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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