Which one of the following protocols CANNOT be used for full duplex Wide Area Network (WAN)
communications?
A.
Synchronous Data Link Control (SDLC)
B.
Serial Line Internet Protocol (SLIP)
C.
Point-to-Point Protocol (PPP)
D.
High-Level Data Link Control (HDLC)
Explanation:
By exclusion SLIP is the correct answer.
Note:
Serial Line Internet Protocol (SLIP) is an older technology developed to support TCP/IP
communications over asynchronous serial connections, such as serial cables or modem dial-up.
Pg 96. Tittel: CISSP Study Guide. SLIP is serial protocol opposed to WAN protocol.
Not SDLC: SDLC is full duplex.
“SDLC was developed to enable mainframes to communicate with remote locations.” Pg 456 Shon
Harris CISSP Certification Exam Guide. This is a WAN protocol.
Not C.
“PPP is a full-duplex protocol that provides bi-directional links over synchronous, asynchronous,
ISDN, frame relay and SONET connections.” Pg. 472 Shon Harris CISSP All-In-One Certification
Exam Guide. PPP is full-duplex.
Not D.
“HDLC is an extension of SDLC, which is mainly used in SNA environments. HDLC provides high
throughput because it supports full-duplex transmissions and is used in point-to-point and
multipoint connections.” Pg 456 Shon Harris CISSP All-In-One Certification Exam Guide. PPP is
full-duplex.