1
GATE CSE 2009
+2
-0.6
Frames of 1000 bits are sent over a 106 bps duplex link between two hosts. The propagation time is 25 ms. Frames are to be transmitted into this link to maximally pack them in transit (within the link).

Suppose that the sliding window protocol is used with the sender window size of 2l, where l is the number of bits identified in the earlier part and acknowledgements are always piggy backed. After sending 2l frames, what is the minimum time the sender will have to wait before starting transmission of the next frame? (Identify the closest choice ignoring the frame processing time.)
A
16 ms
B
18 ms
C
20 ms
D
22 ms
2
GATE CSE 2009
+2
-0.6
Frames of 1000 bits are sent over a 106 bps duplex link between two hosts. The propagation time is 25 ms. Frames are to be transmitted into this link to maximally pack them in transit (within the link).
What is the minimum number of bits (I) that will be required to represent the sequence numbers distinctly? Assume that no time gap needs to be given between transmission of two frames.
A
I = 2
B
I = 3
C
I = 4
D
I = 5
3
GATE CSE 2007
+2
-0.6
The message 11001001 is to be transmitted using the CRC polynomial x3 + 1 to protect it from errors. The message that should be transmitted is:
A
11001001000
B
11001001011
C
11001010
D
110010010011
4
GATE CSE 2007
+2
-0.6
The distance between two stations M and N is L kilometers. All frames are K bits long. The propagation delay per kilometer is t seconds. Let R bits/second be the channel capacity. Assuming that processing delay is negligible, the minimum number of bits for the sequence number field in a frame for maximum utilization, when the sliding window protocol is used, is:
A
$$\left\lceil {{{\log }_2}{{2LtR + 2K} \over K}} \right\rceil$$
B
$$\left\lceil {{{\log }_2}{{2LtR} \over K}} \right\rceil$$
C
$$\left\lceil {{{\log }_2}{{2LtR + K} \over K}} \right\rceil$$
D
$$\left\lceil {{{\log }_2}{{2LtR + 2K} \over {2K}}} \right\rceil$$
GATE CSE Subjects
Theory of Computation
Operating Systems
Algorithms
Digital Logic
Database Management System
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Computer Networks
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General Aptitude
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