Computer Network Test Set 8
Q36 | Bit stuffing refers to |
| i ➥ inserting a ‘0’ in user stream to differentiate it with a flag |
| ii ➥ inserting a ‘0’ in flag stream to avoid ambiguity |
| iii ➥ appending a nibble to the flag sequence |
| iv ➥ appending a nibble to the use data stream |
| Q37 | In cryptography, the following uses transposition cyphers and the keyword is LAYER. Encrypt the following message. (Spaces are omitted during encryption) WELCOME TO NETWORK SECURITY! |
| i ➥ WMEKREETSILTWETCOOCYONRU! |
| ii ➥ EETSICOOCYWMEKRONRU!LTWET |
| iii ➥ LTWETONRU!WMEKRCOOCYEETSI |
| iv ➥ ONRU!COOCYLTWETEETSIWMEKR |
| Q38 | Station A uses 32-byte packets to transmit messages to Station B using a sliding window protocol. The round trip delay between A and B is 80 ms and the bottleneck bandwidth on the path between A and B is 128 kbps. What is the optimal window size that A should use? |
| i ➥ 20 |
| ii ➥ 40 |
| iii ➥ 160 |
| iv ➥ 320 |
| Q39 | A 20 Kbps satellite link has a propagation delay of 400 ms. The transmitter employs the “go back n ARQ” scheme with n set to 10. Assuming that each frame is 100 bytes long, what is the maximum data rate possible? |
| i ➥ 5 Kbps |
| ii ➥ 10 Kbps |
| iii ➥ 15 Kbps |
| iv ➥ 20 Kbps |
| Q40 | In a sliding window ARQ scheme, the transmitter’s window size is N and the receiver’s window size is M. The minimum number of distinct sequence numbers required to ensure correct operation of the ARQ scheme is |
| i ➥ max (M,N) |
| ii ➥ min (M,N) |
| iii ➥ MN |
| iv ➥ M + N |
Weekly Test GATE/NTA NET CSA
36-i
37-
38-
39-
40-iv
36.(I)
37.(ii)
38.(ii)
39.(ii)
40.(iv)
Ans36-i
Ans37-i
Ans38
Ans39
Ans40-iv
36) A
37) B
38)
39)
40) D
36,IV
37,IV
38,IV
39,IV
40,IV