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Wireless Networking Standards
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| bet | 3/3 | | Sana | 02.10.2024 | | Hajmi | 35,6 Kb. | | #273168 |
Bog'liq ADABIYOTLAR802.11 Wireless Networking Standards
802.11 Protocol
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Release
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Frequency
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Channel Bandwidth
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Data rate per stream (Mbps)
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Allowable MIMO streams
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Modulation
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Approx indoor range (m)
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Approx outdoor range (m)
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-
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Jun-97
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2.4
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20
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Up to 2
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1
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DSSS, FHSS
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20
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100
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a
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Sep-99
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5
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20
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Up to 54
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1
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OFDM
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35
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120
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b
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Sep-99
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2.4
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20
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Up to 11
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1
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DSSS
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38
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140
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g
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Jun-03
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2.4
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20
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Up to 54
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1
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OFDM,DSSS
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38
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140
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n
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Oct-09
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2.4/5
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20
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Up to 72.2
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4
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OFDM
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70
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250
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40
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Up to 150
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70
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250
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ac
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Dec-12
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5
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80 / 160
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Up to 866.7
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8
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OFDM
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Â
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Â
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As explained in the 2.4GHz and 5GHz articles, advertised and theoretical speeds are not representative of actual, real world speeds. Therefore the suggested 'real' speeds of the standards could be said to be as follows (please note that throughput speed will vary for each individual wireless network set up so these figure should only be taken as a rough guide):
802.11 Wireless Networking Standards
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802.11 Protocol
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Advertised Speed (Mbps)
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Real World Throughput Speed (Mbps)
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802.11a
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54
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≈ 27.5
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802.11b
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11
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≈ 4.5
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802.11g (11b compatibility on)
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54
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≈ 14.5
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802.11g
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54
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≈ 23
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802.11g MIMO
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108
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≈ 45
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802.11n
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300
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≈ 74
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802.11n
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600
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≈ 144
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802.11ac
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1.3Gbps
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≈ 800
| Channels
You may have heard the term 'Channels' mentioned in these articles and not been sure exactly what it is referring to. Channels are the sub-division of the main operating frequency range into smaller channels in the exact same way as a television or radio does and ultimately operating on one of these smaller bandwidth channels rather than the whole operating frequency range. For the 2.4GHz range, the band, from 2.4000GHz to 2.4835GHz, is divided into 13 channels each with a bandwidth of 22MHz spaced 5MHz apart. For the 5GHz range, the band, from 5.180GHz to 5.805GHz, is divided into 23 channels each with a bandwidth of 20MHz spaced 20MHz apart. These channels are given numbers for ease of reference and are shown below (only UK legal channels are shown):
2.4GHz Channels
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5 GHz Channels
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Channel
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Frequency (MHz)
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Channel
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Frequency (MHz)
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1
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2412
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36
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5180
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2
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2417
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40
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5200
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3
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2422
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44
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5220
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4
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2427
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48
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5240
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5
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2432
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52
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5260
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6
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2437
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56
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5280
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7
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2442
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60
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5300
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8
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2447
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64
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5320
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9
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2452
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100
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5500
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10
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2457
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104
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5520
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11
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2462
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108
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5540
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12
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2467
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112
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5560
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13
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2472
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116
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5580
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14
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2484
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120
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5600
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Â
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Â
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124
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5620
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Â
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Â
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128
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5640
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Â
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Â
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132
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5660
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Â
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Â
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136
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5680
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Â
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Â
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140
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5700
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Â
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Â
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149
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5745
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Â
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Â
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153
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5765
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Â
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Â
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157
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5785
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Â
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Â
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161
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5805
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Channels 1, 6 and 11 are recommended for 2.4GHz operation to avoid the overlapping of channel usage and all channels for 5GHz operation are non-overlapping. The overlapping of channels on the 2.4GHz frequency range is shown in the diagram below:
Security
802.11 Wireless transmissions can be encrypted to improve the security and confidentiality of the data that is being transferred. WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access) and WPA2 are the three types of security available with WPA2 using AES (Advanced Encryption Standard) technology. The recommended encryption method for modern home and consumer networks is WPA2 (AES Pre-Shared Key) and for the Enterprise level, WPA2 along with a RADIUS authentication server (or another type of authentication server) and a strong authentication method such as EAP-TLS.
https://core.ac.uk/download/pdf/234676876.pdf
2.2. bo’lim.
https://www.youtube.com/watch?v=j7DqeakjflI&t=170s
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