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).