Chapter 1 provides an introduction to Wi-Fi industry standards and organizations.

Objectives

• Understand how the 802.11 standards came about
• Understand who creates the standards
• Understand who manages the radio spectrum

History of Wireless Communications

• Electromagnetic wave-based (or wireless) communications have been in use for decades
• The first wireless phone conversation took place in 1880; it was called the “Photophone” (used light as the medium) and communicated between rooftops (invented by Alexander Graham Bell)
• Guglielmo Marconi communicated wirelessly (an “S” was the first letter) across the Atlantic in the first decade of the twentieth century; this stirred government and commercial interest in wireless
• Mobile voice technology was perfected and used widely in the 1940s
• A modem modulates binary data into analog signals and demodulates the analog signals into binary data
• Early wireless devices were proprietary, so systems from different vendors could not communicate
• The Institute of Electrical and Electronics Engineers (IEEE) ratified the first 802.11 standard in 1997; today this is called 802.11-Prime (1 or 2 Mbps data rates)
• 802.11a (54 Mbps) and 802.11b (11 Mbps) were ratified by the IEEE in 1999

Industry Organizations

• Three types: regulation (i.e. FCC), standardization (IEEE, IETF) and compatibility/certification (Wi-Fi alliance)
• Mass acceptance comes when regulation, standardization, and compatibility/certification work work together

Regulatory Domain Government Agencies

• A regulatory domain is a geographic area controlled by a set of laws or policies
• In the United States, the Federal Communications Commission (FCC) is the manging Organization

FCC

• Hertz is the specification for radio frequency; it is the measurement of wave cycles per second
• License-free bands for radio communications: Industrial Scientific Medical (ISM) and Unlicensed National Information Infrastructure (UNII)

Frequency Band	Total Band Width	License-Free Band
2400 - 2500 MHz	100 MHz	ISM
5.15 - 5.25 GHz	100 MHz	U-NII (U-NII-1)
5.25 - 5.35 GHz	100 MHz	U-NII (U-NII-2A)
5.470 - 5.725 GHz	255 MHz	U-NII (U-NII-2C)
5.725 - 5.850 GHz	100 MHz	U-NII (U-NII-3)

• Contention is the process employed by 802.11 WLANs to access the medium for tansmission; this is a normal part of operations. Contention wait times become longer as more stations (STA) access the same channel.
• Equivalent Isotropically Radiated Power (EIRP) is a measurement of a system’s output power after antenna gain
• A Decibel (dB) is a relative measurement of power, whereas a dBm is an absolute measure of power related to the Watt/milliWatt

ITU-R

• The International Telecommunications Union-Radiocommunication (ITU-R) is part of the International Telecommunications Union, which is an agency of the United Nations tasked with providing worldwide leadership in Telecommunications
• The ITU-R maintains a database of frequency assignments worldwide and helps coordinate electromagnetic spectrum management in five regions:
  • A: The Americas
  • B: Western Europe
  • C: Eastern Europe
  • D: Africa
  • E: Asia and Australia

IEEE

• The IEEE strives to be the world’s leading professional association for the advancement of technology
• The organization creates many standards for niche areas within electronics and communications
• While several standards are important to the implementation and support of WLANs IEEE 802.11 is the primary standard
• The 802.11 standard has been amended many times since its inception; at any moment, it exists as “the standard as amended”, which means that amendments, once ratified, become part of the standard.

Wi-Fi Alliance

• The Wi-Fi Alliance is a certification organization that provides testing and interoperability analysis for the wireless industry
• Wi-Fi does not stand for “Wireless Fidelity” as some say; it is only a brand (marketing) name
• The Wi-Fi Alliance offers multiple types of certification programs and provides certificates for certified devices

IETF

• The Internet Engineering Task Force (IETF) is another standards development organization that has had an influence on the wireless industry
  • RFC 3748: Extensible Authentication Protocol (EAP)
  • RFC 2865: Remote Access Dial-in User Service (RADIUS)
  • RFC 5415: Control and Provisioning of Wireless Access Points (CAPWAP) - replaces Lightweight Access Point Protocol (LWAPP)

IEEE Standard Creation Process

• Projects managed by the IEEE, like the 802 project, are divided into working groups like 802.3 (Ethernet) and 802.11 (WLAN)
• A PHY is a physical communication layer
• The IEEE 802.11-1997 standard specified 3 PHYs: Direct Sequence Spread Spectrum (DSSS), Frequency Hopping Spread Spectrum (FHSS), and an Infrared PHY that was never used
• Updates to standards are added as amendments; while still in draft mode, they may be still be modified
• A ratified amendment is stable; after ratification software and hardware development will usually follow

802.11 Amendments

Amendment	Description
802.11a-1999	Switch from DSSS to OFDM (Orthogonal Frequency Division Multiplexing). 5 GHz only, up to 54 Mbps.
802.11b-1999	High-Rate DSSS; 11 Mbps in 2.4 GHz
802.11c-1998	Updates to 802.1D bridging
802.11d-2001	Adds regulatory domains
802.11e-2005	Adds layer 2 MAC controls for QoS (supporting multimedia/voice)
802.11g-2003	DSSS, HR/DSSS, supported, OFDM in 2.4 GHz; up to 54 Mbps but incompatible with 5 GHz OFDM PHY
802.11h-2003	Adds Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC)
802.11i-2004	Counter Mode Cipher Block Chaining Message Authentication Protocol (CCMP) (uses AES), provides for Temporal Key Integrity Protocol (TKIP)
802.11j-2004	802.11 MAC/OFDM PHY can operate in 4.9-5 GHz in Japan/US
802.11k-2008	Allows use of TPC in frequencies other than 5 GHz and provides for reporting of client stats
802.11n-2009	Modifies physical and MAC layers for throughput of 600 Mbps (4 spatial streams, 40 MHz channels); 2.4 and 5 GHz
802.11r-2008	Fast roaming amendment; improve Basic Service Set transitions (BSS) withing Extended Service Sets (ESS)
802.11s-2011	Specifies ESS mesh network
802.11u-2011	Enable handoffs between WLANS and other types of networks
802.11v-2011	Improves radio management, adds standard SNMP MIBs
802.11w-2009	Enhances management frame security
802.11-2007	Rollup to bring all amendments into base document
802.11-2012	Rollup to bring all amendments into base document
802.11ad-2012	60 GHz spec for Directional Multi-Gigabit (DMG) PHY
802.11ae-2012	Specifies management frame prioritization
802.11ac-2013	New PHY for 5 GHz (only); speeds gigabit and higher
802.11af-2013	Television Very High Throughput (TVHT) PHY
802.11-2016	Rollup to bring all amendments into base document, the most recent rollup
802.11ah-2016	< 1 GHz PHY, long range/low data rate (uses for IoT?)

• 802.11-2016 is the most recent rollup of the 802.11 standard

IEEE Standards Impacting WLANs

• IEEE 802.1X-2010: port-based authentication/control for WLANS; critical for enterprise networks
• IEEE 802.3-2015, Clause 33: 802.3af/802.3at - PoE
• IEEE 802.1D-2004: bridging/priority handling (bridging, STP)
• IEEE 802.1Q-2014: priority tagging and VLAN handling for QoS

Wireless Network Types

Wireless LANs

• Mobility: The network can be used while moving
• Nomadic Ability: Ability to move from place to place without active communications while moving
• Fixed Connectivity: No movement
• Access Role: the WLAN provides clients access to wired resouces; AP is fixed while clients may move
• Distribution Role: Wireless bridges provide connectivity (backhaul) between disconnectd wired networks
• Core Role: The WLAN is the network; suitable for small networks usually, not large networks
• Wireless Personal Area Network (WPAN): wireless communications within small range with limited throughput or small-scale mesh (ZigBee, RFID, Bluetooth)
  • Bluetooth can interfere with Wi-Fi, but this is largely eliminated with adaptive frequency hopping
• Wireless Metropolitan Area Networks (WMAN): typically operated by a service provider who leases services to subscribers (WiMAX, requires licensing)
• Wireless Wide Area Networks (WWAN): wireless wide area networks (network that connect multiple WANs together) (Free Space Optics, microwave)

Notes are based on the Certitrek Certified Wireless Network Administrator Official Study Guide (Tom Carpenter and Mitch Dickey).