Refers to protocols in which messages are divided into packets
before they are sent. Each packet is then transmitted
individually and can even follow different routes to its
destination. Once all the packets forming a message arrive at
the destination, they are recompiled into the original message.
Most modern Wide Area Network (WAN) protocols, including TCP/IP,
X.25, and Frame Relay, are based on packet-switching
technologies. In contrast, normal telephone service is based on
a circuit-switching technology, in which a dedicated line is
allocated for transmission between two parties. Circuit-
switching is ideal when data must be transmitted quickly and
must arrive in the same order in which it's sent. This is the
case with most real-time data, such as live audio and video.
Packet switching is more efficient and robust for data that can
withstand some delays in transmission, such as e-mail messages
and Web pages. A new technology, ATM, attempts to combine the
best of both worlds -- the guaranteed delivery of ci