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D -52 Psion Teklogix 9160 G2 Wireless Gateway User Manual
Appendix D: Glossary
CCMP
C
CCMP
Counter mode/CBC-MAC Protocol (CCMP) is an encryption method for 802.11h that uses
AES . It employs a CCM mode of operation, combining the Cipher Block Chaining Counter
mode (CBC-CTR) and the Cipher Block Chaining Message Authentication Code (CBC-
MAC) for encryption and message integrity.
AES-CCMP requires a hardware coprocessor to operate.
CGI
The Common Gateway Interface (CGI) is a standard for running external programs from an
HTTP server. It specifies how to pass arguments to the executing program as part of the
HTTP request. It may also define a set of environment variables.
A CGI program is a common way for an HTTP server to interact dynamically with users.
For example, an HTML page containing a form can use a CGI program to process the form
data after it is submitted.
Channel
The Channel defines the portion of the radio spectrum the radio uses for transmitting and
receiving. Each 802.11 standard offers a number of channels, dependent on how the
spectrum is licensed by national and transnational authorities such as the
Federal
Communications Commission (FCC)
, the
European Telecommunications Standards Institute (ETSI)
, the
Korean Communications Commission , or the Telecom Engineering Center (TELEC) .
CSMA/CA
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is a low-level
network arbitration/contention protocol. A station listens to the media and attempts to
transmit a packet when the channel is quiet. When it detects that the channel is idle, the
station transmits the packet. If it detects that the channel is busy, the station waits a random
amount of time and then attempts to access the media again.
CSMA/CA is the basis of the IEEE 802.11e Distributed Control Function ( DCF ). See also
RTS and CTS .