C-Servers uses two different network stacks:
» for NAT VPS services: we use Libvirt for the entire IPv4 NAT and IPv6 network stack on these services at VirtFusion.
» for Full IPv4 VPSes/add-ons: we use the default MacVTap whenever possible and to the higest extent possible, including IPv6, if feasible.
But you did have OpenVSwitch before, right?
Yes, on our SolusVM-based offers, these use OpenVSwitch for general IPv6 and IPv4 connectivity, and socket-to-socket NAT VPS bridging, through Socat.
We've decided to ditch both systems due to long-term unforeseen resilience specifics with OpenVSwitch that, in practice, limit expansion; and due to the technical challenges that the socat service poses, in practice, to our previous users.