[atlas] Anchors as target hosts for SLA

On 06/06/2017 19:03, Gert Doering wrote:
> On Tue, Jun 06, 2017 at 06:48:33PM +0200, Antonio Prado wrote:
>> This Internet transit should meet the following criteria:
>>
>> average round trip delay (echo request, echo reply) toward
>> $NEAREST_ATLAS_ANCHOR should be less than 100ms on a 10k packets stream
>> of pings; packet loss equal or less than 0.02%
>>
>> pros, cons, recommendations?
> 
> Too simple.  What if that anchor is down, or the anchor host network has
> a network bottleneck towards the transit provider you are using?
> 
> So you need something that averages over multiple anchors - we used to
> do that via TTM ("if our TTM hosts can reach more than 80% of all other
> TTM hosts, we declare the Internet to be in good working condition" - note
> the "80%", because something is always down somewhere) but haven't come
> around to define & implement something based on ATLAS yet.

You could also check the new stability system-tags on the anchors.

That way you only compare with the anchors that are believed to
currently have 'good' reachability.

Cheers,
Colin