Which Layer 2 protocol encapsulation type supports synchronous and asynchronous circuits and has built-in security mechanisms?
A. Frame Relay
B. X.25
C. PPP
D. HDLC
Which Layer 2 protocol encapsulation type supports synchronous and asynchronous circuits and has built-in security mechanisms?
A. Frame Relay
B. X.25
C. PPP
D. HDLC