we have successfully setup a Site-to-site IPSec VPN connection between our two offices in Germany and China. Below are the characteristics of both sites, VPN and current speeds:
VPN Router Zyxel Zywall USG 100
Site's Internet speed: 50/50 Mbps
VPN Router Cisco RV180 Multifunction VPN Firewall
Site's Internet speed: 20/20 Mbps
Ping from Germany to China: 250 - 350 ms
Ping from China to Germany: 250 - 300 ms
File Transfer speeds between sites: avg. 10KB/s
Traceroute from Germany to China
Tracing route to [10.67.8.189] over a maximum of 30 hops:
1 <1 ms 1 ms 1 ms 10.67.5.1
2 * * * Request timed out.
3 * * * Request timed out.
4 370 ms 366 ms 336 ms [10.67.8.189]
As you can see, we have major speed problems, making even Remote Desktop sometimes unusable. Previously, I have used L2TP between these sites and the performance was much better, RDP usable.
Any advice appreciated. Let me know if you need more information.