Appendix D: Glossary
CTS
Psion Teklogix 9160 G2 Wireless Gateway User Manual D-53
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,
www
is the host name of a Web
server and
www.psionteklogix.com
is the fully-qualified name of that server. DNS translates the
domain name
www.psionteklogix.com
to some IP address, for example
66.93.138.219
.
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