Download Introduction to Wireless Networking

Introduction to Wireless Networking
Module-01
Overview of Wireless Standards, Organizations and
Technology
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-1
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Abbreviated Wireless Network History ??dates
• 1830: Professor Joseph Henry transmitted the first practical
electrical signal.
• 1880: Maxwell’s Equations
• 1905: Marconi
• 1920: Radio Receivers
• 1935: Television
• 1941: Radar
• 1958: Satellite
• 1970: ALOHAnet
• 1990: Internet
• 1998: WLAN
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Why Study Wireless Networks? A Partial List
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Cordless phones
Wireless Voice over IP phones
Wireless print servers
Wireless access points, routers, and bridges
Radio Frequency Identification devices
Wireless presentation gateways
Wireless conferencing systems
Laptop computers, PDAs, and other mobile wireless client
device
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Wireless Industry Guided by Three Categories
of Organizations
• Regulation- Boundaries of Operation
– Federal Communications Commission (FCC)
– European Telecommunications Standards Institute (ETSI)
• Power limits and Frequencies
• Standardization- How systems work together
– Institute of Electrical and Electronics Engineers (IEEE)
• 802.11 a, b, g, n
• Compatibility – Tests for interoperability
– Wi-Fi Alliance
• If you buy Wi-Fi certified gear it work with other Wi-Fi gear
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FCC - Federal Communications Commission
• Regulatory Bodies – City, State, Country
• FCC- Born in 1934 to regulate radio, television, cable,
satellite and wire communications
• FCC regulates
– Radio frequencies
– Output power levels
– Indoor and Outdoor usage
• Every country has regulatory bodies
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FCC Wireless Bands
• 1985:Industry, Scientific and Medical Industrial
License-Free Bands – ISM Bands
– 900 MHz band, (900 to 928 MHz range)
– 2.4 GHz band, (2.4 to 2.483 GHz range)
– 5 GHz band, (5.725 to 5.850 GHz range)
• 1997: Unlicensed National Information Infrastructure
U-NII bands
– 5.15 to 5.25 GHz
– 5.25 to 5.35 GHz
– 5.725 to 5.825 GHz
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FCC Unlicensed Bands
Advantages
•No licenses required
•No Fees
•No Permits
•Comply with rules and
build anything
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Disadvantages
•Everyone can use the
bands
•Interference between
users
•Bandwidth Contention
•First-come-first –serve
•Interference from latecomers
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FCC Regulates Frequencies
• Frequencies are grouped into bands
– Wireless LAN bands include: (Hz = Hertz)
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Frequency Band
Total Bandwidth
License-Free Band
2400–2500 MHz
100 MHz
ISM
5.15–5.25 GHz
100 MHz
U-NII
5.25–5.35 GHz
100 MHz
U-NII
5.470–5.725 GHz
255 MHz
U-NII
5.725–5.825 GHz
100 MHz
U-NII
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FCC Power Output Limits-U-NI Bands
Band
Power Output
Limits Area Usage
U-NII 5.15–5.25 GHz
40 mW
Restricted to indoor operations
U-NII 5.25–5.35 GHz
200 mW
Indoor/outdoor
U-NII 5.470–5.725 GHz
200 mW
Indoor/outdoor
U-NII 5.725–5.825 GHz
800 mW
Higher output power assumes
outdoor operations
mw = 1/1000 watt
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Non-USA Standard Organizations
• OfCom-Office of Communication –United Kingdom
• MIC- Ministry of Internal Affairs and
Communications-Japan
• ARIB-Association of Radio and Businesses – Japan
• ACMA-Australian Communications and Media
Authority
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International Telecommunications Union
Radiocommunications Sector (ITU-R)
• 1947: United Nations creates ITU-R to:
– Promote cooperation and technical development
• ITU-R maintains a database of frequencies with five
administrative regions
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Region A: The Americas
Region B: Western Europe
Region C: Eastern Europe
Region D: Africa
Region E: Asia and Australia
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Institute of Electrical and Electronics
Engineers - IEEE (Eye-triple-E)
• World’s leading non-profit professional organization
for the advancement of technology
• Mission –
– promote “the engineering process of creating, developing, integrating,
sharing, and applying knowledge about electronics and information
technologies and sciences for the benefit of humanity and the
profession.”
• 350,000 individual members in 150 countries.
• Nearly 900 active standards with 700 under
development.
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IEEE Wireless Standards
• IEEE 802 project is the most important with multiple
working groups
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IEEE 802.3 (Ethernet)
IEEE 802.11 Wireless LAN (WLAN)
IEEE 802.16 WiMAX
IEEE 802.16 Mobile Broadband
• Most of this course will deal with IEEE 802.11
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IEEE 802.11 Standards
• 1997: First 802.11 ratified (802.11-1997)
• Three ways of implementing a physical
communications layer (PHY)
– Frequency-hopping spread spectrum (FHSS)
– Direct-sequence spread spectrum (DSSS)
– Infrared communications (not implemented extensively)
• All operate at 1Mbps and 2Mbps
• To be covered in depth is subsequence lessons
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IEEE 802.11 Amendments
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IEEE 802.11a – OFDM, 5 GHz U-NII, 54 Mbps
IEEE 802.11b – DSSS, 2.4 Mhz ISM band, 11 Mbps
IEEE 802.11c – Bridging operation
IEEE 802.11d – regularity specifications
IEEE 802.11e – Quality of Service (QoS)
IEEE 802.11F- access point re-association
IEEE 802.11g – DSSS/OFDM, 2.4 Mhz, 54 Mbps
IEEE 802.11h – Dynamic frequency, power control
IEEE 802.11i – important security enhancements
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IEEE 802.11 Amendments
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IEEE 802.11j – 4.9-5 Mhz band in Japan
IEEE 802.11k – channel management above 5 Mhz
IEEE 802.11n –Important 100 Mbps plus WLAN
IEEE 802.11p –Intelligent Transportation Systems
IEEE 802.11r – Roaming amendment
IEEE 802.11s – Extended Mesh network interoperate
IEEE 802.11T – measurement and test conditions
IEEE 802.11u – handoffs between WiMax and WLAN
IEEE 802.11v – device management
IEEE 802.11w – improved management frames
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More IEEE Standards
• IEEE 802.1X – port-based authentication for security
• IEEE 802.3-2005 Clause 33 – defines power over
Ethernet (PoE)
• IEEE 802.1D – bridging priority
• IEEE 802.1Q – priority tagging and VLAN FOR QoS
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IETF – International Engineering Task Force
• Primarily a volunteer organization
• The most important standards organization for the
Internet operation
• Operates on the basis of the Request-For-Comment
(RFC)
– IETF issues an RFC in a technical issue
– After a period of time all responses to the RFC are gather and voted on
• WLAN RFC 3748, RFC 2865 are important for wireless
– RFC 3748 - WLAN security
– RFC 2865 -security and the use of RADIUS server
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Wi-Fi Alliance
• Certification organization for testing and
interoperability
• Eight basic Wi-Fi CERTIFIEDTM programs
• Wi-Fi is just a marketing name; it does not stand for
anything
• Before October 2002 know as the Wireless Ethernet
Compatibility Alliance (WECA)
• Most commercial products will have a Wi-Fi logo
• www.wi-fi.org for more information
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Wi-Fi CERTIFIEDTM Programs
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IEEE 802.11 baseline – meets up to IEEE 802.11n
Wi-Fi Protected Access 2 (WPA2) – based upon IEEE 802.11i
Wi-Fi Multimedia (WMM)- QoS for various applications
WMM Power Save(WMM-PS) – specifications to save battery
power
• Wi-Fi- Protection -Security – Simplified and automated WPA
and WPA2 security setup
• CWG-RF multimedia- defines performance for cellular radios
and handsets
• Voice Personal-application – support for personal and
business voice applications
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Communications Models
• Models are design, management, interoperability
and learning
• OSI Model - seven layers- can be abstract but is very
commonly used
• Core-Distribution-Access Model – a useful model for
wireless networking
• TCP/IP Model - Four layers – good for networks built
around TCP/IP
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OSI Model
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Core – Distribution - Access
• Core Layer – Does not route or manipulate traffic
– High speed traffic – think superhighway
– Backbone of network
– High speed switches and routers
• Distribution Layer – Routes or directs traffic other
nodes
– Medium speed traffic – think city traffic
– Routers and Bridges
• Access Layer – directs traffic to end user
– Relative slower traffic – think local street traffic
– Access Points and Switches
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Core – Distribution – Access Details
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TCP/IP Model
(Transport)
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TCP/IP and OSI Model Maping
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Modulation
• Carrier signal is a continuous electrical signal
– Carries no information
• Three types of modulations enable carrier signals to
carry information
– Height of signal
– Frequency of signal
– Relative starting point
• Modulation can be done on analog or digital
transmissions
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
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Analog and Digital Modulation
• Analog Transmission use analog carrier signals and
analog modulation.
• Digital Transmission use analog carrier signals and
digital modulation.
• Modem (MOdulator/DEModulator): Used when
digital signals must be transmitted over analog
medium
– On originating end, converts distinct digital signals into continuous
analog signal for transmission
– On receiving end, reverse process performed
• WLANs use digital modulation of analog signals
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
(carrier signal)
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Analog vs. Digital Transmissions
Analog Signal = A signal that has continuously varying voltages, frequencies, or
phases. All amplitude values are present from minimum to maximum signal levels.
Digital Signal = A signal in which information is carried in a limited number of
different discrete states or levels; High/Low, One/Zero, 1/0
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
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Analog and Digital Modulation
• Analog Transmission use analog carrier signals and
analog modulation.
• Digital Transmission use analog carrier signals and
digital modulation.
• Modem (MOdulator/DEModulator): Used when
digital signals must be transmitted over analog
medium
– On originating end, converts distinct digital signals into continuous
analog signal for transmission
– On receiving end, reverse process performed
• WLANs use digital modulation of analog signals
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
(carrier signal)
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Frequency and Period
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
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Analog Modulation
• Amplitude: Height of carrier wave
• Amplitude modulation (AM): Changes amplitude so
that highest peaks of carrier wave represent 1 bit
while lower waves represent 0 bit
• Frequency modulation (FM): Changes number of
waves representing one cycle
– Number of waves to represent 1 bit more than number of waves to
represent 0 bit
• Phase modulation (PM): Changes starting point of
cycle
– When bits change from 1 to 0 bit or vice versa
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
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Digital Modulation
• Advantages over analog modulation:
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Better use of bandwidth
Requires less power
Better handling of interference from other signals
Error-correcting techniques more compatible with other digital
systems
• Unlike analog modulation, changes occur in discrete
steps using binary signals
– Uses same three basic types of modulation as analog
Amplitude shift keying (ASK)
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
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Digital Modulation
Frequency shift keying (FSK)
Phase shift keying (PSK)
CWNA Guide to Wireless LANs, Second
EditionCCRI J. Bernardini
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Spread Spectrum Technology Uses
• Spread spectrum is a technique of transmitting radio
signals over multiple frequencies
– The common method of transmitting WLAN signals
– Spread Spectrum will be explained in depth in chapter-3
• Spread spectrum is used by
– Wireless LANs (WLANs)
– Wireless PANs (WPANs)
– Wireless MANs (WMANs)
Use
Examples
Range
Speeds
WLAN /Backhaul
IEEE 802.11
375 ft/ miles
> 2Mbps
WPAN
Bluetooth
1-3 meters
.723 – 3 Mbps
WMAN/ Backhaul
WiMax and EDGE 10 km
~ 40 Mbps
WWAN / backhaul
AT&T microwave
~75-135 kbps
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variable
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Wireless LANs (WLANs)
• The major application of IEEE 802.11
• WLANs provide mobility and unwired fixed
connectivity
• Three primarily roles of WLANs
– Access role
– Distribution role
– Core role
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Wireless PANs (WPAN)
• Wireless Personal Area Networks
• 10 meter radius connectivity
• Primarily Bluetooth Applications
– headsets
– mouse
– PDA
• Uses 2.4 GHz ISM band which can interfere with
802.11 WLAN
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Wireless MANs (WMAN)
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Wireless Metropolitan Area Network
Uses both Point-to-Point and Point-to-Multipoint
WiMAX and IEEE802.16
Leased networks covering multiple miles
Provide QoS mechanisms
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Wireless WANs (WWANs)
• Expansion of WAN technology
– DSL
– ISDN
– Cable
• WWANs connect LANs to backbone
• Uses both Point-to-Point and Point-to-Multipoint
• WWANs provide multi-channel communications
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Last-Mile Delivery
• Last mile is the connection between the ISP and the
end user
– Example: home and telephone central office
– Example: Office and Cable provider hub
• Last mile comes from the old telephone network
design;
– max of 18000 ft to central office
• Last mile can be expensive
• Wireless Internet Service Provider (WISP)
• WISP use WiMAX (IEEE 802.16)
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Major Wireless Applications
• SOHO – Small Office / Home Office
– Less than 25 computers
– Router connections
• Mobile Office Network
– Similar the SOHO but mobile
– Mobile IP usage
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Educational/Classroom Use
Hotspots
Warehousing and Manufacturing
Health Care
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Wireless Hotspots
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Hotspots often use Wi-Fi
Free and wide open
Free and secure
Subscription based
Pay-as-you-go
Mixed
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