Which Layer 2 protocol encapsulation type supports synchronous and asynchronous circuits
and has built-in security mechanisms?
A.
HDLC
B.
PPP
C.
X.25
D.
Frame Relay
Explanation:
PPP: Provides router-to-router and host-to-network connections over synchronous and
asynchronous circuits. PPP was designed to work with several network layer protocols,
including IP. PPP also has built-in security mechanisms, such as Password Authentication
Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP).