802.11 Medium Access Review Questions

DCF is also known as what? (Choose all that apply.)

• Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

• Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

• Data Control Function

• Distributed Coordination Function

802.11 collision detection is handled using which technology?

• Network allocation vector (NAV)

• Clear channel assessment (CCA)

• Duration/ID value

• Receiving an ACK from the destination station

• Positive collision detection cannot be determined

The carrier sense portion of CSMA/CA is performed by using which of the following methods? (Choose all that apply.)

• Virtual carrier-sense

• Physical carrier-sense

• Channel sense window

• Clear channel assessment

If PCF is implemented, it can function in which of the following network environments? (Choose all that apply.)

• Ad Hoc mode

• BSS

• IBSS

• Infrastructure mode

• BSA

Which of the following statements about PCF are true? (Choose all that apply.)

• PCF will work in only a BSS

• PCF can be used in an IBSS

• Both the station and access point must support PCF for it to be used

• The access point will alternate between PCF and DCF mode

• PCF is a form of contention

CSMA/CA and DCF define which mechanisms to ensure that only one 802.11 radio can transmit on the half-duplex RF medium? (Choose all that apply.)

• Random back-off timer

• NAV

• CCMP

• CCA

• Interframe spacing

The 802.11e amendment (now part of the 802.11-2007 standard) defines which of the following medium access methods to support QoS requirements? (Choose all that apply.)

• Distributed Coordination Function (DCF)

• Enhanced Distributed Channel Access (EDCA)

• Hybrid Coordination Function (HCF)

• Point Coordination Function (PCF)

• Hybrid Coordination Function Controlled Access (HCCA)

What information that comes from the wired side network is used to assign traffic into access categories on a WLAN controller? (Choose all that apply.)

• DSCP bits

• Duration/ID

• 802.1D priority tags

• Destination MAC address

• Source MAC address

What are the two reasons that 802.11 radios use physical carrier-sense? (Choose two.)

• Synchronize incoming transmissions

• Synchronize outgoing transmissions

• Reset the NAV

• Start the random back-off timer

• Assess the RF medium

What CSMA/CA mechanism is used for medium contention? (Choose all that apply.)

• NAV

• Interframe spacing

• CCA

• Random back-off timer

• Contention window