NWC203(02)

Use IEEE 802.3 and IEEE 802.11 to discuss differences between wired and wireless LANs. Which of following statements are true about the differences?

• a. Error rate

• b. Collision detection
  

  
  

• c. Station mobility
  

• d. All of the above

Which of following is not a primary responsibility of the MAC sublayer in LANs?

• a. Channel access

• b. Protocol data unit addressing

• c. Reliable connection-oriented service

• d. Fragmentation and reassembly of MAC service data unit

In Ethernet, slot time that is at least the round-trip propagation delay, is the critical system parameter for

• a. upper bound on time to acquire channel

• b. quantum for re-transmission scheduling

• c. upper bound on time to detect collision

• d. All of the above

Which one of the following event is not possible in wireless LAN.

• a. Acknowledgement of data frames

• b. Collision detection

• c. Collision avoidance

• d. Multi-mode data transfer

  
  

In 802.11 protocol, MAC can alternate between Contention Periods (CPs) and Contention-Free Periods (CFPs)

• T

• F

CSMA/CD is not used in DCF because

• a. a station is unable to listen to the channel for collisions while transmitting

• b. physical carrier sense detects the presence of other WLAN users

• c. in idle state, a station is unable to listen to the channel for collisions

• d. None of the above

In infrastructure network supporting voice and data traffic, data traffic is transported through the CP and voice traffic through the CFP

• T

• F

In 802.11 protocol, which of the following statements are true for Basic Service Set (BSS) (2 answers)

• a. Location in a Basic Service Area (BSA)

• b. Multiple BSSs interconnected by Central System (CS)

• c. Distinct collocated BSS's cannot coexist

• d. Stations in BSS can communicate with each other

Consider a Gigabit Ethernet hub with stations at a 100-meter distance and average frame size of 512 bytes. Assume the propagation speed is at 2/3 of light speed. What is the value of normalized delay-bandwidth product?

• a. 0.0122
  
  

• b. 0.122
  

• c. 1.22
  

• d. None of the above

Wireless data communication is compelling, because of (2 answers)

• a. Its easy and low-cost deployment

• b. Its support to personal and mobile devices

• c. Its high reliability to noise and interference

• d. All of the above