Apparent Throttling of Speed on Plusnet Pro

[#1]

I've had enough - leaving Plusnet.
After several days of mainainence work at the exchange and investigation by Plusnet, it all looked OK......steady 13Mb down.
And then, after just 2 episodes of Prison Break on Netflix/Apple TV, my connection dropped to zero speed (but upload speed/line quality/sync/ping all OK)
After a forced reboot, the line was erratic, but testing at around 1Mb down. Bt Speedtester tap3 test failing again.
All this happened at around 21:30L and suddenly sorted itself at abour 23:30L (on a Sat night).....indicative of traffic shaping in my opinion.
I can't go on paying £23 a month for a service that is never stable, so I'm off. MAC code inbound, BE There ISP next.

[#2]

Hi,
Please would you be so kind as to let us know how you get on with your new ISP ?
Assuming you can still post here after leaving Plusnet ?
As if your problem is at the exchange, ....... now moving to cable (which probably is not available otherwise you would have gone down this route) or an ISP with an LLU service at your exchange I would have understood.
Cheers
Bullet

[#3]

I gather than you can only first register on the forums if you are a Plusnet subscriber, however if you subsequently leave Plusnet you can still post on these forums as your registration is not cancelled when you leave.

[#4]

Hi
I am having the same problem at the moment with half speed (3.9), disconnects and 'we may send an engineer'.
You have my sympathy as it does get frustrating.

[#5]

First, It's a shame no one has pointed out that if you have a Line problem (for the non-techie - your wires from your house to the exchange) then moving to a different ISP will not affect your connection, you just take the problem with you, Unless of course you go to Cable which is a separate installation.
Next, unless you go to a more expensive ISP (eg.AAISP) where you may get a bit more attention to them dealing with BTw to sort out a network problem, then you may well find that life gets no easier trying to explain and discuss your problems with Mumbai or wherever rather than Sheffield. (And they still have to deal with Openreach to get your line repaired once the fault is located).
There is no "throttling" as you phrase it - there are "profiles" associated with the package you are on and the traffic management that goes with, but you are on Pro and although it is possible to pick up a default profile after a disconnect, this doesn't happen often and is usually cured by a Gateway hop, but as Jojo has already explained this didn't happen to you.
Throttling is where everything is just slowed down at busy times as eg. on cable.
If you have a dropping connection due to a Line fault, then you can reconnect at a low speed due to the extra noise on the line. This lowers your bRAS IP profile and so lowers your throughput speed. That profile is reflected at the member centre https://portal.plus.net/my.html?action=data_transfer_speed (login required) called (confusingly) Current Line speed. This setting relies on Delta reports suppllied by BTw and there have been problems with those, but a simple request in a thread on this board (or via a ticket) usually gets this resolved once your bRAS IP Profile has recovered due to you reconnectinmg with a higher sync speed.
The problem with a lot of Line faults is that they can be intermittent and so can be difficult to track down, this gets frustrating for all concerned, however there are steps that one needs to go through to help track down such a problem and unforutunately these can get rather tedious.
In summery, Throttling or "traffic shaping" as you put it is not the cause of your problem, it is due to a fault on your telephone line.
Pick up your phone when this is going on and see if you can hear any crackling noises on the line, although not always present.

[#6]

Thanks to all for your help,
So I didn't move to another ISP yet based on the comments from others above.  I've also been out of the country for a bit and decided to see if the line would settle......but it hasn't. It now does seem to be noise margin related....my lastt post on the fault ticket:-

Your Response
10:21am, Thursday 17 May 2012
Got home yesterday to find that my wife has had multiple internet failures whilst I was away. The router had been showing that the internet connection had failed, needing a reboot about 8 times during the last week alone.
Last night I also saw that the noise margin was unusally high at about 44db!? This then settled some at around 5 or 6 db, but it would appear that the software/protocol at the exchange has been dynamically altering my noise margin by large amounts...

Tried streaming film via Netflix and all working fine at about 12Mbs, but as I monitored my noise margin is slowly went down to 3.0, 2.6, 2.3, 2.2db and then the internet failed. Reboot requeired.

Again, it starts of OK and then appears to want to reduce it's noise margin until it fails again, this time more quickly. This all seems to happen after watching about 1.5Gb of streamed video data.

This all points to line interfearence or poor quality software at the exchange surely?

My current stats are showing:-

ADSL Link Downstream Upstream
Connection Speed 18820 kbps 1033 kbps
Line Attenuation 23.0 db 14.9 db
Noise Margin 3.5 db 6.3 db
Shouldn't the noise margin be more like 6.0db (not 3.5db) for downstream data?
Also, I'd like to stop being billed until this problem is resolved....I can't use the service I am paying for!

Please let's sort this out now, it has been years now! Are you suprised I want to leave?

Can you send me another test router or something? I never took you up on the free one? Mabe send that out and see if things are the same?
Anyone got any ideas? I do know that the exchange was upgraded to BT21CN / ADSL 2+ upto 24Mbs service in February. They are also saying they're doing low power trials....

[#7]

It sounds line a bad joint on your line or with one of your connections. As I said add the end of my last post, try listening to your phone line for crackling or other noises. If you can hear any, add the information to your ticket. It sounds like it's intermittent from what you are saying, and a good time to listen would be when you see the Noise Margin going up and down.

[#8]

I presume by you saying that you are thinking of leaving that you have Virgin Media Cable available - if that's not what you are considering moving to another ISP will take the problem with you.

[#9]

Will be trying to stream some Netflix content tonight, so  will try and check if there is any noise on the line if it fails/noise margins vary.
I did drive down to the exchange earlier and noticed a car workshop and a drycleaners next door to the BT exchange building; could these be generating EM noise on the line? Someone told me they call it 'Rain' on the line if there is interfearence that can affect b/band signals.

[#10]

Quote from: baker2009

Someone told me they call it 'Rain' on the line if there is interfearence that can affect b/band signals.

That'll be REIN http://www.kitz.co.uk/adsl/rein.htm

[#11]

Did a bit of monitoring and at about 00:50L this morning, I saw these stats with no audible interfearance on the phone line..:-
ADSL Link Downstream Upstream
Connection Speed 19421 kbps 1040 kbps
Line Attenuation 23.0 db 14.9 db
Noise Margin 43.3 db 6.3 db
And then seconds later, back to :-
ADSL Link Downstream Upstream
Connection Speed 19421 kbps 1040 kbps
Line Attenuation 23.0 db 14.9 db
Noise Margin 2.5 db 6.3 db

what could this be?

[#12]

Quote

Connection Speed 19421 kbps 1040 kbps Line Attenuation 23.0 db 14.9 db Noise Margin 43.3 db 6.3 db

Hmm, it's not possible to get that connection speed along with that noise margin so I'm not sure if the router has interpreted an issue correctly there. However I have seen REIN issues cause spikes in the noise margin like that before.

[#13]

Horray. Finally. I feel I can confidently say that my line is now fixed. Stable 15Mbps Down / 1MBps Up. Rock steady with no drop outs for over 3 weeks. Netflix streaming perfectly.


And where lay the problem you all ask? BT finally checked the exchange and replaced a piece of equipment with a new 'Fujitsu' server which has cured the problem.  After the first week of perfect line quality, I also had my router replaced with the new Plusnet Thomson Wireless N Router (waited a week to prove it was not my router that had casued the fault!) BT are now very keen to run tests with their old equipment on my old router and have asked for me to lend it to them which I will gladly do now that they have seen it was their equipment at fault.
I guess it makes me realise at the end of the day most of us are still under the mighty thumb of BT and it's equipment unless you are lucky enough to have an ISP with it's own equipment in the exchange or be on cable.  This fault has plagued me on and off for 3 years now....I wonder if BT will offer any compensation....?
I also realise that faults like mine are very tricky to pin down, and Plusnet have actually done their best to work with their 'Mother' company BT here.  Their good comms and continuous updates have kept this customer who was on the brink of leaving......;-)
I'll be sure to update this thread if things change!

For those who are intereseted in more details, I can also tell you that BT were running a 'Cool Line' test which is a bit like a 'going into standby mode' power (and yes money) saving system that senses when there is/is no demand on your line for data and drops the signal strengh (hence the extemely high noise margins I saw).  Once it detects a need for increased speed it will put your Noise margin back to about 6 or 3db depending on what they have programmed.  I was asked how I found this, and at the time just wanted stability, so I have requested for this to be 'switched off' and have a less dynamic noise margin profile, sticking to about 6db. Plusnet & BT agreed and the results have been A+ stability and superfast broadband.  It is possible that some routers will not like this type of dynamic noise margin control and may result in multiple disconnects which could confuse the system into droping your sync speed and reducing speed and stability; I think that's why BT want to borrow my Netgear DGN3500.

[#14]

That is very interesting baker2009 are you on the Eastbourne exchange?
I know there are few posters here that will be very interested in this so please keep us updated and give us any technical detail that you can.
A number of us have been aware for some time that there can sometimes be incompatibilities between the chipsets in Modem/routers and chipsets in the DSLAM/MSAN cards in the exchange which can result in odd but not necessarily dramatic behaviour.  Whether this problem is related to that is obviously yet to be discovered.
I'm assuming that it may be one such card that's been replaced by a Fujitsu. Do you know what the old one was? If the assumption is wrong do you have any further detail?
There is also apparently some bugs in some Netgear modem/router firmware in recent times, again whether this problem is related to another or existing bug is yet to be discovered.
The fact that BT want to borrow your DGN3500 for tests is very encouraging, let's hope that the people involved in the investigation are in a position to investigate properly and provide feedback.
Despite your comments about 'being under the thumb of the mighty BT', and 'other ISP's ', I somehow doubt that an investigation would have even got started with some ISP's or their LLU providers, I'd be surprised if you'd even get an intelligible response from the "stalk stalk-ers" of this world.

[#15]

I have heard that the the 'cool broadband' (alias the 21CN low power L2 mode) rollout/experiment has been temporarily suspended and switched off for all those exchanges using it.
Apparantely some routers were loosing the PPP session during the process and there are probably lots of these routers around.
Looks like yours was also having sync problems.
Frankly I'm rather suprised that this sort of thing was not picked up during the in-house development process.  I would have thought BT have examples of pretty well every router made and could near replicate real life conditions in their test facilities.
All has the wiff of a rushed project....
Edit:
It would be very awkward if many existing routers cannot handle L2 mode in practice.  Whether a line could/could not have L2 mode activated would then depend on what router the end user was using at that particular time (lets not even consider the situation where users swap routers!).