Which of the following is not considered a common approach to narrow the field of potentialproblem causes？ （Choose the best answer.）（）

A.Extranet VPN
B.Managed overlay VPN topology
C.Hub-and-spoke VPN topology
D.Central-site VPN topology
E.Full mesh VPN topology
F.Remote-access VPN topology

A.The interface must be configured as a Multilink PPP interface
B.The correct bandwidth should be configured on the interface
C.A QoS policy must not be currently attached to the interface
D.CEF must be enabled
E.AutoQoS must be enabled globally before it can be enabled on the interface
F.An IP address must be configured on the interface if its speed is equal to or less than 768 kbps

A.Serial connection
B.Secure Shell
C.RADIUS
D.Simple Network Management Protocol
E.HTTP
F.Telnet