[dns-operations] Question for fellow users of RIPE ATLAS (broken/saturated probes or what?)

Giovane Moura giovane.moura at sidn.nl
Wed Dec 19 10:30:12 UTC 2018


Hi Philip,

> My preliminary conclusion is that it caused by recording the start time
> of the measurement, for the purpose of computing the response time,
> before all initialisation is complete.

Thanks for addressing this issue and for posting it here.

> V1 and V2 probes can be excluded from measurements using probe tags. V1
> and V2 probes have tags system-v1 and system-v2. To exclude hose probes
> from a measurement add the tags to the exclude list in the probe
> specification of a measurement.

Yep, nice way to go around it.

First I was worried if this issue could have led to artifacts in
measurement studies, which could have probably change conclusions and
findings.

However, I don't think that is the case. First, it only affects  one-off
measurements (ie: 1 query/packet/request per probe) -- I've shown in
this list how built-in measurements were not affected, neither one that
I ran for two hours.

And I am not aware of any measurement study which uses only 1
query/packet/request per probe. Multiple samples is key to avoid
transient conditions,artifacts.

Thanks once again for the clarification  and for providing a solution.

/giovane



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