Appendix
C - GLOSSARY
ACK
Acknowledgment.
Access Point
An access point connects wireless network stations (or clients) to other stations within the wireless
network and also can serve as the point of interconnection between the wireless network and a
wired network. Each access point can serve multiple users within a defined network area. Also
known as a base station.
Antenna Gain
Antennae do not increase the transmission power, but instead focus the signal. Rather than
transmitting in every direction (including the sky and ground), antenna focus the signal either more
horizontally or in one particular direction. This gain is measured in decibels
Bandwidth
The maximum data transfer speed available to a user through a network.
Bridge
A bridge connects two local area networks, and is typically used to connect wireless networks
to wired networks. Bridges usually transfer messages between networks only when the message
destination is on the other network. Messages destined for the network on which they originated
are not passed on to the other network. This reduces traffic on the entire network.
Collision avoidance
A network node procedure for proactively detecting that it can transmit a signal without risking a
collision with transmissions from other network nodes.
Client / Sta / Station
A device on a network that gains access to data, information, and other devices through a server
(access point).
Crossover cable
A cable used for networking two computers without the use of a hub. Crossover cables may also
be required for connecting a cable or DSL modem to a wireless gateway or access point. The cable
is wired so that the signals
“crossover,” connecting transmit signal on one side to receiver signals
on the other.
DHCP
Dynamic Host Configuration Protocol is a utility that enables a server to dynamically assign IP
addresses from a predefined list and limit their time of use so that they can be reassigned. Without
DHCP, an IT manager would need to manually enter in all the IP addresses of all the computers on
the network. When DHCP is used, whenever a computer logs onto the network an IP address is
automatically assigned to it.
DNS
Domain name service (DNS) is a program that translates URLs to IP addresses by accessing a
database maintained on a collection of Internet servers. The program works behind the scenes to
facilitate surfing the Web with alpha versus numeric addresses. A DNS server converts a name like
mywebsite.com to a series of numbers like 107.22.55.26. Every website has its own specific IP
address on the Internet.
Encryption key
An alphanumeric (letters and/or numbers) series that enables data to be encrypted and then
decrypted so it can be safely shared among members of a network. WEP uses an encryption key
that automatically encrypts outgoing wireless data. On the receiving side, the same encryption key
enables the computer to automatically decrypt the information so it can be read. Encryption keys
should be kept secret.
Hub
A multiport device used to connect PCs to a network via Ethernet cabling or via 802.11. Wired hubs
can have numerous ports and can transmit data at speeds ranging from 10 Mbps to multi-Gigabyte
speeds per second. A hub transmits packets it receives to all the connected ports. A small wired
hub may only connect four computers; a large hub can connect 48 or more.
Hz
Hertz. The international unit for measuring frequency, equivalent to the older unit of cycles per
second. One megahertz (MHz) is one million hertz. One gigahertz (GHz) is one billion hertz. The
standard US electrical power frequency is 60 Hz, the AM broadcast radio frequency band is 535
–
1605 kHz, the FM broadcast radio frequency band is 88
–108 MHz, and wireless 802.11b/g LANs
operate at 2.4 GHz.
IEEE
Institute of Electrical and Electronics Engineers, New York, www.ieee.org. A membership
organization that includes engineers, scientists and students in electronics and allied fields.
It has more than 300,000 members and is involved with setting standards for computers and
communications.