UGC NET · PAPER 2
UGC NET Paper 2 Computer Science – Unit 9: Data Communication and Computer Networks PYQ (September 2022)
Q18. Using the RSA algorithm, if p = 13, q = 5 and e = 7, the value of d and the cipher value of '6' with the (e, n) key are
- 7, 4
- 7, 1
- 7, 46
- 55, 1
Directions (Q36–40): A 3000 km long trunk operates at 1.536 Mbps and is used to transmit 64-byte frames using a sliding window protocol. The propagation delay is 6 μs/km.
Q36. The transmission and propagation delays are respectively
- Tt = 333.33 μs, Tp = 18000 μs
- Tt = 300 μs, Tp = 15360 μs
- Tt = 33.33 μs, Tp = 1800 μs
- Tt = 1800 μs, Tp = 33.33 μs
Q37. The minimum number of bits required in the sequence number field of the packet is
- 6 bits
- 7 bits
- 5 bits
- 4 bits
Q39. If only 6 bits are reserved for the sequence number field, the efficiency of the system is
- 0.587
- 0.875
- 0.578
- 0.50
Q45. Which mode is a block-cipher implementation acting as a self-synchronising stream cipher?
- Cipher Block Chaining mode
- Cipher Feedback mode
- Electronic Codebook mode
- Output Feedback mode
Q46. Which one is a connectionless transport-layer protocol of the Internet protocol family?
- Transmission Control Protocol (TCP)
- User Datagram Protocol (UDP)
- Routing Protocol (RP)
- Datagram Control Protocol (DCP)
Q47. Consider an error-free 64 kbps satellite channel used to send 512-byte data frames in one direction, with very short acknowledgements coming back. What is the maximum throughput for a window size of 15?
- 32 kbps
- 48 kbps
- 64 kbps
- 70 kbps
Q48. A classless address is given as 167.199.170.82/27. The number of addresses in the network is
- 64
- 32
- 28
- 30
Q49. Which layer divides each message into packets at the source and reassembles them at the destination?
- Network layer
- Transport layer
- Data link layer
- Physical layer
Q51. Which of the following is correct for the destination address 4A:30:10:21:10:1A?
- Unicast address
- Multicast address
- Broadcast address
- Unicast and broadcast address
Q82. Match List I with List II.
Choose the correct answer from the options given below:
Choose the correct answer from the options given below:
| List I | List II |
|---|---|
| A. DES | I. Key size – 256 |
| B. AES | II. Key size – 1024 |
| C. 3DES | III. Key size – 56 |
| D. RSA | IV. Key size – 168 |
- A-I, B-II, C-IV, D-III
- A-III, B-I, C-IV, D-II
- A-III, B-IV, C-II, D-I
- A-IV, B-II, C-III, D-I
Q83. Match List I with List II (Berkeley socket primitives).
Choose the correct answer from the options given below:
Choose the correct answer from the options given below:
| List I | List II |
|---|---|
| A. BIND | I. Block the caller until a connection attempt arrives |
| B. LISTEN | II. Give a local address to a socket |
| C. ACCEPT | III. Show willingness to accept connections |
| D. SOCKET | IV. Create a new end point |
- A-I, B-III, C-II, D-IV
- A-II, B-III, C-I, D-IV
- A-III, B-II, C-I, D-IV
- A-I, B-II, C-III, D-IV
Q84. Match List I with List II.
Choose the correct answer from the options given below:
Choose the correct answer from the options given below:
| List I | List II |
|---|---|
| A. Physical layer | I. Routing of the signals, divide the outgoing message into packets, act as network controller for routing data |
| B. Data link layer | II. Make and break connections, define voltages and data rates, convert data bits into electrical signal |
| C. Network layer | III. Synchronization, error detection and correction, assemble outgoing message into frames |
| D. Presentation layer | IV. It works as a translating layer |
- A-IV, B-III, C-II, D-I
- A-II, B-III, C-IV, D-I
- A-IV, B-III, C-I, D-II
- A-II, B-III, C-I, D-IV