Some guidance on integrating OTP authentication via SMS

[Santosh Kumar]

Dear All,

I need some guidance regarding OTP authentication via SMS.

I have setup a TACACS+ Server in which I have installed freeradius for 
AAA authentication. Now I need to integrate OTP authentication via SMS 
to freeradius for allowing guest users to access WiFi. As I am unable to 
find the proper procedure document, any kind of guidance or help would 
be appreciated.

Regards, Santosh