You didn't have latency issues or packet loss on the RS and you are still experiencing distortions?
What kind of distortions exactly?
Audio gets slowed down and distorted. it's not constant but it happens often enough to be a serious issue.
used UDP or RTP, so transmissions are not secured against packet loss
I already said there was no packet loss, no jitter. I tested on different networks(client side) and different vps servers,
I suppose that server is in your LAN. Isn't it?
No. It' s a bare metal server in a data center
If you google freeswitch + virtual server\vps you'll see that users are likely to experience issues with vps and freeswitch. They happen often enough for the freeswitch devs to specifically recommend using bare metal servers.
Some manage to make it run OK though.
I thought the problem was with the freeswitch internal timer or something but changing corresponding settings didn't help.
PS CPU load is less than 5-10%, no I\O issues or network issues. It's interesting to note that switching from a pure VPS to a VPS with dedicated cores significantly reduces these distortions. So, the problem is related to virtualization. I just wish i knew if it can be fixed via changing some settings