Which of the following services is not provided by wireless access point in 802.11 WLAN?
| A. | Association |
| B. | Disassociation |
| C. | Error Correction |
| D. | Integration |
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Option: C Explanation : IEEE 802.11 services Click on Discuss to view users comments. |
| A. | Type of service |
| B. | Fragment offset |
| C. | Flags |
| D. | Identification |
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Option: A Explanation : Click on Discuss to view users comments. |
Four channels are multiplexed using TDM. If each channel sends 100 bytes/second and we multiplex 1 byte per channel, then the bit rate for the link is ...............
| A. | 400 bps |
| B. | 800 bps |
| C. | 1600 bps |
| D. | 3200 bps |
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Option: D Explanation : The multiplexer is shown in the Figure.
Each frame carries 1 byte from each channel; the size of each frame, therefore, is 4bytes, or 32 bits. Because each channel is sending 100 bytes/s and a frame carries 1 byte from each channel, the frame rate must be 100 frames per second. The bit rate is 100 × 32 = 3200 bps.
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| A. | 280 |
| B. | 210 |
| C. | 140 |
| D. | 120 |
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Option: A Explanation :
Each cell has six other adjacent cells, in a hexagonal grid. If the central cell uses frequency group A, its six adjacent cells can use B, C, B, C, B, and C respectively. In other words, only 3 unique cells are needed. So the answer is 840/3 = 280 frequencies.
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