In this chapter you will learn how to: Describe the basics of wireless networking
Explain the differences between wireless networking standards
Configure wireless networks
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 Basics
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 Networking Components
Wireless NICs aren't limited to PCs Smartphones can have built-in wireless
Wireless Networking Components
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
Wireless Networking Components
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
Wireless Networking Software
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
Wireless Network Modes
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 con trol over the wireless network
To connect wire lessly to another network, such as the Internet, you need to use infrastructure mode
Wireless Network Modes
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 Networking Security
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
Wireless Networking Security
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
SSID and Administrator Password
SSID and Administrator Password
http://www.phenoelit-us.org/dpl/dpl.html
How secure are default passwords?
Wired Equivalent Privacy (WEP) encryption was meant to secure data being wirelessly transmitted. WEP encryp tion 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 noth ing, but only stops casual prying into a network
Encryption
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
Encryption
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
Encryption
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 effec tive range, speed may decrease to around 1 Mbps before it drops out altogether
Wireless Networking Speed
Speed can also be affected by interference from other wireless devices operating in same frequency range
Cordless phones Baby moni tors Microwave Ovens Solid objects
Deadspots occur when something capable of blocking the radio signal comes between wireless network nodes
Electrical appli ances are very effective at blocking wire less network signals
Other culprits include electrical fuse boxes, metal plumbing, and air conditioning units
Wireless Networking Speed
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
Wireless Networking Range
Standards for Wireless are based on the 802.11 and Bluetooth Standards The IEEE 802.11wireless Ethernet standard defines
methods by which devices can com municate 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
Wireless Networking Standards
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
Wireless Networking Standards
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
Standards
802.11b was the first widely accepted standard in wireless networking 802.11b supports data throughput of up to
11Mbs and maxi mum 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
Standards
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
Standards
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
Standards
Standard
Max. speed
802.1 1a 54 Mbps
802.11b 11 Mbps
802.1 1g 54 Mbps
801.1 1n
100+ Mbps
Max. range 150 feet 300 feet 300 feet 300+ feetFrequency 5 GHz 24GHz 2.4 GHz 2.4 and 5 GHzCompatibility 802.11a 802.11b 802.11b,802.11g 802.11b,802.11g.
802.11 n (802.11a in some cases)
Description Eight available channels. Less prone to interference than802.11b and802.11g.
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.
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