Which choice below denotes a packet-switched connectionless wide area network (WAN)
technology?
A.
ATM
B.
SMDS
C.
X.25
D.
Frame Relay
Explanation:
Switched Multimegabit Data Service (SMDS) is a high-speed, connectionless, packet-switching public
network service that extends LAN-like performance to a metropolitan area network (MAN) or a wide
area network (WAN). It’s generally delivered over a SONET ring with a maximum effective service
radius of around 30 miles. * X.25, defines an interface to the first commercially successful
connection-oriented packet-switching network, in which the packets travel over virtual circuits. *
Frame Relay, was a successor to X.25, and offers a connection-oriented packet-switching network. *
Asynchronous Transfer Mode (ATM), was developed from an outgrowth of ISDN standards, and is
fast-packet, connection-oriented, cell-switching technology. Source: Communications Systems and
Networks by Ray Horak (M&T Books, 2000).