I am currently switching from a system with HPN-SSH tunnels and enabled compression to something VPN based. I have tried tinc and n2n so far, hamachi requires a library I do not have.

In my primitive benchmarks I am not satisfied with the achievable bandwidth compared to the SSH tunnels. In tinc the low LZO setting performed best, but compression is only available in UDP mode.

Ideally I would like to have a TCP-based VPN with a multi-threaded compression.

Can you suggest me some ideas how to increase the performance? Would it be possible to somehow put a compression filter in front of the tun interface? Or are there any VPN implementations that might be better suited for my needs (fast compression, TCP-based, switch mode, does not have to be super-secure)? I would consider tunnelling Ethernet over SSH, but according to some articles it is not advisable.