Dave,

 

I am sure that the algorithm is great, really. It is just that I can't figure 
out from RFC 1305 how it gets calculated: "which can be calculated in a manner 
similar to the filter dispersion described previously". 

 

My first attempt was too similar and I ran the same data points through the 
calculation but with a different "w" but that always gives a result larger than 
the filter dispersion since ¾ is always larger than ½. :-)  That is obviously 
not right.

 

I am suspicious of a particular implementation, especially since one problem 
has been found already.  I want to calculate the dispersion value independently.

 

Regards,

 

David R.

 

>Russel,

 

>he detailed calculations are in the refeence implementation document on 

>the NTP project page and in the NTPv4 Internet Draft. However, if the 

>select dispersion is excessive, it isn't because the algorithm is in 

>error; it's because you really do have large differences in the server 

>population.

 

>Dave

 

>Russell, David wrote:

 

>I am trying to validate an NTP implementation that is exhibiting a lot

>of churn in the cluster algorithm.  Unfortunately I don't think that I

>been able to properly calculate the select dispersion based on RFC1305.

> 

> 

>Can anyone refer me to a more detailed description of the calculations

>or even better some example calculations with test data?

> 

> 

> 

>Regards,

> 

> 

> 

>David

> 

> 

> 

> 

 

 

David R. Russell
CCIE #5751


Dow Jones and Company

GTS - Performance Engineering Group
Office 609-520-4458
Cell 610-909-1129
[email protected]

 

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