Transcript Lecture #2 - Brookdale Community College

Components Review
WLAN Devices
In-building Infrastructure
• 1200 Series (802.11a and 802.11b)
Bridging
• 350 Series (802.11b)
• 1100 Series (802.11b)
•BR350
• 350 Series (802.11b) not shown
•WGB350
• 1400 Series (802.11a)
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Antennas
Antenna
•2.4GHz Antennas
•5 GHz Antennas
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Cable, Accessories, Wireless IP Phone
Cable and Accessories
• Low Loss Cable
• Antenna Mounts
• Lightening Arrestor
• Wireless IP Phone
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Client Adapters
Clients (NICs)
• 350 Series (802.11b)
• 5 GHz client adapter (802.11a)
Drivers are supported for all popular operating systems, including
Windows 95, 98, NT 4.0, Windows 2000, Windows ME, Windows XP,
Mac OS Version 9.x, and Linux.
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Cisco Aironet 350 Series Mini PCI
Adapter
• 2.4 GHz/802.11b
embedded wireless for
notebooks
• 100 mW transmit power
• Must order through PC
manufactures (not
orderable directly through
Cisco)
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Cisco Aironet 1100 Series Access
Point
• Aironet 1100 supports 802.11b
• 802.11b is upgradeable to
802.11g with a mini-PCI
replacement.
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1200 Series Access Point
• An access point (AP) acts as
the center point of a standalone wireless network or as
the connection point
between wireless and wired
networks.
• May provide roaming
functionality with multiple
APs.
• Aironet 1200 is a dual-band
AP that supports both
802.11b and 802.11a.
• 802.11b is upgradeable to
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Guide to Wireless
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802.11g
with aLANs,
mini-PCI
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Cisco Aironet WLAN Solutions for the
Enterprise
Cisco Aironet 1100 Series
Cisco Aironet 1200 Series
Intelligent Enterprise Services at a
Lower Total Cost
Outstanding Enterprise Performance
and Greatest Flexibility
Single 802.11b radio (upgradable to
802.11g with Advanced Encryption
Standard (AES))
Dual-mode 802.11a and 802.11b
support (upgradable to 802.11g with
Advanced Encryption Standard
(AES))
Integrated diversity dipole antennas
for simplified deployment
Two 2.4 GHz antenna connectors for
high gain diversity antennas;
integrated 5 GHz antennas
Indoor environmental specifications,
durable plastic case
Industrial environmental
specifications, rugged metal case
Extra memory and system capacity
for future releases
Extra memory and system capacity
for future releases
Inline and Local Power
Cisco IOS-based operating
system
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Inline and Local Power
Cisco IOS operating system
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Bridges – BR350
• BR350 is designed to
connect two or more
networks, typically
located in different
buildings.
• The BR350 wireless
bridges provide up to 11
Mbps speed.
• The bridge is ideal for
indoor or outdoor
installations subject to
plenum rating and
harsh environments.
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Bridges – WGB350
• Cisco Aironet 350
Series Workgroup
Bridge (WGB350)
quickly connects up to
eight Ethernetenabled laptops or
other portable
computers to a
wireless WLAN,
providing an 11 Mbps
link from these devices
to any Cisco Aironet
802.11b AP or
Wireless Bridge.
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• This bridge is for indoor
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Bridges – 1400
• Cisco Aironet 1400
Series Bridge operates
at speeds up to 54
Mbps.
• High-performance
801.11a wireless bridge
designed to connect
multiple LANs in a
metro area.
• The 1400 can only
operate outdoors in a
fixed point-to-point or
point-to-multipoint
application.
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Cisco Aironet Wireless Bridging Solutions
Cisco Aironet 350 Series
Cisco Aironet 1400 Series
Wireless Bridging at a Lower Total
Cost
Wireless Bridging with high
performance
Single 802.11b radio with data rates
up to 11 Mbps
Single 802.11a radio with data rates
up to 54 Mbps
3 miles typical point to point range
with directional antennas at 11 Mbps
7.5 miles typical point to point range
with directional antennas at 54 Mbps
Two 2.4 GHz antenna connectors for
high gain diversity antennas
Single 5.8 GHz integrated patch
array antenna or antenna connector
for remote antennas
Indoor industrial environmental
specifications, rugged metal case
Outdoor environmental
specifications, tested to NEMA 4
Inline and Local Power
Inline Power via Power Injector LR
VxWorks based operating system
Cisco IOS operating system
QOS, VLANs, and Proxy Mobile IP
QOS, VLANs, and Proxy Mobile IP
Statistics
via telnet
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Antenna Alignment feedback via
LEDs and RSSI port and statistics
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Antennas
• A variety of optional 2.4 GHz
and 5 GHz antennas are
available for Cisco wireless
devices. Antennas should be
chosen carefully to ensure
that optimum range and
coverage is obtained
• Coupling the right antenna
with the right AP allows for
efficient coverage in any
facility, as well as better
reliability at higher data rates.
• A detailed coverage of
antennas will be provided
later in the course.
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Antennas
• Indoor and Outdoor
• WLAN and Bridging
• 2.4 GHz
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•
Outdoor
Bridging
• 5 GHz
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Beyond Laptops:
Other 802.11-Enabled Devices
Epson Printer
HP iPAQ 5450 PDA
PDA’s
Phones
Printers
Projectors
Tablet PC’s
Security Cameras
Barcode scanners
Custom devices for
vertical markets:
–Healthcare
–Manufacturing
–Retail
–Restaurants
Compaq Tablet PC
SpectraLink
Phone
HHP Barcode Scanner
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Sharp M25X Projector
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“Business-Class”vs Consumer WLAN
• Industry has segmented:
consumer vs. business
• “Cisco” offers only “businessclass” products:
–Security
–Upgradeability
–Network management
–Advanced features
–Choice of antennas
–Highest throughput
–Scalability
Consumer wireless products
•
There is a real difference in functionality and administrative
capabilities between Business-class and Consumer
wireless products.
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Wireless LAN Topologies
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Wireless LAN Topologies
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•
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Without a wireless alternative, organizations frequently resort to wide
area networking (WAN) technologies to link together separate facilities.
Contracting for leased-line or other wide-area services often presents a
variety of drawbacks:
• Installation is typically expensive and rarely immediate
• Monthly fees are often quite high for bandwidth
A wireless bridge can typically be purchased and installed in a day with
no recurring
charges.
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Wireless LAN Market
Implications
• Over the last decade, the networking and wireless
communities expected each year to become the year of the
WLAN.
• WLAN technology had some false starts in the 1990s, for a
variety of reasons. Immature technology, security concerns,
and slow connectivity speeds kept WLAN technology from
becoming
a viable
alternative
to wired LANs.
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WLAN growth and applications
Don’t know the source of this and there is considerable
debate whether 802.11a will win out over 802.11b/g
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Momentum is Building in Wireless
LANs
• Wireless LANs are an “addictive” technology
• Strong commitment to Wireless LANs by
technology heavy-weights
–Cisco, IBM, Intel, Microsoft
• Embedded market is growing
–Laptop PC’s with “wireless inside”
–PDA’s are next
• The WLAN market is expanding
from Industry-Specific Applications,
to Universities, Homes, & Offices
• Professional installers and technicians
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will
be in demand
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Wireless LANs Are Taking Off
Future Growth
Due To:
Worldwide WLAN Market
*includes embedded clients, add-on client
cards, & infrastructure equipment for both
the business and consumer segments
($ Billions)
$11.0
$10.0
$9.0
$8.0
$7.0
$6.0
$5.0
$4.0
$3.0
$2.0
$1.0
$0.0
CAGR = 43%
$10.3
$9.0
$6.0
$3.3
$2.6
$1.7
2001
2002
2003
2004
2005
Source: Forward Concepts, 2003
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Standards
High Bandwidth Needs
Low Cost
Embedded in Laptops
Variety of Devices
Voice + Data
Multiple Applications
Security Issues Solved
Ease of Deployment
Network Mgmt. Tools
Enterprise Adoption
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Four main requirements for a WLAN solution
1. High availability — High availability is achieved through system
redundancy and proper coverage-area design.
2. Scalability — Scalability is accomplished by supporting multiple
APs per coverage area, which use multiple frequencies. APs can
also perform load balancing, if desired.
3. Manageability — Diagnostic tools represent a large portion of
management within WLANs. Customers should be able to
manage WLAN devices through industry standard APIs, including
SNMP and Web, or through major enterprise management
applications like CiscoWorks 2000, Cisco Stack Manager, and
Cisco Resource Monitor.
4. Open architecture — Openness is achieved through adherence
to standards such as 802.11a and 802.11b, participation in
interoperability associations such as the Wi-Fi Alliance, and
certification such as U.S. FCC certification.
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Other requirements
• Security — It is essential to encrypt data packets transmitted
through the air. For larger installations, centralized user
authentication and centralized management of encryption keys
are also required.
• Cost — Customers expect continued reductions in price of 15 to
30 percent each year, and increases in performance and
security. Customers are concerned not only with purchase price
but also with total cost of ownership (TCO), including costs for
installation.
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Challenges and Issues
Radio Signal Interference
• Network managers must ensure that different channels are utilized.
• Interference cannot always be detected until the link is actually
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•
implemented.
Because the 802.11 standards use unlicensed spectrum, changing
channels is the best way to avoid interference.
If someone installs a link that interferes with a wireless link, the
interference is probably mutual.
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Radio Signal Interference
• Many other devices such as portable phones, microwave ovens,
wireless speakers, and security devices, also use these
frequencies.
• It is possible for electromagnetic interference (EMI) to be
generated by non-radio equipment operating in close proximity to
the Cisco Aironet WLAN equipment.
• While it is theoretically possible for this interference to directly
affect the reception and transmission of signals, it is more likely to
affect the components of the transmitter.
• To minimize the possible effects of EMI, the best course of action is
to isolate the radio equipment from potential sources of EMI.
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Power Consumption
• Power consumption is always an issue with laptops, because the
•
power and the battery have limited lives.
802.11a uses a higher frequency (5 GHz) than 802.11a/g (2.4 GHz)
which requires higher power and more of a drain on batteries.
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Interoperability
• Non-standard (for now) 802.11 devices include:
• Repeater APs
• Universal Clients (Workgroup Bridges)
• Wireless Bridges
• Cisco bridges, like many other vendor bridges, are proprietary
implementations of the 802.11 standard and therefore vendor
interoperability cannot be attained.
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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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Wireless LAN Security
• Security in the IEEE 802.11 specification—
which applies to 802.11b, 802.11a, and
802.11g—has come under intense scrutiny.
• Researchers have exposed several
vulnerabilities.
• As wireless networks grow, the threat of
intruders from the inside and outside is great.
• Attackers called “war drivers” are continually
driving around searching for insecure WLANs to
exploit.
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Wireless LAN Security
• The IEEE enhanced Wired Equivalent Privacy (WEP) with
Temporal Key Integrity Protocol (TKIP) which provides robust
authentication options with 802.1x to make 802.11-based wireless
LANs secure.
• We will also look at WPA (WiFi Protected Access, TKIP + MIC)
• At the same time, the IEEE is looking for stronger encryption
mechanisms.
• The IEEE has adopted the use of the Advanced Encryption
Standard (AES) to the data-privacy section of the proposed 802.11i
standard.
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Reliability and Connectivity
• Wireless LANs include mechanisms to improve the reliability of the
•
•
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packet transmissions to be at least the same level as wired Ethernet.
Using the TCP/IP protocols will help protect the network against any
loss or corruption of data over the air.
Most WLAN systems use spread-spectrum technology or orthogonal
frequency-division multiplexing (OFDM).We will look at these in much
more detail later.
Too much to go into right now.
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Installation and Site Design Issues—
Bridging
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Installation and Site Design Issues—WLAN
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Health Issues
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IEEE 802.11 Standards Activities
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802.11a: 5GHz, 54Mbps
802.11b: 2.4GHz, 11Mbps
802.11d: Multiple regulatory domains
802.11e: Quality of Service (QoS)
802.11f: Inter-Access Point Protocol (IAPP)
802.11g: 2.4GHz, 54Mbps
802.11h: Dynamic Frequency Selection (DFS) and
Transmit Power Control (TPC)
• 802.11i: Security
• 802.11j: Japan 5GHz Channels (4.9-5.1 GHz)
•CWNA
802.11k:
Measurement
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