A recent Reuters press release has confirmed that after several years, the IEEE has finally approved the 802.11n wireless LAN standard.

802.11n is capable of delivering throughput speeds up to 300Mbps much higher than the already-ratified 802.11g standard, with speeds at only 54Mbps, as there is a substantial speed difference most wireless manufacturers have been offering 802.11n based products (also known as Wireless-N) during the past six years and calling them Draft N products.

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How a wireless network works

A wireless local area network (WLAN) links two or more computers with Network Interface Cards (NICs) through a technology based on radio waves. All devices that can connect to a wireless network are known as stations. Stations can be access points (APs), or clients.

Access points are base stations for the wireless network. They receive and transmit information for the clients to communicate with.

The topology of a wireless network defines how the wireless devices interact with each other, two basic structures exist

• Ad hoc

Mainly used by home users, an Ad hoc topology consists of two or more wireless devices which directly connect to each other In the same range called a basic service area (BSA) creating a basic service set (BSS). Every BSS has an Identification known as a BSSID, also known as the MAC address, which is a unique identifier that is associated with every NIC.

The following diagram illustrates an Ad hoc network

• Infrastructure

This uses an access point, a small unit which acts as a transparent bridge between wireless devices and a standard cabled network, increasing the cabled LAN to include wireless devices. Wireless devices communicate only with the access point and not with each other directly.

All the wireless equipment (access point and client computers) must be configured with the same SERVICE SET IDENTIFIER (SSID) this is a word used to identify the wireless network. The wireless access point will automatically broadcast the SSID to any computers using the correct channel to communicate. The following diagram is an example of the Infrastructure topolog

For any client to join a WLAN, it must know the SSID of the WLAN; therefore, the access points typically broadcast their SSID to let the clients know that an AP is in range.

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