Wi-Fi

Wi-Fi is the trade name for the popular wireless technology used in home networks, mobile phones, video games and other electronic devices that require some form of wireless networking capability. In particular, it covers the various IEEE 802.11 technologies (including 802.11a, 802.11b, 802.11g, and 802.11n).

Wi-Fi technologies are supported by nearly every modern personal computer operating system, most advanced game consoles and laptops, and many printers and other peripherals.

Wi-Fi is short for Wireless Fidelity, a wireless connection that allows all your employees in the company to connect wireless LAN and the Internet.

Origin and meaning of the term "Wi-Fi"

The term "Wi-Fi" suggests "Wireless Fidelity", comparing with the long-established audio recording term "High Fidelity" or "Hi-Fi", and "Wireless Fidelity" has often been used in an informal way, even by the Wi-Fi Alliance itself, but officially the term does not mean anything.

"Wi-Fi" was coined by a brand consulting firm called Interbrand Corporation that had been hired by the Alliance to determine a name that was "a little catchier than 'IEEE 802.11b Direct Sequence'."Interbrand invented "Wi-Fi" as simply a play-on-words with "Hi-Fi", as well as creating the yin yang style Wi-Fi logo.

The Wi-Fi Alliance initially complicated matters by stating that it actually stood for "Wireless Fidelity", as with the advertising slogan "The Standard for Wireless Fidelity",but later removed the phrase from their marketing. The Wi-Fi Alliance's early White Papers still held in their knowledge base: "… a promising market for wireless fidelity (Wi-Fi) network equipment." and "A Short History of WLANs." The yin yang logo indicates that a product had been certified for interoperability.

The Alliance has since downplayed the connection to "Hi-Fi". Their official position is that it is merely a brand name that stands for nothing in particular, and they now discourage the use of the term "Wireless Fidelity".

The Benefits and Challenges of Wi-Fi

Mobility

Wi-Fi offers increased mobility. Among employees who use a laptop will no longer have to worry about connecting their power cable. They will move their offices to the meeting room without losing their connection to the corporate network and Internet.

Ease of Use

For your employees and visitors allowed to log in Wi-Fi has no technical difficulty. Just enter a WEP key or WAP associated with your Wi-Fi base after double-clicking the icon 'Wireless Network Connection. After a short search during which the message "read the network address" appears, the computer connects to the network. The computer keeps the connection settings, just as Wi-Fi is activated once the computer recognizes the Wi-Fi signal and automatically logs the following times.

Low cost

The installation of a Wi-Fi costs less than a cable network for a business, it takes subtract from the budget the cables and connectors networks.For equipment, an access point plus a wireless card and computer peripheral enough. No software is required, a simple operating system is sufficient.

Limitations

Spectrum assignments and operational limitations are not consistent worldwide. Most of Europe allows for an additional 2 channels beyond those permitted in the U.S. for the 2.4 GHz band. (1–13 vs. 1–11); Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect. A very confusing aspect is the fact that a Wi-Fi signal actually occupies five channels in the 2.4 GHz band resulting in only three non-overlapped channels in the U.S.: 1, 6, 11, and three or four in Europe: 1, 5, 9, 13 can be used if all the equipment on a specific area can be guaranteed not to use 802.11b at all, even as fallback or beacon. Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm (100 MW).


Designing a Wi-Fi

Above all, do it on your needs:

How many users, for what purpose, what rate necessary (to be determined by the number of devices connected)?

To design a Wi-Fi network, you need:

• An access point (Access Point): modem, router box or ISP
  
  This is equivalent to a hub or a switch to a cable network. Although Wi-Fi may be the only mode of connection in your company it is often a connection mode complementary to wired network, which often precedes in time.
  The access point provides access to both LAN and the Internet. Today, the majority of modems and box provided by ISPs has Wi-Fi antennas Beyond 20 people, a second access point is recommended (router).
  
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  Every computer and device (PDA, printers, telephones ...) must be equipped with a Wi-Fi to connect to the access point. Today, most mobile computers and fixed a Wi-Fi.
  
  To obtain the necessary equipment to your Wi-Fi, it is your ISP for a small Wi-Fi or specialty shops in the Wi-Fi network for a more important. This applies to MhzShop and WifiSafe. Netgear is one of the best-known brands of modems and routers.

The Risks in Wi-Fi

The nature of the Wi-Fi waves spread outside the walls of your business. If your network is not secure, it presents several risks:

• Intrusion of an unauthorized person on your network
• Privacy: perte the confidentiality of information circulating on your network
• deterioration attacks and damage your company's network

It is therefore essential to prevent access to your network to anyone who does not have authorization and limit the level of user access to prohibit any modification that could turn off your server.

Securing its Wi-Fi

Threats to security

The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2), which began shipping in 2003, aims to solve this problem and is now available on most products. Wi-Fi Access Points typically default to an "open" (encryption-free) mode. Novice users benefit from a zero-configuration device that works out of the box, but this default is without any wireless security enabled, providing open wireless access to their LAN. To turn security on requires the user to configure the device, usually via a software graphical user interface (GUI). Wi-Fi networks that are open (unencrypted) can be monitored and used to read and copy data (including personal information) transmitted over the network, unless another security method is used to secure the data, such as a VPN or a secure web page.

What you should know:

To avoid any intrusion or malicious act must:

• Identify users connected
• Secure data exchange network via Wi-Fi in encrypting data
• Ensure that all devices are secure

How:

The new wireless tools generally offer all the guarantees to prevent intrusions into the network of your business.
When you want to connect to a wireless network, you must enter codes WEP or WAP, attributed to each access point.These codes consist of a suite of 13 to 26 characters, numbers and letters.

More on How to make Wi-Fi secure

Hardware

Standard devices:

A wireless access point (WAP) connects a group of wireless devices to an adjacent wired LAN. An access point is similar to a network hub, relaying data between connected wireless devices in addition to a (usually) single connected wired device, most often an ethernet hub or switch, allowing wireless devices to communicate with other wired devices.

Wireless adapters allow devices to connect to a wireless network. These adapters connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC card. Most newer laptop computers are equipped with internal adapters. Internal cards are generally more difficult to install.

Wireless routers integrate a Wireless Access Point, ethernet switch, and internal Router firmware application that provides IP Routing, NAT, and DNS forwarding through an integrated WAN interface. A wireless router allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem. A wireless router allows all three devices (mainly the access point and router) to be configured through one central utility. This utility is most usually an integrated web server which serves web pages to wired and wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple's AirPort.

Wireless network bridges connect a wired network to a wireless network. This is different from an access point in the sense that an access point connects wireless devices to a wired network at the data-link layer. Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes.

Wireless range extenders or wireless repeaters can extend the range of an existing wireless network. Range extenders can be strategically placed to elongate a signal area or allow for the signal area to reach around barriers such as those created in L-shaped corridors. Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a wireless device connected to any of the repeaters in the chain will have a throughput that is limited by the weakest link between the two nodes in the chain from which the connection originates to where the connection ends.

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An embedded RouterBoard 112 with U.FL-RSMA pigtail and R52 mini PCI Wi-Fi card

Distance records

Distance records (using non-standard devices) include 382 km (237 mi) in June 2007, held by Ermanno Pietrosemoli and EsLaRed of Venezuela, transferring about 3 MB of data between mountain tops of El Aguila and Platillon.The Swedish Space Agency transferred data 310 km (193 mi), using 6 watt amplifiers to reach an overhead stratospheric balloon.

Embedded systems

Wi-Fi availability in the home is on the increase.This extension of the Internet into the home space will increasingly be used for remote monitoring.Examples of remote monitoring include security systems and tele-medicine. In all these kinds of implementation, if the Wi-Fi provision is provided using a system running one of operating systems mentioned above, then it becomes unfeasible due to weight, power consumption and cost issues.

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Embedded serial-to-Wi-Fi module

Increasingly in the last few years (particularly as of early 2007), embedded Wi-Fi modules have become available which come with a real-time operating system and provide a simple means of wireless enabling any device which has and communicates via a serial port.This allows simple monitoring devices – for example, a portable ECG monitor hooked up to a patient in their home – to be created. This Wi-Fi enabled device effectively becomes part of the internet cloud and can communicate with any other node on the internet. The data collected can hop via the home's Wi-Fi access point to anywhere on the internet.These Wi-Fi modules are designed so that designers need minimal Wi-Fi knowledge to wireless-enable their products.