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Good connecting speed - slow download speed...

PNnewbie
Rising Star
Posts: 267
Thanks: 4
Fixes: 1
Registered: 04-07-2008

Good connecting speed - slow download speed...

Hello,
Been having problems with YouTube lately, its always buffering.  When I checked my speeds its obvious there's something amiss.
RouterStats tells me I'm connected at 6275 kbps with a noise margin of 1.9 db.
The Namesco speed checker says I'm downloading at 1033 kbps and uploading at 792 kbps.
Now I'm sure I always used to download at ~5000 - 5500 so I wonder what's gone wrong?
I did try and raise a ticket with Plusnet but couldn't find the appropriate page (must make a shortcut to it as I've had that problem before!!!)
Any ideas?
9 REPLIES
Plusnet Staff
Plusnet Staff
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Registered: 26-11-2011

Re: Good connecting speed - slow download speed...

Hi and welcome to the Forums, even though you've been here a while! Smiley
I've just taken a look at your line and can see that it's dropping out on a fairly regular basis:
<img src="http://community.plus.net/visualradius/generated/image13974825555637.png"/>
Now, you may not notice a large amount of the drops but a good number of the drops result in your connection rate reconnecting at a muhc lower rate, which is probably the reason for you seeing lower speeds.
I would advise visiting http://community.plus.net/library/broadband/broadband-faults-guide-frequent-disconnection-fault-dcn/ to have a read up on how the fault might be affecting you and what you can do to try and rule out anything internal causing the problem. If you feel that you need to raise a fault, you can do this at http://faults.plus.net
Chris Pettitt
Cloud Environments Engineer
Superuser
Superuser
Posts: 11,099
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Registered: 22-08-2007

Re: Good connecting speed - slow download speed...

Hi PNnewbie,
Not so new any more...?
Such a low SNRM rather suggests that you have noise on the line, giving rise to high error rates and thus significant retransmissions.  Speed tests measure the effective data transfer rates.  If because of errors every data package needs to be sent twice before it is received without error, then in broad terms, your data speed is half of your synch speed... without thinking of all of the data transmission protocol (error checking data) overheads added in to the equation.
Posting your full router stats on here will give us some visibility of the error counts for the connection time.
Doing a 17070 option 2 quiet line test will inform us if you have a voice fault on the line, which will need to be fixed by your telephone line supplier before trying to address your broadband issues.
Take a look here - http://community.plus.net/forum/index.php/topic,96155.0.html - for fault finding guidance.  have you tried the router in the master socket?  do you have extension phone wiring?
Post some more information here and advice will be offered as the stats dictate.
PNnewbie
Rising Star
Posts: 267
Thanks: 4
Fixes: 1
Registered: 04-07-2008

Re: Good connecting speed - slow download speed...

Cor that was quick - thanks Townman and Chris...
>>> Not so new any more...? <<< 
No, been around for a while now,  Don't post - or complain - very often as Plusnet service has been good to me apart from the  'very'  occasional hiccup which quickly gets sorted.
Now I'm a trifle embarrassed as within minutes of my initial post the download speed came back up.  Wish I knew why...
Routerstats now reports a connecting speed of 6451 kbps and a noise margin of 1.6 dB.
(That's a bit higher than before, I did re-boot the router though and used DMT to lightly tickle the speeds...)
Namesco speed checker reports downloading at 5209 kbps and uploading at 814 kbps
Now I think all this 'may' be self inflicted.  I've an amateur radio licence and have been trying out a new antenna, running a couple of hundred watts and I suspect RF may have been getting into the pc/router.  I've had a couple of clamp on ferrites on the phone line where it enters the house for a long time, I've also got a mains filter between the router (an elderly DLink) and the mains supply but I suspect I may need some further rf suppression.  Any hams out there had the same problem I wonder?
Now I can get back to my youtube to gloat over Andrea Berg... Tongue
Go on - spoil yoiurselves:-


Thanks again guys for your help.
Superuser
Superuser
Posts: 11,099
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Registered: 22-08-2007

Re: Good connecting speed - slow download speed...

Opps!
Yes potentially self shot in right foot - however, the SNRM is very low... unless you've "fiddled" the router to determine its own SNRM... in which case you have made the ice quite thin and potentially taken the router's operation into to a high error rate margin.
Where synch speed is concerned there are points of no beneficial return in making the synch speed go faster and I do wonder if in tinkering with the SNRM you've passed the point of beneficial improvement?  Being a ham operator, I'm sure you'll understand that there is little point in receiving a signal with a low SNR if you have to resend everything twice before it can be understood.  In the case of your tweaked low SNRM to get a higher synch speed, you might be better off with say a 3dB SNRM, a lower synch speed requiring fewer retransmissions thereby delivering a higher effective data transfer speed.
HTH!
PNnewbie
Rising Star
Posts: 267
Thanks: 4
Fixes: 1
Registered: 04-07-2008

Re: Good connecting speed - slow download speed...

Hi Townman,
Yes totally agree with your comments re the low noise margin, sailing a bit close to the wind I suppose!  It will drop a bit lower mid evening onwards, also if the weather has been bad for a few days (This old DLink will work quite happilly with a fairly low noise margin
PNnewbie
Rising Star
Posts: 267
Thanks: 4
Fixes: 1
Registered: 04-07-2008

Re: Good connecting speed - slow download speed...

Oops - hit the wrong button and posted before I'd completed the reply...
Yes totally agree with your comments re the low noise margin, sailing a bit close to the wind I suppose!  It will drop a bit lower mid evening onwards, also if the weather has been bad for a few days (water in the ducts?)
I'll maybe tweak it upwards a bit just to be sure.  Living about 4 miles from the Exchange I suppose my speed is perfectly acceptable really - an improvement of the old 28k modem I had a few years ago !!!  Most people will have started with a 56k.
Thanks again.
Superuser
Superuser
Posts: 11,099
Thanks: 2,471
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Registered: 22-08-2007

Re: Good connecting speed - slow download speed...

Hi PNnewbie,
I am sure that it will, I guess I did not make my question plain - is the low SNRM the result of the SNRM being managed by the DLM (bad noisy line) or have you forced the router to have a low DLM by 'managing' its innards to squeeze the synch rate?
If the latter, it could be that you are forcing higher than desirable retransmission rates, thereby lowering the effective data transmission speed.  You might find it worthwhile running something like router stats to monitor the error recover counters.  If they run hot, try raising the SNRM a little to see if that lowers the error rates and there by improved data through put.
That said the last Namesco speed test reported 80% of your current synch speed, which is not at all bad.  Personally I'd keep a watchful eye on the error rates, both generally and as the weather changes.  Yes 6+Mbps at 4 miles is quite good.  Are you ADSL or ADSL2?  You are clearly on 21CN... if you needed to squeeze more out of the DS, you might consider capping the US if you do not need the US capacity.
PNnewbie
Rising Star
Posts: 267
Thanks: 4
Fixes: 1
Registered: 04-07-2008

Re: Good connecting speed - slow download speed...

>>>  is the low SNRM the result of the SNRM being managed by the DLM (bad noisy line) or have you forced the router to have a low DLM by 'managing' its innards to squeeze the synch rate? <<<
I've been using DMT but only as an excercise really, interesting bit of software.
Yes I'm on ADSL2, I understand our local exchange (Menai Bridge) updated in Summer 2012 and I think I'm right in saying we're 21CN enabled.
Ref your last comment about capping the up speed, that's interesting.  About the only time I use it is for uploading digital pictures to PhotoBox.  I do however use Echolink and Skype so maybe they could be affected?
Thanks for your interest and help.
Superuser
Superuser
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Registered: 22-08-2007

Re: Good connecting speed - slow download speed...

Quote from: PNnewbie
Yes I'm on ADSL2, I understand our local exchange (Menai Bridge) updated in Summer 2012 and I think I'm right in saying we're 21CN enabled.

Being 21CN enabled and being on ADSL2 are not the same thing.
I am on 21CN and have an uncapped US, but I am on ADSL (ITU-T G.992.1) at the moment as at 50dB attenuation I am arguably right in the middle of the zone which is marginal between ADSL and ADSL2.  I'm running a debate elsewhere here about the (marginal) potential benefit of moving over to ADSL2.  To confirm what you have, you need to know the modulation type being used by your router.
HTH