While operating in DCF mode, stations and access points must use a backoff algorithm in order to arbitrate for medium access. During what specific period of time is the backoff timer decremented?

• A. During the Contention-free Period
• B. During the Contention Window
• C. During the Defer Window
• D. During a DCF Interframe Space
• E. During any part of the Superframe

Given one screenshot of a fragment burst and another screenshot of one of the data frames decoded, determine which statements are true.

• A. The transmitter of this frame is allowed to change its power management mode to Active.D.The transmitter of this frame is allowed to change its power management mode to Active.
• B. The RTS/CTS threshold value on the transmitter is set to 500 bytes.
• C. This fragment is a retransmission.E.This fragment is a retransmission.E.This fragment is a retransmission.
• D. The frame decode shown is of the second fragment in the sequence.
• E. The sequence number of 169 shown in the decode is unique to the communication between the transmitting station and the access point.
• F. The duration value of 508 usec is exactly enough to reserve the medium on behalf of the SIFS and ACK to follow this fragment

In a DCF 802.11g network, when is the Power Management subfield of the Frame Control field set to a value of 1?

• A. On any Data frame sent by the access point subsequent to a PS-Poll frame.
• B. Only in management frames sent by a client station immediately prior to entering a low power state (dozing) that are part of a frame exchange sequence.
• C. On any frame transmitted by a client station operating in Power Save mode.
• D. Only in the PS-Poll frame sent from a client station operating in Power Save mode to an access point after the client station awakens from a low power state (dozing).

Beacon Management frames carry channel information. Channel information can be used by protocol analysts to determine which channel is actually being used when beacons are being received on channels where they are not expected. This situation is often due to cross-channel interference. In an 802.11b Beacon Management frame, what information element carries the current channel information?

• A. Capability Information
• B. Service Set Identifier
• C. CF Parameter Set
• D. Supported Rates
• E. DS Parameter Set
• F. Traffic Indication Map

A wireless network administrator has examined the frame retry counts on several client stations in a WLAN that is not using encryption, and has determined that they are extraordinarily high. For this reason, he has decided to configure station fragmentation thresholds to 400 bytes. With this configuration change, when a data frame with a 1500 byte MSDU is transmitted by one of the wireless client stations to a wired station through an access point, what will be the order and size (in bytes) of the fragments as they're transmitted?

• A. Frame1 = 400, Frame2 = 400, Frame3 = 400, Frame4 = 400, Frame5 = 40
• B. Frame1 = 300, Frame2 = 400, Frame3 = 400, Frame4 = 400
• C. Frame1 = 400, Frame2 = 400, Frame3 = 400, Frame4 = 300
• D. Frame1 = 300, Frame2 = 300, Frame3 = 300, Frame4 = 300, Frame5 = 300
• E. The fragmentation threshold setting on client stations only affects received frames, not transmitted frames
• F. The fragmentation threshold setting on client stations is not a manual adjustment, and can only be auto-configured by access points