I am currently working on L2TPv3 which provides layer 2 VPN and transparently forwards any layer 2 frames from one site of customer to other site over Service Provider's IP network. I want to know that which protocol provides stronger security with efficiency. As in IPsec add another header of ESP or AH at layer 3 while L2TP add its 12 bytes header between IP and Layer 2 frame. In IPsec we use algorithms for encryption and integrity while in L2TP there is no algorithm we use. Kindly comment on the security mechanism of IPsec vs L2TPv3.