[tor-talk] Tor VoIP PBX Architecture Discussion

[Iain Learmonth]

Hi Conrad,

On 20/10/18 06:07, Conrad Rockenhaus wrote:
> 4)	Results of a test were conducted and one second round trip latency was noticed from PSTN to a soft phone connected via Tor (via OpenVPN). Hopefully performance improvement will be noticed with OnionCat.

Tor Metrics has some data on average latencies for client to Onion
service. This is your absolute minimum latency, with the only way to
reduce this being to have latency-aware path selection or to reduce
latencies on the Internet (e.g. by swapping fibre for copper or copper
for microwave).

https://metrics.torproject.org/onionperf-latencies.html

You get benefit from using an Onion Service over using an exit in that
you're using less constrained resources (exits are scarce) but you also
add extra hops to your circuit. For now, these extra hops do increase
latency. Configuring your onion service to not be location hidden would
improve this.

It would be interesting to see what kind of overheads are added by
OnionCat, but I see that this is a project that has an end in sight
unless someone comes up with a way to make it work with v3 Onion
Services. IPv6 addresses are not long enough to encode keys into to make
them self-authenticating. Either we need IPv7 or perhaps some
Onion-native network layer or something else.

If you have the endpoints that support it, Codec2 might give you some
benefits. This was originally designed for amateur-radio low bandwidth
digital voice but is also supported by Asterisk.

It might also be that half-duplex communication (even if implemented
with humans saying "over") could bring benefits as this would allow you
to increase the buffer sizes without having people talking over each other.

Thanks,
Iain.

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