cancel
Showing results for 
Search instead for 
Did you mean: 

Download Speed related to portal current line speed

tonyappuk
Dabbler
Posts: 24
Registered: 25-07-2007

Download Speed related to portal current line speed

I'm syncing at over 11Mhz and my portal line speed is 10.2 Mhz. For some months my maximum download speed as indicated by NetMeter is limited to 7.35Mhz. This has stayed the same with sync speeds varying between (9.5 Mhz and just over 11 Mhz. Without going through the rigmarole of the faultfinder, how do I poke someone to remedy this, please?
Tony
24 REPLIES
Superuser
Superuser
Posts: 11,935
Thanks: 3,301
Fixes: 22
Registered: 22-08-2007

Re: Download Speed related to portal current line speed

Hi Tony,
I think you mean mega-bits (Mb) synch speed rather than mega-hertz (Mhz) transmission frequency - they are quite different!
If I just look at the numbers you quote - the "current speed" reported in the portal should be about 88.2% of the line synch rate.  Thus if you are synching at 11Mbps then the portal should report 9.7Mbps.  So if your portal figure is 10.2Mbps then it is better than what it should be, however higher than "it should be" figures have been known to cause data transfer speed issues, due to data being sent faster than your line can support.
Given that there will be transmission over heads and possible data retransmission, the reported data speeds are not too far off the mark.
I think this needs a full check out - can you please post your full router stats as per the "speed issues" thread at the top of this forum.  Can you please confirm that the speed tests were performed on a computer wired connected to the router and that the router is in the master socket.

Kevin
tonyappuk
Dabbler
Posts: 24
Registered: 25-07-2007

Re: Download Speed related to portal current line speed

Kevin
Thank you for your response but I don't agree that a check out is required. As a long time member of Kitz broadband forum and running DSLStats for details I know the health of my system. I just want to get as much download speed as 10.2 on the portal will allow and thats a bit more than 7.35 (Mhz or Mb, I know the difference but you were right to point it out - I'm a long time retired TV and Radio Transmitter engineer and it was a slip of the pen) Do you have any suggestion as to how I should proceed please. By the way I'm on ADSL2+ at the moment but FTTC should be here soon.
Tony
Superuser
Superuser
Posts: 11,935
Thanks: 3,301
Fixes: 22
Registered: 22-08-2007

Re: Download Speed related to portal current line speed

Tony,
Quote from: tonyappuk
I just want to get as much download speed as 10.2 on the portal will allow

That is what you are getting now, you are not going to get the 10.2Mbps as reported on the portal.
1. Given your 11Mbps synch speed, 10.2Mbps is wrong - 11Mbps * 88.2% = 9.7Mbps.
2. Given your BT profile, the DSLAM is not going to let you go faster than 9.1Mbps
3. You are not going to see sustained throughput at the maximum rate.
If you want to go faster, you need to show evidence that your line is synching below expectations for its attenuation and / or you have a level of errors on the line which indicate the need for a fault rectification.  The gap between 7.35Mbps and 9.1Mbps could be down to a number of things, from you internal wiring, duff router, duff filter or a line issue any of which can give rise to transmission errors and thus impact the end to end effective transmission rates.  Indeed it could even be REIN from a nearby TV device.  Yesterday one user I've been helping for a couple of weeks finally found that his REIN culprit was a Freeview Box.
What is your real problem?  What is it that given the speed and performance you have you cannot do?  Is it possible that you are perceiving a problem and have formed the conclusion that only raw speed (or the lack of it) is the cause?  Sometime with communications (and I am sure you will appreciate this) it can be better to go slower in order to communicate more proficiently.  Communicating as fast as possible and not being understood, thereby requiring retransmission is not efficient.
If you think there is something which needs to be remedied then it needs to be identified.  The routes for identification within the forum available to other customers such as myself is solely through the information you can provide.  Alternatively, if you raise a fault report here the then PN DCT team / faults support team will be able to pick the problem up on Monday.
Kevin
tonyappuk
Dabbler
Posts: 24
Registered: 25-07-2007

Re: Download Speed related to portal current line speed

Kevin
I don't want to belabour the point but my maximum download speed as indicated by NetMeter has remained at 7.35Mb for some months now for all sorts of material and many different sites with a sync speed between 9.2 Mb and now 11.2Mb. I understand about overheads and the fact that I wont get 11.2 Mb throughput but there should have been some change surely! Or is the portal not correct? My router is syncing solidly at 11.2Mb although of course the SNRM drops to a low level at night from about 6 or 7db during the daylight hours..
Tony
Community Veteran
Posts: 5,112
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: Download Speed related to portal current line speed

You could check your IP profile using the BT speedtester. Then there is the issue of why your Plusnet current line speed hasn't been changing to reflect the BT IP profile.
Also I can't see where Townman got 9.1 from. And I would expect that yes, you should be able to see sustained throughput at just under the profile rate.
Superuser
Superuser
Posts: 11,935
Thanks: 3,301
Fixes: 22
Registered: 22-08-2007

Re: Download Speed related to portal current line speed

Quote from: ejs
Also I can't see where Townman got 9.1 from.

He got it from another thread he'd been working on  Embarrassed
@ejs - Thanks !  Shocked
@Tony - Sorry for any confusion.  ejs is right, lets look at your BT profile, however ultimately we - the fellow users - can only advise through the information you obtain and share with us.  Personally I would like to see your router stats before attempting to offer more help.  Please revisit the rest of my last response.
tonyappuk
Dabbler
Posts: 24
Registered: 25-07-2007

Re: Download Speed related to portal current line speed

My BT Profile is 6.5Mb so make of that what you will!
My stats as obtained by DSLStats are
DSLAM/MSAN type: TSTC
DSL mode:      G.992.5 Annex A
Status:        DSL Link Up
Uptime:        3 days, 9:28:58

Downstream Upstream
Attenuation (dB):      38.0 19.6
Connection speed (kbps): 11671 854
SNR margin (dB):        2.7 4.6
Power (dBm):            20.8 12.2
Interleave depth:      64 0
INP:                    1.13 0.40
RSCorr/RS (%):         
RSUnCorr/RS (%):       
ES/hour:                590 0
Tony
Superuser
Superuser
Posts: 11,935
Thanks: 3,301
Fixes: 22
Registered: 22-08-2007

Re: Download Speed related to portal current line speed

Tony,
Thanks, these stats tell a colourful story.  Those stats tell me that you are flying close to the wind / sun depending on how you look at things.  For a 38dB line you are sweating the synch rate at 11Mbps+ with the SNRM nearly touching the ground (sub 3dB).  Have you forced the SNRM to 3dB on the router or is this down to the DLM?  The Error Seconds count (590/hour) is 16% of the hour, which is not ideal - I cannot tell if this is environmental, the line or the effect of pushing the line too hard.
Interesting math - the PN Profile at 10.2Mbps which is spot on for your current 11.671Mbps synch rate.
The crunch however is the 6.5Mbps BT profile (that which limits the DSLAM) - which is not too different from your speed test results.
In conclusion, the BT Profile is wrong - I do not know why, I've seen this recently on another user's thread and it required DCT to do some deep poking in BTOR's backend systems.  This will need to wait until Monday.  Once that is sorted, we can see where your data speed goes and also see if the error rate can be addressed,
Have a good weekend,
Kevin
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: Download Speed related to portal current line speed

Hi Tony,
I've just taken a look at your line. The problem here, from what I can see, is that your IP Profile hasn't updated when it should have. The issue really, is that DLM has detected a number of different sync rates from your connection over the past couple of days.
There's a bit of activity from the DLM side of things as your line is erroring and DLM is trying it's best to control them with Interleaving on the downstream. Your Line Quality has improved with Interleaving on, however, a small amount of errors remain. Your router has, on two occasions dropped the connection to the exchange, perhaps due to a high amount of errors and the line can't cope.
Your IP Profile has updated itself now and your profile set on our systems has followed suit too.
Chris Pettitt
Cloud Environments Engineer
Superuser
Superuser
Posts: 11,935
Thanks: 3,301
Fixes: 22
Registered: 22-08-2007

Re: Download Speed related to portal current line speed

Tony,
So back to my previous line of thinking.  You have been seeing errors on the line, possibly due to local interference.  Installing RouterStats would be useful in examining that possibility.
A full set of speed issue figures would be useful to see how things have changed and if they are now optimal.

Kevin
tonyappuk
Dabbler
Posts: 24
Registered: 25-07-2007

Re: Download Speed related to portal current line speed

Chris
Thank you for your response. I don't think you are correct when you say I have had a different sync rate with the exchange a couple of times over the past couple of days. I run DSLStats and that says DSL Uptime now just over 5 days. I know my line is erroring but I generally manage a sync rate of over 11 Mb and I have done for some weeks now. The improvement started of course when I went to ADSL2+ from the original basic ADSL. However my query is really about my through put rate and why it has stayed the same for weeks at 7.35 Mb as indicated by NetMeter looking as though it is limited. Your comment about the BT line profile being incorrect is right (it was 6.5 Mb) but Plusnet's Line profile/current line speed was updated to 10.2 Mb a few weeks ago. None of those things was the reason for my enquiry. It was with a sync rate of 11.2Mb why was my through put limited to 7.35 Mb? Kitz has suggested that NetMeter shows though put overall without allowing for overheads. Do you think that would account for it?
Just to say I'm pleased with my set up and don't want to set an unwanted hare running but the relationship between Bt's 6.5 Mb, your 10.2 Mb and my 7.35Mb intrigued me.
Kevin
If you had read my comments carefully you would see that I run DSLStats which would show up rein on the SNRM graph and apart from the usual drop in SNRM after dark due to MF interference  there is no indication of rein. It would also be doubtful that the router would remain in sync when the SNRM drops to less than 3dBs. As I said to Chris above my curiosity was stimulated by the apparent disparity between Plusnet's 10.2 line rate and my 7.35 throughput.
Many thanks to you both.
Tony
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: Download Speed related to portal current line speed

Sorry, Tony - I managed to get your line stats mixed up! You're quite right that your sync rate remained unchanged between 15th-19th May.
Prior to that your sync rate was 10152 on 13/05/2014. Prior to this there were a couple of changes, I imagine, DLM tinkering about with the line settings.
Quote
Kitz has suggested that NetMeter shows though put overall without allowing for overheads. Do you think that would account for it?

It's quite likely. I don't use the tool though, but from looking at it, that seems quite reasonable.
Chris Pettitt
Cloud Environments Engineer
kitz
Rising Star
Posts: 817
Thanks: 46
Registered: 08-06-2007

Re: Download Speed related to portal current line speed

Full story
Although the terms are loosely interchangeable... The IPprofile is actually based on the bRAS profile.  
The bRAS profile being higher of the 2, whilst the IPprofile we see quoted by the BTw performance tester makes an allowance for ATM overheads.
So for example if your IPprofile is showing as 7150... then the actual ATM bitrate (bRAS) profile set by BTw on the RAS is  7320.

Both Netmeter and DUmeter when showing speeds record throughput including overheads as they measure speed on the local machine, this is why speeds may be slightly higher with Netmeter than when using online speedtesters such as TBB and speedtestnet which deduct TCP/IP overheads.
I really cba to work out the specifics & maths of all the overheads, but I said it may be some contribution towards Netmeter showing a higher throughput speed than the IPprofile.
I also suggested that considering he has been in sync for quite a while at higher speeds... and that whilst the BTw performance tester was saying 6.5 Mb..  then perhaps Tony  should contact you to double check he hasnt got some sort of stuck IPprofile Smiley
Plusnet Staff
Plusnet Staff
Posts: 6,346
Thanks: 31
Fixes: 5
Registered: 26-11-2011

Re: Download Speed related to portal current line speed

By the time I'd picked this up, everything looked fine.
Stuck IP Profiles seem to be a thing of 20CN (they used to stick at 2000 - not sure if you remember) they are generally sound on 21C. I think it just took it's time updating.
Chris Pettitt
Cloud Environments Engineer