It uses RADIUS based authentication. From your perspective you don't care if it is using username/password with PEAP+MSCHAPv2, EAP-TLS, PEAP_EAP-TLS, etc, you just pass through the RADIUS request and get back an accept or deny.
It's up to the RADIUS server to decide what authentication methods to allow and who to give access to.
>Also is it common to use the same SSID for Corp laptops and mobile phones?
I often use a separate SSID, but I often use different authentication methods per SSID, along with Microsoft NPS, which limits your options a lot.
But as long as the RADIUS server can accept all the methods you want to use, and reply with a group policy to assign then you can certainly use a single SSID.