How do you tell what kind of VPN when you're in a VPN session?

Maybe this is an obvious question, but how do you tell what kind
 of VPN you're running when you're in the middle of a VPN session?

Here's all I did to run a vpn session:
 1. Install openvpn ($ sudo apt-get install openvpn)
 2. Find a VPN config file on the net ($ firefox http://vpngate.net )
 3. Start a VPN session ($ sudo openvpn --config that-file-you-found.ovpn)

Once the vpn session is running, I just want to know *what kind* of VPN
it is that is running. Since I always use the config files from the same
server, you'd think that server web page would tell me, but it doesn't
seem to tell me what kind of vpn session it is that I'm running.

I will attach both a config file and a log file separately (because there
is probably all that I need to know in those files, if I only knew what
to look for).

Googling on what kinds of VPN there are, it seems that absolutely no
web page gives you the information you really need. It's really amazing
how many VPN "tutorials" you can read, none of which give you the  
answer to this question.

Based on reading dozens of VPN tutorial web pages, I can summarize:

1. Point-to-Point Tunneling Protocol (PPTP)
2. Layer 2 Tunnelling Protocol (L2TP) in conjunction with IPsec
3. SSL VPN (Secure Socket Layer)
4. SOCKS

Since the only thing I do to run the VPN is run a given config file
with openvpn, I'm not sure what kind of VPN it is that I'm running.

All I'm asking in this thread is the most basic of questions, which
is *how* do I know what kind of VPN it is that I'm running, once I  
start a VPN session with openvpn?

REF:
http://compnetworking.about.com/od/vpn/a/vpn_tunneling.htm
http://www.internet-computer-security.com/VPN-Guide/VPN-Tutorial-Guide.html
http://www.pcworld.com/article/223044/vpns_for_beginners_to_experts.html