Development
IEEE 802.15.3a was an attempt to provide a higher speed ultra-
wideband PHY enhancement amendment to IEEE 802.15.3 for
applications which involve imaging and multimedia. IEEE
802.15.3a UWB standardisation attempt failed due to contrast
between WiMedia Alliance and UWB Forum. On January 19,
2006 IEEE 802.15.3a task group (TG3a) members voted to
withdraw the December 2002 project authorization request (PAR)
that initiated the development of high data rate UWB standards.
The IEEE 802.15.3a most commendable achievement was the
consolidation of 23 UWB PHY specifications into two proposals
using : Multi-Band Orthogonal frequency-division multiplexing
(MB-OFDM) UWB, supported by the WiMedia Alliance, and
Direct Sequence - UWB (DS-UWB), supported by the UWB
Forum.
The Wireless USB Promoter Group was formed in February 2004
to define the Wireless USB specification. The group consists of
Agere Systems, Hewlett-Packard, Intel, Microsoft, NEC
Corporation, Philips and Samsung.
In May 2005, the Wireless USB Promoter Group announced the
completion of the Wireless USB specification. The first WUSB
products hit the market at the end of 2005[citation needed]. Companies
like Ellisys and LeCroy are supplying development support tools
to facilitate early introduction of the technology.
In June 2006, USB Implementers Forum (USB-IF) offered the first
five-way, multi-vendor interoperable demonstration of Certified
Wireless USB. A laptop with an Intel host adapter using an
Alereon PHY was used to transfer high definition video from a
Philips wireless semiconductor solution with a Realtek PHY, all
using Microsoft Windows XP drivers developed for Wireless USB.
Specifications
Wireless USB specification does not support the use of hubs.
Although a WUSB host supports the architectural limit of 127
devices, a new Wire Adapter device class has been defined. Also
known as a Host Wire Adapter; it acts as a host for a Wireless USB
system and provides a way to upgrade an existing PC to have
wireless USB. In addition a Device Wire Adapter acts as a host for
a wired USB system which allows wired USB devices to be
connected wirelessly to a host PC.
WUSB also supports so-called dual-role devices, which in addition
to being a WUSB client device, can function as a host with limited
capabilities. For example, a digital camera could act as a client
when connected to a computer, and as a host when transferring
pictures directly to a printer.
Competitors: Certified Wireless USB vs WirelessUSB™
"WirelessUSB" by Cypress Semiconductor is not related to
"Certified Wireless USB".
Cypress's "WirelessUSB" is a protocol that uses the 2.4 GHz ISM
band with a range from 10 meters (at max 1 Mbit/s) to 50 meters
(at max 62.5 kbit/s) and is designed for Human Interface Devices
(HIDs), with current offerings from companies such as Belkin,
Logitech, and Virtual Ink.
Other forms of Wireless USB such as those to be offered on the
competing UWB technology based on Freescale pulse method are
also not approved by the USB SIG or the IEEE. The same is also
true for other RF based Wire replacement systems which can carry
USB. The result is that the name 'Certified Wireless USB' had to
be adopted to allow consumers to identify which products would
be adherent to the standard and would support the correct protocol
and data rates
History
The beginning of wireless started with Guglielmo Marconi as he
began working with radio waves (History of Wireless). In 1896,
Marconi was successful and obtained a patent and established the
Wireless Telegraph and Signal Company, the first radio factory in
the world (History of Wireless). By 1901 the first signals were
being sent across the Atlantic Ocean (History of Wireless). The
military found use for this wireless technology is configured the
wireless signals to send data that was heavily encrypted making it
difficult to be cracked which proved to be especially useful during
World War II for the Army and Navy (History of Wireless). The
first radio telephony network for commercial use was made
available to consumers by the Bell Telephone Company in the
early 1950's. The problem with this network was that only a
limited number of people could be on the network. Eventually this
technology was further developed in order to support more people
and to be more reliable. In 1971, researchers at the University of
Hawaii developed the world‟s first WLAN, or wireless local area
network, it was named ALOHAnet (World of Wireless
Networking). In 1982, AMPS (Advanced Mobile Phone Service)
system specification became the radio telephony standard of the
United States. Other countries also developed cellular networks,
some used the United States standard meanwhile, and others used a
different standard. GSM networks are now the more used cellular
phone networks especially in North America.
Types
Wireless LAN: One type of wireless network is a wireless LAN,
or Local Area Network. Similar to other wireless devices, it uses
radio instead of wires to transmit data back and forth between
computers on the same network as was the case for ALOHNET.
Global System for Mobile Communications (or GSM) is another
type of wireless network. The GSM network is divided into three
major systems which are the switching system, the base station
system, and the operation and support system (Global System for
Mobile Communication (GSM)). The cell phone connects to the
base system station which then connects to the operation and
support station; it then connects to the switching station where the
call is transferred where it needs to go (Global System for Mobile
Communication (GSM)). This is used for cellular phones, is the
most common standard and is used for a majority of cellular
providers.
Personal Communication Service or PCS refers to a radio band
that can be used by mobile phones in North America. Sprint
happened to be the first service to set up a PCS.
D-AMPS, which stands for Digital Advanced Mobile Phone
Service, is an upgraded version of AMPS but it is being phased out
due to advancement in technology. The newer GSM networks are
replacing the older system.
Wi-Fi is a commonly used wireless network in computer systems
which enable connection to the internet or other machines that
have Wi-Fi functionalities. Wi-Fi networks broadcast radio waves
that can be picked up by Wi-Fi receivers that are attached different
computers (How Wi-Fi Works).
Fixed Wireless Data is a type of wireless data network that can be
used to connect two or more buildings together in order to extend
or share the network bandwidth without physically wiring the
buildings together.
Pros and Cons
Wireless networks allow you to eliminate messy cables. Wireless
connections offer more mobility, the downside is there can
sometimes be interference that might block the radio signals from
passing through. One way to avoid this is by putting the source of
your wireless connection in a place that the signal will have as
little interference as possible. Sometimes nearby networks are
using the same frequencies, this can also cause interference within
the network and can reduce its performance.
Compatibility issues also arise when dealing with wireless
networks. Different components not made by the same company
may not work together, or might require extra work to fix
compatibility issues. To avoid this, purchase products made by the
same company so that there are fewer compatibility issues.
Wireless networks, in terms of internet connections, are typically
slower than those that are directly connected through an Ethernet
cable. Though the speed is slower, most things will still move at
the same speed except for things like video downloads. Though
wireless technology continues to develop, it is now easier to get
networks up and running cheaper and faster than ever before.
A wireless network is more vulnerable because anyone can try to
break into a network broadcasting a signal. Many networks offer
WEP - Wired Equivalent Privacy - security systems which have
been found to be vulnerable to intrusion. Though WEP does block
some intruders, the security problems have caused some businesses
to stick with wired networks until security can be improved.
Another type of security for wireless networks is WPA - Wi-Fi
Protected Access. WPA provides more security to wireless
networks than a WEP security set up. The use of firewalls will help
with security breaches which can help to fix security problems in
some wireless networks that are more vulnerable.
Uses
Wireless networks have significantly impacted the world as far
back as World War II. With the use of wireless networks,
information could be sent oversees or behind enemy lines easily
and quickly and was more reliable. Since then wireless networks
have continued to develop and its uses have significantly grown.
Cellular phones are part of huge wireless network systems. People
use these phones daily to communicate with one another. Sending
information over seas is only possible through wireless network
systems using satellites and other signals to communicate across
the world otherwise getting information Emergency services such
as the police department utilize wireless networks to communicate
important information quickly. People and businesses use wireless
networks to send and share data quickly whether it be in a small
office building or across the world.
Companies
There are different companies that provide different wireless
services some are listed below.
1. Cellular Company
• Cingular Wireless, Verizon Wireless, Sprint Nextel, Alltel
Wireless, T-Mobile
2. Wireless Internet Networks
• Verizon Wireless, Sprint Nextel, Cingular
WWAN
WWAN, which stands for Wireless Wide Area Network, is a form
of wireless network.
A WWAN differs from a WLAN (e.g. wireless LAN) because it
uses cellular network technologies such as GPRS / CDMA2000 /
GSM / CDPD / Mobitex/HSDPA to transfer data. These cellular
technologies are offered regionally, nationwide, or even globally
and are provided by a wireless service provider such as: AT&T
Wireless, Cingular Wireless, Sprint PCS or Verizon for a monthly
usage fee.
Various computers now have integrated WWAN capabilities (Such
as HSDPA in Centrino). This means that the system has a cellular
radio (GSM/CDMA) built in, which allows the user to send and
receive data.
There are two basic means that a mobile network may use to
transfer data: Packet-switched Data Networks (GPRS/CDPD) or
Circuit-switched dial-up connections.
The biggest strength of WWANs is security. These networks
incorporate sophisticated encryption and authentication methods,
making them more secure.
Hotspot (Wi-Fi)
From Wikipedia, the free encyclopedia
(Redirected from Wireless campus)
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Hotspots are venues that offer Wi-Fi access. The public can use
their laptop, PDA, or Dual-mode phone to access the Internet. Of
the estimated 150 million laptops, 14 million PDAs, and other
emerging Wi-Fi devices sold per year for the last few years, most
include the Wi-Fi feature.
For venues that have broadband service, offering wireless access is
as simple as purchasing one AP and connecting the AP with the
gateway box. Hotspots are often found at restaurants, train stations,
airports, libraries, coffee shops, bookstores, and other public
places. Many universities and schools have wireless networks in
their campus.
Brief History of Hotspots
WiFi hotspots were first proposed by Brett Stewart at the
NetWorld/InterOp conference in the San Francisco Moscone
Center in August of 1993. Stewart did not use the term 'hotspot' but
referred to public accessible wireless LANs. Stewart went on to
found the companies PLANCOM in 1994 (for Public LAN
Communications, which became MobileStar and then the hotspot
arm of T-Mobile) and subsequently Wayport in 1996.
The term 'HotSpot' may have first been advanced by Nokia about
five years after Stewart first proposed the concept.
During the dotcom boom and subsequent bust in the year 2000,
dozens of companies had the notion that Wi-Fi could become the
payphone for broadband. On June 24, 2004, Ed Sutherland from
Wi-Fi Planet reports, "Hotspots are Dead -- Long Live Hotspots."
The original notion was that users would pay for broadband access
at hotspots. Although some companies like T-mobile, MyHotZone
and Boingo have had some success with charging for access, over
90% of the over 300,000 hotspots offer free service to entice
customers to their venue.
Free hotspots continue to grow. Wireless networks that cover
entire cities, such as Municipal broadband have mushroomed.
MuniWireless reports that over 300 metropolitan projects have
been started.
Many business models have emerged for hotspots. The final
structure of the hotspot marketplace will ulitimately have to
consider the intellectual property rights of the early movers;
portfolios of more than 1000 allowed and pending patent claims
are held by some of these parties.
Wireless security
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Wireless networks are very common, both for organizations and
individuals. Many laptop computers have wireless cards pre-
installed for the buyer. The ability to enter a network while mobile
has great benefits. However, wireless networking has many
security issues. Crackers have found wireless networks relatively
easy to break into, and even use wireless technology to crack into
non-wireless networks. Network administrators must be aware of
these risks, and stay up-to-date on any new risks that arise. Also,
users of wireless equipment must be aware of these risks, so as to
take personal protective measures.
Security Risks
The risks to users of wireless technology have increased
exponentially as the service has become more popular. There were
relatively few dangers when wireless technology was first
introduced. Crackers had not yet had time to latch on to the new
technology and wireless was not commonly found in the work
place. Currently, however; there are a great number of security
risks associated with wireless technology. Some issues are obvious
and some are not. At a corporate level, it is the responsibility of the
IT department to keep up to date with the types of threats and
appropriate counter measures to deploy. Security threats are
growing in the wireless arena. Crackers have learned that there is
much vulnerability in the current wireless protocols, encryption
methods, and in the carelessness and ignorance that exists at the
user and corporate IT level. Cracking methods have become much
more sophisticated and innovative with wireless. Cracking has
become much easier and more accessible with easy-to-use
Windows-based and Linux-based tools being made available on
the web at no charge. IT personnel should be somewhat familiar
with what these tools can do and how to counteract the cracking
that stems from them.
Wireless being used to crack into non-wireless networks
Some organizations that have no wireless access points installed do
not feel that they need to address wireless security concerns. This
is a common deceptive inference. In-Stat MDR and META Group
have estimated that 95% of all corporate laptop computers that will
be purchased in 2005 will be equipped with wireless. Issues can
arise in a supposedly non-wireless organization when a wireless
laptop is plugged into the corporate network. A cracker could sit
out in the parking lot and break in through the wireless card on a
laptop and gain access to the wired network. This problem is
aggravated by what is referred tnts. This can be a major security
risk. If no security measures are implemented at these access
points, it is no different from providing a patch cable out the back
door for crackers to plug into whenever they wish.
Types of unauthorized access to company networks
Accidental Association
Unauthorized access to company wireless and wired networks can
come from a number of different methods and intents. One of these
methods is referred to as “accidental association”. This is when a
user turns on their computer and it latches on to a wireless access
point from a neighboring company‟s overlapping network. The
user may not even know that this has occurred. However, this is a
security breach in that proprietary company information is exposed
and now there could exist a link from one company to the other.
This is especially true if the laptop is also hooked to a wired
network.
Malicious Association
“Malicious associations” are when wireless devices can be actively
made by crackers to connect to a company network through their
cracking laptop instead of a company access point (AP). These
types of laptops are known as “soft APs” and are created when a
cracker runs some software that makes his/her wireless network
card look like a legitimate access point. Once the cracker has
gained access, he/she can steal passwords, launch attacks on the
wired network, or plant trojans. Since wireless networks operate in
the Layer-2 world, Layer-3 protections such as network
authentication and virtual private networks (VPNs) offer no
protection. Wireless 802.1x authentications do help with protection
but are still vulnerable to cracking. The idea behind this type of
attack may not be to break into a VPN or other security measures.
Most likely the cracker is just trying to take over the client at the
Layer-2 level.
Ad-Hoc Networks
Ad-hoc networks can pose a security threat. Ad-hoc networks are
defined as peer to peer networks between wireless computers that
do not have an access point in between them. While these types of
networks usually have little security, encryption methods can be
used to provide security.
Non-Traditional Networks
Non-traditional networks such as personal network Bluetooth
devices are not safe from cracking and should be regarded as a
security risk. Even bar code scanners, handheld PDAs, and
wireless printers and copiers should be secured. These non-
traditional networks can be easily overlooked by IT personnel that
have narrowly focused on laptops and APs.
Identity Theft (MAC Spoofing)
Identity theft (or MAC Spoofing) occurs when a cracker is able to
listen in on network traffic and identify the MAC address of a
computer with network privileges. Most wireless systems allow
some kind of MAC filtering to only allow authorized computers
with specific MAC IDs to gain access and utilize the network.
However, a number of programs exist that have network “sniffing”
capabilities. Combine these programs with other software that
allow a computer to pretend it has any MAC address that the
cracker desires, and the cracker can easily get around that hurdle.
Man-In-The-Middle Attacks
A man-in-the-middle attack is one of the more sophisticated
attacks that have been cleverly thought up by crackers. This attack
revolves around the attacker enticing computers to log into his/her
computer which is set up as a soft AP (Access Point). Once this is
done, the cracker connects to a real access point through another
wireless card offering a steady flow of traffic through the
transparent cracking computer to the real network. The cracker can
then sniff the traffic for user names, passwords, credit card
numbers...etc. One type of man-in-the-middle attack relies on
security faults in challenge and handshake protocols. It is called a
“de-authentication attack”. This attack forces AP-connected
computers to drop their connections and reconnect with the
cracker‟s soft AP. Man-in-the-middle attacks are getting easier to
pull off due to freeware such as LANjack and AirJack automating
multiple steps of the process. What was once done by cutting edge
crackers can now be done by script kiddies, less knowledgeable
and skilled crackers sitting around public and private hotspots.
Hotspots are particularly vulnerable to any attack since there is
little to no security on these networks.
Denial of Service
A Denial-of-Service attack (DoS) occurs when an attacker
continually bombards a targeted AP (Access Point) or network
with bogus requests, premature successful connection messages,
failure messages, and/or other commands. These cause legitimate
users to not be able to get on the network and may even cause the
network to crash. These attacks rely on the abuse of protocols such
as the Extensible Authentication Protocol (EAP).
Network Injection
The final attack to be covered is the network injection attack. A
cracker can make use of access points that are exposed to non-
filtered network traffic. Specifically broadcast network traffic such
as “Spanning Tree” (802.1D), OSPF, RIP, HSRP…etc. The
cracker injects bogus networking re-configuration commands that
affect routers, switches, and intelligent hubs. A whole network can
be brought down in this manner and require rebooting or even
reprogramming of all intelligent networking devices.
Counteracting Risks
Risks from crackers are sure to remain with us for any foreseeable
future. The challenge for IT personnel will be to keep one step
ahead of crackers. Members of the IT field need to keep learning
about the types of attacks and what counter measures are available.
Methods of counteracting security risks
There are many technologies available to counteract wireless
network intrusion, but currently no method is absolutely secure.
The best strategy may be to combine a number of security
measures.
There are three steps to take towards securing a wireless network:
1. All wireless LAN devices need to be secured
2. All users of the wireless network need to be educated in
wireless network security
3. All wireless networks need to be actively monitored for
weaknesses and breaches
MAC ID filtering
Most wireless access points contain some type of MAC ID filtering
that allows the administrator to only permit access to computers
that have wireless functionalities that contain certain MAC IDs.
This can be helpful; however, IT personnel must remember that
MAC IDs over a network can be faked. Cracking utilities such as
SMAC are widely available, and some computer hardware also
gives the option in the BIOS to select any desired MAC ID for its
built in network capability.
Static IP Addressing
Disabling at least the IP assignment function of the network's
DHCP server, with the IP addresses of the various network hosts
then set by hand, will also make it more difficult for a casual or
unsophisticated intruder to log onto the network., especially if the
subnet size is also reduced from one of the standard default
settings to what is absolutely necessary and if permitted but unused
IP addresses are blocked by the access point's firewall. In that case,
where no unused IP addresses are available, a new user can log on
without detection using TCP/IP only if he or she stages a
successful Man in the Middle Attack using appropriate software.
WEP encryption
Main article: Wired Equivalent Privacy
WEP stands for Wired Equivalency Privacy. This encryption
standard was the original encryption standard for wireless. As its
name implies, this standard was intended to make wireless
networks as secure as wired networks. Unfortunately, this never
happened as flaws were quickly discovered and exploited. There
are several open Source utilities like aircrack-ng, weplab,
WEPCrack or airsnort can be used by crackers to break in by
examining packets and looking for patterns in the encryption. WEP
comes in different key sizes. The common key lengths are
currently 128- and 256-bit. The longer the better as it will increase
the difficulty for crackers. However, this type of encryption has
seen its day come and go. In 2005 a group from the FBI held a
demonstration where they used publicly available tools to break a
WEP encrypted network; and it only took three minutes! WEP
protection is better than nothing, though generally not as secure as
the more sophisticated WPA-PSK encryption. The problem is that
if a cracker gets a lock on your network, it is only a matter of time
until the code is cracked.
WPA
Main article: Wi-Fi Protected Access
Wi-Fi Protected Access (WPA) is an early version of the 802.11i
security standard that was developed by the WiFi Alliance to
replace WEP. The TKIP encryption algorithm was developed for
WPA to provide improvements to WEP that could be fielded as
firmware upgrades to existing 802.11 devices. The WPA profile
also provides optional support for the AES-CCMP algorithm that
is the preferred algorithm in 802.11i and WPA2.
WPA Enterprise provides either RADIUS based authentication
using 802.1x. WPA Personal uses a Pre-shared Shared Key (PSK)
to establish the security using an 8 to 63 character passphrase. The
PSK may also be entered as a 64 character hexadecimal string.
Weak PSK passphrases can be broken using an off-line dictionary
attacks by capturing the messages in the four-way exchange when
the client reconnects after being deauthenticated. Wireless suites
such as aircrack-ng can crack a weak passphrase in less than a
minute. WPA Personal is secure when used with „good‟
passphrases or a full 64-character hexadecimal key.
WPA2
Main article: IEEE 802.11i
WPA2 is a WiFi Alliance branded version of the final 802.11i
standard. The primary enhancement over WPA is the inclusion of
the AES-CCMP algorithm as a mandatory feature. Both WPA and
WPA2 support EAP authentication methods using RADIUS
servers and preshared key (PSK) based security.
802.1X
Main article: IEEE 802.1X
This is an IEEE standard for access of wireless and wired LANs. It
provides for authentication and authorization of LAN nodes. This
standard defines the Extensible Authentication Protocol (EAP)
which uses a central authentication server. Unfortunately, during
2002 a Maryland professor discovered some shortcomings.
LEAP
Main article: Lightweight Extensible Authentication Protocol
This stands for the Lightweight Extensible Authentication
Protocol. This protocol is based on 802.1X and helps minimize the
original security flaws by using WEP and a sophisticated key
management system. This also uses MAC address authentication.
LEAP is not safe from crackers. THC-LeapCracker can be used to
break Cisco‟s version of LEAP and be used against computers
connected to an access point in the form of a dictionary attack.
PEAP
Main article: Protected Extensible Authentication Protocol
This stands for Protected Extensible Authentication Protocol. This
protocol allows for a secure transport of data, passwords, and
encryption keys without the need of a certificate server. This was
developed by Cisco, Microsoft, and RSA Security.
TKIP
Main article: TKIP
This stands for Temporal Key Integrity Protocol and the acronym
is pronounced as tee-kip. This is part of the IEEE 802.11i standard.
TKIP implements per-packet key mixing with a re-keying system.
It also provides a message integrity check. These avoid the
problems of WEP.
RADIUS
Main article: RADIUS
This stands for Remote Authentication Dial In User Service. This
is an AAA (authentication, authorization and accounting) protocol
used for remote network access. This service provides an excellent
weapon against crackers. RADIUS was originally proprietary but
was later published under ISOC documents RFC 2138 and RFC
2139. The idea is to have an inside server act as a gatekeeper
through the use of verifying identities through a username and
password that is already pre-determined by the user. A RADIUS
server can also be configured to enforce user policies and
restrictions as well as recording accounting information such as
time connected for billing purposes.
Smart Cards, USB Tokens, & Software Tokens
This is a very high form of security. When combined with some
server software, the hardware or software card or token will use its
internal identity code combined with a user entered PIN to create a
powerful algorithm that will very frequently generate a new
encryption code. The server will be time synced to the card or
token. This is a very secure way to conduct wireless transmissions.
Companies in this area make USB tokens, software tokens, and
smart cards. They even make hardware versions that double as an
employee picture badge. Currently the safest security measures are
the smart cards / USB tokens. However, these are expensive. The
next safest methods are WPA2 or WPA with a RADIUS server.
Any one of the three will provide a good base foundation for
security. The third item on the list is to educate both employees
and contractors on security risks and personal preventive measures.
It is also IT‟s task to keep the company workers' knowledge base
up-to-date on any new dangers that they should be cautious about.
If the employees are educated, there will be a much lower chance
that anyone will accidentally cause a breach in security by not
locking down their laptop or bring in a wide open home access
point to extend their mobile range. Employees need to be made
aware that company laptop security extends to outside of their site
walls as well. This includes places such as coffee houses where
workers can be at their most vulnerable. The last item on the list
deals with 24/7 active defense measures to ensure that the
company network is secure and compliant. This can take the form
of regularly looking at access point, server, and firewall logs to try
and detect any unusual activity. For instance, if any large files
went through an access point in the small hours of the morning, a
serious investigation into the incident would be called for. There
are a number of software and hardware devices that can be used to
supplement the usual logs and usual other safety measures.
Steps in Securing A Wireless Network
The following are some basic steps that should be taken to secure a
wireless network, in order of importance:
1. Turn on encryption. WPA2 encryption should be used
if possible. WPA encryption is the next best alternative,
and WEP is better than nothing.
2. Change the default password needed to access a
wireless device — Default passwords are set by the
manufacturer and are known by crackers. By changing
the password you can prevent crackers from accessing
and changing your network settings.
3. Change the default SSID, or network name — Crackers
know the default names of the different brands of
equipment, and use of a default name suggests that the
network has not been secured. Change it to something
that will make it easier for users to find the correct
network. You may wish to use a name that will not be
associated with the owner in order to avoid being
specifically targeted.
4. Disable File and Print Sharing if you don't need it —
this can limit a cracker's ability to steal data or
commandeer resources in the event that they get past
the encryption.
5. Access points should be arranged to provide radio
coverage only to the desired area if possible. Any
wireless signal that spills outside of the desired area
could provide an opportunity for a cracker to access the
network without entering the premises. Directional
antennas should be used, if possible, at the perimeter
directing their broadcasting inward. Some access points
allow the signal strength to be reduced in order to
minimise such signal leakage.
6. Divide the wired and wireless portions of the network
into different segments, with a firewall in between. This
can prevent a cracker from accessing a wired network
by breaking into the wireless network.
There are some often-recommended security steps that are not
usually of any benefit against experienced crackers (they will
however prevent the larger group of inexperienced users from
gaining access to your network easily, should they find your
password). These are:
Disabling the SSID broadcast option — Theoretically, hiding the
SSID will prevent unauthorised users from finding the network. In
fact, while it will prevent opportunistic users from finding the
network, any serious cracker can simply scan your other network
traffic to find the SSID. It will also make it harder for legitimate
users to connect to the network, since they must know the SSID in
advance and type it in to their equipment. Hiding the SSID will not
prevent anyone from reading the data that is transmitted, only
encryption will do that.
Enabling MAC address filtering — MAC address filtering will
prevent casual users from connecting to your network by
maintaining a list of MAC addresses that are allowed accesss, (or
not) but a serious cracker will simply scan your network traffic to
find a MAC address that is allowed access, then change their
equipment to use that address. Any new equipment will require
another MAC address to be added to the list before it can be
connected. Again, enabling MAC address filtering will not prevent
anyone from reading the data that is transmitted without
encryption.
Wireless sensor network
A wireless sensor network (WSN) is a wireless network
consisting of spatially distributed autonomous devices using
sensors to cooperatively monitor physical or environmental
conditions, such as temperature, sound, vibration, pressure, motion
or pollutants, at different locations.[1][2] The development of
wireless sensor networks was originally motivated by military
applications such as battlefield surveillance. However, wireless
sensor networks are now used in many civilian application areas,
including environment and habitat monitoring, healthcare
applications, home automation, and traffic control.[1][3]
In addition to one or more sensors, each node in a sensor network
is typically equipped with a radio transceiver or other wireless
communications device, a small microcontroller, and an energy
source, usually a battery. The size of a single sensor node can vary
from shoebox-sized nodes down to devices the size of grain of
dust.[1] The cost of sensor nodes is similarly variable, ranging from
hundreds of dollars to a few cents, depending on the size of the
sensor network and the complexity required of individual sensor
nodes.[1] Size and cost constraints on sensor nodes result in
corresponding constraints on resources such as energy, memory,
computational speed and bandwidth.[1]