Workshop

active hub
An active hub is one that has intelligence built into it (for example, to make it error tolerant). See
also hub.
adapter
A hardware device used to connect devices to a motherboard. In networking context, an Ethernet
adapter/card.
adaptive pulse code modulation
A method of encoding voice into digital format over communication lines.
adaptive routing
Routing designed to adapt to the current network load. Adaptive routing routes data around
bottlenecks and congested network areas.
Address Resolution Protocol (ARP)
Maps IP addresses to physical addresses.
administrator
Either a human being charged with controlling a network or the supervisory account in Windows
NT. (Whoever has administrator privileges in NT can—but need not necessarily—hold complete
control over his or her network, workgroup, or domain.)
ADSL
See Asymmetric Digital Subscriber Line.
AIX
A flavor of UNIX from International Business Machines (IBM). AIX runs on RISC workstations
and PowerPCs.
American National Standards Institute
See ANSI.
analog system
This term is generally used to describe the telephone system, which uses analog technology to
convert voice to electronic signals. Many telephones in modern office systems are digital, which
means that if you plug your modem into the jack, you risk damage to the modem.
Anonymous FTP
FTP service available to the public that allows anonymous logins. Anyone can access anonymous
FTP with the username anonymous and his or her email address as a password.
ANSI
The American National Standards Institute. Check out http://www.ansi/org for more information
on ANSI.
answer-only modem
A modem that answers but cannot dial out. (These are useful for preventing users from initiating
calls from your system.)
applet
A small Java program that runs in a Web browser environment. Applets add graphics, animation,
and dynamic text to otherwise lifeless Web pages.
application gateway
Firewall device that disallows direct communication between the Internet and an internal, private
network. Data flow is controlled by proxies that screen out undesirable information or hosts. See