Why does the dl speed grinds to a halt if your uploading

Phil2008

Phil2008

Phil2008

Soldato
Joined
17 Dec 2004
Posts
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Im uploading a file to my mate, and it just kills the download speed if I use more then 20% of the upload speed(upload speed is only 60kb)... Aso why is the upload speed sooo much slower then the download speed.
 
It shouldn't kill things if you're only using 20% or so of your upload.

The reason that having a very busy upload will kill your downstream is down to the way TCP, Transmission Control Protocol (of TCP/IP) works. When you get sent a packet of data your PC will confirm to the sender that it was received. If the confirmation is not received by the sender than that packet gets sent again.

If your upload is very busy then the acknowledgement packets don't get through which can result in a huge amount of re-transmission.

Generally speaking, TCP/IP is used when it's important that ALL the data gets through. An email for example, if you're missing some of the data then the email isn't readable. There's also UDP where there is no acknowledgement. UDP is used for VoIP as if a packet of VoIP traffic arrives 1/2 second late then it may as well not bother as the conversation has moved on so it's better to have a very brief dip in the conversation than have part of a word arrive out of sequence.
 
If you have a big delta between upload and download speed it doesn't take using much of the upload % wise before the download suffers (due to the ack situation as mentioned above). 60KB seems quite low compared to modern download speeds?
 
Yeah my dl speed is roughly 8mb normally and up is 0.6mb, Like atm Ive set the upload speed at a crappy 5kb, because browsing the net is just horrible and slow if I increase the up speed much more.
 
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