Refer to the exhibit. In the communication between host 1 and host 2 over the point-to-point WAN,
which protocol or technology is represented by dashed line A?

A.
IP

B.
T1

C.
ppp

D.
IEEE 802.3

Explanation:
This question is to examine knowledge point about WAN connectivity. The communication
between two host computers is based on network layer; therefore their communication is actually
IP communication, Generally, IEEE 802.2 refers to Ethernet. T1/E1 represents two data
transmission speed standards. T1 is a North American Standard, which support 1.544Mbps
dedicated circuit telephone data transmission. It is made of 24 autonomous channels and
transmission speed of each one is 64kpbs, which can use simultaneously to transmit voice and
data. PPP(Point-to-Point Protocol) is a link layer protocol which is designed simple link circuit such
as transmit data between coequal cells. This link circuit supplies duplex operation and transmit
data packet in order. The purpose of the design is mainly about creating point-to-point connection
through dial-up or autonomous channels to transmit data, making it the common solution of
connection between different host computers, network bridges and routers.