Which VoIP components can permit or deny a call attempt on the basis of a network’s available bandwidth？（）

A.used to verify the identity of the peer
B.used between the initiator and the responder to establish a basic security policy
C.used to establish a symmetric shared key via a public key exchange process
D.used for asymmetric public key encryption

A.Static secure MAC address
B.Dynamic secure MAC address
C.Pervasive secure MAC address
D.Sticky secure MAC address

A.Enable the highest level of Syslogging available to ensure you log all possible event messages
B.Use SSH to access your Syslog information
C.Log all messages to the system buffer so that they can be displayed when accessing the router
D.Syncronize clocks on the network with a protocol such as Network Time Protocol