Which of the following statements are true about IPsec VPNs? (Choose three.)

A.
IPsec increases overhead and bandwidth.

B.
IPsec operates at the layer 2 of the OSI model.

C.
End-user’s network applications must be properly pre-configured to send traffic across the IPsec VPN.

D.
IPsec protects upper layer protocols.

E.
IPsec operates at the layer 3 of the OSI model.