Sat uplink issues

[Florian Lohoff]

Hi,
we are running unbounds in satellite connected networks. When unbound
forwards its request directly via the Sat link everything is fine. 
prefetching etc etc. When we use a customer supplied upstream cache
in front of the sat link it seems we are running into issues.

Typically when we hit the upstream cache we'll get responses within
1ms - But when the upstream cache needs to query over the sat link
the very same forwarder suddenly may take 3000ms.

This causes unbound to retry the query multiple times and responses
will eventually come but it seems they are too late to actually
get accepted.

My guess is that the average rtt for the forwarder is pretty low
and the exceptional multi-second resolving breaks the dynamic 
timeout calculation.

My first idea was to play with infra-cache-min-rtt and set it 
to something like 2-3000ms which will obviously blow up horribly
in case of loss in the network.

Anything else?

Flo
-- 
Florian Lohoff                                                 f at zz.de
        UTF-8 Test: The 🐈 ran after a 🐁, but the 🐁 ran away
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