Mark
works as a Network Administrator for NetTech Inc. He wants to connect the company’s headquarter
and its regional offices using a WAN technology. For this, he uses packet-switched connection.
Which of the following WAN technologies will Mark use to connect the offices? Each correct answer
represents a complete solution. Choose two.

A.
ISDN

B.
X.25

C.
Frame Relay

D.
Leased line

Explanation:
According to the question, Mark will use X.25 or Frame Relay WAN connection for
connecting the headquarter and regional offices. Frame Relay
and X.25 are packet-switched connections.
A packet-switched connection is a type of network in which packets, which are small units of data,
are routed through a network. The
communication is based on the destination address contained within each packet. Packet-switched
connections are logical circuits to make
connection between two sites. These logical circuits are also called virtual circuits. A virtual circuit is
not tied to any physical circuit, and
therefore it is possible to make multiple logical circuits on a single physical circuit. Frame relay and
X.25 are examples of packet-switched
networks.
Answer option A is incorrect. ISDN is a type of circuit switched-connection.
A circuit-switched connection is a type of network in which a physical circuit is established between
two end-points for the duration of the
connection. During this time, none else can use the physical lines involved. Circuit-switched
connections are dial-up connections that include
two types of connections: asynchronous and synchronous serial connections. Plain old telephone
system (POTS) uses asynchronous serial
connections, whereas ISDN uses synchronous serial connections.
Answer option D is incorrect. Leased line is not a type of packet-switched connection. Leased lines
are used for short distance connection and
when you have a constant amount of traffic on the connection with a requirement of guaranteed
bandwidth.