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عنوان : شبکه های بی سیم Wi-Fi پژوهشگر : سمانه آرزو مندی استاد راهنما : جناب آقای اعظمی فر PowerPoint PPT Presentation


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حضرت آیت الله خامنه ای : پیشرفت کشور تنها بر اساس الگوی اسلامی - ایرانی امکان پذیر است و مهمترین وظیفه نخبگان اعم از دانشگاهی و حوزوی تنظیم نقشه جامع پیشرفت کشور براساس مبانی اسلام است. عنوان : شبکه های بی سیم Wi-Fi پژوهشگر : سمانه آرزو مندی استاد راهنما : جناب آقای اعظمی فر

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عنوان : شبکه های بی سیم Wi-Fi پژوهشگر : سمانه آرزو مندی استاد راهنما : جناب آقای اعظمی فر

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: - .


:

Wi-Fi

:

:

86


... .

.


  • (LAN ) (Wired ) (Wireless ) . Ethernet Wi-Fi .


  • ( ) .

  • (Access Point ) 30 ( ) .


  • (Wireless) .

    WiFi . .

    12 2002 700 2008


  • :

    Indoor Outdoor .

  • Indoor :

    . Indoor .


  • Outdoor :

    Outdoor . Line Of Sight Access Point .


Outdoor Point To Point Point To Multipoint Mesh .

  • Point To point :

    . AccessPoint .

  • Point To Multi Point :

    .

  • Mesh :

    Mesh . .


  • :

  • -

    . .


-

. .


  • 802.11

  • -

  • -

  • -

  • -

  • -


. . Wi-Fi .


  • wi-fi wireless fidelity wireless . WLAN IEEE 802.11 Wi-Fi .

  • WLAN 802.11a 802.11g . (WECA) .


  • . 100 (5/30 ) . . . 11Mbps / . .11b+ mbps . .11a 54Mbps 5GHz . .11b


  • Wi-Fi - . . . . 50 100 .


WiFi

  • WiFi . .


  • :

  • 1.- ... ( Hot Spot)

    2- (Data)

  • 3-. (VOIP)

  • 4- (CCTV , Video Conference)

  • 5.- (Security)


11 . 802

. (Ad Hoc) 802.11 IBSS . ( ) .


  • . . . ( ) .


  • . . :

  • - - - - -


  • CSMA/CA CSMA/CD . . . CSMA/CA DIFS .


  • IEEE 802.11 : . . ( ) .


  • 802.11b . Ad hoc - (AP=Access Point).

  • AP . AP 802.11b . AP BSS(Basic Service Set) . BSS ESS(Extended Service Set) . ESS .


  • IEEE 802.11 June 1997 WLAN . PHY MAC .


  • : Physical Layer . ( ).

  • : Data Link Layer. (packets) . . (sub layer) Medium Access Control(MAC) (Access)

    Logical Link Control (error checking) .


Wifi


  • wifi 802.11 . . . . wap ( ) .wap .


802.11

  • 802.11b

  • . b .. 802.11b . 802.11b 2.4 GHz( ) Wi-Fi 95% .

  • DSSS FHSS . 1 2 .


802.11a

  • .a 802.11b . 802.11a 2001 .

    5GHz 54Mbps . 802.11b .

    802.11a 54 Mbps . OFDM . IEEE 802.11a :6,9,12,18,24,36,48,54 Mbps 6,12,24 .


802.11g

  • .g . Wi-Fi .

  • IEEE 802.11b 2.4 GHz ( ISM) OFDM . PBCC . 802.11g 802.11b .


e11 . 802

  • a,b,g (Voice & Video Packet) . (Latency) .


wifi

  • . (roice) wifi .


wifi

  • :

  • : wifi


wifi

  • 1) : 50 .

  • 2) : wifi .

  • 3) : .


  • 4) : wifi .

  • 5) : .

  • 6) : .



  • Rouge Access Point Problem: WiFi . Rouge Access Point (Access Point WiFi( . hacking .


  • WiFi: Access Point . .


  • Wi-Fi .

  • IEEE 802.1x

  • WEP - Wired Equivalent Privacy

  • WPA - Wi-Fi Protected Access

  • TKIP - Temporal Key Integrity Protocol


DoS:

  • ( ) . Airmagnet.

  • DoS DoS .

  • QoS wireless DMZ IDS DoS .


:

  • 12 802.11 12 .


  • . . 2001 Boston 100 44 .

  • .


11 . 802

  • 802.11 . WEP (Wired Equivalent Privacy) . 802.11 . WEP .


802.11 ( WEP)


WIFI

  • .802.11b . . .


  • :

  • DSSS

  • FHSS

  • . 1 2 16-PPM 4-PPM .


Wi-Fi

  • Wi-Fi Wi-Fi . Wi-Fi 802.11a 802.11b 802.11g 802.11g 802.11b . PCMCIA USB .

  • PCI USB . .


WiMax

.

Base Station .


WiMAX .

  • :


  • . .

  • b/g/a 802.11 laptop .


  • Access Point PCI PCMCIA USB .

  • LAN 802.11 .

  • Access Point


  • 802.11a 802.11g 54Mbps .

  • Half-Duplex Ethernet .

  • Access Point Ethernet Shared .


  • Access Point 802.11g Half-Duplex 54Mbps 25Mbps Full-Duplex . 5 Access Point 5Mbps 25Mbps . Access Point Online .

  • 100Kbps .


  • WLAN Ethernet ! WLAN Ethernet Mobility . WLAN .

  • ! . .


  • (Worm) Access Point . . Worm Access Point Hang Access Point .


.


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