At 02:07 PM 23/02/2006, Randy Bush wrote:
HD Ratio Ratio Mean Std Dev
0.98 1.04868 0.02285
0.97 1.25899 0.03363
0.96 1.45854 0.03371
0.95 1.63073 0.02848
0.94 1.78332 0.01859
and what does .98 do to the flight ceiling of small folk?
randy
I'll respond to this question, but in the interests of not wishing to
overwhelming a whole swag of mailing lists I'll make this my last posting
on this topic today.
An HD Ratio of 0.98 imposes a higher efficiency target than the existing
80% rate for all prefix sizes smaller than a /16, and lower than 80% for
allocations greater than a /16 (e.g. an HD Ratio of 0.98 implies an
efficiency threshold of 72% for a /9 allocation.)
As an example, if you had an end use population of between 3,277 and 6,554
numbered devices you would qualify for a /19 allocation under an 80% rule,
while under an HD Ratio of 0.98 the end use population is between 3,468 and
6,841, corresponding to a required address efficiency level of 84% on this
address block in order to qualify for a further address allocation.
The use of an HD Ratio of 0.96 corresponds to an 80% efficiency level for a
/24, so that 0.96 is no worse than 80% for all allocations, whereas
HD Ratios greater than 0.96 impose an efficiency constraint greater than
80% on the smaller address blocks (/16 through to /24) - this can be
easily modelled on any spreadsheet of course.
regards,
Geoff
