TLS - TLS requires a login name and a certificate issued by the target Radius server. The login name and the certificate allow the Radius server to authenticate user identity. The user can choose to authenticate the identity of the Radius server by selecting the Validate Server
Certificate checkbox.
TTLS - TTLS requires a login name, password and additional TTLS protocols. The TTLS protocol is required to match the one on the target Radius server. Optionally authenticate the Radius server identity by checking the Validate Server Certificate checkbox.
PEAP - PEAP requires a login name, password and a PEAP protocol. The PEAP protocol is required to match the one used on the target Radius server. Optionally authenticate the Radius server identity by checking the Validate Server Certificate checkbox.
LEAP - LEAP is a Cisco based 802.1x authentication scheme. LEAP requires a login name and password for user authentication.