A.To prevent customers from running TDP with the ISP routers
B.To prevent customers from running LDP with the ISP routers
C.To prevent other ISPs from running LDP with the ISP routers
D.To prevent man-in-the-middle attacks
E.To use CBAC to shut down Distributed Denial of Service attacks
F.To use IPS to protect against session-replay attacks
G.None of the above

A.IKE keepalives are unidirectional and sent every ten seconds
B.IPsec uses the Encapsulating Security Protocol （ESP） or the Authentication Header （AH）protocol for exchanging keys
C.To establish IKE SA, main mode utilizes six packets while aggressive mode utilizes only threepackets
D.IKE uses the Diffie-Hellman algorithm to generate symmetrical keys to be used by IPsec peers