Neon-komputadór

Wireless Ethernet

A relatively new standard established by the Institute of Electrical and Electronic Engineers (IEEE), known as IEEE 802.11b, has been introduced and is supported by a group called the Wireless Ethernet Compatibility Alliance (WECA). These networks operate at a maximum speed of 11mbps, slightly more than Ethernet, but only about 1/10th of Fast Ethernet and 1/100th of the speed of Gigabyte Ethernet. Wireless Ethernet has a high level of interoperability - just like the normal wired Ethernet. Operating at the 2.4ghz range they share the same spectrum as many security devices, portable 'phones and so forth and these may, in sufficient density, affect the performance of the Wireless Ethernet. Within a relatively short distance (100 metre radius) however it is highly improbable that there would ever be any signal loss.

A Wireless Ethernet consists of two major devices. First is an Access Point or AP. a large brick sized device that has a RJ-45 port to optionally connect to an existing conventional Ethernet network (or hub or switch) and a radio transceiver, and inbuilt encryption and communications software. The other device is a NIC which has been specially adapted for wireless communication, with a fixed or detachable antenna. The client machine "lock on" to the strongest signal and automatically go into "roam" mode to switch to a different AP if that AP has a stronger signal strength and less errors. The effective number of users per access point varies with the model used with the low-cost Cisco Aironet340 providing support for 10 users and with other models providing access for up to 2,048 users.

Whilst Wireless Ethernet has previously been developed according to a star network typology like the standard Ethernet there are line-of-sight issues present in this typology. A new network typology for wireless, called mesh typology allows the router to communicate in all other nodes thus creating a multi-hop routed cloud, which is self-healing, load-balancing and scalable (up to 100 nodes in some instances) and the potential to route around major physical obstacles such as multi-story buildings, hills and the like.

Wireless Ethernet is undoubtedly most useful for laptop computers although there is no reason why they cannot be just as easily used for desktop computers, although the cost of wireless NICs is more expensive and Access Points aren't exactly cheap either. In most circumstances given the significant reduction in bandwidth and the additional cost of Access Points and NICs, wireless networking isn't yet a cost-effective option. But there are exceptions - and East Timor's geography is indeed possibly one of them - where the difficulty of wiring means that Wireless is the best option.

This is a rapidly developing technology and significant attention should be paid to it. There are other wireless standards, but Wireless Ethernet seems destined to be the most successful. One worthy of note however is Bluetooth. Whilst relatively slow (up to 400kbps) this standard is used over short distances connect notebooks, PDA, mobile phones and so forth as well as providing security identification.