Chapter 5 Flashcards
Original IEEE 802.11 Features?
Physical Layer
MAC Sublayer of the Data-Link layer
Data rates of 1 and 2 Mbps
Defined three Physical layer specifications?
Infrared (IR)
Frequency Hopping Spread Spectrum (FHSS)
Direct Sequence Spread Spectrum (DSSS)
IEEE 802.11b
Was released in 1999 Backwards compatible Defined High-Rate DSSS (HR-DSSS) HR-DSSS added 5.5 and 11Mbps 2.4 Ghz to 2.4835 Uses CCK Uses Barker Code Defined PBCC
What is CCK?
Spreading/Coding technique called Complementary Code Keying
What is PBCC?
Packet Binary Convolutional Code
IEEE 802.11a
1999 Not backwards compatible Defined OFDM Eight data rates, 6, 9, 12, 18, 24, 36, 48, 54 Operated in less crowded 5Ghz bands Total of 12 channels, 4 in each band Each band is 100 Mhz wide
What is OFDM?
Orthogonal Frequency Division Multiplexing
802.11g
2003 Backwards compatible with 11 DSSS and 11b HR-DSSS Defined ERP ERP had 8 data rates 2.4Ghz to 2.4835Ghz
What is ERP?
Extended Rate Physical
802.11h
2003 Defined: - Dynamic Frequency Selection - Transmit Power Control Introduced new UNII-2 Extended band 11 additional channels
What is DFS?
Dynamic Frequency Selection
Required for radio cards in the UNII-2 and UNII-2 Extended bands
Radar-detection and Radar-interference avoidance technology
Used to satisfy regulatory requirements
What is TPC?
Transmit Power Control
Used to regulate the power levels used by OFDM radios in the 5Ghz frequency bands
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DFS and TPC information is exchanged between clients and APs inside management frames
802.11i
2004 WEP was introduced in 1997 Open System authentication Shared Key authentication (security risks) WEP was cracked around 2001 Defined stronger encryption Robus Security Network (RSN)
802.11e
2005
Defines Layer 2 MAC methods need to meet QoS requirements
HCF was introduced
Wi-Fi Alliance QoS certification was known as WMM
What is HCF?
Hybrid Coordination Function
Two access methods to provide QoS
- Enhanced Distributed Channel Access (EDCA)
- Hybrid Coordination Function Controlled Channel Access (HCCA)
What is WMM?
Wi-Fi Multimedia
802.11r
2008 Known as Fast BSS Transition Known as Secure Roaming Defines Robust Secure Network Proposed due to time restraints of roaming for applications
802.k
2008
Provides a means of Radio Resource Measurement (RRM)
Defines a mechanism in which client station resource data is gathered and processed by an AP or controller
Client can also request information
Transmit Power Control
TPC contents?
Client Statistics
Channel Statistics
Neighbor Reports
802.11w
2009
Designed to deliver management frames in a secure manner
To prevent DoS attacks
802.11n
2009 Designed to increase throughput in both the 2.4 Ghz and 5Ghz bands Defined High Throughput (HT) Data rates up to 600Mbps Uses MIMO technology
802.11v
2011
Provides the ability to configure client stations wireless from a central management point
Defines Wireless Network Management
802.11s
2011
Designed to standardize mesh networking
Uses mesh routing protocol call Hybrid Wireless Mesh Protocol
Mesh devices include?
Mesh Point
Mesh Access Point
Mesh Point Portal
802.11ac
Goal of throughput above 1Gbps Will define Very High Throughput Uses 5Ghz bands Wider channels - 80Mhz and 160Mhz New modulation 256-QAM Improved MIMO and beamforming
802.11ad
2012 Defines VHT enchancements Using higher frequency 60GHz band Potentially up to 7Gbps Less range Requires new encryption mechanisms
802.11af
Allows the use of Wi-Fi in the TV whitespace frequencies between 54Mhz and 790Mhz
Lower frequencies would require lower data rates
For long-distance outdoor transmissions
802.ah
Defining the use of Wi-Fi frequencies below 1Ghz
Would have greater range
Can enhance IoT or M2M communication
