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Upstream speed drop

highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Upstream speed drop

Before I enter the dark recesses of the PN problem reporting system I was wondering if anyone had some other self-help suggestions.
I have been using a SamKnows box for a few months now.  Here is the complete trace for the downstream throughput.  It does show a downward trend (and would be worse if I could go back to the time I had fibre installed) but may just be down to more fibre connections on the cab.  In figures the graph goes from 58Mbps to 47Mbps, profile is currently around 52Mbps.
http://www.sunhillow.eu/down.jpg
The upstream is the problem though. The trace shows a big drop, from 15Mbps to 4Mbps, profile is the usual 20Mbps.
http://www.sunhillow.eu/up.jpg
I've tried using the test socket, reterminating the incoming wires (shhh!), rebooting everything a number of times, connecting straight into the modem (eliminating the router and SamKnows box) and testing from a different computer.  After every test a speedtest still shows the lower speeds.  One other symptom is that after an unexpected disconnection, which does seem to happen more often than it ever used to, it sometimes takes a couple of hours to re-sync (stale session maybe?).
One thought was that it might be the BT modem going faulty?  It does seem strange to me though that if it is a line fault, which I suppose it most likely, that the upstream is hit much more badly than the downstream - I would have expected it to be the other way round?
Any suggestions please?
Ian
12 REPLIES
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
Fixes: 1
Registered: ‎13-07-2012

Re: Upstream speed drop

Hi Ian,
I've tested your line and it's identified a potential fault, I've raised this with our suppliers and should hear back within the next 24 hours the progress with this.
I'll update you.

Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
Fixes: 1
Registered: ‎13-07-2012

Re: Upstream speed drop

This will require an engineer visit, this has been located externally so it will not require you to be in your premises. We'll receive the next update within the next 48 hours.
highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Re: Upstream speed drop

Chris,
Thanks very much for looking into it so quickly.
They are currently building a new main road between me and the cab, perhaps the work has damaged the existing cabling.  I shall await the results of the visit.
highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Re: Upstream speed drop

Chris,
The broadband engineer came this morning but couldn't see the HR that you saw yesterday.  He agreed there was something strange though, the upstream attenuation was higher than it should be, but couldn't find any reason.
After a chat with his help desk, who also scratched their heads, the did a "soft" reset with the promise of a "hard" one later.
The speeds have increased, but not back to the levels I was seeing before.
Bottom line is that we agreed it was best to leave it as is for the minute, to see if it degrades again, and if it reoccurs do a lift and shift.
Thanks again for arranging the visit
Ian
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
Fixes: 1
Registered: ‎13-07-2012

Re: Upstream speed drop

Hi Ian,
I've taken a look and can see that the engineer notes match what you say. The fault will remain open for the next 14 days so  I'd if we monitor for a few days we can always push this back if needed.
highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Re: Upstream speed drop

Chris,
It's 3 days now since the OR engineer came and things are looking much better, although I think there is still something not quite right. FWIW, the "hard" reset that BT were going to do never seemed to happen, the line has been up constantly since the engineer left.
There still does seem to be a discrepancy in the profile/speeds though.
Upstream has a profile of 20Mbps and a consistent throughput of around 12.8 (according to SamKnows).  Before the "problem" I was seeing 13 or 14.
Downstream has a BT profile of 58.07, my PN control panel is showing a "current line speed" of 52.2 and SamKnows is showing a consistent actual throughput of around 49.1.  With that BT profile I would have expected a throughput closer to the 56 or 57 I was getting before.
Is it possible that, because of the earlier problems, there has been a maximum throughput threshold been put on the line, either by BT or, looking at my PN "current line speed", yourselves?.
njay
Grafter
Posts: 184
Registered: ‎05-04-2013

Re: Upstream speed drop

It looks like PN current speed hasn't updated to match IP profile and so 52mbs is the max you will get hence samknows of 49 would be about right as this is normally a bit lower than line rate. Doing a PPP disconnect and reconnect might jog it into life.
highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Re: Upstream speed drop

So you're saying that the "profile" shown on my connection details should normally reflect the BT profile and is active, in that it throttles the connection at the PN end, rather than purely an indication of what the BT line manager is doing. 
I wasn't aware of that, thanks, and it would explain what I am seeing.  Can I assume there is a PlusNet profile for both upstream and downstream?
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
Fixes: 1
Registered: ‎13-07-2012

Re: Upstream speed drop

Hi,
I've checked over your connection and it certainly seems to have improved, your upstream is currently syncing at 13.6Mb/s.
We only have a downstream profile that we set, this is currently at 61.4Mb/s.
Highlighted
highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Re: Upstream speed drop

Chris,
Thanks yet again.
As you say, the PN profile is now 61.4 (it was 52.2 when I checked yesterday).  The BT profile is 58.07 but actual throughput is around 49.2.  I'll leave it for a bit, to see if it needs a bit of time to synchronise the various settings and, if it doesn't change, will reboot the modem as suggested.
The original upstream problem does seem to have disappeared though.
highfield5
Grafter
Posts: 28
Registered: ‎27-10-2012

Re: Upstream speed drop

Chris,
This problem has been slowly returning over the last couple of months.  It looks like the HR is still present, although the engineer who called back in May couldn't see it, so I've been leaving it alone in the hope that it will cause a proper line fault that will be easier to find.  I'm currently running at 18Mbps down and 5Mbps up - should be around 55 / 15.
The engineer was talking about a lift and shift if the problem reoccurred, so could you see if that is still an option please.
Ian
Plusnet Alumni (retired) chrispurvey
Plusnet Alumni (retired)
Posts: 5,369
Fixes: 1
Registered: ‎13-07-2012

Re: Upstream speed drop

Hi Ian,
I can see your speeds have lowered, the DLM has set your profile to 6Mb/s on your upstream which you're currently syncing at, but your downstream is way below.
It does seem we'll need to go down the fault route, could you complete our faults wizard and we'll get that picked up.