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Glossary

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0-9

10BaseT: The most common cabling method for Ethernet. 10BaseT conforms to IEEE standard 802.3. It was developed to enable data communications over unshielded twisted pair (telephone) wiring at speeds of up to 10 megabits per second up to distances of approximately 330 feet on a network segment. (See Ethernet).
3G: The term refers to digital, packet-switched technology and is used to describe the third-generation of mobile telephony which brings video and broadband Internet access to mobile phones. The first generation was represented by analog cellular phones and the second generation by digital cellular networks.
802.11a: An IEEE standard for a wireless network that operates at 5 GHz with rates up to 54Mbps.
802.11b: An IEEE standard for a wireless network that operates at 2.4 GHz with rates up to 11Mbps.
802.11d: An IEEE specification that allows for configuration changes at the Media Access Control layer (MAC layer) level to comply with the rules of the country in which the network is to be used. (See MAC).
802.11e: An IEEE standard that adds Quality of Service (QoS) features and multimedia support to the existing 802.11b, 802.11g, and 802.11a wireless networks. (See QoS, WMM).
802.11g: An IEEE standard for a wireless network that operates at 2.4 GHz Wi-Fi with rates up to 54Mbps.
802.11h: 802.11h supports Dynamic Frequency Selection(DFS) and Transmit Power Control(TPC) requirements to ensure coexistence between Wi-Fi and other types of radio frequency devices in the 5 GHz band.
802.11i: An IEEE standard specifying security mechanisms for 802.11 networks. 802.11i makes use of the Advanced Encryption Standard (AES) block cipher. The standard also includes improvements in key management, user authentication through 802.1X and data integrity of headers. (See 802.1X, AES, WPA2).
802.11j: An IEEE specification for wireless networks that incorporates Japanese regulatory requirements concerning wireless transmitter output power, operational modes, channel arrangements and spurious emission levels.
802.11n: A taskgroup of the IEEE 802.11 committee whose goal is to define a standard for high throughput speeds of at least 100Mbps on wireless networks. The standard is expected to be ratified by 2007. Some proposals being fielded by the taskgroup include designs for up to 540 Mbps. Multiple-Input-Multiple-Output (MIMO) technology, using multiple receivers and multiple transmitters in both the client and access point to achieve improved performance is expected to form the basis of the final specification. (See Mbps, MIMO).
802.1X: A standard for port-based authentication, first used in wired networks, that was adapted for use in enterprise WLANs to address security flaws in WEP, the original security specification for 802.11 networks. 802.1X provides a framework for authenticating users and controlling their access to a protected network and dynamic encryption keys to protect data privacy. (See EAP, WEP, WPA, WPA2).
802.3: The standard defining wired Ethernet networks. (See Ethernet).

A

Ad-Hoc mode: An old term used to describe a device-to-device network. (See device-to-device network, peer-to-peer network).
AES: Advanced Encryption Standard. The preferred standard for the encryption of commercial and government data using a symmetric block data encryption technique. It is used in the implementation of WPA2. (See 802.11i, WPA2).
AP: Access point. A device that connects wireless devices to another network, that being a wireless LAN, Internet Modem or others.
Applet: A small application or utility program, usually written In the Java programming language that is designed to do a very specific and limited task. Applets are most commonly used in hand-held mobile devices.
Application software: A computer program that is designed to do a general operational task such as word processing or payroll. Internet browsers and graphic design programs are also considered applications. Application software runs on top of the operating system.
Association: Describes the establishment and maintenance of the wireless link between devices. (If security is enabled, the devices cannot do anything but exchange security credentials with this link). (See authentication).
Authentication: The process that occurs after association to verify the identity of the wireless device or end user and allow access to the network. (See association, 802.1X, WPA, WPA2).

B

Backbone: The central part of a large network that links two or more sub-networks. The backbone is the primary data transmission path on large networks such as those of enterprises and service providers. A backbone can be wireless or wired.
Bandwidth: The maximum transmission capacity of a communications channel at any point in time. Bandwidth, usually measured in bits per second (bps), determines the speed at which information can be sent across a network. If you compare the communications channel to a pipe, bandwidth represents the pipe width and determines how much data can flow through the pipe at any one time. The greater the bandwidth, the faster data can flow. (See bps).
Bluetooth wireless technology: A technology designed for short-range, wireless communications among computing devices and mobile products, including PCs and laptop computers, personal digital assistants, printers, and mobile phones. Designed as a cable-replacement, Bluetooth enables short-range transmission of voice and data in the 2.4 GHz frequency spectrum within a range of about 30 feet. (See WPAN).
bps: Bits per second. A measure of data transmission speed across a network or communications channel; bps is the number of bits that can be sent or received per second. It measures the speed at which data is communicated and should not be-but often is-confused with bytes per second (Bps, in this reference the B is capitalized while in bps lower case is used). While "bits" is a measure of transmission speed, "bytes" is a measure of storage capacity. (See bandwidth, Mbps).
Bridge: A wireless device that connects multiple networks together. (See router).
Broadband: A comparatively fast Internet connection possessing sufficient bandwidth to accommodate multiple voice, data and video channels simultaneously. Cable, DSL and satellite are all considered to be broadband channels; they provide much greater speed than dial-up Internet access over telephone wires. (See cable modem, DSL).
Broadband modem: A device that connects a local computer or network to a high-speed Internet service, such as DSL or Cable Internet. (See cable modem, DSL).
BSSID: Basic Service Set Identifier. A unique address that identifies the access point/router that creates the wireless network. (See SSID).
Bus adapter: A special adapter card that installs in a PC's PCI or ISA slot and enables the use of PC Card radios in desktop computers. Some companies offer one-piece PCI or ISA Card radios that install directly into an open PC or ISA slot.

C

Cable modem: A device used with broadband Internet service provided by a traditional cable TV service. Cable modems convert analog data from the cable TV system into a digital format that can be used by a computer. (See broadband modem).
Channel: One portion of the available radio spectrum that all devices on a wireless network use to communicate. Changing the channel on the access point/router can help reduce interference.
Client: Any computer connected to a network that requests files and services (files, print capability) from the server or other devices on the network. The term also refers to end users. (See AP).
Client devices: Wi-Fi client devices include PC Cards that slide into laptop computers, mini-PCI modules embedded in laptop computers and mobile computing devices, as well as USB radios and PCI/ISA bus Wi-Fi radios. Client devices usually communicate with hub devices like access points and gateways. (See AP, client).
Collision avoidance: A means of proactively detecting whether a node on an Ethernet network can transmit a signal without risk that it will collide with other traffic on the network. (See CSMA/CA, CSMA/CD).
Crossover cable: A twisted-pair cable used to network two computers without use of a hub. Instead of traveling in direct parallel paths between plugs, the signals "crossover," reversing the sending and receiving wire pairs on each end. Crossover cables may be required to connect a cable or DSL modem to a wireless router or access point.
CSMA/CA: Carrier Sense Multiple Access/Collision Avoidance. The principal media access control strategy used in 802.11 networks to avoid data collisions. It is a "listen before talk" method of minimizing collisions. The network node checks to see if the transmission channel is clear before a data packet is sent. (See collision avoidance, CSMA/CD).
CSMA/CD: Customer Sense Multiple Access/Collision Detection. The principal media access control strategy used to manage traffic and reduce noise on wired Ethernet networks. It allows a network device to transmit data after detecting a channel is available. If two devices transmit data simultaneously, the sending device detects the collision of data packets and retransmits after a random time delay. (See collision avoidance, CSMA/CA).

D

DC power module: Modules that convert Alternate Current (AC) power to Direct Current (DC) for the operation of electronic and computer equipment. Depending on the manufacturer and product, these modules can range from typical "wall wart" transformers that plug into a wall socket to larger, enterprise-level Power Over Ethernet systems that inject DC power into the Ethernet cables to provide power to the access points.
Device-to-device network: Two or more devices that connect using wireless network devices without the use of a centralized wireless access point. Also known as a peer-to-peer network. (See ad hoc mode, Peer-to-peer network).
DHCP: Dynamic Host Configuration Protocol. A protocol for dynamically assigning IP addresses from a pre-defined list to nodes on a network. When they log on, network nodes automatically receive an IP address from a pool of addresses served by a DHCP. The DHCP server provides (or leases) an IP address (to a client for a specific period of time. The client will automatically request a renewal of the lease when the lease is about to run out. If a lease renewal is not requested and it expires, the address is returned to the pool of available IP addresses. Using DHCP to manage IP addresses simplifies client configuration and efficiently utilizes IP addresses. (See IP address).
Dial-up: A connection to a remote network, or the Internet, using a standard modem and telephone connection, or Plain Old Telephone Service (POTS). (See POTS).
Diversity antenna: An antenna system that uses multiple antennas to reduce interference and maximize reception and transmission quality.
DNS: Domain Name Service. An Internet service that translates alphanumeric domain names to assigned IP addresses and vice versa. The term is typically used to describe the server which makes the translation. Every website has its own specific IP address on the Internet. DNS typically refers to a database of Internet names and addresses which translates the alpha-numeric names to the official Internet Protocol numbers and vice versa. For instance, a DNS server converts a name like mywebsite.com to a series of numbers like 107.22.55.26. (See IP, IP address).
DSL: Digital Subscriber Line. A dedicated digital circuit between a residence or business and a telephone company's central office. It allows high-speed data, voice and video transmissions over existing twisted-pair copper Plain Old Telephone Service (POTS) telephone wires. (See broadband, POTS).
Dual-band: A device that is capable of operating in two frequencies. On a wireless network, dual-band devices are capable of operating in both the 2.4 GHz (802.11b/g) and 5 GHz (802.11a) bands. In cellular phone technology, dual-band devices typically operate in both the GSM900 and GSM1800 frequencies, allowing a greater number of roaming options. (See Tri-mode).

E

EAP: Extensible Authentication Protocol. A protocol that provides an authentication framework for both wireless and wired Ethernet enterprise networks. It is typically used with a RADIUS server to authenticate users on large networks. EAP protocol types are used in the 802.1X-based authentication in WPA-Enterprise and WPA2-Enterprise. (See 802.1X, EAP, LEAP, RADIUS, TLS, WPA-Enterprise, WPA2-Enterprise).
EAP-SIM: Specifies a mechanism for mutual authentication and session key agreement using the GSM-SIM and used in GSM-based mobile phone networks.
EAP-TLS: Extensible Authentication Protocol Transport Layer Security
EAP-TTLS/MSCHAPv2: EAP-Tunneled TLS/Microsoft Challenge Authentication Handshake Protocol. Securely tunnels clients authentication within TLS records
Encryption: A mechanism for providing data confidentiality. (See 802.11i, RC4, TKIP, WEP, WPA, WPA2).
Enterprise: Any large corporation, business or organization. The enterprise market can incorporate office buildings, manufacturing plants, warehouses and research and development facilities, as well as large colleges and universities.
ESSID: Extended Service Set Identifier. A name used to identify a wireless network. (See SSID, network name).
Ethernet: The most popular international standard technology for wired Local Area Networks (LANs). It provides from 10 Mbps transmission speeds on basic 10BastT Ethernet networks to 100 Mbps transmission speeds on Fast Ethernet networks, 1000 Mbps on Gigabit Ethernet, and 10,000 Mbps on 10 Gigabit Ethernet. (See 802.3)

F

FIPS 140-2: The Federal Information Processing Standard that defines the requirements of security technologies used in the handling and processing of information within government agencies. (See 802.11i, AES, WPA2).
Firewall: A system of software and/or hardware that resides between two networks to prevent access by unauthorized users. The most common use of a firewall is to provide security between a local network and the Internet. Firewalls can make a network appear invisible to the Internet and can block unauthorized and unwanted users from accessing files and systems on the network. Hardware and software firewalls monitor and control the flow of data in and out of computers in both wired and wireless enterprise, business and home networks. They can be set to intercept, analyze and stop a wide range of Internet intruders and hackers. (See Intrusion detection).
FireWire: A high-speed serial bus system defined by the IEEE 1394 standard for input/output technology that connects multimedia and storage peripherals to a PC. FireWire is similar to USB (Universal Serial Bus) and can provide a bandwidth of about 400 Mbps. FireWire was the original brand name for Apple Computer's implementation of the specification. Today many Windows systems have FireWire capabilities, as well. Other names for products that perform the same function include 1394 (Linux) and iLink (Sony).
Firmware: Software routines that are embedded as read-only memory (ROM) in a computer chip or hardware device to prevent modification of the routines. Unlike random access memory (RAM), read-only memory stays intact in the absence of electrical power. Startup routines and low-level input/output instructions are stored in firmware.

G

Gateway: In the wireless world, a gateway is an access point with additional software capabilities such as providing NAT and DHCP. Gateways may also provide VPN support, roaming, firewalls, various levels of security, etc.
GPRS: General Packet Radio Service. A radio technology used in GSM networks that transmits digital data packets, much like Internet protocols do, for both voice and data without the need of a dedicated circuit for always-on access to data. This allows for more efficient communication and faster data rates. (See 3G, GSM).
GPS: Global Positioning System. A system that uses satellites, receivers and software to allow users to determine their precise geographic position. (See War driving).
GSM: Groupe Speciale Mobile, or Global System for Mobile Communications. A 2G digital standard for cellular phone communications adopted by many countries around the world. Its frequency bands range from 900-1800MHz. (See 3G, GPRS).

H

Hotspot: A location where users can access the Internet using Wi-Fi laptops and other Wi-Fi enabled devices. Access may be provided free or for a fee. Hotspots are often found at coffee shops, hotels, airport lounges, train stations, convention centers, gas stations, truck stops and other public meeting areas. Corporations and campuses often offer it to visitors and guests. Hotspot service is sometimes available aboard planes, trains and boats. (See Wi-Fi ZONE).
Hub: A multi-port device used to connect client devices to a wired Ethernet network. Hubs can have numerous ports and can transmit data at speeds ranging from 10 to 1000 Mbps per second to all the connected ports. A small wired hub may only connect 4 computers; a large hub can connect 48 or more. (See Router).
HZ: Hertz, not the car rental company. 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; 802.11a devices operate in the 5 GHz band; 802.11b and g devices operate in the 2.4 GHz band.

I

I/O: Input/Output. The term used to describe any operation that transfers data to or from a computer. (See MIMO).
IEEE: Institute of Electrical and Electronics Engineers. A global technical professional society and standards-setting organization serving the public interest and its members in electrical, electronics, computer, information and other technologies.
IEEE 802.11: The family of specifications developed by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 committee which establishes standards for wireless Ethernet networks. 802.11 standards define the over-the-air interface between wireless clients and a base station, or access point that is physically connected to the wired network. (See 802.11, IEEE).
iLink: Sony Corp's name for the high-speed serial bus system defined by the IEEE 1394 standard for input/output technology that connects multimedia and storage peripherals to a PC. (See FireWire).
Infrastructure mode: An old term used to describe a wireless network consisting of devices connected to a network using a centralized wireless access point. One of two types of wireless network modes; the other is a device-to-device network (also known as peer-to-peer or ad hoc mode). (See ad hoc mode, device-to-device network, peer-to-peer network).
Internet appliance: A computing device used primarily for Internet access. It can be Wi-Fi enabled or connected to a wired network and generally offers customized web browsing, touch-screen navigation, with built-in e-mail services, entertainment and personal information management applications. Applications cannot be installed independently.
Intrusion detection: A security service that monitors and analyzes system events to identify security breaches to the network and provide real-time warnings when an unauthorized intrusion, or break-in, to the network is attempted. (See Rogue, War chalking, War driving).
IP: Internet Protocol. The basic communications protocol of the Internet. (See IP address, TCP/IP).
IP (Internet Protocol) telephony: Technology that supports voice, data and video transmission via IP-based LANs, WANs, and the Internet. This includes VoIP (Voice over IP).
IP address: Internet Protocol address. IP Version 4, the most widely used Internet protocol, provides 32-bit number that identifies the sender or receiver of information sent across the Internet. An IP address has two parts: The identifier of the particular network on the Internet and the identifier of the particular device (which can be a server or a workstation) within that network. The newer IP, Version 6, provides a 128-bit addressing scheme to support a much greater number of IP addresses. (See DHCP, DNS, IP).
IP telephony: A general term referring to technologies that use IP packet-switched connections to exchange voice, data, video, and other forms of information traditionally carried over public telephone networks. (See IP, VoIP).
IPX-SPX: IPX, short for Internetwork Packet Exchange, a networking protocol used by the Novell NetWare operating systems. Like UDP/IP, IPX is a datagram protocol used for connectionless communications. Higher-level protocols, such as SPX and NCP, are used for additional error recovery services. Sequenced Packet Exchange, SPX, a transport layer protocol (layer 4 of the OSI Model) used in Novell Netware networks. The SPX layer sits on top of the IPX layer (layer 3) and provides connection-oriented services between two nodes on the network. SPX is used primarily by client/server applications. Whereas the IPX protocol is similar to IP, SPX is similar to TCP. Together, therefore, IPX-SPX provides connection services similar to TCP/IP.
ISA: A type of internal computer bus that allows the addition of card-based components like modems and network adapters. ISA has been replaced by PCI and is not very common anymore.
ISDN: Integrated Digital Services Network-A service offered by most telephone carriers that provides high-speed digital service for voice and data over ordinary telephone lines. ISDN uses standard POTS copper wiring to deliver voice, data or video. (See broadband, POTS).
ISO Network Model: A model developed by the International Standards Organization (ISO) that defines seven levels, or layers, in a network. By standardizing these layers and the interfaces that connect them, different portions of a given protocol can be modified or changed as technologies advance or systems requirements are altered. The seven layers are, beginning at the lowest layer: Physical, Data link, Network, Transport, Session, Presentation, Application. The IEEE 802.11 Standard encompasses the physical layer (PHY) and the lower portion of the data link layer which is often referred to as the Media Access Control (MAC) sub-layer. (See PHY).
ISS: A special software application that allows all PCs on a network access to the Internet simultaneously through a single connection and Internet Service Provider (ISP) account.

L

LAN: A system of connecting PCs and other devices within the same physical proximity for sharing resources such as an Internet connections, printers, files and drives. When Wi-Fi is used to connect the devices, the system is known as a wireless LAN or WLAN. (See WAN, WLAN, WMAN, WPAN).
LEAP: Lightweight Extensible Authentication Protocol-A proprietary Cisco protocol used for 802.1X authentication on wireless LANs (WLANs). (See 802.1X, EAP).

M

MAC address: Media Access Control address. A unique hardware number that identifies each device on a network. A device can be a computer, printer, etc. (See IP address).
MAN: Metropolitan Area Network. A data network, typically operated by a municipality or communications carrier that provides high-speed service within a geographical area such as a college campus, town or city. A MAN is larger than a Local Area Network (LAN) but smaller than a Wide Area Network (WAN). (See WiMAX).
Mapping: Assigning a PC to a shared drive or printer port on a network.
Mbps: Megabits per second. A measurement of data speed that is roughly equivalent to a million bits per second. (See bps).
Mesh network: A communications network with least two pathways to each node, forming a net-like organization. When each node is connected to every other node, the network is said to be fully meshed. When only some of the nodes are linked, switching is required to make all the connections and the network is said to be partially meshed, or partially connected.
MIC: Message Integrity Check. A technology that is employed to prevent an attacker from capturing data packets, altering them and resending them. The MIC provides a strong mathematical function in which the receiver and the transmitter each compute and then compare the MIC. If it does not match, the data is assumed to have been tampered with and the packet is dropped. (See Packet, TKIP, WPA, WPA2).
MIMO: Multiple-Input-Multiple-Output. An advanced signal processing technology that uses multiple receivers and multiple transmitters in both the client and access point to achieve data throughput speeds of 100Mbps. (See 802.11n).
Mobile professional: Often called "road warrior." Any employee or professional person who travels frequently and requires the ability to regularly access his or her corporate networks, via the Internet, to post and retrieve files and data and to send and receive e-mail from remote locations. (See hotspot, roaming).

N

NAT: Network Address Translation. A network capability that enables multiple of computers to dynamically share a single incoming IP address from a dial-up, cable or DSL connection. NAT takes a single incoming public IP address and translates it to a new private IP address for each client on the network. (See DHCP, IP address).
Network name: A name used to identify a wireless network. (See ESSID, SSID)
NIC: Network Interface Card. A wireless or wired PC adapter card that allows the client computer to utilize network resources. Most office wired NICs operate at 100 Mbps. Wireless NICs operate at data rates defined by 802.11 standards. (See PC card).

P

Packet: A unit of information transmitted from one device to another on a network. A packet typically contains a header with addressing information, data, and a checksum to insure data integrity. (See MIC).
Pass phrase: A series of characters used to create a key which is used by Wi-Fi Protected Access (WPA). (See PSK, WPA).
PC Card: A removable, credit-card-sized memory or I/O device that fits into an expansion slot on a notebook computer or a personal digital assistant (PDA). PC Cards are used primarily in notebook computers and PDAs. PC Card peripherals include Wi-Fi network cards, memory cards, modems, wired NICs, and hard drives. (See NIC, PCI).
PCI: Peripheral Component Interconnect. A high-performance I/O (input/output) computer bus that allows expansion slots to be spaced closely for high-speed operation. (See NIC, PC Card).
PCMCIA: Expansion cards now referred to as "PC Cards" were originally called "PCMCIA Cards" because they met the standards created by the Personal Computer Memory Card International Association.
PDA: Personal Digital Assistant. Smaller than laptop computers but with many of the same computing and communication capabilities, PDAs range greatly in size, complexity and functionality. PDAs can provide wireless connectivity via embedded Wi-Fi Card radios, slide-in PC Card radios, or Compact Flash Wi-Fi radios. (See PC Card).
PEAP: PEAP-Protected Extensible Authentication Protocol. A protocol proposed by Microsoft, Cisco and RSA Security for 802.1X authentication on wireless LANs (WLANs). (See EAP, LEAP).
PEAPv0/EAP-MSCHAPv2: Protected Extensible Authentication Protocol, a protocol developed jointly by Microsoft, RSA Security and Cisco for transmitting authentication data, including passwords, over 802.11 wireless networks. PEAP authenticates wireless LAN clients using only server-side digital certificates by creating an encrypted SSL/TLS tunnel between the client and the authentication
PEAPv1/EAP-GTC: Protected Extensible Authentication Protocol, a protocol developed jointly by Microsoft, RSA Security and Cisco for transmitting authentication data, including passwords, over 802.11 wireless networks. PEAP authenticates wireless LAN clients using only server-side digital certificates by creating an encrypted SSL/TLS tunnel between the client and the authentication
Peer-to-peer network: A wireless or wired computer network that has no server or central hub or router. All the networked PCs are equally able to act as a network server or client, and each client computer can talk to all the other wireless computers without having to go through an access point or hub. However, since there is no central base station to monitor traffic or provide Internet access, the various signals can collide with each other, reducing overall performance. (See Ad hoc mode, Device-to-device network).
PHY: The physical, or lowest, layer of the OSI Network Model. In a wireless network, the PHY defines parameters such as data rates, modulation method, signaling parameters, transmitter/receiver synchronization, etc. Within an actual radio implementation, the PHY corresponds to the radio front end and baseband signal processing sections. (See ISO Network Model).
Plug-and-play: Features that provide for automatic configuration of add-ons and peripheral devices such as wireless PC Cards, printers, scanners and multimedia devices. (See PC Card).
POTS: Plain Old Telephone Service. The traditional analog telephone service provided by most common carriers. (See broadband, dial-up, DSL, ISDN).
Print server: A network device, often a computer, that connects to at least one printer, allowing it to be shared among computers on a network.
Proxy server: A technique used in larger companies and organizations to improve network operations and security. The proxy server receives requests intended for another server to prevent direct communication between two or more networks. The proxy server forwards allowable data requests to remote servers and/or responds to data requests directly from stored remote server data.
PSK: A mechanism in Wi-Fi Protected Access (WPA)-Personal that allows the use of manually entered keys or passwords to initiate WPA security. The PSK is entered on the access point or home wireless gateway and each PC that is on the Wi-Fi network. After entering the password, Wi-Fi Protected Access automatically takes over. It keeps out eavesdroppers and other unauthorized users by requiring all devices to have the matching password. The password also initiates the encryption process which, in WPA is Temporal Key Integrity Protocol (TKIP) and in WPA2 is Advanced Encryption Standard (WPA2). (See TKIP, WPA-Personal, WPA2-Personal).

Q

QoS: Quality of Service. Required to support wireless multimedia applications and advanced traffic management. QoS enables Wi-Fi access points to prioritize traffic and optimize the way shared network resources are allocated among different applications. Without QoS, all applications running on different devices have equal opportunity to transmit data frames. That works well for data traffic from applications such as web browsers, file transfers, or e-mail but it is inadequate for multimedia applications. Voice over Internet Protocol (VoIP), video streaming, and interactive gaming are highly sensitive to latency increases and throughput reductions and require QoS. QoS extensions for 802.11 networks will be addressed in the upcoming IEEE 802.11e standard. (See 802.11e, WMM).

R

RADIUS: Remote Access Dial-Up User Service. A standard technology used by many major corporations to protect access to wireless networks. RADIUS is a user name and password scheme that enables only approved users to access the network; it does not affect or encrypt data. The first time a user wants access to the network, secure files or net locations, he or she must input his or her name and password and submit it over the network to the RADIUS server. The server then verifies that the individual has an account and, if so, ensures that the person uses the correct password before she or he can get on the network. RADIUS can be set up to provide different access levels or classes of access. For example, one level can provide blanket access to the Internet; another can provide access to the Internet as well as to e-mail communications; yet another account class can provide access to the Net, email and the secure business file server. Like other sophisticated security technologies, RADIUS comes in a variety of types and levels. (See EAP, WPA, WPA2).
Range: The distance covered by a wireless network or radio device. Depending on the environment and the type of antenna used, Wi-Fi signals can have a range of up to a mile.
RC4: An encryption cipher designed RSA Data Security. It allows key lengths up to 1024 bits and is a component in many encryption schemes, including SSL, WEP, and TKIP. (See SSL, WEP, TKIP).
Repeater: A wireless repeater is a device that extends the coverage of an existing access point by relaying its signal. A wireless repeater does not do intelligent routing performed by wireless bridges and routers.
Residential gateway: A wireless device that allows multiple devices accessing a home network, including PCs and peripherals to access the Internet and communicate with one another. (See gateway).
RFID: Radio Frequency Identification. An electronic identification technology that uses radio frequency signals to read identifying data contained in tags on equipment and merchandise. An alternative to bar codes.
RJ-45: Standard connectors used in Ethernet networks. They appear similar to standard RJ-11 telephone connectors. However, RJ-45 connectors can have up to eight wires, whereas telephone connectors have only four.
Roaming: The ability to move seamlessly from one area of Wi-Fi or cellular phone coverage to another with no loss in connectivity. Roaming also refers to the ability of road warriors to wirelessly connect to the Internet from different hotspots without confronting the array of schemes used by different providers to authorize use and track billing. Roaming agreements among providers allow mobile professionals to a single authentication and authorization scheme to have all charges resolved to a single bill. (See hotspot, mobile professional).
Rogue: An unauthorized access point installed on a company's WLAN, typically by a user. Rogue access points present security risks. They rarely conform to the organization's security policies and, typically, no security at all is enabled on them. Rogues present open, insecure interfaces to the company's network. (See intrusion detection).
Router: A wireless router is device that accepts connections from wireless devices to a network and includes a network firewall for security, and provides local network addresses. (See hub).

S

Satellite broadband: Wireless high-speed Internet service provided by satellites. Some satellite broadband connections are two-way-up and down. Others are one-way, with the satellite providing a high-speed downlink and then using a dial-up telephone connection or other land-based system for the uplink to the Internet. (See broadband, dial-up).
Security supplicant: Client software that coordinates authentication and session key creation.
Server: A computer that provides resources or services to other computers and devices on a network. Types of servers can include print servers, Internet servers, mail servers, and DHCP servers. A server can also be combined with a hub or router. (See DHCP, hub, router).
Site survey: A comprehensive facility study performed by network managers to insure that planned service levels will be met when a new wireless LAN, or additional WLAN segments to an existing network, are deployed. Site survey's are usually performed by a radio frequency engineer and used by systems integrators to identify the optimum placements of access points to insure that planned levels of service are met. Site surveys are sometimes conducted following the deployment to insure that the WLAN is achieving the necessary level of coverage. Site surveys can also be used to detect rogue access points. (See intrusion detection, rogue).
Sniffer: A software program that monitors network traffic. Sniffers can capture data being transmitted on a network and are sometimes used illegitimately to hack a network.
SOHO: The term describes an office or business with ten or fewer computers and/or employees.
SSID: A unique 32-character network name, or identifier, that differentiates one wireless LAN from another. All access points and clients attempting to connect to a specific WLAN must use the same SSID. The SSID can be any alphanumeric entry up to a maximum of 32 characters. (See ESSID, network name).
SSL: SSL-Secured Sockets Layer. A protocol used to secure Internet communications. SSL is commonly used to encrypt transactions on online retail and banking. SSL encrypts the exchange of information between a user's browser and Web server so only the intended parties can read it. When an SSL session begins, the server sends its public key to the browser. The browser then sends a randomly generated secret key back to the server in order to have a secret key exchange for that session. (See RC4).
Subnetwork, or subnet: An IP address range that is part of a larger address range. Subnets are used to subdivide a network address of a larger network into smaller networks. Subnets connect to other networks through a router. Each individual wireless LAN will typically use the same subnet for all of its clients. (See IP address, router).
Switch: A type of hub that controls device usage to prevent data collisions and insures optimal network performance. A switch acts as a network traffic cop: Rather than transmitting all the packets it receives to all ports, as a hub does, a switch transmits packets to only the receiving port. (See hub).

T

TCP: Transmission Control Protocol. The Transport level protocol used with the Internet Protocol (IP) to route data across the Internet. (See IP, TCP/IP).
TCP/IP: The underlying technology of Internet communications. While IP handles the actual delivery of data, TCP tracks the data packets to efficiently route a message through the Internet. Every computer in a TCP/IP network has its own IP address that is either dynamically assigned at startup (See DHCP) or permanently assigned as a static address. All TCP/IP messages contain the address of the destination network, as well as the address of the destination station. This enables TCP/IP messages to be transmitted to multiple networks (subnets) within an organization or worldwide. For example, when a user downloads a web page, TCP divides the page file on the web server into packets, numbers the packets, and forwards them individually to the user's IP address. The packets may be routed along different paths before reaching the user's address. At the destination, TCP reassembles the individual packets, waiting until they have all arrived to present them as a single file. (See IP, IP address, packet, TCP).
Throughput: Usually measured in bps, Kbps, Mbps or Gbps, throughput is the amount of data that can be sent from one location to another in a specific amount of time. (See bps, Mbps).
TLS: Transport Layer Security. A newer version of the SSL protocol, It supports more cryptographic algorithms than SSL. TLS is designed to authenticate and encrypt data communications, preventing eavesdropping, message forgery and interference. (See EAP, SSL).
Tri-mode: In the Wi-Fi context, tri-mode refers to devices which are 802.11b, a, and g-compatible. In the mobile context, tri-mode describes a cellular phone that is capable of using analog, digital and GSM frequencies. (See dual band).

U

USB: A high-speed bidirectional serial connection between a PC used to transfer data between the computer and peripherals such as digital cameras and memory cards. The USB 2.0 specification, announced in 2000, provides a data rate of up to 480 Mbps, 40 times faster than the original specification which provided only 12 Mbps.
UWB: Ultra Wideband. A relatively new term that is used to describe a technology known since the early 1960s as "carrier-free", "baseband" or "impulse". UWB transmits and receives extremely short bursts of radio signals, typically a few trillionths of a second to a few billionths of a second (nanoseconds) in duration. These bursts produce waveforms that are extremely broadband.

V

Voice over Wi-Fi: VoIP services delivered over wireless networks. Sometimes referred to as wireless voice over IP. (See IP telephony, VoIP).
VoIP: Voice over Internet Protocol. A technology for transmitting ordinary telephone calls over the Internet using packet-based networks instead of standard public switched telephone networks or Plain Old Telephone Service (POTS). (See IP telephony, Voice over Wi-Fi).
VPN: Virtual Private Network. A network layer encryption scheme that allows remote clients to securely connect to their corporate networks using the Internet. Most major corporations today use VPN to protect their remote-access workers and their connections. It works by creating a secure virtual "tunnel" from the end-user's computer through the end-user's access point or gateway, through the Internet, all the way to the corporation's servers and systems. It also works for wireless networks and can effectively protect transmissions from Wi-Fi equipped computers to corporate servers and systems.

W

WAN: Wide Area Network (WLAN). A data communications network that spans large local, regional, national or international areas and is usually provided by a public carrier (such as a telephone company or service provider).The term is used to distinguish between phone-based data networks and Wi-Fi networks. Phone networks are considered WANs and Wi-Fi networks are considered Wireless Local Area Networks. (See LAN, WMAN, WPAN).
WAP: Wireless Applications Protocol. A protocol designed to deliver applications to mobile devices, including cell phones, pagers, two-way radios, smartphones and communicators.
War chalking: The practice of indicating the presence of both secured and unsecured wireless networks by using chalk to mark nearby buildings or sidewalks.
War driving: The practice of driving around with a GPS, laptop equipped with WNIC and an antenna (usually built into the WNIC) to document the location of secured and unsecured WLANs. The locations of the WLANs derived from the GPS readings, and their corresponding SSIDs, are published in databases that live on the Internet. War driving derives its name from the movie, War Games, in which hackers gained access to traditional networks by randomly dialing telephone numbers until a modem answered. (See GPS).
WEP: The original security standard used in wireless networks to encrypt the wireless network traffic. (See WPA).
Wi-Fi CERTIFIED™: The certification standard designating IEEE 802.11-based wireless local area network (WLAN) products that have passed interoperability testing requirements developed and governed by the Wi-Fi Alliance. (See Wi-Fi Interoperability Certificate).
Wi-Fi Interoperability Certificate: A statement that a product has passed interoperability testing and will work with other Wi-Fi CERTIFIED™ products. (See Wi-Fi CERTIFIED).
Wi-Fi Protected Setup: Wi-Fi Protected Setup™ (previously called Wi-Fi Simple Config) is an optional certification program developed by the Wi-Fi Alliance designed to ease set up of security-enabled Wi-Fi networks in home and small office environments. Wi-Fi Protected Setup supports methods (pushing a button or entering a PIN into a wizard-type application) that are familiar to most consumers to configure a network and enable security.
Wi-Fi ZONE: A certification program of the Wi-Fi Alliance® that allows users to easily identify public hotspot locations that have Wi-Fi connectivity available. The program allows customers from anywhere in the world to look for a single Wi-Fi ZONE brand. The Wi-Fi ZONE logo assures users that they will be able to get a fast, reliable Internet connection in a coffee shop, hotel, airport, convention center or other public venue. (See hotspot).
Wi-Fi®: A term developed by the Wi-Fi Alliance to describe wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards. (See Wi-Fi CERTIFIED™ ).
WiMAX: Worldwide Interoperability for Microwave Access. Refers to the 802.16 standard being developed by the IEEE to provide a wireless coverage of up to 31 miles. It operates in the 2 to 11 GHz bands and enables connectivity without a direct line-of-sight to a base station although line-of-site is probably required to achieve connectivity at the distance of 31 miles.. It provides shared data rates up to 70 Mbps, which, according to WiMAX proponents, is enough bandwidth to simultaneously support more than 60 businesses and hundreds of homes. (See WMAN).
Wireless network: Devices connected to a network using a centralized wireless access point. (See WLAN).
WLAN: Wireless Local Area Network. A type of local-area network in which data is sent and received via high-frequency radio waves rather than cables or wires. (See LAN, wireless network).
WMAN: Wireless Metropolitan Area Network-A wireless data network that is comparable to a cell phone network in that users throughout a metropolitan area can freely access the Internet. WiMAX technology provides the basis of WMAN networks. (See WiMAX).
WMM®: The WMM® mark indicates that a product has successfully completed testing under the Wi-Fi Alliance's Wi-Fi Multimedia™ certification program for multimedia features that improve the user experience for audio, video and voice applications. In order to qualify for WMM certification, a product must implement multimedia features based on a subset of the IEEE 802.11e QoS draft standard, which add prioritized capabilities to wireless networks and optimize their performance when multiple concurring applications - each with different latency and throughput requirements - compete for network resources. By using products certified under the WMM program, end-user satisfaction is maintained in a wider variety of environments and traffic conditions. Products that qualify for WMM certification make it possible for home network users and enterprise network managers to decide which data streams are most important and assign them a higher traffic priority. (See 802.11e, QoS).
WMM™ Power Save: WMM Power Save is a set of features for Wi-Fi networks that increase the efficiency and flexibility of data transmission in order to conserve power. WMM Power Save has been optimized for mobile devices running latency-sensitive applications such as voice, audio, or video, but can benefit any Wi-Fi device. WMM Power Save uses mechanisms included in the IEEE 802.11e standard and is an enhancement of IEEE 802.11 legacy power save. With WMM Power Save, the same amount of data can be transmitted in a shorter time while allowing the Wi-Fi device to remain longer in a low-power "dozing" state.
WPA2™: The Wi-Fi Protected Access 2^™ and WPA2 marks indicate that a product has successfully completed testing under the Wi-Fi Alliance's Wi-Fi Protected Access 2 certification program for wireless network security features. The features tested and certified through the WPA2 program provide stronger data protection and network access control that the features tested and certified through the WPA program. They provide enterprise and consumer Wi-Fi users with a high level of assurance that only authorized users can access their wireless networks. Based on the ratified IEEE 802.11i standard, the advanced security protocol provides government grade security by implementing the National Institute of Standards and Technology (NIST) FIPS 140-2 compliant AES encryption algorithm and 802.1X-based authentication. There are two versions of certification available through the WPA2 program: WPA2-Personal, and WPA2-Enterprise. WPA2-Personal certifies a standard that protects unauthorized network access by utilizing a set-up password. WPA2-Enterprise certifies a standard that verifies network users through a server. The standard certified through WPA2 is backward compatible with the standard certified through WPA. Like the standard certified through WPA, the standard certified through WPA2 uses the 802.1X/EAP framework as part of the infrastructure that ensures centralized mutual authentication and dynamic key management and offers a pre-shared key for use in home and small office environments. This advanced security protocol is designed to secure all versions of 802.11 devices, including 802.11b, 802.11a, and 802.11g, multi-band and multi-mode. (See WPA2-Enterprise, WPA2-Personal).
WPA2™ - Enterprise: The Wi-Fi Protected Access 2 - Enterprise mark indicates that a product has successfully completed testing under the Wi-Fi Alliance's Wi-Fi Protected Access 2 certification program and meets the criteria established to ensure stronger data protection for multiple users and large managed networks. These criteria prevent unauthorized network access by verifying network users through an authentication server. (See WPA2).
WPA2™ - Personal: The Wi-Fi Protected Access 2 - Personal mark indicates that a product has successfully completed testing under the Wi-Fi Alliance's Wi-Fi Protected Access 2 certification program and meets the criteria established to ensure stronger data protection and prevent unauthorized network access for small networks. (See WPA2, PSK).
WPAN: Wireless Personal Area Network. A network that wirelessly connects personal devices centered within a radius of about 30 feet such as an individual's workspace or room environment in a home. WPAN technologies include Bluetooth and others defined by the IEEE 802.15 standard. Devices specifications include low data rates (250 kbps, 40 kbps, and 20 kbps), and multi-month to multi-year battery life and include such things as joy sticks and interactive toys. WPAN devices operate in unlicensed international frequency bands and can communicate directly with one another, a concept called "plugging in". (See Bluetooth wireless technology).