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View Full Version : A lil confused about RWIN

Macbeth
12-12-01, 11:50 AM
It seems there is some kind of ration with ping and bandwidth when dealing with RWIN values. Is this true? It seems that a lower RWIN reduces ping and bandwidth, and a higher RWIN increases ping and bandwidth. Can someone confirm this?
Augusto
12-12-01, 11:58 AM
you are right . high number means big packets so the ping takes more time.

low number = little packets. , less ping time
Macbeth
12-12-01, 03:13 PM
Hmm, sounds nice. I use my cable mainly for the excellent pings that I can get, and I rarely use it for downloading anything bigger than 20 megs. So it would benefit me to set a low RWIN value? Right now it's set at 20440. My connection speed is 768/256
MikeyMan
12-12-01, 06:40 PM
The size of the Receive Window does not effect ping time. Test it yourself if you want.

The RWIN is the amount of data, in bytes that will be received before an ACK(nolegement) is sent incidating to the server you are downloading from that you have recieved all information, continue sending more packets. The MTU, the Max Transmission Unit is the amount in bytes per packet. In theory, the smaller the MTU, the lower the ping (by like 2ms or so, there is a rather lengthy equation if you want specifics) due to the smaller packets. Edit.... Hey, look what I found - http://www.speedguide.net/editorials/packet_size.shtml

You could say; It's easier to catch baseballs than medicine balls. With broadband today, you're throwing that medicine ball at the Jolly Green Giant, who can easily use that larger ball.

Back then and now, most of the country is on dial-up. (more bandwidth for us)
Microsoft's default RWIN for older OS's has been 8192 and the MTU at 576 since that was determinted to be the optimum settings for dial-up by Microsoft. Of course, when was Microsoft correct on the first try, eh?
Anyhow, with the new OS's, like Win2k, the default RWIN is somewhere in the 14k - 17k range (I forget off the top of my head) with the popularity of broadband. Of course, for modern broadband, most of the time, that is also too low. Thus, the speed tweaking sites (and scams) were born.