What is difference between Point to Point and Point to Multipoint wirelss connections?

Point to point describes applications such as connecting two buildings together this is also the scenario described when the term bridging is used. Point to multipoint describes an application where a central point connects to a lot of other points (a single building connecting to multiple buildings, or even multiple clients connecting to the same access point)

Aren’t Wireless LANs insecure?

Saying a wireless LAN is insecure is like complaining a car, with central locking, an immobiliser and alarm is insecure when it is unlocked. All Wireless Access points support some degree of security, most people do not turn this security on, and as such Wireless technology was perceived as being insecure.

Some of the common security steps include: -

Physical Security: By using appropriate antennas it is possible to restrict the propagation of the radio waves as needed. So if a link is to be based in a building, using a patch antenna attached to the wall will severely restrict the amount of radio waves that propagate through that wall and so the ability to pick up this information. Failure to address physical security could be likened to hanging a network cable out of a window.

MAC Layer security: The 802.11 standard specifies two main technologies to secure the MAC layer of the wireless network.

WEP: Wired Equivalent Privacy uses keys to encrypt the data that is being transmitted, without the appropriate key the data is unreadable to anyone receiving the data. WEP is a “crackable” standard, this means that using appropriate software, and a few days of monitoring the wireless network it is possible to gain the key and therefore decrypt the data.

WPA: WiFi Protected Access has been introduced by the WiFi alliance in order to provide increased security until the 802.11 standard ratifies a more secure method than WEP, it once again uses keys to encrypt the data being transmitted, but in this case the keys are constantly changed to prevent them from being recovered using software. WPA is currently regarded as “uncrackable”.

VPN: Virtual Private Networks are a technology that is used to allow secure communications across public networks (primarily the Internet). These same technologies can also be used to secure data being transmitted across wireless mediums. Once again these devices encrypt data so that without the correct keys the data is unreadable, there are various technologies used including DES, 3DES and AES. The American Military regard 3DES (pronounced triple DES) as secure.

Using a combination of these technologies it is possible to restrict how can pick up your signal, when they have intercepted it they have to decrypt the MAC layer, and once this has been completed they have to decrypt the VPN layer, this level of security far exceeds the security used on cabled systems and makes other means of gathering the information (such as staff corruption) much more attractive and likely.

What is WiFi? is it the same as 802.11?

The Wireless devices that most people refer to as WiFi are in fact devices based on the 802.11 set of standards. The 802.11 standard was defined by the IEEE in order to allow different vendors to communicate using Radio Waves (though a form of InfraRed communication is also defined in this standard). The WiFi alliance was set up in order to test various vendors equipment for interoperability, 802.11 is the standard, WiFi proves that it has been tested for interoperability with other vendors equipment.