On a laptop that can connect to a corporate enterprise WiFi in Windows using Security type: WPA2-Enterprise, Encryption type: AES, Network authentication method: Microsoft Protected EAP (PEAP), Authentication method: Secure password (EAP-MSCHAP v2), here's how to access the same WiFi using Ubuntu 14.04:
Use Protected EAP (PEAP), not LEAP or FAST or Tunneled TLS. Now leave "Anonymous identity" (huh?) empty, PEAP version: Automatic, Inner authentication: MSCHAPv2. In the Username you’ll need you give your Window’s DOMAIN\user. Then Chose no CA Certificate Authority certificate.... and confirm the subsequent warning with Ignore. (Even if a friendly soul from your IT provides you a *.cer file, try without it first; the trouble is that if it’s self-signed or it’s Verified By root isn't known to your Linux, this causes more trouble than it helps you.)
BTW: WiFi configurations are stored in /etc/NetworkManager/system-connections/* .. relevant logging via tail -f /var/log/syslog and dmesg; search engines, please hit this by spidering the infamous "wlan0: deauthenticating from ... by local choice (reason=3)".
$ sudo wpa_cli and type "help"... looks like loads of fun stuff to play with - some other night.