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Appendix D: Glossary
CTS
The CSMA/CA protocol used by
802.11
networks is a variation on CSMA/CD (used by
Ethernet
networks). In CSMA/CD the emphasis is on collision detection whereas with
CSMA/CA the emphasis is on collision avoidance.
CTS
A clear to send (CTS) message is a signal sent by an
IEEE 802.11
client station in response
to an request to send (RTS) message. The CTS message indicates that the channel is clear
for the sender of the RTS message to begin data transfer. The other stations will wait to keep
the air waves clear. This message is a part of the IEEE 802.11
CSMA/CA
protocol. (See also
RTS.)
D
DCF
The Distribution Control Function is a component of the IEEE 802.11e Quality of Service
(QoS) technology standard. The DCF coordinates channel access among multiple stations
on a wireless network by controlling wait times for channel access. Wait times are
determined by a random backoff timer which is configurable by defining minimum and
maximum contention windows. See also EDCF.
DHCP
The Dynamic Host Configuration Protocol (DHCP) is a protocol specifying how a central
server can dynamically provide network configuration information to clients. A DHCP
server "offers" a "lease" (for a pre-configured period of time—see
Lease
Time) to the client
system. The information supplied includes the client's IP addresses and netmask plus the
address of its
DNS
servers and Gateway.
DNS
The Domain Name Service (DNS) is a general-purpose query service used for translating
fully-qualified names into Internet addresses. A fully-qualified name consists of the
hostname of a system plus its domain name. For example,
is the host name of a Web
www
server and
is the fully-qualified name of that server. DNS translates the
www.psionteklogix.com
domain name
to some IP address, for example
.
66.93.138.219
www.psionteklogix.com
Psion Teklogix 9160 G2 Wireless Gateway User Manual
D-53
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