Wireless Networking

Wireless Networking

This topic will present basic information about wireless networking which are technology, configuration, scanning, authentication, and antenna type.

Until today, wireless network technology has 4 standards which can be seen on the table below

type	802.11a	802.11b	802.11g	802.11n
throughput	up to 54 mbps	up to 11 mbps	up to 54 mbps	up to 540 mbps
frequency	5Ghz	2.4 GHz	2.4 GHz	5 GHz or 2.4 GHz

There are 2 wireless network configuration which are BSS and IBSS.
Basic Service Set (BSS) is the most common configuration where a Wireless AP communicates with its host such as PCs. To be able to recognize the AP, the client searches for access points and uses the Service Set Identifier (SSID) which is basically a case sensitive name up to 32 character. The SSID can be set in the AP to be seen public or to be hidden.
Independent Basic Service Set (IBSS) is the second configuration where the clients communicate with each other independently or peer-to-peer. This type of configuration does not need an AP.

In order for the PC to be able to communicate to the AP, a method called Scanning must be used. There are 2 types of scanning which are active and passive.
In active scanning, the client makes the initiative and sends Probe requests, asking APs to send Probe Responses and waits for the Probe Response.
In passive scanning, the client hears and waits for Probe Responses from the AP.
If there are more than 1 Probe Responses found, the user can choose which one it wants to use.

Authentication is also needed for network security purposes. It will do this after it hears the Probe Response and the selected network is chosen by the user. There are several authentications. The first one is "Open," where everyone can access the network. The second one is "Shared Key"where only users that know the key can access the network (WEP, EAP, WPA and WPA2).

The antenna type for AP consists of several types. A point-to-point antenna is an antenna that has a very small beam and is usually used to create a point-to-point connection with another AP. A directional antenna has a limited coverage for serving only specific areas of customer. An omni-directional antenna is an antenna that has coverage to every direction and is used to serve all customers near the AP. However, the radius length of the coverage is more limited than point-to-point connection for the same power.

-- 26 November 2010 --