Fortinet Auto Discovery VPN (ADVPN)

http://kb.fortinet.com/kb/microsites/microsite.do?cmd=displayKC&docType=kc&externalId=FD39360

http://cookbook.fortinet.com/configuring-advpn-in-fortios-5-4-dynamic-hub-and-spoke-vpns/#comment-3708628335


http://cookbook.fortinet.com/configuring-advpn-fortios-5-4-redundant-hubs-expert/