Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: Poor download speed but good sync speed  (Read 3537 times)

RobN

  • Member
  • **
  • Posts: 15
Poor download speed but good sync speed
« on: October 23, 2010, 06:14:41 PM »

Since Tuesday of this week I have been experiencing poor download speeds during the day,particularly bad in the evening.I have not previously experienced this,normally I've been getting a pretty solid 6000 - 6250kbps both day and night with pings around 30-40ms.At it's worst I'm now getting only around 600kps with pings as high as 200ms.From about 11pm to 7am there are no problems and I can consistently get at least 6000kbps.
I have rock solid sync speeds of 448kps upload and  7616kps download with SNR margin of 10-11.There doesn’t appear to be any congestion at the local exchange and there’s no noise on the line

Also when the speeds are low they are also variable see these speedtest.net results

http://www.speedtest.net/result/1001816056.png
http://www.speedtest.net/result/1001817488.png
http://www.speedtest.net/result/1001820706.png
« Last Edit: October 23, 2010, 06:47:29 PM by RobN »
Logged

waltergmw

  • Kitizen
  • ****
  • Posts: 2776
Re: Poor download speed but good sync speed
« Reply #1 on: October 23, 2010, 11:52:22 PM »

Hi RobN,

It would help if you provided information on your ISP, tariff and modem stats.
Assuming that your modem is synchronising correctly at all times and without excessive error counts, some contention seems the most likely cause.
If so it could be anywhere en route through your ISP's network.
Another possibility is that a FUP trigger level has been exceeded which causes throttling during busy periods.

Kind regards,
Walter
Logged

RobN

  • Member
  • **
  • Posts: 15
Re: Poor download speed but good sync speed
« Reply #2 on: October 24, 2010, 08:03:00 AM »

ISP is Madasafish(Plusnet),I'm on max premier which is 50GB per month so far this month i've used 26GB so no throttling

Router always syncs correctly and errors are very low
Logged

waltergmw

  • Kitizen
  • ****
  • Posts: 2776
Re: Poor download speed but good sync speed
« Reply #3 on: October 24, 2010, 09:06:42 AM »

Hi again RobN,

Here is the link to gather your modem's statistics:-

http://www.kitz.co.uk/adsl/frogstats.php

You might well glean more information about any local performance issues by joining:-

http://usergroup.plus.net/pugit/

Kind regards,
Walter
Logged

RobN

  • Member
  • **
  • Posts: 15
Re: Poor download speed but good sync speed
« Reply #4 on: October 24, 2010, 10:22:58 AM »

Sync Speed - 7616kps down  448kps up
Attenuation - 13
SNR Margin - 12
TX CRC errors - 5
RX CRC errors - 3
Logged

waltergmw

  • Kitizen
  • ****
  • Posts: 2776
Re: Poor download speed but good sync speed
« Reply #5 on: October 24, 2010, 12:17:49 PM »

Hi again,
RobN,

It's possible that you have a noise source as with an (assumed) downstream attenuation of 13dB you should be synchronising at the maximum of 8128 on a DSL Max service.

Firstly have you read and acted upon:-

http://www.kitz.co.uk/adsl/socket.htm

Routerstats might also illuminate a problem.

Kind regards,
Walter
Logged

RobN

  • Member
  • **
  • Posts: 15
Re: Poor download speed but good sync speed
« Reply #6 on: October 24, 2010, 05:32:36 PM »

7616kps is the highest I've ever got.I thought 8128 was only achieveable with interleaving off?

Two tests I have done today:-

Early morning    http://www.speedtest.net/result/1002360025.png

Recently   http://www.speedtest.net/result/1002883088.png
« Last Edit: October 24, 2010, 06:10:32 PM by RobN »
Logged

waltergmw

  • Kitizen
  • ****
  • Posts: 2776
Re: Poor download speed but good sync speed
« Reply #7 on: October 24, 2010, 10:54:46 PM »

Yes you're correct

http://www.kitz.co.uk/adsl/interleaving.htm

You haven't mentioned if you've observed any FEC errors.

You could experiment with interleaving but I suggest that, after checking house wiring and filters, Routerstats might be a way to discover if you have varying noise patterns.

Perhaps others here might have different ideas ?

Kind regards,
Walter
Logged
 

anything