CIT 1100
In this chapter you will learn how to:
 Describe the basics of wireless
networking
 Explain the differences between
wireless networking standards
 Configure wireless networks
A wireless network eliminates the need for
network cabling to connect PCs to one another
 Instead of a physical set of wires, wireless
networks use radio waves to communicate
 The wireless radio wave networks you'll be
supporting are those based on the most
common implementation of the IEEE 802.11
wireless Ethernet standard (Wi-Fi) and those
based on Bluetooth technology
Wireless networking capabilities of one form or
another are built into many modern computing
devices
 Wireless Ethernet and Bluetooth capabilities
are available as integrated components, or
they can easily be added using PCI or PCie
 You can also add wireless network
capabilities using an external USB wireless
NIC cards
Wireless NICs aren't limited to PCs
Smartphones can have built-in wireless
To extend the capabilities of a wireless Ethernet
network, such as by connecting to a wired network
or by sharing a high-speed Internet connection,
you need a Wireless Access Point
 A WAP centrally connects wireless network nodes
the same way that a network hub or switch
connects wired PCs
Configuring wireless networking software is
greatly simplified, network adapters are Plug and
Play so any late version of Windows recognizes
one when installed into a PCI or PCie slot, or a
USB port
 Networks need a name which you will be
prompted for during configuration
Click on the Wireless select ICON
Select Wireless network by Name
There are two different methods available with
wireless ad hoc mode and infrastructure mode
 Ad hoc mode, also called peer-to-peer mode,
each node is in direct contact with each other
node
 Ad hoc mode networks are easier to configure
than infrastructure-mode networks
◦ Suited for small groups of computers that need to
transfer files or share printers
◦ Also good for temporary networks such as study
groups or business meetings
There are two different methods available with
wireless ad hoc mode and infrastructure mode
 Infrastructure mode use one or more WAPs to
connect
 Designed for wireless network with many PCs,
needs to have centralized control over the
wireless network
 To connect wirelessly to another network, such
as the Internet, you need to use infrastructure
mode
One of the major complaints about wireless
networking is that it offers weak security
 Often the only requirement to access a wireless
network is walk into an unsecured WAP's
coverage area and turn on your wireless device
 Unsecured Data packets float through the air
instead of traveling safely wrapped up inside
network cabling
 These packets can be intercepted
Wireless networks use multiple methods to secure
access to the network itself and secure the data being
transferred
 Changing the default Service Set Identifier (SSID)
parameter- also called the network name- and
administrator password is the first step
 The SSID is a 32-bit identifier for your WAP that is
meant to be unique, but many WAPs ship with the
same SSID and remain unchanged by unsuspecting
users
 Enabling wireless encryption - Wired Equivalent
Privacy (WEP), Wi-Fi Protected Access (WPA), or WPA2
ensures that the data packets are secure in transit
The main security weaknesses in wireless
networks is that out of the box, no security is
configured
 Wireless devices want to be heard, and by
default WAPs are configured to broadcast
their presence to their maximum range,
welcoming all other wireless devices that
respond
 Always change the default SSID to something
unique, and change the administrator
password right away
How secure are default passwords?
http://www.phenoelit-us.org/dpl/dpl.html
Wired Equivalent Privacy (WEP) encryption was
meant to secure data being wirelessly
transmitted. WEP encryption uses a standard
40-bit encryption to scramble data packets
 Unfortunately WEP can be cracked in a matter
of minutes using software readily available off
the Internet
 WEP is better than nothing, but only stops
casual prying into a network
Wireless Protected Access (WPA) encryption
addresses the weaknesses of WEP it functions as a
security protocol upgrade to WEP-enabled devices
 WPA offers security enhancements such as an
encryption key integrity-checking feature and user
authentication through the industry-standard
Extensible Authentication Protocol (EAP)
 The use of EAP is a huge security improvement
over WEP. User names and passwords are
encrypted and therefore much more secure
Recent versions of Mac OS-X and Microsoft
Windows support WPA2 for securing wireless
networks
 WPA2 uses Advanced Encryption Standard (AES),
among other improvements, to provide a secure
wireless environment
 WPA2 should be the security used on all Wireless
systems
Wireless speeds depend on several factors mostly
dependent upon the standard used by the wireless
device
 Another factor affecting speed is the distance
between wireless nodes (or between wireless
nodes and centralized WAPs).
◦ Devices dynamically negotiate top speed at which they
can communicate without dropping too many data
packets
◦ Speed decreases as distance increases, so the maximum
throughput speed is achieved only at extremely close
range (less than about 25 feet).
◦ At the outer reaches of a device's effective range, speed
may decrease to around 1 Mbps before it drops out
altogether
Speed can also be affected by interference from
other wireless devices operating in same frequency
range
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Cordless phones
Baby monitors
Microwave Ovens
Solid objects
Deadspots occur when something capable of
blocking the radio signal comes between wireless
network nodes
Electrical appliances are very effective at blocking
wireless network signals
Other culprits include electrical fuse boxes, metal
plumbing, and air conditioning units
Range is greatly affected by outside factors,
Interference from other wireless devices will
affects range, as does interference from solid
objects
 Range can be increased in a couple of ways:
◦ Installing multiple WAPs to permit "roaming"
between one WAP's coverage area and another
◦ Install a higher-gain antenna on some models that
increases a single WAP's range
◦ Directional antennas can be used to dramatically
increase range in specific directions
Standards for Wireless are based on the 802.11 and
Bluetooth Standards
 The IEEE 802.11wireless Ethernet standard defines
methods by which devices can communicate using
spread-spectrum radio waves
 Spread-spectrum broadcasts data in small, discrete
chunks over the different frequencies (channels)
available within a certain frequency range
 802.11-based wireless technologies broadcast and
receive on one of two license free industrial,
scientific, and medical (ISM) radio bands: 2.4 GHz
and 5.8 GHz
Currently Wi-Fi is the most widely adopted type of
wireless networking used by homes, public places,
coffee shops, libraries…
 Only wireless devices that conform to the extended
versions of the 802.11 standard- 802.11a, 802.11b,
802.11g, and 802.11n- are Wi-Fi certified
 Certification comes from the Wi-Fi Alliance, a
nonprofit industry group made up of more than 175
member companies designing and manufacturing
wireless networking products
 Most wireless equipment will communicate with
different devices, 802.11b will communicate with
802.g, the exception is 802.11a which operates on a
different frequency
802.11a differs from all others in significant ways:
 802.11-based standards operates on a different
frequency range, 5GHz
 This less-used frequency range means that
802.11a devices are less prone to interference
from other devices
 802.11a also offers considerably greater
throughput than 802.11b, reaching speeds up to
54 Mbps
 Range is somewhat less about 150 feet
 Despite the superior speed of 802.11a, it isn't
widely adopted in the PC world
802.11b was the first widely accepted standard in
wireless networking
 802.11b supports data throughput of up to
11Mbs and maximum range of 300 feet
 In a typical office environment, its maximum
range is lower
 Downside to 802.11b - it uses a very popular
frequency 2.4 GHz band which is already
crowded with baby monitors, garage openers,
microwaves, and wireless phones, so you're likely
to run into interference from other wireless
devices
802.11g uses the best of both 802.11a and b creating
a single standard
 802.11g offers transfer speeds equivalent to
802.11a, up to 54 Mbps, with the wider 300-foot
range of 802.11b
 More importantly, 802.11g runs in the 2.4 GHz
band, so it is backward-compatible with 802.11b,
meaning that the same 802.11g WAP can service
both 802.11b and 802.11g wireless nodes
 The 802.11g standard is popular, but losing ground
to the newest version, 802.11n
802.11n standard brings improvements to Wi-Fi
networking- faster speeds, new antenna technology
 802.11n specification requires all but handheld
devices to use multiple antennae - a feature called
multiple in/multiple out (MIMO), enabling the
devices to make multiple simultaneous connections
 With up to four antennae, 802.11n devices can
achieve amazing speeds up to 600 Mbps
 Like 802.11g, 802.11n WAPs run in the 2.4 GHz
band, supporting earlier, slower 802.11b/g devices
 The 802.11n standard also has a more powerful
so-called dual-band capable of supporting
802.11a devices as well as 802.11b/g devices
Standard
802.1 1a
802.11b
802.1 1g
801.1 1n
Max. speed
54 Mbps
11 Mbps
54 Mbps
100+ Mbps
Max. range
150 feet
5 GHz
802.11a
300 feet
24GHz
802.11b
300 feet
2.4 GHz
802.11b,802.11g
300+ feet
2.4 and 5 GHz
802.11b,802.11g.
802.11 n (802.11a
in some cases)
Eight available
channels.
Less prone to
interference than
802.11b and
802.11g.
Fourteen channels
available in the 2.4
GHz band (only 11
of which can be
used in the U.S. due
to FCC regulations).
Improved security
enhancements
Fourteen channels
available in the
2.4GHz band
(only 11 of which
can be used in the
U.S. due to FCC
regulations)
Same as 802.11 g but
adds the 5 GHz band
that 802.11a uses.
Frequency
Compatibility
Description