Is all the network traffic forwarded by VPN Center?

[cst_zf]

I build a L2 site-2-site VPN with a VPN Center in Windows Azure.

I want to know:
1. if all the traffic is sent to the Center and then forwarded to other site, or they are just sent to each other directly?
2. How can an IT admin find there's a softether Center or Bridge in his network?

[thisjun]

>1. if all the traffic is sent to the Center and then forwarded to other site, or they are just sent to each other directly?
The former is correct.

>2. How can an IT admin find there's a softether Center or Bridge in his network?
In default settings, IT admin can detect SoftEther by DDNS communication or port scan.