31. In a classful addressing, first four bits in Class A IP address is
a. 1010
b. 1100
c. 1011
d. 1110
Answer: (a).1010

32. Consider the following S1 and S2 :

S1 : A hard handover is one in which the channel in the source cell is retained and used for a while in parallel with the channel in the target cell.

S2 : A soft handover is one in which the channel in the source cell is retained and only then the channel in the target cell is engaged.
a. S1 is true and S2 is not true
b. S1 is not true and S2 is true
c. Both S1 and S2 are true
d. Both S1 and S2 are not true
Answer: (d).Both S1 and S2 are not true

33. How many distinct stages are there in DES algorithm, which is parameterized by a 56-bit key?
a. 16
b. 17
c. 18
d. 19
Answer: (a).16

34. Which of the following algorithms is not a broadcast routing algorithm?
a. Flooding
b. Multi-destination routing
c. Reverse path forwarding
d. All of the above
Answer: (c).Reverse path forwarding

35. The period of a signal is 10 ms. What is its frequency in Hertz?
a. 10
b. 100
c. 1000
d. 10000
Answer: (b).100

36. For n devices in a network, ____ , number of duplex-mode links are required, for a mesh topology.
a. n(n + 1)
b. n(n - 1)
c. n(n + 1) /2
d. n(n - 1)/2
Answer: (c).n(n + 1) /2

37. How many characters per second (7 bits + 1 parity) can be transmitted over a 3200 bps line if the transfer is asynchronous? (Assuming 1 start bit and 1 stop bit)
a. 300
b. 320
c. 360
d. 400
Answer: (b).320

38. Which of the following is not a field in TCP header ?
a. Sequence number
b. Fragment offSet
c. Checksum
d. Window size
Answer: (b).Fragment offSet

39. What is the propagation time if the distance between the two points is 48,900 ? Assume the propagation speed to be 2.4 x 108 meter/second in cable.
a. 0.5 ms
b. 20 ms
c. 50 ms
d. 200 ms
Answer: (d).200 ms

40. _________________ is a bit-oriented protocol for communication over point-to-point and multi-point links . 
a. Stop-and-wait
c. Sliding window
d. Go-back-N
Answer: (a).Stop-and-wait

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