Хвостат Хвостатыч (hvostat_hvostat) wrote,
Хвостат Хвостатыч
hvostat_hvostat

"How to Calculate TCP throughput for long distance WAN links"

http://bradhedlund.com/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/

Экстракт:

So lets work through a simple example. I have a 1Gig Ethernet link from Chicago to New York with a round trip latency of 30 milliseconds. If I try to transfer a large file from a server in Chicago to a server in New York using FTP, what is the best throughput I can expect?


Ну и ответ с формулой:
First lets convert the TCP window size from bytes to bits. In this case we are using the standard 64KB TCP window size of a Windows machine.

64KB = 65536 Bytes. 65536 * 8 = 524288 bits

Next, lets take the TCP window in bits and divide it by the round trip latency of our link in seconds. So if our latency is 30 milliseconds we will use 0.030 in our calculation.

524288 bits / 0.030 seconds = 17476266 bits per second throughput = 17.4 Mbps maximum possible throughput
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