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Dynamic IP Address
A temporary IP address that is assigned by the DHCP server to a device. Devices retain dynamic IP addresses only for
the duration of their networking session. When a device disconnects from the network, the IP address is recaptured by
the DHCP server and becomes available for reassignment to another device. See also, DHCP,
IP
Address,
IP
Address
Translation,
Static IP
Address, and Translation.
EAP
(Extensible Authentication Protocol) An extension to PPP. EAP is a general protocol for authentication that also
supports multiple authentication methods (for example, public key authentication and smart cards). IEEE 802.1x
specifies how EAP should be encapsulated in LAN frames. In wireless communications using EAP, a user requests
connection to a
WLAN
through an AP, which then requests the identity of the user and transmits that identity to an
authentication server such as RADIUS. The server asks the AP for proof of identity, which the AP gets from the user
and then sends back to the server to complete the authentication.
ECommerce
A business venture between a supplier and its customers using online services (for example, the Internet). Both parties
use online services to conduct business transactions. Transactions may include generating orders, invoices, and
payments, and submitting inquiries. Also known as Enterprise.
ESS
(Extended Service Set) See
infrastructure
mode.
Ethernet
A Local Area Network (LAN) protocol developed by Xerox Corporation in cooperation with DEC and Intel in 1976.
Ethernet uses a bus or star topology and supports data transfer rates of 10 Mbps. The Ethernet specification served as
the basis for the IEEE 802.3 standard, which specifies the physical and lower software layers. Ethernet is one of the
most widely implemented LAN standards. A newer version of Ethernet, called 100Base-T (or Fast Ethernet), supports
data transfer rates of 100 Mbps. The latest version, Gigabit Ethernet, supports data rates of 1 Gigabit (1,000 Mbps) per
second. See also, Mbps.
Fast Ethernet
See Ethernet.
FCC
(Federal Communications Commission) US wireless regulatory authority. The FCC was established by the
Communications Act of 1934 and is charged with regulating Interstate and International communications by radio,
television, wire, satellite and cable.
FDM
(Frequency Division Multiplexing) A multiplexing technique that uses different frequencies to combine multiple
streams of data for transmission over a communications medium. FDM assigns a discrete
Carrier frequency
to each
data stream and then combines many modulated carrier frequencies for transmission. For example, television
transmitters use FDM to broadcast several channels at once.
FHSS
(Frequency Hopping Spread Spectrum) One of two types of spread spectrum radio—the other being Direct-Sequence
Spread Spectrum (DSSS). FHSS is a transmission technology used in
WLAN
transmissions where the data signal is
modulated with a narrowband carrier signal that "hops" in a random but predictable sequence from frequency to
frequency as a function of time over a wide band of frequencies. The signal energy is spread in time domain rather than
chopping each bit into small pieces in the frequency domain. This technique reduces interference because a signal from
a narrowband system will only affect the spread spectrum signal if both are transmitting at the same frequency at the
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