[atlas] probe selection criteria on "WW" measurements

Hi Paul,

On 7/24/14, 3:26 PM, Paul Vlaar wrote:
> Hi, I have two questions regarding probe selection for UDMs.
>
> When I specify for example that I want to run an ongoing measurement on
> 250 probes in the "WW" region, will these probes remain the same
> throughout the lifecycle of the measurement (unlimited) or will these be
> somehow randomized every time the measurement is run?
>
> Secondly, I am wondering about even spread of probe location in doing
> such a measurement. For instance I am as much interested in results from
> regions that have only a few probes, as I am interested in results from
> those regions that are better served. When I look at the results so far
> of a test measurement, it appears that I'm receiving results from 35
> probes in US, but only 3 from FI and none from NO. The latter surprises
> me a bit since there are 100 probes reported in NO, so why aren't there
> any results from those coming back?
The main reason for this is that when you specify only WW the only 
criterion to pick a probe is how busy it is in terms of how many 
measurements probes is assigned. We don't try to make any balance 
(country/region/ASN/prefix) except how busy is it and which controller 
they are connected.
>
> While I understand that countries with more probes will likely yield
> more results, I am wondering if there is any method to get a better
> "country-balanced" result for measurements ran in "WW".
I am afraid not at the moment. But, maybe there is something to consider 
for the future since I think other people have request it and we have 
internally discuss about it.
>
> Thanks,
>
> 	~paul
>
Regards,
Andreas