|
|
|
When the CNA system calculates a bill for the link, it will sort all of the samples obtained during the billing period, by size. All samples whose values are greater than the value of the specified percentile are discarded, and the billable rate is determined by the highest sample that remains.
If the percentile calculation (number of samples times percentile value) results in a fractional value, the result will be rounded up or down depending on how you entered the usage-reporting percentile command. If you added the plus-one keyword, the result will be rounded up. If you did not, it will be rounded down.
NOTE: The CNA system obtains its samples from edge routers at intervals you specify. These intervals are not guaranteed to coincide exactly with the sampling interval used by the service provider. When you specify the plus-one keyword, the usage estimate will tend to be slightly higher than indicated by the actual data points obtained from the edge router. Estimates on the high side should help prevent CNA billing reports underestimating the real bill sent by your service provider.
Assume that the example contract specifies a 95th percentile usage threshold (actual bill is based on the tier reached by the sample represented by the 95th percentile, allowing a small number of spikes into the next higher billing tier without penalty).
For example, if your sample interval produced 16 samples for the billing period, and the samples had the following values:
rank value ------------ 1. 2 2. 3 3. 4 4. 4 5. 5 6. 6 7. 6 8. 7 9. 8 10. 9 11. 15 12. 16 13. 17 14. 18 15. 19 16. 25
...and the percentile value is left at its default of ninety fifth, then the billable rate will be either 19 or 25 depending on whether you used the plus-one keyword. (In order to simplify for this demonstration, the example shows an unreasonably low number of non-representative values.)
The 95th percentile for the 16 values is calculated by determining 95 percent of 16:
16 * .95 = 15.2
Since rank cannot be fractional, the number has to be rounded up or down to the nearest integer.
If you did not specify the plus-one keyword, the calculated percentile value would be rounded down to 15. The fifteenth sample in the set has the value of 19, which would represent your billable rate in megabits per second (mpbs).
If you did specify the plus-one keyword, the calculated percentile value would be rounded up to 16. The sixteenth sample in the set has the value of 25 mbps.
If your contract is based on a percentile other than 95, add the following line to the CNA configuration while still in link-configuration mode, and specify the actual percentile value, such as 90:
Avaya_ANS (config-engine-link)# usage percentile 90
NOTE: If your contract specifies 95th percentile, you do not need to enter the percentile command--default is 95th percentile.
|
|
|