On 03/29/2012 01:07 PM, Ali C. Begen (abegen) wrote:
I suppose these were random losses? This is just putting numbers into the TCP throughput algorithm from the TCP-Friendly RFC using its parameter p, and trying to see what the implications of the result are.
I presume that p was assumed to be random in the derivation of the formula.
-----Original Message----- From: rtp-congestion-bounces@alvestrand.no [mailto:rtp-congestion-bounces@alvestrand.no] On Behalf Of Harald Alvestrand Sent: Thursday, March 29, 2012 1:04 PM To: rtp-congestion@alvestrand.no Subject: [R-C] Simplifying the TCP throughput algorithm
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
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