User's Guide

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DHCP: dynamic host configuration protocol. A method for dynamically assigning IP addresses
to devices on a network. Issues IP addresses automatically within a specified range to devices
such as PCs when they are first powered up. The device retains the use of the IP address for a
specific license period defined by the system administrator.
DSSS: direct sequence spread spectrum. Combines a data signal at the sending station with a
higher data rate bit sequence, which many refer to as a chip sequence (also known as processing
gain). A high processing gain increases the signal’s resistance to interference. The minimum
processing gain that the FCC allows is 10, and most products operate under 20.
EAP: extensible authentication protocol. A general point-to-point protocol that supports
multiple authentication mechanisms. Defined in RFC 2284, EAP has been adopted by IEEE
802.1X as an encapsulation protocol for carrying authentication messages in a standard message
exchange between a user (client or supplicant) and an authenticator.
EAPoL: EAP over LAN. An encapsulated form of the Extensible Authentication Protocol
(EAP), defined in the IEEE 802.1X standard, that allows EAP messages to be carried directly
by a LAN media access control (MAC) service between a user (client or supplicant) and an
authenticator.
EAP-TLS: extensible authentication protocol with transport layer security. Used for 802.1X
authentication. EAP-TLS supports mutual authentication and uses digital certificates to address
the mutual challenge. The authentication server responds to a user authentication request with a
server certificate. The user then replies with its own certificate and validates the server certificate.
EAP-TLS algorithm derives session encryption keys from the certificate values. The
authentication server in turn sends the session encryption keys for a particular session to the
user after validating the user certificate.
encryption: Any procedure used in cryptography to translate data into a form that can be
decrypted and read only by its intended receiver.
Ethernet: A LAN architecture that uses CSMA to allow the sharing of a bus-type network.
IEEE 802.3 is a standard that defines Ethernet.
Ethernet repeater: Refers to a network element that provides Ethernet connections among
multiple other elements sharing a common collision domain. Also referred to as a shared
Ethernet hub.
FHSS: frequency-hopping spread-spectrum. One of two types of spread-spectrum radio
technology used in wireless LAN (WLAN) transmissions. The FHSS technique modulates the
data signal with a narrowband carrier signal that “hops” in a predictable sequence from
frequency to frequency as a function of time over a wide band of frequencies. Interference is
reduced, because a narrowband interferer affects the spread-spectrum signal only if both are
transmitting at the same frequency at the same time. The transmission frequencies are
determined by a spreading (hopping) code. The receiver must be set to the same hopping code
and must listen to the incoming signal at the proper time and frequency to receive the signal.