CWNA EXAM COMPLETE STUDY SET
4-Way Handshake - ANSWER A protocol that uses a frame exchange
between two stations (STAs)
to create dynamic encryption keys that are unique to any two radios.
Either preshared key
(PSK) or 802.1X authentication creates a Pairwise Master Key (PMK)
that seeds the 4-Way Handshake process. The four-frame exchange
completes the authentication process once the
final encryption keys are created.
6 dB rule - ANSWER Doubling the distance between a transmitter and
receiver will decrease the received signal by 6 dB. Halving the distance
between a transmitter and a receiver will
increase the received signal by 6 dB
802.1X - ANSWER The 802.1X standard is a port-based access control
standard. 802.1X provides an authorization framework that allows (or
disallows) traffic to pass through a port and
thereby access network resources. An 802.1X framework may be
implemented in either a
wireless or wired environment. The three main components of an 802.1X
framework are
the supplicant, the authenticator, and the authentication server.
absorption - ANSWER The most common RF behavior is absorption. If
a signal does not bounce off an object or move around it, the signal will
be absorbed to some extent by the object. Most materials will absorb
some amount of an RF signal.
access point () - ANSWER (AP) A half-duplex radio device that
provides distribution services (network connectivity) to either associated
stations or other access points.
acknowledgment () - ANSWER (ACK) The ACK frame is one of the
control frames and one of the key
,components of the 802.11 CSMA/CA media access control method.
Because 802.11 is a
wireless medium that cannot guarantee successful data transmission,
the only way for a station to know that a frame it transmitted was
properly received is for the receiving station
to notify the transmitting station. This notification is performed using an
ACK. The ACK frame is a very simple frame consisting of 14 octets of
information.
active gain - ANSWER Active gain is the increase of a signal's
amplitude caused by the use of an
amplifier on the wire that connects the transceiver to the antenna. The
amplifier is usually
bidirectional, meaning that it increases the AC voltage both inbound and
outbound. Active
gain devices require the use of an external power source and must be
approved by regulatory
authorities for use with most wireless systems.
active manual survey - ANSWER An active manual survey is a site
survey method in which a radio card is associated to an access point. An
active survey can gauge metrics, such as CRC errors and layer 2
retransmissions, which are not measurable during a passive survey.
Active mode - ANSWER Active mode is a power management state in
which the client device is
always awake and does not enter a sleep state for battery preservation.
active scanning - ANSWER Active scanning is a technique by which
client stations proactively
discover access points via a probe request/probe response exchange.
ad hoc - ANSWER An 802.11 network service set. See independent
basic service set (IBSS).
Ad Hoc mode - ANSWER A common term used to refer to a station that
is configured to connect to
,an independent basic service set. See also independent basic service
set (IBSS).
adjacent-cell interference - ANSWER Degradation of performance that
is a result of radios transmitting on channels that share overlapping
frequency space.
adjacent channel - ANSWER The next or previous numbered channel.
See also channel.
Advanced Encryption Standard () - ANSWER (AES) The AES
algorithm, based on the Rijndael algorithm, is a block cipher that offers
much stronger protection than the RC4 streaming cipher. AES is used to
encrypt 802.11 wireless data by using an encryption method known as
Counter Mode with Cipher Block Chaining Message Authentication Code
(CCMP). The AES algorithm encrypts data in fixed data blocks with
choices in encryption key strength of 128, 192, or
256 bits.
Aggregate MAC Protocol Data Unit () - ANSWER (A-MPDU) A frame
aggregation technique that combines multiple MAC Protocol Data Units
(MPDUs) into a single frame transmission. See
also MAC Protocol Data Unit (MPDU).
Aggregate MAC Service Data Unit () - ANSWER (A-MSDU) A frame
aggregation technique that combines
multiple MAC Service Data Units (MPDUs) into a single frame
transmission. The
aggregated MAC Service Data Units (MSDUs) have a single destination
when wrapped together in a single frame. Multiple MSDUs are encrypted
by using the same dynamic
encryption key. See also Mac Service Data Unit (MSDU).
airtime fairness - ANSWER A proprietary mechanism used to prioritize
transmissions from stations with higher data rates over stations using
lower data rates. Instead of allocating equal
access opportunities to the network by devices, the goal of airtime
fairness is to allocate
, equal time.
all-band interference - ANSWER All-band interference is RF
interference that occurs across an entire
frequency range that is being used. The term all-band interference is
typically associated
with frequency hopping spread spectrum (FHSS) communications that
disrupt 802.11
communications.
alternating current () - ANSWER (AC) An electrical current with a
magnitude and direction that varies cyclically—as opposed to direct
current, the direction of which stays in a constant form. The shape and
form of the AC signal—defined as the waveform—is known as a
sine wave.
amplification - ANSWER The increase of a signal's amplitude by the
use of an external device.
amplifier - ANSWER An RF amplifier takes the signal that is generated
by the transceiver, increases it, and sends it to the antenna. An amplifier
provides an overall increase in power by adding electrical energy to the
signal, which is referred to as active gain. Unidirectional amplifiers
perform the amplification in only one direction, either when transmitting
or when receiving.
Bidirectional amplifiers perform the amplification in both directions.
amplitude - ANSWER The height, force, or power of a wave. Often
referred to as signal strength.
amplitude-shift keying () - ANSWER (ASK) varies the amplitude, or
height, of a signal to represent the binary data. ASK is a current state
technique, where one level of amplitude can represent a 0 bit and
another level of amplitude can represent
a 1 bit.
announcement traffic indication message () - ANSWER (ATIM) A
unicast frame that is used in an
4-Way Handshake - ANSWER A protocol that uses a frame exchange
between two stations (STAs)
to create dynamic encryption keys that are unique to any two radios.
Either preshared key
(PSK) or 802.1X authentication creates a Pairwise Master Key (PMK)
that seeds the 4-Way Handshake process. The four-frame exchange
completes the authentication process once the
final encryption keys are created.
6 dB rule - ANSWER Doubling the distance between a transmitter and
receiver will decrease the received signal by 6 dB. Halving the distance
between a transmitter and a receiver will
increase the received signal by 6 dB
802.1X - ANSWER The 802.1X standard is a port-based access control
standard. 802.1X provides an authorization framework that allows (or
disallows) traffic to pass through a port and
thereby access network resources. An 802.1X framework may be
implemented in either a
wireless or wired environment. The three main components of an 802.1X
framework are
the supplicant, the authenticator, and the authentication server.
absorption - ANSWER The most common RF behavior is absorption. If
a signal does not bounce off an object or move around it, the signal will
be absorbed to some extent by the object. Most materials will absorb
some amount of an RF signal.
access point () - ANSWER (AP) A half-duplex radio device that
provides distribution services (network connectivity) to either associated
stations or other access points.
acknowledgment () - ANSWER (ACK) The ACK frame is one of the
control frames and one of the key
,components of the 802.11 CSMA/CA media access control method.
Because 802.11 is a
wireless medium that cannot guarantee successful data transmission,
the only way for a station to know that a frame it transmitted was
properly received is for the receiving station
to notify the transmitting station. This notification is performed using an
ACK. The ACK frame is a very simple frame consisting of 14 octets of
information.
active gain - ANSWER Active gain is the increase of a signal's
amplitude caused by the use of an
amplifier on the wire that connects the transceiver to the antenna. The
amplifier is usually
bidirectional, meaning that it increases the AC voltage both inbound and
outbound. Active
gain devices require the use of an external power source and must be
approved by regulatory
authorities for use with most wireless systems.
active manual survey - ANSWER An active manual survey is a site
survey method in which a radio card is associated to an access point. An
active survey can gauge metrics, such as CRC errors and layer 2
retransmissions, which are not measurable during a passive survey.
Active mode - ANSWER Active mode is a power management state in
which the client device is
always awake and does not enter a sleep state for battery preservation.
active scanning - ANSWER Active scanning is a technique by which
client stations proactively
discover access points via a probe request/probe response exchange.
ad hoc - ANSWER An 802.11 network service set. See independent
basic service set (IBSS).
Ad Hoc mode - ANSWER A common term used to refer to a station that
is configured to connect to
,an independent basic service set. See also independent basic service
set (IBSS).
adjacent-cell interference - ANSWER Degradation of performance that
is a result of radios transmitting on channels that share overlapping
frequency space.
adjacent channel - ANSWER The next or previous numbered channel.
See also channel.
Advanced Encryption Standard () - ANSWER (AES) The AES
algorithm, based on the Rijndael algorithm, is a block cipher that offers
much stronger protection than the RC4 streaming cipher. AES is used to
encrypt 802.11 wireless data by using an encryption method known as
Counter Mode with Cipher Block Chaining Message Authentication Code
(CCMP). The AES algorithm encrypts data in fixed data blocks with
choices in encryption key strength of 128, 192, or
256 bits.
Aggregate MAC Protocol Data Unit () - ANSWER (A-MPDU) A frame
aggregation technique that combines multiple MAC Protocol Data Units
(MPDUs) into a single frame transmission. See
also MAC Protocol Data Unit (MPDU).
Aggregate MAC Service Data Unit () - ANSWER (A-MSDU) A frame
aggregation technique that combines
multiple MAC Service Data Units (MPDUs) into a single frame
transmission. The
aggregated MAC Service Data Units (MSDUs) have a single destination
when wrapped together in a single frame. Multiple MSDUs are encrypted
by using the same dynamic
encryption key. See also Mac Service Data Unit (MSDU).
airtime fairness - ANSWER A proprietary mechanism used to prioritize
transmissions from stations with higher data rates over stations using
lower data rates. Instead of allocating equal
access opportunities to the network by devices, the goal of airtime
fairness is to allocate
, equal time.
all-band interference - ANSWER All-band interference is RF
interference that occurs across an entire
frequency range that is being used. The term all-band interference is
typically associated
with frequency hopping spread spectrum (FHSS) communications that
disrupt 802.11
communications.
alternating current () - ANSWER (AC) An electrical current with a
magnitude and direction that varies cyclically—as opposed to direct
current, the direction of which stays in a constant form. The shape and
form of the AC signal—defined as the waveform—is known as a
sine wave.
amplification - ANSWER The increase of a signal's amplitude by the
use of an external device.
amplifier - ANSWER An RF amplifier takes the signal that is generated
by the transceiver, increases it, and sends it to the antenna. An amplifier
provides an overall increase in power by adding electrical energy to the
signal, which is referred to as active gain. Unidirectional amplifiers
perform the amplification in only one direction, either when transmitting
or when receiving.
Bidirectional amplifiers perform the amplification in both directions.
amplitude - ANSWER The height, force, or power of a wave. Often
referred to as signal strength.
amplitude-shift keying () - ANSWER (ASK) varies the amplitude, or
height, of a signal to represent the binary data. ASK is a current state
technique, where one level of amplitude can represent a 0 bit and
another level of amplitude can represent
a 1 bit.
announcement traffic indication message () - ANSWER (ATIM) A
unicast frame that is used in an
