Section 11-2

1. List two advantages of wireless networking. 1. User mobility in the workplace. 2. A cost-effective networking media for use in areas that is difficult or too costly to wire.

2. What are the three areas defined for the IEEE 802.11 standard? 1. Physical Layer (PHY) The method of transmitting the data, which may be either RF or infrared (although infrared is rarely used.) 2. Medium Access Control (MAC) I. The reliability of the data service. II. Access control to the shared wireless medium. III. Protecting the privacy of the transmitted data. 3. MAC management protocols and services I. Authentication, association, data delivery, and privacy.

3. What is an ad hoc network? 1. In this network, the wireless clients (stations) communicate directly with each other. This means the clients have recognized the other stations in the WLAN and have established a wireless data link. 2. The fundamental topology of the WLAN is the Basic Service Set (BSS). This is also called the independent Basic Service Set, or ad hoc network.

4. What is the purpose of an Extended Service Set? 1. By adding multiple access points to the network, the range of mobility of a wireless client in the LAN is extended. 2. Definition - The use of multiple access points to extend user mobility Hand-off.

5. What are the four physical layer technologies being used in 802.11 wireless networking? 1. Direct Sequence Spread Spectrum (DSSS) 2. Frequency Hopping Spread Spectrum (FHSS) 3. Infrared 4. Orthogonal Frequency Division Multiplexing (OFDM)

6. Describe the frequency spectrum for the DSSS channels in 802.11b wireless networking. 1. implements 14 channels (each consuming 22 MHz) over approximately 90 MHz of RF spectrum in the 2.4 GHz ISM (industrial, scientific, and medical) band.

North American DSSS Channels
Channel Number Frequency (GHz) 1 2.412 2 2.417 3 2.422 4 2.427 5 2.432 6 2.437 7 2.442 8 2.447 9 2.452 10 2.457 11 2.462

7. Define a pseudorandom sequence as it applies to FHSS. 1. Pseudorandom means the sequence appears to be random but in fact does repeat, typically after some lengthy period of time. 2. FHSS uses 79 channels (each 1 MHz wide) in the ISM 2.4 GHz band. FHSS requires that the transmitting and receiving units know the hopping sequence (the order of frequency changes) so that a communication link can be established and synchronized.

8. What must the FHSS transmitting and receiving units know to communicate? 1. Hopping Sequence - The order of frequency changes.

9. What is the frequency range used by 802.11a, and what modulation technique is used? 1. 5 GHz 2. Orthogonal Frequency Division Multiplexing (OFDM)

10. What is the maximum data rate for the following: a. 802.11b b. 802.11a c. 802.11g d. 802.11n

a. 11 Mbps b. 54 Mbps c. 54 Mbps d. 200+ Mbps

11. Define MIMO as it applies to 802.11n. 1. Multiple Input Multiple Output (MIMO) 2. MIMO uses a technique called space-division multiplexing, where the data stream is split into multiple parts called spatial streams. The different spatial streams are transmitted using separate antennas. With MIMO, doubling the spatial streams doubles the effective data rate.

12. What is the purpose of the power-save mode in 802.11n? 1. 802.11n only uses multiple data paths when faster data transmission is required—thus saving power.

Section 11-3

13. What is the purpose of an access point? 1. Provides a bridge between the wireless LAN and the wired network.

14. How does the access point know if a wireless data packet is intended for its network? A. The answer is the 802.11 wireless LAN devices use an SSID to identify what wireless data traffic is allowed to connect to the network. B. the SSID is the wireless service set identifier, basically a password that enables the client to join the wireless network.

15. What is an association, and what is its purpose? A. The access point uses the SSID to determine whether the client is to become a member of the wireless network. B. The term association is used to describe that a wireless connection has been obtained.

16. Draw a picture of a point-to-point wireless connection.

17. Draw a picture of a point-to-multipoint wireless network.

18. What are the key issues to be obtained from conducting a site survey for each of the following? A. indoor 1. Electrical Power 2. Wired network connection point(s) 3. Access point placement 4. RF coverage - user mobility 5. Bandwidth supported 6. Identify any significant RF interference b. outdoor 1. Electrical power (base access point) 2. Connection back to the home network 3. Antenna selection 4. Bandwidth supported 5. RF coverage 6. Identify any significant RF interference.

-------------------------------------------------------------------------------------------------------
Section 11-4

19. In what frequency band does Bluetooth operate? 1. 2.4 GHz ISM

20. How many output power classes does Bluetooth have? List the power level and the operating range for each class. 1. 3 2. Power Class Maximum Output Power Operating Distance 1 20 dBm ~ 100 m 2 4 dBm ~ 10 m 3 0 dBm ~ 1 m

21. What is a piconet? 1. An ad hoc network of up to eight Bluetooth devices. a. Examples: Computer, Mouse, Headset, Earpiece, and so on.

22. What is the purpose of the inquiry procedure in Bluetooth? 1. When a Bluetooth device is enabled, it uses an inquiry procedure to determine whether any other Bluetooth devices are available. 2. This procedure is also used to allow itself to be discovered.

23. What is the purpose of the paging procedure in Bluetooth? 2. The paging procedure is used to establish and synchronize a connection between two Bluetooth devices.

24. Define the term backscatter. 1. Refers to the reflection of the radio waves striking the RFID tag and reflecting back to the transmitter source with its stored unique identification information.

25. What are the three parameters that define an RFID system? 1. Means of powering the tag 2. Frequency of operation 2. Communications protocol (also called the air interface protocol)

26. Explain how power is provided to a passive RFID tag. 1. Power is provided to the tag by rectifying the RF energy, transmitted from the reader, that strikes the RF tag antenna. 1. The rectified power level is sufficient to power the ICs on the tags and also provides sufficient power for the tag to transmit a signal back to the reader.

27. Cite three advantages for using an active RFID tag. 1. The power consumption of the G2C501 is 10μA in the sleep mode and uses two AA batteries with an expected lifetime of five years. 2. The G2C501 also works in the standard 915 MHz range. 3. The G2C501 also has location capability. 1. This is accomplished by making Receive Signal Strength Indicator (RSSI) measurements from three separate access points.

28. What are the three frequency bands typically used for RFID tags? 1. Low Frequency (LF) 2. High Frequency (HF) 3. Ultra-high Frequency (UHF)

29. What is the WiMax frequency standard for the United States? 1. United States - Unlicensed 5.8GHz and licensed 2.5 GHz spectrum. 2. Internationally 3.5 GHz 3. Worldwide Interoperability for Microwave Access (WiMax)

30. Why was OFDM selected for WiMax? 1. This signaling format was selected for the WiMAX standard IEEE 802.16a standard because of its improved NLOS (non line-of-sight) characteristics in the 2 GHz to 11 GHz frequency range. 1. An OFDM system uses multiple frequencies for transporting the data, which helps minimize multipath interference problems. Some frequencies may be experiencing interference problems, but the system can select the best frequencies for transporting the data. 2. Orthogonal Frequency Division Multiplexing (OFDM)

31. How does WiMax differ from Wi-Fi? 1. The WiMAX (IEEE 802.16e) media access control (MAC) layer differs from the IEEE 802.11 Wi-Fi MAC layer in that the WiMAX system has to compete only once to gain entry into the network.

-------------------------------------------------------------------------------------------------------
Section 11-5

32. What is the most important thing to do if using a wireless network? 1. The wireless security features are turned on.

33. What is the purpose of wireless beacons? 1. In WLAN equipment, the beacons are transmitted so that a wireless user can identify an access point to connect to. 2. Definition - Used to verify the integrity of a wireless link.

34. What information can be obtained from a wireless beacon? 1. The Service Set Identifier (SSID) of the network.

35. What is the purpose of WEP? 1. Wired Equivalent Privacy (WEP) is used to encrypt and decrypt wireless data packets. 2. The exchange and the return of the encrypted text verifies that the client has the proper WEP key and is authorized to be a member of the wireless network.

36. List four guidelines for wireless security. 1. Make sure the wireless security features are turned on. 2. Use firewalls and intrusion detection on your WLAN. 3. Improve authentication of the WLAN by incorporating 802.1x features. 4. Consider using third-party end-to-end encryption software to protect the data that might be intercepted by an unauthorized user. 5. Whenever possible, use encrypted services such as SSH and Secure FTP.

37. Describe the steps used by WPA2 to authenticate a user. 1. WPA2 is an improved version of WPA. The 802.1x standard enhances wireless security by incorporating authentication of the user. Cisco Systems uses an 802.1x authentication system called LEAP. In Cisco LEAP, the user must enter a password to access the network. This means that if the wireless client is being used by an unauthorized user, the password requirement will keep the unauthorized user out of the network.

38. What is a RADIUS server? 1. A Remote Authentication Dial-In User Service (RADIUS) service is sometimes used to provide authentication. This type of authentication helps prevent unauthorized users from connecting to the network. Additionally, this authentication helps to keep authorized users from connecting to rouge of unauthorized access points.