[tor-talk] VOIP over Tor: PTT remark

[Van Gegel]

I did some tests now and have comments to the PTT mode.
I used TCP socket with disabled Nagle algorithm to send packets, the data
is sent in portions of 140 bytes every 80 mS for recipient?s hidden
service.
Absolute delivery delay of the first packet was less than the average
delay for continuous transmission, but subsequent packets jitter was
considerably greater.
I noticed that at least 10-20 seconds of continuous delivery is kind of
tunnel adaptation and reduced jitter. Still, the beginning of the
sentence was interrupted, some packages rejected by codec due to
significant jitter. In addition, after transmission some of the data
remains in the channel during tens of seconds and and delivered
immediately only after the start of the new transmission.
In TORFone 0.2 I have provided the possibility of transferring some dummy
packages after each voice packet to ?push? it and saturate channel. Most
likely, the dummy packages are also needed in voice chat, but it will
significantly increase the load on the server.