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Appendix D. Glossary

10-BASE T Ethernet

Standard for wired networks that use phone-like plugs.


A catchall term used to refer to a proprietary high-speed wireless network using spectrums leased by telecommunications carriers that is proposed and/or has partially been developed.


The general standard for wireless networking, defined by the IEEE.


A relatively new version of the 802.11 wireless standard that is faster than 802.11b (it runs at speeds up to 25Mbps) and uses the 5GHz spectrum. 802.11a is not backward compatible with 802.11b, the older flavor of Wi-Fi.


Original flavor of 802.11 wireless networking, or Wi-Fi. 802.11b uses the 2.4GHz spectrum and has a theoretical speed of 11 Mbps.


The current most popular version of the 802.11 wireless standard, both newer and faster than 802.11b. 802.11g runs on the 2.4GHz spectrum, is backward compatible with 802.11b, and has a theoretical speed of 54Mbps.


The name given by the IEEE to the security standard requiring encryption of transmissions, substantially similar to the “Wi-Fi Protected Access,” or WPA2 for short, standard promoted by the Wi-Fi Alliance.


A new 802.11 wireless standard that promises to deliver speeds of well over 100Mbps using both the 2.4GHz and 5GHz spectrums. So far, 802.11n has not yet received IEEE approval, and the details of the standard are the subject of industry controversy.


The IEEE standard designation for the standard used by WiMAX, a wireless technology that promises much greater bandwidth than Wi-Fi and 802.11.

access control layer

Baked into the Wi-Fi standards; specifies how a Wi-Fi device, such as a mobile computer, communicates with another Wi-Fi device, such as a wireless access point, and specifies a unique hardware identifier for each network device. Also called MAC layer.

access point

A broadcast station that Wi-Fi computers can communicate with. Also called AP, hotspot, and base station. Access points are used as the central point for a network of Wi-Fi computers.

access point/router

This common hardware combination combines the functionality of a Wi-Fi access point with that of a network router.

ad hoc mode

Wi-Fi computers in the ad hoc mode communicate directly with one another in a peer-to-peer fashion without using an access point to intermediate network communication. (In contrast, a wireless network with a central access point uses infrastructure mode.)


Apple's name for the 802.11b flavor of Wi-Fi.

AirPort Extreme

Apple's name for the 802.11g flavor of Wi-Fi.


The process of ensuring that an individual is who he or she claims to be; note that (as opposed to authorization) authentication does not automatically confer any rights to assets such as files.


The security process that handles access rights to assets such as files.


A short-range connectivity solution designed for data exchange between devices such as printers, cell phones, and PDAs that use the 2.4GHz spectrum. Bluetooth is incompatible (meaning, does not work) with any of the 802.11 wireless networking standards.


Wireless bridges are used to connect one part of a network with another. They are often used to extend the range of a network and/or to add non-PC devices to a network. Wireless bridges can be set up using dedicated hardware; however, they can also be configured using the software in your Centrino laptop.


Fast delivery of Internet services. The predominant means for the delivery of broadband are cable and DSL, although if 802.11n and WiMAX deliver on their promises, they will become very viable broadband delivery technologies.


Broadband Internet delivery over the same cable used to bring in television content, primarily to residential subscribers.


See [Intel Centrino mobile technology]

A chipset is a group of integrated circuits that can be used together to serve a single function and are therefore manufactured and sold as a unit. The functions that make up the core logic of a computer or other electronic device are often performed by a chipset.


A device or program connected to a server of some sort. Typically, a client is a personal computer connected to a server computer that relies on the server to perform some operations.

client-server network

In a client-server network, a centralized server computer controls and polices many of the basic functions of the network, and intermediates the communications between the computers on the network.

closed node

A Wi-Fi broadcast that is protected by WEP.

CompactFlash (CF) card

Used to add memory (and in some cases other functionality, such as Wi-Fi connectivity) to PDAs, digital cameras, and other handheld devices.


Double Data Rate (DDR) is a type of SDRAM in which data is sent on both the rising and falling edges of clock cycles in a data burst.


Dynamic Host Configuration Protocol, a standard for assigning dynamic Internet Protocol (IP) addresses to devices on a network.

Direct Sequence Spread Spectrum (DSSS)

Technology used to prevent collisions and avoid interference between devices operating on the same wireless spectrum.

directional antenna

An antenna used to focus a transmission in a specific direction, used in point-to-point Wi-Fi broadcasts, also called a yagi.


Demilitarized zone, an isolated computer or subnetwork that sits between an internal network that needs to remain secure and an area that allows external access.


The Domain Name System (sometimes called Domain Name Service) translates more or less alphabetic domain names into IP addresses.


Digital Subscriber Line, a technology used to deliver broadband Internet services over telephone lines.

dumpster diving

Going through trash to find personal information, often with the intention of obtaining identifying information and passwords to gain access to online assets.

dynamic IP addressing

The provision of IP addresses to computers dynamically.


Unit of measure (equivalent isotropically radiated power) for the strength of an antenna.


The translation of data using a secret code; used by WEP to achieve security for Wi-Fi networks.

encryption key

The key used to encrypt the transmissions of a Wi-Fi network protected by WEP; the password needed to access a Wi-Fi network.

Ethernet port

A socket that accepts a 10BASE-T Ethernet wire.


Federal Communications Commission. Seehttp://www.fcc.gov for more information.


A firewall is a blocking mechanism—either hardware, software, or both—that blocks intruders from accessing a network or an individual computer; an intermediary program that can be configured to control access both to and from a private network.

free radio spectrum

Bands of the radio spectrum, such as 2.4GHz and 5GHz, that do not require a license from the FCC. Wi-Fi uses these bands for its transmissions, as do other household appliances such as cordless phones and microwaves.


The oscillations, or movement from peak to trough, of the electromagnetic wave created by a radio transmission.


The amount of gain provided by an antenna means how much it increases the power of a signal passed to it by the radio transmitter.


Gigahertz. One gigahertz equals 1,000 megahertz (MHz).


An area in which Wi-Fi users can connect to the Internet, whether for pay or free.


A simple wired device used to connect computers on a network.


Institute of Electrical and Electronics Engineers. See http://www.ieee.org for more information.

infrastructure mode

A Wi-Fi network in infrastructure mode uses an access point to intermediate network traffic (as opposed to ad hoc mode, which features direct peer-to-peer communication).

Intel Centrino

See [Intel Centrino mobile technology]
Intel Centrino mobile technology

A platform incorporating Intel's technologies designed specifically for mobile computing with integrated wireless LAN capability. It combines a central processing unit (CPU) and chipset designed for mobile computing with wireless LAN functionality using the Wi-Fi standards. The great bulk of today's laptop computers are built using Intel Centrino mobile technology.


Someone who gains illicit access to a private network.


An incident involving illicit access to a network by an intruder.

IP address

A hexadecimal tuplet that denotes a node on the Internet or other network.

isotropic radiation pattern

If an antenna has an isotropic radiation pattern, the antenna transmits radio waves in all three dimensions equally.


Internet service provider, such as the cable or phone company providing you Internet access using dial-up, cable, or DSL.


Information technology department, usually in a large enterprise.


Used to encrypt transmissions on a protected wireless network.


Local area network, such as the network in your home or small office.


The beverage of choice to sip at a coffee shop while you are connected to the Internet via Wi-Fi.

logical topology

The logical data flow on a network.

MAC address

Media access control layer address; unique identification number of each network device.

MAC filtering

Creating a secure Wi-Fi network by using the MAC address of each device on the network (and only allowing devices with a known MAC address).

MAC layer

Media access control layer.

See also [access control layer]


Megabytes per second.

Media access control layer

See [access control layer]

Megahertz. In a radio spectrum, 1 megahertz means one million vibrations per second.


Short for modulator-demodulator. A modem is a device that lets a computer transmit data over telephone or cable lines and connects your cable or DSL Internet service to your computer or your network.


Two or more connected computers.

Network Address Translation (NAT)

Translates local network addresses to ones that work on the Internet.

network name

See [SSID]

Network interface card, used to connect a computer to a wired network.

omnidirectional antenna

An antenna that sends broadcast signals in all directions.

open node

A Wi-Fi broadcast that is not protected by WEP.

Open-System authentication

So-called Open-System authentication is used when no authentication is required because it does not provide authentication, only identification of the MAC address of a wireless client that is connected.

Open System Interconnection (OSI)

A general reference model that describes how different applications and protocols interact on network-aware devices. The MAC and PHY layers of Wi-Fi compliant devices fit within the OSI model.

PC Card

Card that fits in the PCMCIA slot that is present on most laptops. Also called PCMCIA cards.

PCI Card

Card that fits into the PCI expansion slot inside a Windows desktop computer.


Personal Computer Memory Card International Association, which is the name of the organization that has devised the standard for cards that can be added to laptops. For more information see http://www.pcmcia.org.


Also called an expansion slot, used to add PC cards to a laptop.


Personal Digital Assistant, a handheld computer.

peer-to-peer network

In a peer-to-peer network, computers communicate directly with each other.


The act of illicitly accessing a private computer or network, usually performed by an intruder and resulting in an intrusion.


An advanced class of CPUs for personal computers made by Intel Corporation.

Pentium M

A CPU of the Pentium class especially designed for mobile computers.

Physical layer (PHY)

Baked into the Wi-Fi standards; handles transmission between nodes (or devices) on a Wi-Fi network. In other words, it is primarily concerned with connectivity at the hardware level.

physical topology

The way a network is connected.


Point-to-Point Protocol over Ethernet, usually used with DSL for broadband connectivity to the Internet.


An agreed upon format for transmitting data between devices.

See also [standard]

radio bands

Contiguous portions of the radio spectrum—for example, the FM band.

radio spectrum

The entire set of radio frequencies.

Radius server

A server used for remote user authentication. Specifically, a Radius server is used to implement WPA authentication, authorization, and encryption on a wireless network using a key that changes automatically at a regular interval.


Random access memory.

random access memory (RAM)

Used to temporarily store instructions and information for the microprocessor of a computer or other device.


The ability to use a Wi-Fi network provider other than your Wi-Fi network provider through your original account.


A device that directs traffic between one network and another—for example, between the Internet and your home network.


Synchronous dynamic random access memory (SDRAM) is RAM that delivers bursts of data at high speeds using a synchronous interface.


A computer or device on a network that manages network resources.

Shared Key authentication

In Shared Key authentication, an access point sends out random bytes, which the wireless computer requesting access must encrypt using the shared key and send back to the access point. The access point then decrypts using the shared key and verifies that the result matches the original.

shoulder surfing

Reading confidential information on a computer over someone's shoulder.

social engineering

Tricking a person into revealing his password or other confidential information related to computers and networks.


Small office or home office.


Service set identifier, used to identify the “station” broadcasting a Wi-Fi signal. Also called the network name, or wireless network name. Apple calls the SSID for its AirPort products the AirPort ID.


Used in engineering to mean the technical form of something such as a message or a communication.

See also [protocol]

static IP address

An IP address that does not change.


An intelligent hub used to connect computers on a network.


Transmission Control Protocol/Internet Protocol, a protocol used by the Internet and other networks to standardize communications.


A network topology is the arrangement of a network.


Universal serial bus, used to connect peripheral devices such as a mouse to a computer.


Voice over IP, a technology that enables telephone calls to be placed over the Internet.


Virtual private network, software used to “tunnel” through the Internet to provide secure access to remote resources.


Wide area network, such as the Internet.


Wireless application protocol, used to provide Internet capabilities, such as Web browsing, to “thin” wireless devices, such as mobile phones.

War chalking

The use of chalk markings on a sidewalk to identify Wi-Fi networks.

War driving

Cruising in a car with a Wi-Fi laptop looking for unprotected Wi-Fi networks.


Wired equivalent privacy, an encryption security standard built in to the current versions of Wi-Fi.


Short for wireless fidelity, is the Wi-Fi Alliance's name for a wireless standard, or protocol, used for wireless networking using the 802.11 standards.

Wi-Fi Alliance

A not-for-profit organization that certifies the interoperability of wireless devices built around the 802.11 standard. See http://www.wi-fi.org for more information.

Wi-Fi directory

A site on the Internet that provides tools to help you find Wi-Fi hotspots.

Wi-Fi finder

A device that senses the presence of active Wi-Fi networks.

Wi-Fi network provider

A company that provides access, usually for a fee, to multiple Wi-Fi hotspots.

Wi-Fi Protected Access

See [802.11i]

WiMAX is a new wireless technology (based on the IEEE 802.16 standard) that promises much greater bandwidth than Wi-Fi and 802.11. At the time of this writing, there are no commercial WiMAX deployments.

Wireless bridge

See [bridge]

Wi-Fi Protected Access;

See also [802.11i]


Wi-Fi Protected Access–Pre-Shared Key encryption means that the wireless computer and the access point must have the same pass phrase in order to set a wireless connection. WPA-PSK does not require a Radius server.


See [directional antenna]



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