What is Wi-Fi?
Wi-Fi is a facility which is allowing laptop, computers, smartphones, tablet or many other devices to connect to the Internet or communicate with one another wirelessly within a particular distance.
Wi-Fi or WiFi is a technology for wireless local area networking with devices based on the IEEE 802.11 standards. 802.11 is the "radio frequency" needed to transmit Wi-Fi. Devices that can use Wi-Fi technology include personal
computers, video-game consoles, smartphones, digital cameras, tablet computers, digital audio players and modern printers. Wi-Fi compatible
devices can connect to the Internet via a WLAN network and a wireless access point. Such an access point (or hotspot) has a range of about 20
meters (66 feet) indoors and a greater range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometers achieved by using multiple overlapping access points.
Wi-Fi most commonly uses the 2.4 gigahertz Ultra-High Frequency(UHF) and 5 gigahertz Super High Frequency (SHF) ISM radio bands. Having no physical connections, it is more vulnerable to attack than wired connections, such as Ethernet.
To connect to a Wi-Fi LAN, a computer has to be equipped with a Wireless Network Interface Controller (WNIC). The combination of a computer and interface controller is called a station. For all stations that share a single radio frequency communication channel, transmissions on this channel are received by all stations within range. The transmission is not guaranteed to be delivered
and is, therefore, a best-effort delivery mechanism.
An 802.11 WNIC can operate in two modes known as infrastructure mode and ad hoc mode:
Infrastructure mode :
In an infrastructure mode network, the WNIC needs a wireless access point: all data is transferred using the access point as the central hub. All wireless nodes in an infrastructure mode network connection to an access point. All nodes connecting to the access point must have the same service set identifier (SSID) as the access point, and if a kind of wireless security is enabled on the access point they must share the same keys or other authentication parameters.
Ad hoc mode :
In an ad hoc mode network the WNIC does not require an access point but rather can interface with all other wireless nodes directly. All the nodes in an ad hoc network must have the same channel and SSID.
Routers that incorporate a digital subscriber line modem or a cable modem and a Wi-Fi access point, often set up in homes and other buildings, provide Internet access and internetworking to all devices connected to them, wirelessly or via cable.
Similarly, battery-powered routers may include a cellular Internet radio modem and Wi-Fi access point. When subscribed to a cellular data carrier, they allow nearby Wi-Fi stations to access the Internet over 2G, 3G, or 4G networks using the tethering (phone-as-modem) technique. Many smartphones have a built-in capability of this sort, including those based on Android, BlackBerry, iOS (iPhone) and Windows Phone.
Wireless range-extenders or wireless repeaters can extend the range of an existing wireless network. Strategically placed range-extenders can elongate a signal area or allow for the signal area to reach around barriers such as those pertaining in L-shaped corridors.
An access point compliant with either 802.11b or 802.11g, using the stock antenna might have a range of 100m (330ft). The same radio with an external semi parabolic antenna (15dB gain) might have a range over 20 miles.
Wi-Fi is a facility which is allowing laptop, computers, smartphones, tablet or many other devices to connect to the Internet or communicate with one another wirelessly within a particular distance.
Wi-Fi or WiFi is a technology for wireless local area networking with devices based on the IEEE 802.11 standards. 802.11 is the "radio frequency" needed to transmit Wi-Fi. Devices that can use Wi-Fi technology include personal
computers, video-game consoles, smartphones, digital cameras, tablet computers, digital audio players and modern printers. Wi-Fi compatible
devices can connect to the Internet via a WLAN network and a wireless access point. Such an access point (or hotspot) has a range of about 20
meters (66 feet) indoors and a greater range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometers achieved by using multiple overlapping access points.
Wi-Fi most commonly uses the 2.4 gigahertz Ultra-High Frequency(UHF) and 5 gigahertz Super High Frequency (SHF) ISM radio bands. Having no physical connections, it is more vulnerable to attack than wired connections, such as Ethernet.
To connect to a Wi-Fi LAN, a computer has to be equipped with a Wireless Network Interface Controller (WNIC). The combination of a computer and interface controller is called a station. For all stations that share a single radio frequency communication channel, transmissions on this channel are received by all stations within range. The transmission is not guaranteed to be delivered
and is, therefore, a best-effort delivery mechanism.
An 802.11 WNIC can operate in two modes known as infrastructure mode and ad hoc mode:
Infrastructure mode :
In an infrastructure mode network, the WNIC needs a wireless access point: all data is transferred using the access point as the central hub. All wireless nodes in an infrastructure mode network connection to an access point. All nodes connecting to the access point must have the same service set identifier (SSID) as the access point, and if a kind of wireless security is enabled on the access point they must share the same keys or other authentication parameters.
Ad hoc mode :
In an ad hoc mode network the WNIC does not require an access point but rather can interface with all other wireless nodes directly. All the nodes in an ad hoc network must have the same channel and SSID.
Routers that incorporate a digital subscriber line modem or a cable modem and a Wi-Fi access point, often set up in homes and other buildings, provide Internet access and internetworking to all devices connected to them, wirelessly or via cable.
Similarly, battery-powered routers may include a cellular Internet radio modem and Wi-Fi access point. When subscribed to a cellular data carrier, they allow nearby Wi-Fi stations to access the Internet over 2G, 3G, or 4G networks using the tethering (phone-as-modem) technique. Many smartphones have a built-in capability of this sort, including those based on Android, BlackBerry, iOS (iPhone) and Windows Phone.
Wireless range-extenders or wireless repeaters can extend the range of an existing wireless network. Strategically placed range-extenders can elongate a signal area or allow for the signal area to reach around barriers such as those pertaining in L-shaped corridors.
An access point compliant with either 802.11b or 802.11g, using the stock antenna might have a range of 100m (330ft). The same radio with an external semi parabolic antenna (15dB gain) might have a range over 20 miles.
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