Wireless Networking IEEE 802.11 Standards Module-03B by tas62516

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									              Wireless Networking

             IEEE 802.11 Standards
                  Module-03B
                  Jerry Bernardini
           Community College of Rhode Island


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           Presentation Reference Material
• CWNA Certified Wireless Network
  Administration Official Study Guide
  (PWO-104), David Coleman, David Westcott,
  2009, Chapter-5

• http://www.ieee802.org/11/
• http://en.wikipedia.org/wiki/IEEE_802.11




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                        IEEE 802.11 Standards
• Institute of Electrical and Electronic Engineers (IEEE) a professional society
  activity to establish standards
• Hierarchical documents using clauses and sub-clauses
• Task Groups (TGb, TGa, …) are used to study topics
• Other Task Groups include: Ethernet, 802.3, 802.5, 802.15
• Task Groups designated by letters; a, b, g, n …
• Defines wireless technology at Physical (PHY) and MAC sub- layer of Data
  link layer
• Upper layer not addressed except of QoS




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                802.11-1997 (802.11 legacy)

• Original version of the standard IEEE 802.11, released in June1997 and clarified
  in 1999
• ISM 2.4 GHz. band
• Forward correcting codes code.
• Infrared operating at 1 Mbps
• Frequency Hopping Spread Spectrum (FHSS); at 1, 2 Mbps
• Direct Sequence Spread Spectrum (DSSS); at 1, 2 Mbps
• Legacy 802.11 with direct-sequence spread spectrum was rapidly supplanted
  and popularized by 802.11b.
• Standard revised in 1999, 2003, 2007




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                            IEEE 802.11 b

•   Defined as High-Rate DSS (HR-DSS) and Clause 18 devices
•   Uses 2.4 GHz ISM band
•   Support data rates of 1, 2, 5.5, 11 Mbps
•   Phase modulation and encoding spread spectrum
•   Complementary Code Keying (CCK) and Barker Coding
•   Manufacture dependent backward compatibility
•   Interference from other products operating in the 2.4 GHz band;
    microwave ovens, Bluetooth devices, baby monitors and cordless
    telephones




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                            IEEE 802.11 a

•   IEEE standard in 1999 (same year as 802.11b)
•   Uses UNII 5 GHz band – less crowded that 2.4 GHz band
•   Updated in Clause 17 802.11-2007
•   Orthogonal Frequency Division Multiplexing (OFDM) used instead of DSSS
•   Supports 6, 9,12, 18, 24, 36, 54 Mbps
•   Not all vendors support all rates
•   Not compatible with 802.11b,802.11g and legacy 802.11
•   Simultaneous operation with 802.11b,802.11g
•   Originally not adapted because of high frequency component costs




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                           IEEE 802.11 g
• 2003 standard (Clause 19) for 2.4 GHz band
• Referred to as Extended Rate Physical (ERP)
• OFDM based and the same as 802.11a
• Backward compatibility with 802.11b (ERP-DSSS/CCK)
• Supports 6, 9, 12, 18, 24, 36, 48, 4 Mbps
• Rapidly adopted by consumers because of speed ,
• Dual-band 802.11a/b, dual-band/tri-mode and b/g in a single adapter card
  and AP are available.
• Like 802.11b, 802.11g devices suffer interference from other 2.4 GHz
  products
• Equipment must support three modes and protection mechanism:
      – B-only mode
      – G-only mode
      – B/G-mode


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                               IEEE 802.11 n
•   Started in 2004, final ratification October 2009 (textbook still lists as draft)
•   Defined as High Throughput (HT) ( Clause 20)
•   Major goal: increase throughput over 802.11a/b/g
•   Backward compatible to 802.11a/b/g
•   Supports speeds over 100 Mbps
•   Multiple-Input-Multiple-Output (MIMO) to compensate for multipath
•   Requires multiple antennas and dual radios for full standard
•   Many other newer features to be covered later
•   Even before final ratification WiFi Alliance certified 802.11n draft 2
•   Must support multiple modes and protection mechanism:
     – N-only mode (Greenfield mode)
     – A-only mode
     – B/G-mode



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                          IEEE 802.11 d

• 2001 standard International use and (country-to-country) roaming
  extensions
• Defines differences between countries country codes , frames and
  beacons
• Configuration parameters for FHSS (legacy use)
• Details in 802.11-2007 clause 9.8




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                          IEEE 802.11 F
 •   An attempt to standardize wireless roaming
 •   Vendors did not adapt the recommendations
     uniformly
 •   Roaming will probably not work between vendor
 •   Two things must happen for roaming
      – New AP must inform original AP a station is
         associating with the new AP and want
         buffered packets
      – Original AP must forward buffered packets
         to new AP
 •   802.11F never ratified and withdrawn in
     February 2006
 •   Light AP’s and WLAN controller minimize the
     need for inter-vendor roaming standard
 •   Recommend practice is to use Inter-Access Point
     Protocol (IAPP)


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                      IEEE 802.11 h

 • Standard to define mechanism for Dynamic Frequency
   Selection (DFS)
 • Standard to define mechanism for Transmit Power Control
   (TPC)
 • Radar detection and WLAN control
 • Increased frequency space in UNII-2 band
 • Amendent now in 11.8 and 11.9 of 802.11-2007




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                        IEEE 802.11 i
  • 802.11 from 1997 to 2004 only support 64-bit Wired
    Equivalent Privacy (WEP) encryption
  • WEP was cracked in 2003- no long recommended
  • 802.11i improves wireless security
  • Stronger encryption methods
  • Counter Mode with Cipher Block Chaining Message
    Authentication Code Protocol (CCMP) and Advanced
    Encryption Standard (AES)
  • Temporal Key Integrity Protocol (TKIP)
  • RC-4 Stream cipher
  • Extensible Authentication Protocol (EAP)
  • WiFi Protection Access 2 (WAP2)
  • Wireless Security is important - CWSP
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                        IEEE 802.11 j

• Standard to gain Japanese regulatory approval for MAC and
  802.11a PHY improvements
• Japan 802.11a radio cards to operate at 5.15 to 5.25 GHz and
  4.9 to 5.091 GHz
• Option for Japan to operate OFDM with 10 MHz spacing,
  increasing number of bandwidth rates




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                       IEEE 802.11 e
• Amendment for Quality of Service (QoS)
• Voice and Video are not latency and jitter tolerant
• Voice over IP (VoWIP) and VoWiFi
• Defines layer two MAC methods to meet QoS
• Distributed Coordination Function (DCF)– random method to
  determine which application runs first
• Point Coordination Function (PCF) –Polls clients for appilcation
  priority
• Hybrid Coordination Function Control Channel Access (HCCA)-
  AP is given ability to set station priority
• Wi-Fi Alliance Wi-Fi Multimedia (WMM)


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            IEEE 802.11 k




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            IEEE 802.11 r




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           IEEE 802.11 m




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            IEEE 802.11 p




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            IEEE 802.11 s




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            IEEE 802.11 T




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            IEEE 802.11 u




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            IEEE 802.11 v




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           IEEE 802.11 w




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            IEEE 802.11 y




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            IEEE 802.11 z




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           IEEE 802.11 aa




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