My VPN is l2tp only or l2tp over ipsec

I'm trying to setup a VPN connection in my Edgerouter POE with this tutorial: https://help.ubnt.com/hc/en-us/articles/204950294-EdgeMAX-L2TP-Server

I'm use iPad air and connect vpn with L2TP protocol same picture og can connect to server without any problem. 

But I'll ask about my vpn protocol is only L2TP or L2TP over ipsec ?  how to check it ?

thanks anyway

Regards

Anooruk