Data Communication and Networking – X.25 protocol MCQS

1. The size of the header of a long data packet at the PLP level is ___________ bytes

2. In the short format, the size of an RR packet is _________ bytes.

3. In the long format, the size of an RR packet is _________ bytes.

4. X.25 is a _______ protocol.

5. In the short format, the size of the RNR packet is _________ bytes.

6. X.25 has _________ layers.

7. In the long format, the size of an RNR packet is _________ bytes.

8. X.25 protocol uses ____________.

9. In the short format, the size of an REJ packet is _________ bytes.

10. The PLP packet is used in the _______ layer of the X.25 protocol.

11. In the long format, the size of an REJ packet is _________ bytes.

12. X.25 uses the ___________ protocol at the data link layer.

13. When a DTE receives a corrupted PLP packet, it sends an _________ control packet to the sender DTE.

14. The LAPB protocol is a version of the _________ protocol.

15. When a DTE receives an error-free PLP packet and is ready to receive more packets, it sends an _________ control packet to the sender DTE.

16. Which layer in X.25 handles connection establishment?

17. When a DTE receives an error-free PLP packet, but is not ready to receive more packets, it sends an _________ control packet to the sender DTE.

18. X.25 uses _______ connections.

19. When X.25 uses the short format, the number of PLP packets in transition can be up to __________.

20. End-to-end addressing for X.25 is done by the _______ protocol.

21. When X.25 uses the long format, the number of PLP packets in transition can be up to __________.

22. The Triple-X protocols associated with X.25 are_____________.

23. A DTE receives PLP packets with sequence numbers 23, 24, 27. What control packet should be sent to the sender?

24. The virtual circuit identifier in X.25 is called the _______.

25. A DTE receives PLP packets with sequence numbers 23, 24, 25. What control packet should be sent to the sender if the receiver is ready to receive more packets?

26. The LCN in X.25 is _______ bits.

27. A DTE receives PLP packets with sequence numbers 23, 24, 25. What control packet should be sent to the sender if the receiver is not ready to receive more packets?

28. The LCN in X.25 can define theoretically up to ___________ virtual circuits.

29. A DTE using the short format sends a PLP packet with P(S) = 7. What is the sequence number of the next packet?

30. Hop-to-hop flow and error control in X.25 is done at the _______ layer

31. A DTE wants to send a PLP data packet to another DTE. The packet should be encapsulated in an _______

32. End-to-end flow and error control is done at the ____________ layer

33. A DTE wants to send a PLP RR packet to another DTE. The packet should be encapsulated in an _______ at the data link layer.

34. A DTE which is connected to a DCE can use _______ LCN(s) to create connections for 10 application programs.

35. A DTE wants to send a PLP call request packet to another DTE. The packet should be encapsulated in an _______ at the data link layer

36. Multiplexing in X.25 is done at the _______ layer.

37. An acknowledgment at the PLP layer is encapsulated in _________ at the data link layer.

38. The window size for a short packet at the PLP layer is _________.

39. A control packet such as a registration request at the PLP layer is encapsulated in _________ at the data link layer.

40. The window size for a long packet at the PLP layer is _________.

41. When a DTE wants to acknowledge the receipt of a frame from the local DCE, it uses ______________

42. The size of the header of a short data packet at the PLP level is ___________ bytes

43. Every PLP packet is encapsulated in ___________ at the data link layer.

44. An I-frame carries ____________.

45. An S-frame carries ____________.

46. A U-frame carries ____________.

47. Which of the following is true?

48. Which of the following is true?