15. If certificate is temporarily put on hold this is known as a) Certificate Revocatiorn b) Certificate Suspension c) Key Distraction d) Key Escrow 16. Which of the following is a protocol for PKI? a) CEP b) PKIX c) ISAKMP d) All of the above 17. Which of the following is AAA protocol ? a) Kerberos b) RADIUS c) TACACS+ d) All of the above 18. What is EAP, CHAP, MS-CHAP? a) Authentication protocol b) Tunneling protocol c) Cryptography protocol d) PKI protocol 19. Which of the following is a Tunneling Protocol which VPN can use to interconnect computers or networks? a) PPTP b) MPLS c) IPSec Transport Mode d) All of the above . Which of the following protocols can work in Tunnel Mode and Transport Mode (without encapsulation)? a) GRE b) IPSec c) PPTP d) L2TP