Which of the following was designed to support multiple network types over the same serial link?

A.
Ethernet

B.
SLIP

C.
PPP

D.
PPTP

Explanation:
Point-to-Point Protocol (PPP) is a full – duplex protocol used for the transmission of TCP/IP packets over
various non-LAN connections, such as modems, ISDN, VPNs, Frame Relay, and so on. PPP permits multiple
network layer protocols to operate on the same communication link.
Incorrect Answers:
A: Ethernet is a link layer protocol in the TCP/IP stack, but Ethernet is not used for serial links.
B: SLIP is a predecessor of PPP which do not support multiple network types over a single link.
D: PPTP is a tunneling protocol which uses a control channel over TCP and a GRE tunnel operating to
encapsulate PPP packets. PPTP tunnels do not handle network types.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 683