NET 211 - Wireless Networking

Review for Second Test

The following questions are provided to help you study for the second test. Do not expect to see these exact questions on the test.

  1. How many layers are in the ISO-OSI network model? What are their names?

  2. In which direction does an outbound message flow through the ISO-OSI model layers?

  3. What is remarkable about narrowband transmission with regard to IEEE 802.11 standards?

  4. What are some of the reasons to prefer spread spectrum tranmission over narrowband transmission?

  5. What is the purpose of frequency hopping spread spectrum transmission?

  6. What was the "human pressure" that led Hedy Lamarr and George Antheil to invent FHSS?

  7. What is dwell time, with regard to FHSS? What must happen when it is reached?

  8. How often does a Bluetooth transmitter change to a new frequency?

  9. Which layer of he ISO model is associated with data clusters called frames?

  10. The text introduces Media Access Control functions as part of the MAC layer. It is actually a sublayer, of what real layer?

  11. The text explains that the Physical layer is considered to have sublayers with regard to wireless methods. What are those sublayers?

  12. What are the main three sections of an 802.11b frame?

  13. What is the frequency band used by 802.11b? What about 802.11a?

  14. What are the major drawbacks of 802.11a and 802.11b?

  15. What kind of modulations were used in 802.11a? Why were more and more complicated methods necessary?

  16. How many non-overlapping channels are available in the US under 802.11b?

  17. How many non-overlapping channels are available in the US under 802.11a?

  18. How many non-overlapping channels are available in the US under 802.11n? Why is that a complicated answer?

  19. What is a guard interval?

  20. One of the distinguishing features of 802.11n is its 77 MCS types. Which are the most important, and why?

  21. What is a Basic Service Set?

  22. What is the difference between a Service Set Identifier, and a Basic Service Set Identifier?

  23. What is a Basic Service Area?

  24. What does dynamic rate switching do to data rates from one end of a BSA to the other?

  25. What is the definition of an Extended Service Set that references BSSs?

  26. Compare Layer 2 roaming to Layer 3 roaming.

  27. How is an Independent Basic Service Set different from the other two service set types?

  28. How does a Service Data Unit become a Protocol Data Unit? Why does this happen?

  29. What is a Maximum Transmission Unit? What are the values for 802.3 and 802.11 LANs?

  30. What is the most common strategy for setting a limit on MTU size in wireless LANs?

  31. What is some of the information that we expect to find in a beacon frame?

  32. What kind of frame holds the BSSID?

  33. What is the difference between passive and active scanning?

  34. Compare Open System Authentication with Shared Key Authentication.

  35. What are the two main options for wireless LANs under the Distributed Coordination Function.

  36. What is the hidden node problem? Why would it not occur in an 802.3 network?

  37. What are some common home or office devices that emit RF interference on the 2.4 GHz band?

  38. What are two building materials that commonly obstruct RF signals?

  39. Think about the differences between a manual site survey and a predictive site survey. Which is likely to be more accurate? Why?

  40. What is a spectrum analyzer? Why is it a more complicated tool than an 802.3 sniffer?

  41. What should be the standard recommendation about placement of access points, and channels they use?

  42. What is the acceptable standard for packet loss in a voice over WiFi system?

  43. How do packet delay and jitter affect voice over WiFi systems?