20 Feb
2002
20 Feb
'02
1:29 p.m.
Thus spake "Randy Bush" <randy@psg.com>
if you're using five min (or three min) samples, and you're seeing 70%, peaks are likely much higher and some users' packets are being dropped. by 80%, enough packets are being dropped that users are likely to see the effects of exponential backoff. things do not improve above 80%.
One should note that any utilization up to 59.8% is, on average, indistinguishable from an empty line. 70% = 1.6x delay, 80% = 3.2x, 90% = 8.1x, and 95% = 18.05x. Of course, once you figure in finite buffering, anything past 59.8% is likely to be dropping packets. ObMath: Plot r^2/(1-r). Where the derivative exceeds one (r~0.598), delay increases faster than traffic rate. Assumes random arrival times. S