You can't differ between F.R and VPN.
The F.R is one of the WAN connection like TDM, ISDN...
And if you mean VPN as IPSec VPN, this technology is used over the public network to be able to connect your private network, this will encrypt your traffic going to your private network in a tunnel.
Some helpful documents,
F.R -> http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/frame.htm
VPN -> http://compnetworking.about.com/od/vpn/l/aa010701a.htm
let me know if you have any questions!
Please rate if it does.
Abd Alqader
