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