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Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

StuS
Newbie
Posts: 5
Registered: 23-08-2012

Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Hi.
Months ago I moved from 40/10 to 80/20 and my speed immediately plummeted from around 37 to 15Mb for about a week and was very unstable.  It slowly picked back up and then settled around 37, and more recently about 40.8Mb - I always thought that 40 seemed a bit of a strange/convenient number, as though I had been been capped to my old speed, but that's not (possibly) my current issue.
I've just moved to the Unlimited package (thanks Plusnet, it's great to finally have an unlimited option!) and my current status is this:
Plusnet member centre page:
Estimated line speed:
    54Mb (Accurate to within +/- 1Mbit) - Checked on 2013-03-22 09:48:18
Current line speed:
    78 Mb
BT wholesale page:
Download speed achieved during the test was - 39.96 Mbps
For your connection, the acceptable range of speeds is 16 Mbps-40.97 Mbps .
Additional Information:
IP Profile for your line is - 40.97 Mbps
Upload speed achieved during the test was - 6.73Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps

I could understand if the estimate is wrong (I'm not really sure how it's calculated) but should my line speed be nearly twice the estimate?  And if the estimate is wrong, shouldn't my profile be higher?
Apologies if I'm just not understanding the numbers correctly.  They just seem a little weird to me.
Thanks.
12 REPLIES
kmilburn
Grafter
Posts: 902
Thanks: 2
Registered: 30-07-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

The Current Line Speed being higher than the estimate is usually a good thing.
The Current Line Speed does seem odd though as it would normally be  a smidge lower than the IP Profile (the active synch speed).
As it stands,  it would be the IP Profile that is the limiting factor in the speeds your seeing.
Given the mismatch between the Current Line Speed and the IP Profile (and its difference from the estimate), it's probably worth raising a fault.
Community Veteran
Posts: 19,099
Thanks: 434
Fixes: 21
Registered: 31-08-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Actually having the Current Line Speed higher than the BT IP Profile isn't such a good thing because if data is sent to your line faster that it can handle, packets will get dropped at random, which rather defeats the object of Traffic Management to ensure that high priority traffic isn't dropped.
Funnily enough I posted a bit about this the other day, which I've edited slightly to be more applicable here -
Just to clarify, these Current Line speeds at the start of a new package/connection aren't "incorrectly reported" figures. They are the values set by Plusnet (so as not to unfairly cap a line), depending on the type of connection, until a BT IP Profile is established for the connection. On ADSL this normally takes 2 days (+ any delay in the Delta report going from BT systems to Plusnet systems and processing by Plusnet), I think it's a bit quicker on Fibre.
The default values IIRC are 37Mbps for 40/10 FTTC, 78MBps for 80/20 FTTC, 21Mbps for 21CN and I think 7.15Mbps for 20CN. A few years back it used to be 2Mbps for ADSL as the BT IP profile was set at that value by BT's systems for 2 days but this unfairly restricted speeds for people with faster connections.
However on Fibre, unless you've had a new PPP session the correct Profile isn't always getting updated on the relevant servers. So the best thing to do is log into the Router, go to the Internet box and click Disconnect to drop the PPP session. Wait about 30 seconds and then click Connect. Do this before running the BT Diagnostic speedtest.
All this can, as you've seen, cause confusion, but a lot of people don't check the Current Line speed (Login required) as they may not be aware of it.
Having established a new PPP session, run the BTw Performance test (ignore the red preamble except make sure no other programs are using the Internet) and at the end of the first run, click the Further Diagnostics button, enter just your Phone number and Run the Further Diagnostics Test - which will show the correct BT IP Profile for the Line (+ the sync speeds on ADSL.)  The current Line speed should update, but it may take a couple of days!
FYI on FTTC, DS sync speed = Profile x1.033.
Plusnet Help Team
Plusnet Help Team
Posts: 12,850
Thanks: 112
Fixes: 36
Registered: 27-04-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Let us know if you don't see any improvement over the next few days StuS
If this post resolved your issue please click the 'This fixed my problem' button
 Adam Walker
 Plusnet Help Team
StuS
Newbie
Posts: 5
Registered: 23-08-2012

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Thanks for the replies.
I just popped home and tried Anotherone's suggestion, but unfortunately nothing seems to have changed.  I'll leave it a day or so and then give it another go.
Community Veteran
Posts: 19,099
Thanks: 434
Fixes: 21
Registered: 31-08-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

The Update to the Current Line Speed is probably lagging just like ADSL(2+) then Roll eyes  What did the speedtester give the profile as?
StuS
Newbie
Posts: 5
Registered: 23-08-2012

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

The profile was exactly the same  Cry   
leader
Grafter
Posts: 261
Registered: 02-02-2013

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Might be wise to consider an unlocked bt openreach modem so line stats can be obtained ? (It's frustrating BT locked the standard issue units down so much)
Unlocked HG612, combined with Bald_Eagle's software can really help in highlighting potential issues.
Some more info here : http://community.plus.net/forum/index.php/topic,112858.0.html
Cheers
leo
Community Veteran
Posts: 19,099
Thanks: 434
Fixes: 21
Registered: 31-08-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

I'm not sure how much of an improvement one might expect, if any, moving to 80/20 from 40/10 when you aren't at maximum speed on 40/10. It could just be that the estimate was somewhat generous, unless you have a faulty line of course - hear any noise on it at all?
It would not be wise to consider unlocking the modem, if you brick it you'd end up with an expensive bill from Openreach. If you got desperate because you thought there was an unresolved issue with the line, then buying an unlocked one off eBay would be the best option and leave your original one intact to put on-line should Openreach ever need to attend.
Bald_Eagle1
Grafter
Posts: 313
Registered: 24-06-2011

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Having access to the stats from an unlocked modem will NOT tell you the cause of any faults, but it will at least tell you what the symtoms are.
Knowing the symptoms can often direct users, ISPs & BT to likely causes or at least indicate that further detailed testing by an engineer is required, with little risk of being charged for the privilege.
Theoretically, Plusnet's Current Line Speed, following a suitable period of connection time, should be updated each time BT's IP Profile changes.
BT are supposed to send delta reports to Plusnet whenever an IP Profile change is detected.
We are not sure how reliable this system is. Perhaps Adam could expand on how it is intended to operate.
One problem is that a connection can resync 'on the fly' very quickly. Too quickly to be detected on many occasions, so Plusnet don't see it in their logs as a new PPP session isn't initiated.
Initiation of a new PPP session is the trigger to update BT's IP Profile, so quite often that isn't updated either (both upward and downward).
So, Plusnet aren't aware that their Current Line Speed needs to be adjusted.
This is often confusing for usres as a high IP Profile can be seen from the BT test, yet throughput is much lower as it is based upon actual sync speed which COULD actually be much lower than the reported IP Profile.
Conversely, if a connection has improved & resyncs at a higher speed, unless the IP Profile is also updated, throughput will then be low & based upon the reported IP Profile.
Your connection MIGHT be resyncing regularly & thus Interleaving may be set at a HIGH depth. This also restricts sync speeds & throughput, also increasing latency etc.
You may have a lot of Impulse Noise affecting your connection.
In which case automatically applied Impulse Noise Protection may be at a high level, again affecting speeds.
Due to all these factors (& more), your connection may suffer from many errored seconds and/or the Meantime Between Error Rate (MBER) may be very short, again causing DLM to impose speed restrictions to improve stability.
ISPs & BT can see some of this data that is obtainable from an unlocked modem, but I'm not sure how much of it they can actually see.
Again, Adam may be able to confirm for us?
I have seen evidence on some connections of a short period of instability causing DLM to 'cap' speeds & remain so capped for a very long time.
Occasionally, the capping is reduced in stages until the connection reaches its peak compromise between speed & stability.
Quite often, the cap has remained in place, needing an engineers visit to then request DLM to be reset.
AIUI, ISPs cannot directly request a DLM reset & they cannot reset SNR either as that is fully controlled via DLM.
Without access to an unlocked modem's stats & just running various speed tests isn't sufficient proof of a 'faulty' connection as so many external influences can affect speed test results.
Your connection may not actually be 'faulty' as such. It may just be that it has taken quite a long time of DLM monitoring it 24/7 for it to settle at a lower speed than it has on occasion been capable of.
When DLM has been reset (following engineering repairs to the external cabling etc.) my connection syncs at around 35Mb for a short while.
Over a period of some months, sync speed gradually tailed off to around 30Mb or slightly less.
It stayed ther for a number of months before dropping to around 26Mb.
Statistical evidence of my connection remaining stable, but 'noisier' suggests crosstalk from new users being connected, again affecting speeds.
You may currently be experiencing any one or a number of those factors, potentially a high resistance cable joint, bridged taps etc. etc. etc..
The stats from an unlocked modem would at least provide SOME clues as to what is going on.
Finally, you could be affected by REIN from say a plasma TV a few doors away or a faulty fridge compressor motor or a central heating thermostat/pump.
Some of these would show regular timed error patterns in your stats & possibly warrant further investigation.
HTH.
Community Veteran
Posts: 19,099
Thanks: 434
Fixes: 21
Registered: 31-08-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Thanks Bald_Eagle1, that's very helpful and I'm sure a number of people will find that useful.
StuS
Newbie
Posts: 5
Registered: 23-08-2012

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Quote from: _Adam_Walker_
Let us know if you don't see any improvement over the next few days StuS

Hi Adam,
I left things for a while, then a couple of days ago I disconnected via the router web page, powered the router and modem off for 5 mins, and then powered them on again.  These are the results:
Plusnet member centre page:
Estimated line speed:
    54Mb (Accurate to within +/- 1Mbit) - Checked on 2013-03-22 09:48:18
Current line speed:
    78 Mb
BT wholesale page:
Download speedachieved during the test was - 38.49 Mbps
For your connection, the acceptable range of speedsis 16 Mbps-39.66 Mbps .
Additional Information:
IP Profile for your line is - 39.66 Mbps
Upload speed achieved during the test was - 6.71Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps
It all looks pretty much the same to me, though my downstream profile seems to have dropped a tiny bit
Community Veteran
Posts: 19,099
Thanks: 434
Fixes: 21
Registered: 31-08-2007

Re: Moved to Unlimited FTTC, now utterly confused about my expected speed/profile

Turning of the BT modem is not recommended as previously mentioned. However, in a case where the Profile is well below what it ought to be, then that can be considered. But if that is to be done, previous recommendations have been to turn it off for an hour minimum. This should be done in daylight hours when background noise is likely to be lower and so a better sync speed may be obtained.