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| 802.11, or IEEE 802.11, is a type of radio
technology used for wireless local area networks (WLANs). It is a standard
that has been developed by the IEEE (Institute of Electrical and Electronic
Engineers), http://standards.ieee.org.
The IEEE is an international organization that develops standards for
hundreds of electronic and electrical technologies. The organization uses a
series of numbers, like the Dewey Decimal system in libraries, to
differentiate between the various technology families.
The 802 subgroup (of the IEEE) develops
standards for local and wide area networks with the 802.11 section reviewing
and creating standards for wireless local area networks.
Wi-Fi , 802.11, is composed of several
standards operating in different radio frequencies: 802.11b is a standard
for wireless LANs operating in the 2.4 GHz spectrum with a bandwidth of 11
Mbps; 802.11a is a different standard for wireless LANs, and pertains to
systems operating in the 5 GHz frequency range with a bandwidth of 54 Mbps.
Another standard, 802.11g, is for WLANS operating in the 2.4 GHz frequency
but with a bandwidth of 54 Mbps. |
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| An IEEE specification for wireless
networking that operates in the 5 GHz frequency range (5.725 GHz to 5.850
GHz) with a maximum 54 Mbps data transfer rate. The 5 GHz frequency band is
not as crowded as the 2.4 GHz frequency, because the 802.11a specification
offers more radio channels than the 802.11b. These additional channels can
help avoid radio and microwave interference. |
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| International standard for wireless
networking that operates in the 2.4 GHz frequency range (2.4 GHz to 2.4835
GHz) and provides a throughput of up to 11 Mbps. This is a very commonly
used frequency. Microwave ovens, cordless phones, medical and scientific
equipment, as well as Bluetooth devices, all work within the 2.4 GHz
frequency band. |
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| Similar to 802.11b, but this standard
provides a throughput of up to 54 Mbps. It also operates in the 2.4 GHz
frequency band but uses a different radio technology in order to boost
overall bandwidth. |
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| A wireless LAN transceiver or "base
station" that can connect a wired LAN to one or many wireless devices.
Access points can also bridge to each other.
There are various types of access points
and base stations used in both wireless and wired networks. These include
bridges, hubs, switches, routers and gateways. The differences between them
are not always precise, because certain capabilities associated with one can
also be added to another. For example, a router can do bridging, and a hub
may also be a switch. But they are all involved in making sure data is
transferred from one location to another.
A bridge connects devices that all use the
same kind of protocol. A router can connect networks that use differing
protocols. It also reads the addresses included in the packets and routes
them to the appropriate computer station, working with any other routers in
the network to choose the best path to send the packets on. A wireless hub
or access point adds a few capabilities such as roaming and provides a
network connection to a variety of clients, but it does not allocate
bandwidth. A switch is a hub that has extra intelligence: It can read the
address of a packet and send it to the appropriate computer station. A
wireless gateway is an access point that provides additional capabilities
such as NAT routing, DHCP, firewalls, security, etc. |
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| A client setting that provides independent
peer-to-peer connectivity in a wireless LAN. An alternative set-up is one
where PCs communicate with each other through an AP. See access point and
Infrastructure mode. |
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| A technology specification for linking portable computers, personal
digital assistants (PDAs) and mobile phones for short-range transmission of
voice and data across a global radio frequency band without the need for
cables or wires. Bluetooth is a frequency-hopping technology in the 2.4 GHz
frequency spectrum, with a range of 30 feet. |
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| A product that connects a local area network (LAN) to another local area
network that uses the same protocol (for example, wireless, Ethernet or
token ring). Wireless bridges are commonly used to link buildings in
campuses. |
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| A comparatively fast Internet connection. Services such as ISDN, cable
modem, DSL and satellite are all considered broadband as compared to dial-up
Internet access. There is no official speed definition of broadband but
services of 100Kbps and above are commonly thought of as broadband. |
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| A kind of converter used to connect a computer to a cable TV service
that provides Internet access. Most cable modems have an Ethernet out-cable
that then attaches to the user's Wi-Fi gateway. |
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| A type of antenna system that uses two antennas to maximize reception
and transmission quality and reduce interference. |
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| Various technology protocols for high-speed data, voice and video
transmission over ordinary twisted-pair copper POTS (Plain Old Telephone
Service) telephone wires. |
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| 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. |
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| The identifying name of an 802.11 wireless network. When you specify
your correct ESSID in your client setup you ensure that you connect to your
wireless network rather than another network in range. (See SSID.) The ESSID
can be called by different terms, such as Network Name, Preferred Network,
SSID or Wireless LAN Service Area. |
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| International standard networking technology for wired implementations.
Basic 10BaseT networks offer a bandwidth of about 10 Mbps. Fast Ethernet
(100 Mbps) and Gigabit Ethernet (1000 Mbps) are becoming popular. |
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| A system that secures a network and prevents access by unauthorized
users. Firewalls can be software, hardware or a combination of both.
Firewalls can prevent unrestricted access into a network, as well as
restrict data from flowing out of a network. |
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| 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.
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| A place where you can access Wi-Fi service. This can be for free or for
a fee. HotSpots can be inside a coffeeshop, airport lounge, train station,
convention center, hotel or any other public meeting area. Corporations and
campuses are also implementing HotSpots to provide wireless Internet access
to their visitors and guests. In some parts of the world, HotSpots are known
as CoolSpots. |
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| A client setting providing connectivity to an AP. As compared to Ad-Hoc
mode, whereby PCs communicate directly with each other, clients set in
Infrastructure Mode all pass data through a central AP. The AP not only
mediates wireless network traffic in the immediate neighborhood, but also
provides communication with the wired network. See Ad-Hoc and AP. |
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| A 32-bit number that identifies each sender or receiver of information
that is sent across the Internet. An IP address has two parts: an identifier
of a particular network on the Internet and an identifier of the particular
device (which can be a server or a workstation) within that network. |
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| A network capability that enables a houseful of computers to dynamically
share a single incoming IP address from a dial-up, cable or xDSL connection.
NAT takes the single incoming IP address and creates new IP address for each
client computer on the network. |
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| 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. |
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| 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. |
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| A computer system feature that provides for automatic configuration of
add-ons and peripheral devices such as wireless PC Cards, printers, scanners
and multimedia devices. |
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| Used in larger companies and organizations to improve network operations
and security, a proxy server is able 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. |
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| Standard connectors used in Ethernet networks. Even though they look
very similar to standard RJ-11 telephone connectors, RJ-45 connectors can
have up to eight wires, whereas telephone connectors have only four. |
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| Moving seamlessly from one AP coverage area to another with no loss in
connectivity. |
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| A device that forwards data packets from one local area network (LAN) or
wide area network (WAN) to another. Based on routing tables and routing
protocols, routers can read the network address in each transmitted frame
and make a decision on how to send it via the most efficient route based on
traffic load, line costs, speed, bad connections, etc. |
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| The process whereby a wireless network installer inspects a location
prior to putting in a wireless network. Site surveys are used to identify
the radio- and client-use properties of a facility so that access points can
be optimally placed. |
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| A 32-character unique identifier attached to the header of packets sent
over a WLAN that acts as a password when a mobile device tries to connect to
the BSS. (Also called ESSID.) The SSID differentiates one WLAN from another,
so all access points and all devices attempting to connect to a specific
WLAN must use the same SSID. A device will not be permitted to join the BSS
unless it can provide the unique SSID. Because an SSID can be sniffed in
plain text from a packet, it does not supply any security to the network. An
SSID is also referred to as a Network Name because essentially it is a name
that identifies a wireless network. |
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| Commonly used encryption scheme used by many online retail and banking
sites to protect the financial integrity of transactions. 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 |
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| Found in larger networks, these smaller networks are used to simplify
addressing between numerous computers. Subnets connect to the central
network through a router, hub or gateway. Each individual wireless LAN will
probably use the same subnet for all the local computers it talks to. |
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| A type of hub that efficiently controls the way multiple devices use the
same network so that each can operate at optimal performance. A switch acts
as a networks 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. |
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| A protocol used along with the Internet Protocol (IP) to send data in
the form of individual units (called packets) between computers over the
Internet. While IP takes care of handling the actual delivery of the data,
TCP takes care of keeping track of the packets that a message is divided
into for efficient routing through the Internet. For example, when a web
page is downloaded from a web server, the TCP program layer in that server
divides the file into packets, numbers the packets, and then forwards them
individually to the IP program layer. Although each packet has the same
destination IP address, it may get routed differently through the network.
At the other end, TCP reassembles the individual packets and waits until
they have all arrived to forward them as a single file. |
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| The underlying technology behind the Internet and communications between
computers in a network. The first part, TCP, is the transport part, which
matches the size of the messages on either end and guarantees that the
correct message has been received. The IP part is the user's computer
address on a network. Every computer in a TCP/IP network has its own IP
address that is either dynamically assigned at startup or permanently
assigned. 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. |
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| A high-speed bidirectional serial connection between a PC and a
peripheral that transmits data at the rate of 12 megabits per second. The
new USB 2.0 specification provides a data rate of up to 480 Mbps, compared
to standard USB at only 12 Mbps. 1394, FireWire and iLink all provide a
bandwidth of up to 400 Mbps. |
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| Voice transmission using Internet Protocol to create digital packets
distributed over the Internet. VoIP can be less expensive than voice
transmission using standard analog packets over POTS (Plain Old Telephone
Service). |
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| A type of technology designed to increase the security of information
transferred over the Internet. VPN can work with either wired or wireless
networks, as well as with dial-up connections over POTS. VPN creates a
private encrypted tunnel from the end user's computer, through the local
wireless network, through the Internet, all the way to the corporate servers
and database. |
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| A communication system of connecting PCs and other computing devices
across a large local, regional, national or international geographic area.
Also used to distinguish between phone-based data networks and Wi-Fi. Phone
networks are considered WANs and Wi-Fi networks are considered Wireless
Local Area Networks (WLANs). |
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| Basic wireless security provided by Wi-Fi. In some instances, WEP may be
all a home or small-business user needs to protect wireless data. WEP is
available in 40-bit (also called 64-bit), or in 108-bit (also called
128-bit) encryption modes. As 108-bit encryption provides a longer algorithm
that takes longer to decode, it can provide better security than basic
40-bit (64-bit) encryption. |
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| Also referred to as LAN. A type of local-area network that uses
high-frequency radio waves rather than wires to communicate between nodes. |
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