[R-C] Simplifying the TCP throughput algorithm

[Colin Perkins]

On 29 Mar 2012, at 13:04, Harald Alvestrand wrote:
> I did some extremely rough numerical experiments with the TCP throughput algorithm.
> 
> Results for TCP throughput in bits/sec at MSS=1440 bytes at various loss rates:
> 
> 0.001% loss: Throughput 4.5 Mbits/sec (HD can survive)
> 0.01% loss: Throughput 1.4 Mbits/sec
> 0.1% loss: Throughput 458 Kbits/sec (VGA can survive)
> 1% loss: Throughput 144 Kbits/sec (good audio can survive)
> 10% loss: Throughput 43 Kbits/sec (crappy audio can survive)
> 
> These are stable in the first 2 digits over a large range of RTT (1 ms to 100 ms).
> 
> Interesting numerical result: In all cases, the second term of the TCP throughput denominator is less than 1% of the first term, so a reasonable approximation is:
> 
> T = s / sqrt(p * 2/3)
> 
> That's a simple formula.


Add the RTT, and you get the usual TCP throughput approximation. That seemed to be the suggestion to use from ICCRG.

-- 
Colin Perkins
http://csperkins.org/