Link Layer Question Pool

  1. What is QoS?
  2. What is the purpose of the ATM Adaptation Layer?
  3. What are the sizes of the ATM header and the payload?
  4. Why are ATM cells "small"?
  5. Explain the operation of IEEE 802.3.
  6. An IEEE 802.3 transceiver has two connections. Describe them.
  7. For a DIX Ethernet frame, provide the name and length for each field (in order, from first to last):
    Name: Length:
  8. For a IEEE 802.3 frame, provide the name and length for each field (in order, from first to last):
    Name: Length:
  9. The CRC is a method for:(indicate correct answer then explain)
    a. Correct some errors.
    b. Correcting all errors.
    c. Detecting some errors.
    d. Detecting all errors.
    e. Reducing the bit error rate.
    [Briefly explain]
  10. In what situations, if any, is IEEE 802.3 more efficient than IEEE 802.5?
  11. What is the major difference between IEEE 802.3 and DIX ethernet?
  12. Name the kinds of address that an Ethernet adapter must recognize.
  13. Name and explain the three major concepts in CSMA/CD.
  14. What is the purpose of the "binary exponential backoff" algorithm used in CSMA/CD?
  15. Why is the Destination field present before the Source field in an Ethernet frame?
  16. List and explain two major techniques for error recovery.
  17. What is the difference between error detection and error correction? Give examples where each is most appropriate.
  18. List several forms of error detection.
  19. What is the major difference between ABP and SRP? Which is more efficient?
  20. The technique of delaying acknowledgements so that they can be hooked onto the next outgoing data is known as: a. selective repeat b. pipelining c. piggybacking d. forwarding
  21. List two reasons why an acknowledgement might be deliberately delayed by the receiver.
  22. What is the IEEE standard concerning Token Ring protocol? What speed(s) are used?
  23. In an original token ring system, which runs at 4Mbps, what is the most significant factor to decide the maximum frame size in the system?
  24. What is the difference between RAR and RAT token passing policies? What protocol uses RAR? Which one uses RAT? Why?
  25. What is the difference between a connection-oriented and a connectionless Layer 2?
  26. What is flow control?
  27. Define and compare congestion control and flow control.
  28. Give 2 strategies to control congestion.
  29. What is IEEE 802.2?
  30. Give the four topologies and an example of each.
  31. What is a multicast address? A broadcast address?
  32. Explain the operation of a transparent, learning, filtering bridge.
  33. Define the three major properties of a T-L-F bridge.
  34. What information is contained in the table entries of a bridge?
  35. Based on information exchanged in the Spanning Tree protocol, bridges do (what?) to prevent (what?). {Explain}
  36. Spanning tree protocol (IEEE 802.1d) is most often used with which of the following network types: (circle one) 802.2, 802.3, 802.4, 802.5
  37. Name one advantage each of T and SR bridges.
  38. Source routing is most often used with which of the following network types
    (circle one) 802.2, 802.3, 802.4, 802.5
  39. What is promiscuous mode?
  40. Why do we restrict the data/pad field in the ethernet frame to be at least 46 bytes?
  41. Explain the operation of IEEE 802.5 (ignore startup; assume no errors).
  42. The purpose behind error checking in a connection-oriented layer 2 is:
  43. One place where network error checking does not occur is:
  44. One path where network error checking does not occur is: