Chapter 1 Overview of Wireless Standards, Organizations, and Fundamentals.

Chapter 1• Overview of Wireless Standards,

Organizations, and Fundamentals

Exam Essentials• Know the three industry organizations

– Understand the roles and responsibilities of the regulatory domain authorities, the IEE, and the Wi-Fi Alliance.

• Understand Core, Distribution and Access– Know where 802.11 technology is deployed in

fundamental network design• Understand wavelength, frequency, amplitude,

and phase– Know the definitions of each RF characteristics

• Understand the concepts of modulation– ASK, FSK, PSK are three carrier signal modulation

techniques

History of WLAN

• Trace back to 19th century scientists– Radio Frequency

• WWII– Tramsitting encrypted plans over RF

• Spread Spectrum Technology created

• 1970s-Aloha Net

• 1990s-Early commercial development

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Standards Organizations

• FCC

• IEEE

• Wi-Fi Alliance

• ISO

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FCC

• Regulates Communication in the US• Regulate Licensed and Unlicensed

– Wireless LAN mostly in unlicensed

• Regulates:– Frequency– Bandwidth– Maximum Power of the intentional Radiator– Maximum equivalent isotropically radiated power

(EIRP)– Use (indoor and/or outdoor)

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FCC

• Regulates Communication in the US• Regulate Licensed and Unlicensed

– Wireless LAN mostly in unlicensed

• Regulates:– Frequency– Bandwidth– Maximum Power of the intentional Radiator– Maximum equivalent isotropically radiated power

(EIRP)– Use (indoor and/or outdoor)

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Federal Communications Commission

• Manage RF for USA

• 802.11 wireless can use both licensed and unlicensed frequencies

• Unlicensed means no cost to users– 2.4 Ghz industrial, scientific and Medical

(ISM)– 5 Ghz Unlicensed National Inforamtion

Infrastructure (UNII) band

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ITU-R• Manages global spectrum of RF

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IEEE• Defines the 802 series standards

– 802.3 Ethernet– 802.11 Wireless

• Document the technical and equipment basics– Can be different interpretations

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Wi-Fi Alliance• Starting with 802.11b manufacturers

formed WECA– Promote technology– Support interoperability

• In 2000, WECA became WiFi Alliance

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Interoperability Certifications• Addressed the issue of standards

• Help growth and progression

• Allow interoperability

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Wi-Fi Protected Access (WPA) Certification Overview

• Created due to weak security in initial standards• Interim solution before 802.11i

– Temporal Key Integrity Protocol (TKIP)– Passphrase– 802.1X/EAP

• Two Modes– Personal

• Home Office

– Enterprise• Larger Deployment (Servers)

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Wi-Fi Protected Access 2 (WPA 2.0) Certification Overview

• Post 802.11i– WPA 2.0

• Personal and Enterprise• More advanced security

– Personal mode security uses a passphrase• Generates a 256 bit preshared key

– Enterprise mode uses 802.1X/EAP• Port based authentication designed for enterprises• Strong security and external authentication

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Wi-Fi Protected Access 2 (WPA 2.0) Certification Overview

WiFi Alliance Security Mechanism

Authentication Mechanism

Cipher Suite/Encryption Mechanism

WPA-Personal Passphrase TKIP/RC4

WPA_Enterprise 802.1x/EAP TKIP/RC4

WPA2.0 Personal Passphrase CCM/AES or TKIP/RC4

802.1x/EAP CCM/AES or TKIP/RC4

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Wi-Fi Multimedia (WMM) Certification Overview

• Proactive certification for 802.1e– Address QOS for wireless networks

• WMM Validates the features of 802.11e– Vendor neutral QOS approach– Ciritical for interoperability

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Wi-Fi Multimedia Power Save (WMM-PS) Certification Overview

• Designed for Mobile devices with battery issues– VoIP Phones– Notebooks– PDAs– Headsets– Mice – Keyboards

• Allow “dozing” to save battery• May affect performance

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Wi-Fi Protected Setup (WPS) Certification Overview

• Designed for simple set up of wireless for SOHO networks

• Requires support for two types of authentication – Push Button Config (PBC)– PIN based config

• Enables automatic configuration of network names and WPA2 security

• Both methods need to be supported• Near Field Communications also supported

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ISO• Identifies standards for business,

government and society

• Created the OSI model for computers networking– Not implemented, but often referenced

• Should understand the layers

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OSI Model– Layer 7- Application– Layer 6-Presentation– Layer 5- Session– Layer 4- Transport– Layer 3-Network– Layer 2-Data Link

• LLC• MAC

– Layer 1-Physical

• Please Do Not Throw Sausage Pizza Away• All People Seem To Need Data Processing

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Core, Distribution, Access• Core

– No routing-High Speed Switching– Redundant Solutions

• Distribution– Router Traffic between LANS/VLANS– Wireless Bridges can operate here

• Access– Slower delivery to end user devices– To the desktop– 802.11 Mostly implemented at access layer

• Access points

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Communications Fundamentals• Most people have a basic idea about

transfer of data

• This section gives more background on fundamental communications for wireless

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Carrier Signals• Need to be able to transmit two

states:– 1 or 0

• AC or DC alone wont do it, need to alternate or modulate

• The base signal that is modified is called the Carrier Signal

• The method of adjusting it is the modulation technique

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Amplitude and Wavelength

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Key wave terms• Amplitude is a measure of the height of a wave.

The higher the amplitude, the higher the power.• Wavelength is the measure of the length

between peaks.• Frequency is how often the peaks come in a

period of time, usually measured in Hertz (times per second).

• Phase is usually used to refer to the relationship between two waveforms of the same frequency. Phase is measured in degrees.

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Amplitude and Wavelength

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Phase

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Keying Methods• Signal transmitted from the transceiver

has to be manipulated to let receiver distinguish between 1 and 0– This is the keying method– Also known as modulation techniques

• Amplitude Shift Keying

• Frequency Shift Keying

• Phase Shift Keying

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Current State Keying• Uses the current (in time) value to show a 1 or 0• Whatever the current state is is the binary 0

– Other state is 1

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State Transition Keying• The change, or lack of change will signify

a 0 or 1

• 0 is a change in state

• 1 is no change in state of signal

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Amplitude-Shift Keying• Uses the height, or amplitude of the wave

to signal change.

• Current state technique– A shift indicates a change from current signal

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Frequency-Shift Keying• Uses the frequency, or number of cycles per

second to indicate change.• Current state technique

– A shift indicates a change from current signal

• Used in legacy (older) 802.11 technologies

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Phase-Shift Keying• Varies the phase of a signal to represent

data

• State Transition technique

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Phase-Shift Keying-Advanced• Can encode multiple bits per symbol as

well– Use four different phases

• Multiple Phase shift Keying

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Exam Essentials• Know the three industry organizations

– Understand the roles and responsibilities of the regulatory domain authorities, the IEE, and the Wi-Fi Alliance.

• Understand Core, Distribution and Access– Know where 802.11 technology is deployed in

fundamental network design• Understand wavelength, frequency, amplitude,

and phase– Know the definitions of each RF characteristics

• Understand the concepts of modulation– ASK, FSK, PSK are three carrier signal modulation

techniquesPg 21