I used Ubuntu 22 and Strongswan 5.9.5 to setup a WAN connection over a high latency (240ms) line like this:
A == VPN1 == VPN2 == VPN3 == B A and B are servers in two servers networks VPN1 and VPN2 are two Strongswan 5.9.5 on Ubuntu 22, managed by me. VPN3 is a VPN device not managed by me. VPN2 has a total network bandwidth of 20Mb/s. The test is to copy files between these servers using rsync. A, pulling files from B, can only reach 150Kb/s A. pushing files to B, can reach 20Mb/s VPN1, pulling files from B, can only reach 150Kb/s VPN2, pushing files to B, can reach 20Mb/s VPN2, pulling files from B, can reach 20Mb/s VPN2, pushing files to B, can reach 20Mb/s iperf3 client on A and iperf3 server on B can reach 20Mb/s. Multiple rsync on A, pulling files from B, can push the network bandwidth usage higher. I tested 4 concurrent rsync processes and reached 10Mb/s. During all of these tests, CPU load and memory usage of VPN2 is minimal. No other workloads. Does anyone have a clue? Thank you. JM.
