Currently, I’m looking for the best solution to connect 2 sites with each other. I had in mind to purchase 2 Mikrotik routers and create a bridged VPN tunnel. Both sites have low-latency 100mb uplinks, and I’d like to get the most out of them, so I have a few questions:
[] What type of VPN has the lowest overhead in this type of situation?
[] Does the performance of the various RouterBoard models (e.g. RB750GL vs. RB450G) really have an impact on the VPN performance?
[*] Could anyone give any indication of the speed I could expect of a VPN tunnel in this situation?
The least secure ones will get you the best throughput, so EoIP or GRE will net you the best performance, but offer no encryption or security. They also require static IPs and cannot dial into a server to setup a connection. If you have static IPs on both sides of the connection, then there’s no problem.
Yes different boards will have different performance capabilities. With playing around with EoIP and GRE in my lab, I was able to get near wirespeed on two 493’s in my office using the built in bandwidth test with two 450G’s. The more processing power the board has, the more traffic is able to go over the tunnel. If you have 100Mbps links, I would recommend a 450G at minimum. A lot of it also depends on what other services and firewall rules you want to have on the router. It might be worth it to look at a Power PC based RouterBoard too for extra processing power.
If you want to use one of the PPP based VPNs for more security, you will see significantly less bandwidth.
I use OpenVPN for Site to Site VPN tunnels with RB450G, and seen transfer speeds up to 10-15Mbps. It’s pretty stable too, but if connection goes up/down, sometimes the IP address on the Ovpn Client gets “stuck”/invalid, and before tunnel re-connects successfully, i have to log-in and delete that Dynamic ip address from the ovpn client router. Happens rarely though, once a few months, and even less often with v5.8. So far so good.