Plusnet Speed Drop - and fobbing me off

I've had Plusnet unlimited fibre since July 2013. When it was installed I had a througput down of 75Mbps (speedtest.net) and an upload of about 18Mbps. Over the past year the download has dropped a little, however since November 14 we've experienced lots of little local power outages which has caused the BT vdsl modem (ECI) to reset. Ever time it has reset it's dropped a little in speed, and is now down to 59Mbps throughput. This is a drop in speed of over 20% from the beginning.

I've installed a UPS yesterday for the modem, to ensure that when the power drops, the modem remains connected.

So I decided yesterday to call up Plusnet (spoke to Adam) to ask them to get the line reset. They gave me a cock and bull story about BT capping the lines because they are oversubscribing the cabinet, I'm pretty sure that it's the IP profile has dropped due to the frequent retrains and it just needs a reset. Can't budge them so I ask for my MAC code.

I have been with them nigh on 2 years and had no intention of leaving prior to this as the service has on the whole been good; I can't believe that rather than get this sorted they'd prefer to lose a customer!

Is there any hope of getting this resolved - I would even consider a contribution to the cost of an Openreach engineer getting it reset? Am I correct in thinking that the profile has dropped as a result of the frequent retrains?

Thanks.

Yes - post this here:

Plusnet Fibre Forum

The Plusnet guys will pick it up - much more clued up than the general customer support.

As long as there's no underlying line fault your speed would rise back up over time anyway but could take weeks.

In a way, yes the IP Profile could have dropped because of the retrains. It sounds that the person you spoke to has some training but not sufficient to explain the fairly complex mechanism over the phone. That isn't surprising for front-line support at a large ISP.

Having said that, the capping due to over-subscription at the cabinet is utter tripe.

It isn't the IP Profile itself that is the problem. That is calculated as a percentage (96.79%) of the connection/sync speed, which with the ECI modem that Openreach gave given you can't be seen in any simple way.

What will have happened is that the DLM in the cabinet will have intervened, altering the line parameters to stop the disconnections. It doesn't know they were because of power faults that have been fixed.

With luck all that has happened is that it has introduced Interleaving and raised the noise margin. Both of which lower the sync. The good news is that after a few weeks of stability both of these will be returned to normal.

Because that return is automatic it is very rare for any ISP to arrange for it to be done manually. If you were down at 5Mbps maybe it would be easier.

However, a system called banding may also have been applied. That generally did, and I think still does, need an engineer visit who then requests a reset once convinced you haven't got a problem that would cause it to be re-applied by the system. It sets a maximum and minimum speed for the connection. There is this table but I believe it may be out of date . I can't really tell you much more about that.

If you haven't done so you should post about this problem in the fibre section of the Plusnet Community forums and/or in the Plusnet forum here. The Community one is likely to get a quicker response from the higher level support staff that monitor it more regularly than the one here, (though I think they are basically Mon-Fri staff. Some certainly do sometimes look in at weekends). The are generally excellent and will be able to check if it is just the interleaving and noise margin such, or if it is banding. I'm sure they will sort it out if it's the latter.

It would be a shame if you left over this. As long as you do get sensible results from them.

I type too much . At least we are both recommending the same.

Many thanks - have now done so.

Thank you for your comprehensive reply!

I got the feeling that the 'capping' line was tripe - it just didn't sound right.

Reading your comments about the banding and looking at the chart you posted, if I do a line check with another ISP it is indeed showing 64-80mb, so it does look like banding may be the issue of the day.

I agree it would be a shame if I left over this, however I feel that sometimes you have to make a stand and vote with your feet.

I'm looking at Zen or A&A should this not get resolved in any event.

If you run the BT Wholesale Performance Test, (ignore all the red instructions for now and just say Yes), then click the Further Diagnostics at the bottom of the results page, we get better info.

Please copy and paste the full contents of the down and up text boxes. We don't need the graphics.

I've just looked at the replies to your Community post. I'm most unimpressed by all the reactions - completely ignoring the power cuts you've had .

Get that IP Profile (and the other info) off the tester I asked for . We need to see it.

Here are the results:

1. Best Effort Test: -provides background information.

Download Speed
56.3 Mbps

0 Mbps 65.33 Mbps
Max Achievable Speed

Download speedachieved during the test was - 56.3 Mbps
For your connection, the acceptable range of speedsis 40 Mbps-65.33 Mbps .
Additional Information:
IP Profile for your line is - 65.33 Mbps

2. Upstream Test: -provides background information.

Upload Speed
14.68 Mbps

0 Mbps 20 Mbps
Max Achievable Speed

Upload speed achieved during the test was - 14.68Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps


We were unable to identify any performance problem with your service at this time.
It is possible that any problem you are currently, or had previously experienced may have been caused by traffic congestion on the Internet or by the server you were accessing responding slowly.
If you continue to encounter a problem with a specific server, please contact the administrator of that server in the first instance.

I've just noticed that the ping time has doubled - it looks like interleaving has been turned on - that is absolutely no good, My son is an avid gamer and this needs to go because I'll get the grief!

Thanks.

That IP Profile means your sync speed is about 67,497kbps. If the (base) latency has gone up by exactly 8ms I think you can safely assume it is just interleaving and both speed and latency will self-correct. It is usually getting on for 4 weeks after stability returns, which your UPS should ensure.

BT Wholesale are possibly the ones that won't do the reset. I think Openreach will, but charge. You could try telling PN you will pay for an engineer visit, but that could be well over £100 unless you are lucky.

I'm afraid Matthew's response looks like merely a specification of your product as ordered, and not related to current performance. The "Error protection off" I think would normally refer to interleaving, but if it was still off your latency would not have doubled.

Another thing to check is the "Current line speed" in your Member Centre >> Connection settings >> High speed broadband. I would expect it to read 65.3 or 65.32Mbps.

Edited by RobertoS (Sat 07-Mar-15 17:33:30)

See also this Community post.

In reply to a post by RobertoS:

I've just looked at the replies to your Community post. I'm most unimpressed by all the reactions - completely ignoring the power cuts you've had .

It depends on how large or small all those "little" drops in speed were when the power cuts were happening.

If any one of them dropped by between 10% and 20%, then it is likely to have been a DLM intervention. Smaller drops after a big drop could then be DLM making adjustments. But without the big drop, any small drops are more likely to be explained by crosstalk.

And, yes, crosstalk can knock 20% off your speed, or more, in little bits.

From across the various posts, it looks like the sync speed has dropped from roughly 80Mbps to 67Mbps, and if Matthew was right, then this is without DLM intervention. Over 18 months, I find that kind of drop entirely plausible.

As an example, my attainable dropped from roughly 90Mbps to 78Mbps over the course of around 30 months, on a cab that had already been stood for over a year. When DLM intervened (which happened twice) it temporarily dropped another 7Mbps.

The power cuts are something that *could* cause a problem with DLM, but it isn't guaranteed. If the whole area suffered from the power cut, then this might have been ignored: DLM has a mechanism to make allowances for wide-area events.
http://www.kitz.co.uk/adsl/DLM_system.htm#WideAreaEv...

The original support agent got his reasoning muddled, absolutely, but Plusnet seem to have played it straight otherwise - BT won't accept a report to just reset DLM. BT also won't accept a fault until the speed drops into the 10th percentile of speeds for similar lines (ie well below the bottom of the speed range, which is the 20th percentile), or the speed drops by more than 20% in a very short space of time. BT seem to have been getting stricter on this ... which means ISPs are too.

Even when an Openreach engineer turns up to investigate a fault that has been accepted, he isn't allowed to ask for DLM to be rest unless he has actually fixed a hard fault.

Some engineers will perform a reset as part of their investigations - especially if they feel that the "limited" way the line is now working is helping to mask the actual fault. But Openreach equally want to stop engineers from just resetting DLM, and then claiming to the householders that "There, it is fixed" only for speed drops to return when DLM intervenes again 48 hours later.

Leaving to a new ISP isn't likely to change any of these limitations.

Now it's funny you should mention the HG612:

https://drive.google.com/file/d/0Bzj4Ilqxsx4VaWx6Unh...

Attainable down rate 71300 yet line rate is 60996 (about 8pm tonight)

Looks like a cap to me...

My download speeds are in th 50s' now, and Plusnet are still fobbing off.

It depends on how the OP is measuring his ping. If he's using the BTW checker, then it's completely inaccurate.

There are also other factors (including which gateway the OP is on) which could be responsible for a latency increase.

I thought you had an ECI?
That difference between Attainable and Line Rate is about right for that caused by interleaving.

Are you on Windows? If so telnet into it. Instructions:-
************************************************************
Welcome Visiting Huawei Home Gateway
Copyright by Huawei Technologies Co., Ltd.
Login:admin
Password:
ATP>sh

BusyBox v1.9.1 (2014-01-21 16:44:38 CST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

# xdslcmd info --show
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 15507 Kbps, Downstream rate = 60240 Kbps
Bearer: 0, Upstream rate = 15585 Kbps, Downstream rate = 53385 Kbps
...
...
**************************************************************

But give us the full output .

Don't hold your breath for PN to resolve this. I've been having issues with them for 18 months.
4 or 5 engineers, lots of swearing, still no resolution.
My fibre line speed drops by 50% for days at a time then spontaneously goes back up (using a Bipac 8800NL) or the whole thing will drop with no signal at all for hours or days (the record I think is 8 days without a service).

No resolution, constantly fobbed off, BT engineers haven't a clue what's going on. Nobody will actually step up and take proper responsibility for trying to get to the bottom of the problem.

My contract term is up in a few months and although I'm loath to leave PN as they're generally one of the better outfits and I've been with them for over 10 years, I will seriously consider upping sticks when the time comes. However inconvenient this will be.