Network Arbitration and Contention JN0-452 Practice Questions (Page 2)

Questions 6–10

1. 6application · medium

   A network engineer is explaining to a colleague why Wi-Fi cannot use the same collision detection mechanism as wired Ethernet. The colleague asks why Wi-Fi uses collision avoidance instead of collision detection. Which reason best explains this design choice?

   • AA wireless radio cannot transmit and listen for collisions simultaneously because the transmit signal would overwhelm the receiver
   • BWi-Fi uses a centralized access point that prevents collisions, so detection is unnecessary
   • CWi-Fi frames are too large to detect collisions during transmission
   • DWi-Fi uses a different frequency band than Ethernet, making collision detection impossible
   Reveal Solution Discussion Select an answer first
2. 7application · medium

   A network engineer is analyzing the performance of a Wi-Fi network with high retransmission rates. The engineer observes that after a collision, the backoff timer is selected from a larger range of values. What is the primary purpose of increasing the contention window after a collision?

   • ATo increase the data rate of the retransmission
   • BTo decrease the interframe space for the retransmission
   • CTo reduce the probability of another collision by spreading out retransmission attempts
   • DTo allow the retransmission to bypass the physical carrier sensing
   Reveal Solution Discussion Select an answer first
4. 8foundation · easy

   Which mechanism is used by a station to determine that the medium is busy even if it cannot detect the actual RF signal?

   • ARTS/CTS handshake
   • BBeacon frame synchronization
   • CPhysical carrier sensing
   • DVirtual carrier sensing via the NAV
   Reveal Solution Discussion Select an answer first
5. 9foundation · easy

   What is the role of the Distributed Coordination Function (DCF) in an 802.11 wireless network?

   • AIt defines the basic contention-based medium access method using CSMA/CA and random backoff
   • BIt prioritizes traffic by assigning different backoff times based on access categories
   • CIt manages the association and authentication of stations to the access point
   • DIt provides a contention-free access method using a point coordinator to poll stations
   Reveal Solution Discussion Select an answer first
6. 10foundation · easy

   How does the hidden node problem affect contention in a Wi-Fi network?

   • AIt increases the probability of collisions because hidden stations cannot perform carrier sensing on each other
   • BIt has no effect on contention because the access point resolves all collisions
   • CIt causes stations to use a larger contention window, reducing throughput
   • DIt decreases contention because hidden stations are not competing for the medium
   Reveal Solution Discussion Select an answer first