Transcript Introduction to Wireless LANs

Wireless LAN
Introduction
Olga Torstensson
Halmstad University
© 2003, Cisco Systems, Inc. All rights reserved.
FWL 1.0—1-1
Wireless LAN
• WLAN
• Bridging
• Access Point
• Bridge
• Antenna
• Wi-Fi™
© 2003, Cisco Systems, Inc. All rights reserved.
FWL 1.0—1-2
Major Factors
There are four major factors to consider
before implementing a wireless network:
• High availability
• Scalability
• Manageability
• Open architecture
© 2003, Cisco Systems, Inc. All rights reserved.
FWL 1.0—1-3
Wireless Technologies
WAN
(Wide Area Network)
MAN
(Metropolitan Area Network)
LAN
(Local Area Network)
PAN
(Personal Area
Network)
PAN
LAN
MAN
WAN
Bluetooth
802.11a, 11b, 11g
HiperLAN2
802.11
MMDS, LMDS
GSM, GPRS,
CDMA, 2.5–3G
Speed
<1 Mbps
2–54+ Mbps
22+ Mbps
10–384 Kbps
Range
Short
Medium
Medium–Long
Long
Peer-to-Peer
Device-to-Device
Enterprise
Networks
Fixed, Last
Mile Access
PDAs, Mobile
Phones, Cellular
Access
Standards
Applications
© 2003, Cisco Systems, Inc. All rights reserved.
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Wireless Technologies
© 2003, Cisco Systems, Inc. All rights reserved.
FWL 1.0—1-5
In Building WLAN
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Site to Site WLAN
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WLAN Markets
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Radio Signal Interference
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Power Consumption
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Interoperability
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Wireless LAN Security:
Lessons
“War Driving”
Hacking into WEP
Lessons:
•
Security must be turned on (part of the installation process)
•
Employees will install WLAN equipment on their own
(compromises security of your entire network)
•
WEP keys can be easily broken (businesses need better security)
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Reliability and Connectivity
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Installation and Site Design Issues—
Bridging
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FWL 1.0—1-14
Installation and Site Design Issues—WLAN
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Health Issues
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IEEE 802.11 Standards Activities
802.11a:
802.11b:
802.11d:
802.11e:
802.11f:
802.11g:
802.11h:
802.11i:
802.11j:
802.11k:
© 2003, Cisco Systems, Inc. All rights reserved.
5GHz, 54Mbps
2.4GHz, 11Mbps
Multiple regulatory domains
Quality of Service (QoS)
Inter-Access Point Protocol (IAPP)
2.4GHz, 54Mbps
Dynamic Frequency Selection (DFS)
and Transmit Power Control (TPC)
Security
Japan 5GHz Channels (4.9-5.1 GHz)
Measurement
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WLAN Speeds & Frequencies
802.11g
2.4 GHz – OFDM/CCK
54 Mbps
802.11a
5 GHz – OFDM
54 Mbps
802.11b
2.4 GHz – CCK
11 Mbps
Proprietary

Jan’99
IEEE 802.11a/b
Ratified
Jan’00
© 2003, Cisco Systems, Inc. All rights reserved.
Jan’01
Jan’02
Jan’03
Jan’04
FWL 1.0—1-18