CWNA Chapter1

8/2/2019 CWNA Chapter1

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Chapter 1 Overview of Wireless Standards,

Organizations, and Fundamentals


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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-FiAlliance.

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


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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 computersnetworking

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 onfundamental communications for wireless

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Carrier Signals Need to be able to transmit twostates:

1 or 0

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

The base signal that is

modified is called the CarrierSignal

The method of adjusting it isthe modulationtechnique

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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 lengthbetween peaks.

Frequency is how often the peaks come in aperiod 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 keyingmethod

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 persecond 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 representdata

State Transition technique

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Phase-Shift Keying-Advanced Can encode multiple bits per symbol aswell

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-FiAlliance.

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

CWNA Chapter1

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