

Re: FTTC - Massive drop in sync speed

No worries, let me know how it goes.
KevinG
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Re: FTTC - Massive drop in sync speed

Hmm, don't know what's going on now - showing 38179/16997, very low downstream, but no longer limited to 40/10 it seems.
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
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Registered: 13-07-2012

Re: FTTC - Massive drop in sync speed

Let me know how the engineer visit goes tomorrow, looks like it needed!
KevinG
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Re: FTTC - Massive drop in sync speed

I certainly will! I'm avoiding the temptation to disconnect/reboot anything at the moment.
KevinG
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Re: FTTC - Massive drop in sync speed

The engineer has been and gone and my profile has been reset. He couldn't find anything wrong with the line and his equipment was showing a maximum rate of 73 Mbps. He had a very long conversation with the BT Wholesale person and there seems to be a suggestion that the problem originated with the recent voice line fault although, as I said, there were no apparent problems visible to me until a week later. Incidentally, on the response to my ticket, I noticed that there had been a disconnection between about 8pm on Saturday 2nd March and 5am on Sunday 3rd - I don't know why this would have been, we were away and everything was connected. There were no power cuts. It seems more likely to me that this has something to do with the problem than the voice line fault.
Anyway, following the reset the sync speed was 71212/20000 (nice!) and the IP profile 68.93. The engineer did have to disconnect the modem again to plug his tester into the test socket to complete the mandatory line checks, and when plugged back in, sync had dropped to 68014/20000 - 3 meg lost, just like that! My Plusnet line speed is still 36.8 Mbps so I cannot make use of the speed yet. I realise this should sort itself out but if you could give it a nudge, that would be appreciated.
The engineer was very helpful and he thought it was pretty ridiculous that they had to go through this palaver to get a profile rest. I don't understand why the ISP cannot request it and only if there is then still a problem, send an engineer.
Thanks for all your help with this, Chris.
Plusnet Help Team
Plusnet Help Team
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Re: FTTC - Massive drop in sync speed

Thanks for your feedback on the engineer visit. I've just update the profile on our side for you.
The way fibre works it isn't possible for us to reset SNR or ask for the profile on BT's side to be updated which explains why we have to go via their faults process if there's an issue with that.
Adam
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
KevinG
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Re: FTTC - Massive drop in sync speed

Thanks Adam, I realise the ISP cannot request this for fibre, that was my point, hopefully one day BT will relax the rules as the current system seems rather inefficient and labour-intensive. Thanks for changing the profile, for some reason I'm still only getting about 35 Mbps on speed tests, maybe I'll reboot the router.
KevinG
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Re: FTTC - Massive drop in sync speed

OK, that fixed it!