Uploading slows downloading

[#1]

Hi there, New kid on the block, generally delighted with Plusnet 
Sorry, I've looked but not found a thread that already answers this question.
Why is it that when I upload anything, send an e mail, a Pando package, anything. My download, surfing, refresh comes to an almost grinding halt.?
Even my internet radio loses it's buffer, and that has a ridiculously low bitrate.
As soon as the e mail is sent, the Pando is sent (or paused) etc normal service is resumed on the receiving side, browsing gets fast again and internet radio reception is recovered.
Any ideas please?
Can I resolve it, or is it a Plusnet/Exchange thing?
thanks
Ian 

[#2]

It might be something to do with your security package as it certainly isn't a Plusnet server thing

[#3]

Thanks, I'm with Bitdefender........... didn't do it with my previous ISP.
just turned off the firewall, and sent a test e mail, no different I'm afraid.
Confusion reigns, I'm baffled.

[#4]

Just found this.................... If I'm honest, I don't understand it.
Oh, and by the way, I neither upload nor download from/to anything "dodgy"
This is an issue of your internet provider, it is not an Ubuntu problem.
The reason behind this misbehavior is that you certainly use an ADSL line which is by design asynchronous. That means that you have a wide download bandwith and a very narrow upload bandwith. You should know that TCP/IP protocol (the one we all use to surf/download from the internet) requires that for every data packet that gets in, one ACK packet needs to get out in order to tell the remote server the previous packet correctly arrived at his destination. If the remote server does not receive any ACK packet it does not send you any further data packet.
Now, since you saturate with an upload (i.e. high P2P uploads) all your upload bandwith your provider provides you, your network interface has to queue the ACK packets, thus the remote server slows down the data packets thinking there is a traffic jam on your internet connection. And that is what actually happens!
You should definitely complain with your internet provider for this! Or maybe just buy an internet access where DL/UL speed are not so different. I.e. a 4Gbit/0,2Gbit connection will never reach its full download speed if you use up all your upload bandwith.

[#5]

think you have the units incorrect on your last line
do you know what your speed are?  the quickest way to see is do a mybroadband speed test  http://www.mybroadbandspeed.co.uk/
for instance my current is

[#6]

Thanks Pierre, I copied and pasted that piece from elsewhere............ currently, I've got.

[#7]

Can you post your router stats?

[#8]

looks like you are on plain ADSL, the normal up load speed is about 500kb, so if you are uploading at max speed it will take just 500kb away from you down load speed of  5809kb  so you will end up with about 5300, i.e. not a large percentage

[#9]

The only time I have seen anything like that was when one of my children's computers had a P2P service running without an upload limit (it wasn't downloading at the time) and it killed my downstream speeds. I think it was because the router was saturated and the small upstream check packages were getting heavily stalled.
Why you should get that just uploading files I have no idea.
Which router are you using

[#10]

Thanks all, Belkin f5d8361-4

Is the attached pic the required  stats?

[#11]

its possible you are on ADSL2  you downstream rate is 9724.
The other bad thing is that you are using a very unsecure security that can be cracked in second WEP, you should be using WPA  at least
I will leave it up to the others to take you further

[#12]

Thanks, I'll sort the security post haste.

[#13]

If you do a lot of uploading you should benefit from requesting your upstream speed be uncapped which would probably double the upload speed. You can request that by raising a ticket.
However the basic problem is that correct receipt of downstream packets has to be acknowledged before the server will send any more. Usually RWIN is increased to reduce the frequency at which ACK (acknowledgement) packets have to be sent. Windows XP computers need that setting manually whereas it is set dynamically on Windows Vista and 7. Sorry, I don't know how Ubunto handles this.
You could liken the problem to the ACK packet trying to join a road with streaming (upload) traffic going past. It has to queue until there is a small gap to slot in. Until the server receives the ACK it doesn't send further data so download pauses. Uncapping upload speed might help. Are there any settings to reduce Pando (and large email) upload speeds to avoid the connection being swamped?

[#14]

Thank you, I sort of undersdtand that, I'm actually using 7, although on a dual boot system with XP.......... I wonder if XP will respond differently.....
The ubuntu bit was just a forum page where I found someone with a similar problem.
One of the major frustrations is that Pando uploads at a snails pace, and yet still slows everything down ridiculously.
I'll have a play.
Thanks again

[#15]

If you try this with XP almost certainly you will need to increase RWIN to around 150000. This is most conveniently done using DrTCP from dslreports. Download the .exe file, it's a very small application. It doesn't install on your computer, just double-click the icon to run it. With XP you could also try a tweak test.
Make sure the MTU on your router is at least as large as that on your computer to avoid packet fragmentation (1500 suggested).