Wireless Networks

Wireless networks
Authors: P. Nicopolitidis, M. S. Obaidat, G. I. Papadimitriou, A. S. Pomportsis
Publisher: John Wiley & Sons
PDF | 422 pages | 3,0mb | English language | ISBN 0470845295

Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or all of the communication path and the network is the totality of switches, transmission links and terminals used for the generation, handling and receiving of telecoms traffic. Wireless networks are rapidly evolving, and are playing an increasing role in the lives of people throughout the world and ever-larger numbers of people are relying on the technology directly or indirectly.

The area of wireless communications is an extremely rich field for research, due to the difficulties posed by the wireless medium and the increasing demand for better and cheaper services. As the wireless market evolves, it is likely to increase in size and possibly integrate with other wireless technologies, in order to offer support for mobile computing applications, of perceived performance equal to those of wired communication networks.
Wireless Networks aims to provide an excellent introductory text covering the wireless technological alternatives offered today. It will include old analog cellular systems, current second generation (2G) systems architectures supporting voice and data transfer and also the upcoming world of third generation mobile networks. Moreover, the book features modern wireless technology topics, such as Wireless Local Loops (WLL), Wireless LANs, Wireless ATM and Personal Area Networks (such as Bluetooth).

Provides an easy to use reference which presents a clear set of technologies per chapter.
Features modern wireless technology topics, such as Wireless Local Loops (WLL), Wireless LANs, Wireless ATM, Personal Area Networks (such as Bluetooth) and Ad-hoc wireless networks. Progresses through the developments of first, second, third, fourth generation cellular systems and beyond. Includes helpful simulation examples and examples of algorithms and systems. Essential reading for Senior undergraduate and graduate students studying computer science, telecommunications and engineering, engineers and researchers in the field of wireless communications and technical managers and consultants.

Provides an easy to use reference which presents a clear set of technologies per chapter. Features modern wireless technology topics, such as Wireless Local Loops (WLL), Wireless LANs, Wireless ATM, Personal Area Networks (such as Bluetooth) and Ad-hoc wireless networks. Progresses through the developments of first, second, third, fourth generation cellular systems and beyond. Includes helpful simulation examples and examples of algorithms and systems. Essential reading for Senior undergraduate and graduate students studying computer science, telecommunications and engineering, engineers and researchers in the field of wireless communications and technical managers and consultants.

More and more people now have a wireless network - a network which is not connected by cables. The data is transferred through the air, by means of radio signals. The advantage is that you can sit on the sofa and use a laptop without the risk of tripping over network cables.

Wireless networks are more vulnerable than ordinary networks. They require extra security, which is why particular attention is devoted to wireless networks on the security pages.

Discovered!
There is a growing group of hobbyists who regularly search for wireless networks. They tour an area with a laptop, scanning for signals from wireless networks. This is known as war-driving, war-walking or war-cycling, depending on the means of transport used. Some people then mark the networks they find; this is known as 'War-chalking'.
There are even websites with maps of areas that have been 'sniffed'. Entire cities are being mapped in this way. War-chalking is not illegal, but penetrating someone's network without permission is.
There are countless tools that can be used to trace a wireless network. These are fairly easy to find and use. Any laptop with a wireless network card and a sniffer program can be used for war-driving.

Risks
Once your wireless network has been discovered, it is very likely to be abused.
For example, people may make free use of your bandwidth while you are paying for the data traffic. Moreover, the data on your network will not be secure if your wireless network is not secured, which means your privacy can easily be infringed. Read about the associated risks, for example in connection with spyware and phishing.
All kinds of other harmful practices also take place. For example, spam may be sent through your connection. Or your network may be used to break into other computers. Fraud may also be committed, such as phishing.

If abuse takes place via your connection, it will not be possible to trace it back any further than your computer. Hence you cannot prove that you yourself are not the culprit. Victims of internet abuse may take legal action, so make sure you are not blamed for other people's misdeeds.

Secure your wireless network
An unprotected wireless network is even more vulnerable than an ordinary network. Prevent abuse being perpetrated on or through your wireless network. Details are given below of how this can be done in two stages.

1. Restrict access to your network
Anyone who wishes to use your network must have your permission. Technical settings can be used to grant or deny access.

In order to establish a connection with a wireless network, a computer must have a wireless network card. Such a network card has its own unique number known as a 'MAC address'. You can set your wireless router in such a way that only computers with a known MAC address can access your network. You enter these addresses manually. The helpdesk pages (NL) show how to secure a Thomson SpeedTouch 580 wireless modem. The left-hand column explains how to find out the MAC address of a card. Make sure you use the address of the wireless card and not the address of another network card.

Only allowing 'known' computers onto your network does not constitute sufficient security. It provides a very thin layer of protection which can easily be circumvented. Because just like ordinary mail, internet traffic operates with an addressee and a sender's address. Each piece of traffic, or data packet, which you send therefore contains your MAC address. In their standard form, your data packets can be read by others. Anyone with a wireless network card in the vicinity of your wireless modem can pick up and read your internet traffic. That is how they find your MAC address.
To gain access to your network, intruders replace their MAC address with yours. They make their laptop appear to be a known computer by spoofing your MAC address. XS4ALL therefore recommends that you encrypt your data.

2. Make your messages unreadable
Encrypt all the data that passes between your computer and your wireless modem by encoding it. This type of security is known as encryption. Only computers which have the correct decryption key can then receive readable packets and send them to your wireless modem. Conversely, your wireless modem can only decrypt packets which have been packed with your unique key. Other traffic will not be processed.
You can choose from two standard ways of encrypting data for wireless networks: the now obsolete WEP (Wired Equivalent Privacy) and the new and more effective WPA (Wi-Fi Protected Access). One of these protocols, or possibly both, will usually be present on your computer and router. You will find them on your computer in the configuration screen, in your wireless network settings.
You enter the WEP or WPA settings yourself. In fact, all you have to do is set your own key. You set this on the router, and on every individual computer you wish to allow to access your wireless network. The key should be the same on all systems. Do not make your key too easy.

If you find all this too complicated, ask for help. The security of your network is worth the effort. If you do not secure your network, it will only be a question of time before someone abuses it.

http://rapidshare.com/files/4865272/wlessnwx.rar

password = www.AvaxHome.ru