Why does CSMA/CD not work for medium access control of WLAN? What is the alternative mechanism of CSMA/CD? Write steps of operation to implement such an alternative mechanism.
The basic idea behind CSMA/CD is that a station needs to be able to receive while transmitting to detect collision. When there is a collision the station receives two signal: its own signal and the signal transmitted by a second station. To distinguish between the situation when there is a collision and when there is no collision, the received signals must be significantly different. The signal must add a significant amount of energy to the one created by the first one.in a wired network, the received signal has almost same energy as the sent signal because of the amplifiers which amplifies the energy between the sender and the receiver. but in a wireless network, much of the sent energy is lost in transmission. The received signal adds only 5% to 10% additional energy which is not useful for effective collision detection. So CSMA/CD does not work for WLAN.
Since the collision cannot be detected in WLAN by CSMA/CD, so the collision must be avoided. To avoid collision CSMA/CA is used.
What is hand-off? What are the different hand-off strategies? Discuss the merits and demerits of each such strategy?
Briefly describe the congestion control, slow start and fast retransmit mechanism.
What are hidden station problem and exposed station problem in WLAN? How are the problems solved?
What is meant by access control? What are the contention-based and contention free access control mechanisms?
What are the difference between linear and non-linear data structure?
Define packet switching and circuit switching. What is MANET?
Write a C program to print pattern below:
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