[R-C] Simplifying the TCP throughput algorithm

[Harald Alvestrand]

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.

                  Harald