Wi-Fi or WiFi ( ) is a technology for wireless area radio network devices based on IEEE 802.11 standards. Wi-Fi is a trademark of the Wi-Fi Alliance, which limits the use of the term Wi-Fi Certified for products that successfully complete interoperability certification testing.
Devices that can use Wi-Fi technology include personal computers, video-game consoles, smartphones and tablets, digital cameras, smart TVs, digital audio players and modern printers. Wi-Fi compatible devices can connect to the Internet through WLAN and wireless access points. Such access points (or hotspots) have a range of about 20 meters (66 feet) in the room and a larger range outdoors. Hotspot coverage can be as small as a single space with a wall blocking radio waves, or a large area of ​​square kilometers that is achieved by using multiple overlapping access points.
Wi-Fi most commonly uses 2.4 gigahertz (12 cm) UHF and 5.8 gigahertz (5 cm) SHF ISM radio bands, these bands are divided into multiple channels. Each channel can be shared by multiple networks. This wavelength is best suited for line of sight. Many common ingredients absorb or reflect, which further limit the range, but may tend to help minimize interference between different networks in dense environments. At close range, multiple versions of Wi-Fi, running on the appropriate hardware can reach speeds in excess of 1 Gbps.
Anyone within range with a wireless network interface controller can try to access the network; Because of this, Wi-Fi is more vulnerable to attacks (called eavesdropping) than wired networks. Wi-Fi Protected Access is a technology family created to protect mobile information across Wi-Fi networks and includes solutions for private and corporate networks. The security features of Protected Wi-Fi Access have included stronger protections and new security practices as security landscape changes over time.
Video Wi-Fi
Histori
In 1971, ALOHAnet connected the Hawaiian Islands with the UHF wireless packet network. ALOHAnet and ALOHA protocols are the early pioneers for Ethernet, and then the IEEE 802.11 protocol, respectively.
A decision in 1985 by the U.S. Federal Communications Commission. released ISM band for unlicensed use. These frequency bands are the same ones used by appliances such as microwave ovens and may be subject to interference.
In 1991, NCR Corporation with AT & amp; T Corporation invented the predecessor to 802.11, which is intended for use in cashier systems, under the name WaveLAN.
Australian radio astronomer Dr John O'Sullivan along with his colleagues Terence Percival, Graham Daniels, Diet Ostry, and John Deane developed the key patents used in Wi-Fi as a by-product of the Commonwealth Scientific and Industrial Research (CSIRO) Research Project, "experiment failed to detect burst mini black hole size of atomic particles". Dr O'Sullivan and his colleagues are credited with creating Wi-Fi. In 1992 and 1996, CSIRO obtained a patent for a method which was later used in Wi-Fi to "not detect" the signal.
The first version of the 802.11 protocol was released in 1997, and provides up to 2 Mbit/s link speeds. It was updated in 1999 with 802.11b to allow 11 Mbit/s link speed, and this proved to be popular.
In 1999, the Wi-Fi Alliance formed as a trade association to hold Wi-Fi trademarks where most products are sold.
Wi-Fi uses a large number of patents held by many different organizations. In April 2009, 14 technology companies agreed to pay CSIRO $ 1 billion for CSIRO patent infringement. This led Australia to label Wi-Fi as an Australian discovery, although this has been the subject of some controversy. CSIRO won a further $ 220 million settlement for a Wi-Fi patent infringement in 2012 with a global company in the United States that is required to pay CSIRO licenses estimated to be worth an extra $ 1 billion in royalties. In 2016, wireless local area network Test Bed was selected as Australia's contribution to the A History of the World in 100 Objects exhibition held at the National Museum of Australia.
Etymology
The name Wi-Fi , used commercially at least in early August 1999, was created by the Interbrand brand consulting firm. The Wi-Fi Alliance has hired Interbrand to create a name that's "a bit more interesting than 'IEEE 802.11b Direct Sequence'." Phil Belanger, founding member of the Wi-Fi Alliance leading the "Wi-Fi" election, has stated that Interbrand found Wi-Fi as a hi-fi word syllable.
Interbrand also makes Wi-Fi logos. The yin-Wi-Fi logo that demonstrates a product certification for interoperability.
The Wi-Fi Alliance uses the nonsense advertising slogan "The Standard for Wireless Fidelity" for a short time after the brand name was created. However, his name was never officially "Wireless Fidelity". However, the Wi-Fi Alliance is also called "Wireless Fidelity Alliance Inc" in several publications and the IEEE website itself has stated "WiFi is the short name for Wireless Fidelity".
Non-Wi-Fi technologies intended for fixed points, such as Motorola Canopy, are usually described as fixed wireless. Alternative wireless technologies include standard phones, such as 2G, 3G, 4G, and LTE.
This name is sometimes written as WiFi , Wifi , or wifi , but this is not approved by the Wi-Fi Alliance.
Wi-Fi ad-hoc mode
Wi-Fi nodes operating in ad-hoc mode refer to devices that talk directly to each other without first talking to the access point (also known as base station). The ad-hoc mode was first discovered and realized by Chai K. Toh in 1996 of the invention of Wi-Fi ad-hoc routing, implemented on Lucent WaveLAN 802.11a wireless on IBM ThinkPads over a node-size scenario covering more than a mile. The success was recorded at Mobile Computing magazine (1999) and was subsequently published officially in the IEEE Transactions on Wireless Communications , 2002 and ACM SIGMETRICS Performance Evaluation Review , 2001.
Maps Wi-Fi
Wi-Fi certification
IEEE does not test equipment to meet their standards. The nonprofit Wi-Fi alliance was formed in 1999 to fill this void - to establish and enforce standards for interoperability and backward compatibility, and to promote wireless local area network technologies. In 2010, the Wi-Fi Alliance comprised more than 375 companies from around the world. The Wi-Fi Alliance enforces the use of Wi-Fi brands for technologies based on IEEE 802.11 standards from the IEEE. These include local area network (WLAN) connections, devices for device connectivity (such as Wi-Fi Peer to Peer aka Wi-Fi Direct), private area network (PAN), local area network (LAN) and even limited limited area connections network (WAN). Manufacturers with membership in the Wi-Fi Alliance, whose products pass the certification process, get the rights to mark the product with a Wi-Fi logo.
Specifically, the certification process requires compliance with IEEE 802.11 radio standards, WPA and WPA2 security standards, and EAP authentication standards. Certification can optionally include IEEE 802.11 design standard testing, interaction with mobile phone technology in converged devices, and features related to security, multimedia, and power saving settings.
Not every Wi-Fi device is shipped for certification. The lack of Wi-Fi certification does not necessarily mean that the device is not compatible with other Wi-Fi devices. The Wi-Fi Alliance may or may not provide sanction of derivative terms, such as Super Wi-Fi, created by the US Federal Communications Commission (FCC) to describe the proposed network in the UHF TV band in the US.
Terminology
To connect to a Wi-Fi LAN, the computer must be equipped with a wireless network interface controller. The combination of computers and interface controllers is called station . For all stations that share a single radio frequency communication channel, the transmission on this channel is received by all stations within range. Transmission is not guaranteed to be shipped and is therefore the best delivery mechanism. A carrier wave is used to transmit data. Data is arranged in packets on Ethernet links, called "Ethernet frames".
A set of services is the set of all devices associated with a particular Wi-Fi network. Services may be local, independent, extended or mesh.
Each service set has a corresponding identifier, a 32-byte Service Set Identifier (SSID), that identifies a particular network. The SSID is configured in devices that are considered part of the network, and delivered in packets. Receiver ignores wireless packets from network with different SSID.
Usage
Internet access
Wi-Fi technology can be used to provide Internet access to devices that are within range of a wireless network connected to the Internet. The coverage of one or more interconnected access points ( hotspots ) can be extended from as small as a few rooms up to an area of ​​many square kilometers. Coverage in a larger area may require a group of access points with overlapping coverage. For example, outdoor public Wi-Fi technology has been successfully used in wireless mesh networks in London, England. An international example is Fon.
Wi-Fi provides services in private homes, businesses, and public spaces in Wi-Fi hotspots that are set up either free of charge or commercially, often using captive portal web pages for access. Organizations and businesses, such as airports, hotels, and restaurants, often provide free hotspots to attract customers. Fans or authorities who want to provide services or even to promote business in certain areas sometimes provide free Wi-Fi access.
Routers that combine digital subscriber line modems or cable modems and Wi-Fi access points, often installed in homes and other buildings, provide Internet access and internetworking to all connected devices, wirelessly or via cable.
Similarly, battery-powered routers may include mobile internet radio modems and Wi-Fi access points. When subscribing to a mobile data carrier, they allow nearby Wi-Fi stations to access the Internet via 2G, 3G or 4G networks using withdrawal techniques. Many smartphones have this kind of built-in capabilities, including Android, BlackBerry, Bada, iOS (iPhone), Windows Phone and Symbian, though operators often disable the feature, or charge a separate fee to enable it, especially for customers with unlimited data plan. "Internet packages" provide independent facilities of this type as well, without the use of smartphones; examples include MiFi- and WiBro-branded devices. Some laptops that have cellular modem cards can also act as Wi-Fi Internet access points.
Wi-Fi also connects places that normally do not have network access, such as kitchens and garden sheds.
Google intends to use this technology to allow rural areas to enjoy connectivity by leveraging the extensive mix of projection and routing services. Google also intends to bring connectivity to Africa and some parts of Asia by launching a hot air balloon that will allow internet connection with Wi-Fi technology.
Wi-Fi all over the city
In the early 2000s, many cities around the world announced plans to build Wi-Fi networks across the city. There are many successful examples; in 2004, Mysore (Mysuru) became the first active Wi-Fi city in India. A company called WiFiyNet has set up a hotspot in Mysore, which includes the complete city and several nearby villages.
In 2005, St. Cloud, Florida, and Sunnyvale, California, became the first city in the United States to offer free Wi-Fi across the city (from MetroFi). Minneapolis has generated $ 1.2 million in profit each year for its providers.
In May 2010, London mayor Boris Johnson pledged to have London-wide Wi-Fi in 2012. Some areas including Westminster and Islington already have extensive outdoor Wi-Fi coverage at the time.
Officials in the South Korean capital of Seoul are moving to provide free Internet access in over 10,000 locations around the city, including outdoor public spaces, main roads and densely populated residential areas. Seoul will provide rental to KT, LG Telecom and SK Telecom. The company will invest $ 44 million in the project, which will be completed by 2015.
Wi-Fi wide campus
Many traditional university campuses in developed countries provide at least some Wi-Fi coverage. Carnegie Mellon University built the first wireless Internet network across the campus, named Wireless Andrew, on its campus in Pittsburgh in 1993 before Wi-Fi branding originated. In February 1997 the CMU Wi-Fi zone was fully operational. Many universities collaborate on providing Wi-Fi access to students and staff through Eduroam's international authentication infrastructure.
Wi-Fi ad hoc versus Wi-Fi instantly
Wi-Fi also allows direct communication from one computer to another without an access point intermediary. This is called an ad hoc Wi-Fi transmission. This wireless ad hoc network mode has proven popular with multi-player gaming consoles, such as Nintendo DS, PlayStation Portable, digital cameras, and other consumer electronics devices. Some devices can also share their Internet connection using ad hoc, become a hotspot or "virtual router".
Similarly, the Wi-Fi Alliance promotes Wi-Fi Direct specifications for file transfer and media sharing through new discovery-and security methodologies. Wi-Fi Direct was launched in October 2010.
Another direct mode of communication over Wi-Fi is the Tunneled Direct Link Setup (TDLS), which allows two devices on the same Wi-Fi network to communicate directly instead of the access point.
Wi-Fi radio spectrum
802.11b and 802.11g using the 2.4 GHz ISM band, operating in the United States under Section 15 of the Regulations and Regulations. Because of these frequency band options, 802.11b and g equipment can sometimes be interfered with microwave ovens, cordless phones, and Bluetooth devices.
Spectrum assignments and operational limitations are not consistent across the world: Australia and Europe allow for two additional channels (12, 13) beyond the 11 allowed in the United States for the 2.4 GHz band, while Japan has three more (12-14). In the US and other countries, 802.11a and 802.11g devices may operate without a license, as permitted under Section 15 of FCC Rules and Regulations.
Wi-Fi signal occupies five channels in the 2.4 GHz band. Any two different five channel numbers, like 2 and 7, do not overlap. The saying is often repeated that channels 1, 6, and 11 are only non-overlapping channels, therefore, are not accurate. Channels 1, 6, and 11 are the only non-overlapping three groups in North America and the United Kingdom. In Europe and Japan using Channels 1, 5, 9, and 13 for 802.11g and 802.11n are recommended.
802.11a uses the 5 GHz U-NII band, which, for most of the world, offers at least 23 non-overlapping channels rather than the 2.4 GHz ISM frequency band, where adjacent channels overlap.
Interference
Wi-Fi connection may be disrupted or internet speed is lowered by having other devices in the same area. The Wi-Fi protocol is designed to divide the channels fairly, and will work with little or no interruption. However, many 2.4-GHz 802.11b and 802.11g access-default points to the same channel on initial startup, contributing to congestion on certain channels. Wi-Fi contamination, or the excessive number of access points in the area, may prevent access and interfere with other devices from other access points and with a decrease in signal-to-voice (SNR) ratio between access points. In addition, interference can be caused by overlapping channels in the 802.11g/b spectrum. These problems can be problematic in areas with high density, such as large apartment complexes or office buildings with multiple Wi-Fi access points.
In addition, other devices use 2.4 GHz bands: microwave ovens, ISM tape devices, security cameras, ZigBee devices, Bluetooth devices, video senders, cordless phones, baby monitors, and, in some countries, amateur radios, all of which can causing significant additional disruption. This is also a problem when cities or other large entities (such as universities) seek to provide wide area coverage.
These bands are allowed for use with low power transmitters, without the need for licenses and with some restrictions. However, while unintentional disturbance is common, users who are consciously found to cause intentional interruptions to other users, especially to try to monopolize these bands locally for commercial purposes, have been given a large fine.
Communication protocol
The IEEE 802.11 standard is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) communications in the 2.4, 3.6, 5, and 60 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee (IEEE 802). The basic version of the standard was released in 1997, and has undergone subsequent amendments. Standards and amendments provide the basis for wireless network products using the Wi-Fi brand. While each amendment was officially revoked when incorporated in the latest version of the standard, the business world tends to market to revisions because it briefly demonstrates the capabilities of their products. As a result, in the market, each revision tends to be its own standard.
Range and speed
Wi-Fi operational coverage depends on factors such as frequency band, radio power output, receiver sensitivity, antenna gain and antenna type and modulation techniques. In addition, the signal propagation characteristics can have a major impact.
At greater distances, and with greater signal absorption, speed is usually reduced.
Transmitter power
Compared to mobile phones and similar technologies, Wi-Fi transmitters are low-power devices. In general, the maximum amount of power that Wi-Fi devices can transmit is limited by local regulations, such as FCC Part 15 in the US. Equivalent isotropically (EIRP) radiation power in the EU is limited to 20 dBm (100 mW).
To achieve the requirements for wireless LAN applications, Wi-Fi has higher power consumption compared to some other standards designed to support wireless private area network (PAN) applications. For example Bluetooth provides a much shorter propagation range between 1 and 100 m and generally has lower power consumption. Other low power technologies such as ZigBee have a fairly long range, but data rates are much lower. Wi-Fi high power consumption makes battery power on multiple mobile devices a concern.
Antenna
Access points correspond to 802.11b or 802.11g, using omnidirectional stock antennas may have a range of 100 m (0.062 mi). The same radio as a semi-external parabolic antenna (gain of 15 dB) with a similarly equipped receiver at the far end may have a range of more than 20 miles.
The higher gain rating (dBi) indicates further deviation (generally towards horizontal) from theoretical radiator, perfectly isotropic, and therefore the antenna can project a usable signal further in a particular direction, compared to the same output power on the isotropic antenna more. For example, an 8 dBi antenna used with a 100 mW driver will have the same horizontal range as a 6 dBi antenna that is driven at 500 mW. Note that this assumes that the radiation in the vertical is lost; this may not be the case in some situations, especially in large buildings or inside waveguide. In the example above, a directional waveguide can cause a low power antenna of 6 dBi to project further in one direction rather than an 8 dBi antenna that is not in a waveguide, even if both are driven at 100 mW.
On wireless routers with removable antennas, it is possible to increase the range by installing an improved antenna that has a higher gain in a particular direction. The outdoor range can be increased up to many kilometers through the use of high gain directional antennas on routers and remote devices (s).
MIMO
Some standards, such as IEEE 802.11n and IEEE 802.11ac for Wi-Fi enabled devices have multiple antennas. Some antennas allow equipment to focus on remote end devices, reduce interference in the other direction, and provide stronger useful signals. This greatly improves network coverage and speed without exceeding legal power limits.
IEEE802.11n can be more than double the range. Distance also varies with the frequency band. Wi-Fi in the 2.4 GHz frequency block has a slightly better range than Wi-Fi in the 5 GHz frequency block used by 802.11a (and optionally by 802.11n).
Under optimal conditions, IEEE802.11ac can achieve 1Gb/s communication rates.
Alternative
For best performance, some people only recommend the use of wireless networks as supplements for wired networks.
Researchers have developed a number of "no new cabling" technologies to provide an alternative to Wi-Fi for applications where inadequate Wi-Fi coverage and where installing new cables (such as CAT-6) are impossible or cost-effective. For example, ITU-T G.hn standards for high-speed local area networks use existing home wiring (coaxial cable, telephone line and power line). Although G.hn does not provide some of the advantages of Wi-Fi (such as mobility or outdoor use), it is designed for applications (such as IPTV distribution) where indoor distance is more important than mobility.
Many mobile devices also use mobile phone networks to provide access to the Internet when out of range of Wi-Fi networks. This is done, rather than relying entirely on cell networks because Wi-Fi networks are often cheaper for mass data usage.
Radio propagation
With line-of-sight Wi-Fi signals usually work best, but Wi-Fi signals can be affected by absorption, reflection, and diffraction through and around the structure.
Due to the complex nature of radio propagation at typical Wi-Fi frequencies, especially the reflection effect of signals from trees and buildings, the algorithm can only estimate the strength of Wi-Fi signals for any particular area associated with the transmitter. This effect does not apply equally to long distance Wi-Fi, since longer links usually operate from minarets that transmit over the surrounding foliage.
The practical range of Wi-Fi basically limits the use of mobile phones for applications such as inventory-taking machines in warehouses or in retail spaces, barcode reading devices at check-out stands, or receiving/delivery stations. The use of mobile Wi-Fi over a wider range is limited, for example, for use as in cars moving from one hotspot to another. Other wireless technologies are better suited for communicating with moving vehicles.
- Distance Notes
Distance records (using non-standard devices) include 382 km (237 million) in June 2007, hosted by Ermanno Pietrosemoli and EsLaRed from Venezuela, transferring about 3 MB of data between the ÃÆ' guila and Platillon peaks. Swedish Space Agency data transfer 420 km (260 mi), using a 6 watt amplifier to reach overhead stratosphere balloon.
Throughput
When the 802.11 specification evolves to support higher throughput, bandwidth requirements are also increased to support it. 802.11n uses a radio/dual bandwidth spectrum (40 MHz) compared to 802.11a or 802.11g (20 MHz).76 This means there is only one 802.11n network on the 2.4 GHz band in a particular location, without interruption/from WLAN traffic others. 802.11n can also be set to limit itself to 20 MHz bandwidth to prevent interruptions in dense communities.
Many new consumer devices support the latest 802.11ac standard, which uses exclusive 5 GHz bands and capable multi-station WLAN throughput of at least 1 gigabit per second, and a single station output of at least 500 Mbit/s. In the first quarter of 2016, the Wi-Fi Alliance certified devices that complied with 802.11ac standards as "Wi-Fi CERTIFIED ac". This new standard uses advanced signal processing techniques such as multi-user MIMO and 4X4 Spatial Multiplexing streams, and large channel bandwidth (160 MHz) to achieve Gigabit throughput. According to a study by IHS Technology, 70% of all access point sales revenue In the first quarter of 2016 came from 802.11ac devices.
Many access points
Increasing the number of Wi-Fi access points for the network provides redundancy, better coverage, support for fast roaming and overall network capacity improvements by using more channels or by defining smaller cells. Except for the smallest implementations (such as a home or small office network), Wi-Fi implementations have moved towards a "thin" access point, with more network intelligence placed in centralized networking tools, placing individual access to a "dumb" transceiver role. Outdoor applications can use mesh topology.
When multiple access points are deployed, they are often configured with the same SSID and any security settings to form an "additional set of services". WiFi client devices will usually connect to the access point that can provide the strongest signal in the set of services.
Hardware
Wi-Fi enables wireless deployment of local area network (LAN). Also, spaces where cables can not run, such as outside areas and historic buildings, can host wireless LANs. However, building walls of certain materials, such as rocks with high metal content, can block Wi-Fi signals.
Since the beginning of 2000 manufacturers are building wireless network adapters to most laptops. The chipset price for Wi-Fi continues to decline, making it an economical network option included in more devices.
Different brands of access point access points and client network interfaces can interoperate at the basic service level. Products designated as "Wi-Fi Certified" by a backward compatible Wi-Fi Alliance. Unlike phones, any standard Wi-Fi device will work anywhere in the world.
Standard device
The wireless access point (WAP) connects a group of wireless devices to an adjacent wired LAN. The access point resembles a network hub, passing data between connected wireless devices in addition to a single (usually) connected wired device, most often a hub or an Ethernet switch, enabling wireless devices to communicate with other wired devices.
The wireless adapter allows the device to connect to a wireless network. This adapter is connected to devices using various external or internal interconnections such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC Card. As of 2010, most new laptop computers come with built-in internal adapters.
Wireless routers integrate Wireless Access Point, Ethernet switches, and internal router firmware applications that provide IP routing, NAT, and DNS forwarding through an integrated WAN-interface. The wireless router allows a wired and wireless Ethernet device to connect to a single (usually) WAN device such as a cable modem or DSL modem. The wireless router allows all three devices, especially access points and routers, to be configured through a central utility. This utility is usually an integrated web server that can be accessed by wired and wireless LAN clients and is often optional for WAN clients. This utility may also be applications running on the computer, as is the case with AirPort Apple, which is managed with the AirPort Utility on macOS and iOS.
The wireless network bridge connects the wired network to the wireless network. Bridges are different from access points: access points connect wireless devices to wired networks in the data-link layer. Two wireless bridges can be used to connect two wired networks via wireless links, useful in situations where cable connections may not be available, such as between two separate homes or for devices that do not have wireless networking capabilities (but have wired networking capabilities) consumer; alternatively, wireless bridges can be used to enable devices that support cable connections to operate on a wireless network standard faster than supported by wireless networking features (inbuilt or inbuilt dongles) powered by the device (eg Enabling Wireless- Speed ​​N (up to speed maximum supported on wired Ethernet ports on bridges and connected devices including wireless access points) for devices that only support Wireless-G). A dual-band wireless bridge can also be used to enable 5 GHz wireless network operation on devices that only support 2.4 GHz wireless network functionality and have a wired Ethernet port.
Wireless range-extenders or wireless repeaters can extend the range of existing wireless networks. Strategically placed range climbers can lengthen the signal area or allow the signal area to reach around obstacles such as those associated with L-shaped corridors. Wireless devices connected through the repeater will experience increased latency for each hop, as well as from the maximum available data throughput reduction. Additionally, the effect of additional users using networks using the range of wireless coverage is to use available bandwidth faster than will happen where, but one user migrates around the network using extender. For this reason, wireless extensions work best in networks that support very low throughput traffic requirements, such as for cases where but one user with Wi-Fi-equipped tablets migrates around the combined extended parts and is not renewed from the total connected network. In addition, wireless devices connected to one repeater in a chain will have data throughput also limited by the "weakest link" that exists in the chain between where the connection originated and where the connection ended. Networks using wireless extensions are also more susceptible to degradation from interference from neighboring access points that restrict parts of the extended network and which happen to occupy the same channel as the extended network.
The security standard, Wi-Fi Protected Setup, allows embedded devices with a limited graphical user interface to connect to the Internet with ease. Wi-Fi Protected Setup has 2 configurations: Push Button Configuration and PIN configuration. This embedded device is also called the Internet of Things and is an embedded system that operates with low power batteries. A number of chip manufacturers and Wi-Fi design modules for embedded Wi-Fi, such as GainSpan.
Embedded system
Increasingly in recent years (especially in 2007), embedded Wi-Fi modules are available that incorporate real-time operating systems and provide a simple means of wirelessly enabling any device that owns and communicates through the serial port. This allows the design of a simple monitoring device. An example is a portable ECG device that monitors patients at home. This Wi-Fi enabled device can communicate over the Internet.
This Wi-Fi module is designed by OEMs so that implementers only need a bit of Wi-Fi knowledge to provide Wi-Fi connectivity for their products.
In June 2014, Texas Instruments introduced the first ARM Cortex-M4 microcontroller with a dedicated onboard WiFi MCU, SimpleLink CC3200. It makes the embedded system with Wi-Fi connectivity possible to build as a single chip device, which reduces the cost and minimum size, making it more practical to build wireless network controllers into cheap ordinary objects.
Network security
The main problem with wireless network security is the simplified access to the network compared to traditional cable networks such as Ethernet. With a wired network, one must gain access to a building (physically connected to the internal network), or through an external firewall. To enable Wi-Fi, you only need to be within range of Wi-Fi networks. Most business networks protect sensitive data and systems by trying to prohibit external access. Enabling wireless connectivity reduces security if the network uses inadequate or missing encryption.
An attacker who has gained access to a Wi-Fi network router can initiate a DNS spoofing attack against other users of the network by forging a response before the requested DNS server has a chance to reply.
Secure method
Common sizes to prevent unauthorized users involve hiding access point names by disabling SSID broadcasts. While effective against ordinary users, it is not as effective as a security method because SSID is broadcast clearly in response to client SSID requests. Another method is to only allow computers with known MAC addresses to join the network, but the specified eaves may be able to join the network by spoofing the official address.
Wired Equivalent Privacy (WEP) encryption is designed to protect against casual reconnaissance but is no longer considered safe. Tools such as AirSnort or Aircrack-ng can quickly restore the WEP encryption key. Due to WEP weakness, Wi-Fi Alliance approves Wi-Fi Protected Access (WPA) that uses TKIP. WPA is specifically designed to work with older equipment typically through firmware upgrades. Although more secure than WEP, WPA has been aware of its vulnerabilities.
WPA2 is more secure using Advanced Encryption Standard introduced in 2004 and is supported by most new Wi-Fi devices. WPA2 is fully compatible with WPA. By 2017, a gap in the WPA2 protocol is found, allowing key replay attacks, known as KRACK.
Defects in features added to Wi-Fi in 2007, called Wi-Fi Protected Setup (WPS), allow the security of WPA and WPA2 to be bypassed and effectively damaged in many situations. The only remedy by the end of 2011 is to turn off Wi-Fi Protected Setup, which is not always possible.
Virtual Private Networks are often used to secure Wi-Fi.
Data security risks
The older wireless encryption standard, Wired Equivalent Privacy (WEP), has proven to be easily broken even when configured properly. Wi-Fi Protected Access (WPA and WPA2) encryption, which became available on the device in 2003, aimed at solving this problem. Wi-Fi access points are usually by default to encryption-free mode ( open ). Novice users benefit from a zero configuration device that works out of the box, but this standard does not allow any wireless security, providing open wireless access to the LAN. To enable security requires the user to configure the device, usually through the software graphical user interface (GUI). On unencrypted Wi-Fi networks connecting devices can monitor and record data (including personal information). Such networks can only be secured by other means of protection, such as a VPN or a secure Hypertext Transfer Protocol via Transport Layer Security (HTTPS).
Wi-Fi Protected Access encryption (WPA2) is considered safe, provided strong passwords are used. In 2018, WPA3 was announced as a replacement for WPA2, enhancing security.
Pitching
Piggybacking refers to access to a wireless internet connection by bringing your own computer within the reach of someone else's wireless connection, and using that service without explicit permission or knowledge from customers.
During the early popular adoption of 802.11, providing an open access point for anyone within range of use is encouraged to develop a wireless community network, especially since average people only use a fraction of their downstream bandwidth at any given time.
Hijacking and recreational mapping of other people's access points has been known as bullying. Indeed, many access points are intentionally installed without security turned on so they can be used as a free service. Providing access to someone's internet connection in this way may violate the Terms of Service or contract with the ISP. These activities do not result in sanctions in most jurisdictions; however, law and case law are very different across the world. The proposal to leave graffiti describes the available services called warchalking. A court case in Florida stipulates that owner's laziness is not a valid reason.
Piggybacking often happens by accident - unknown technical users can not change default "unsafe" settings to their access point and the operating system can be configured to connect automatically to available wireless networks. A user who happens to start a laptop around the access point may find the computer has joined the network without any clear indication. In addition, users who intend to join a single network may end up with another if the latter has a stronger signal. In combination with the automatic discovery of other network resources (see DHCP and Zeroconf) it may be able to direct wireless users to send sensitive data to the wrong intermediate when looking for a destination (see Man-in-the-middle attack). For example, a user might inadvertently use an insecure network to log in to a website, thus making incoming credentials available to anyone who listens, if the website uses unsafe protocols like ordinary HTTP without TLS (HTTPS).
Unauthorized users can obtain security information (factory preset passwords and/or PIN Wi-Fi Protected Settings) from labels on wireless access points can use this information (or connect with Wi-Fi Protected Setup pushbutton method) to perform unauthorized and/or unlawful activities.
Health issues
The World Health Organization (WHO) said "no expected health effects from exposure to RF fields from base stations and wireless networks", but noted that they promote research into the effects of other RF sources. Although the International Agency of the WHO for Research on Cancer (IARC) then classifies the radio frequency electromagnetic field as "the carcinogenic possibility in humans (Group 2B)" (the category used when "causal relationships are considered credible, but when opportunities, biases or confounders can not rule out with confidence reasonable "), this is based on the risks associated with using a cordless phone rather than a Wi-Fi network.
The UK Health Protection Agency reported in 2007 that Wi-Fi exposure for a year produced "the same amount of radiation from a 20-minute phone call".
A study review involving 725 people claiming electromagnetic hypersensitivity, "... suggests that 'electromagnetic hypersensitivity' is not associated with the presence of EMF, although more research on this phenomenon is needed."
See also
- Gi-Fi - a term used by some trade press to refer to a faster version of the IEEE 802.11 standard
- Indoor positioning system
- Li-Fi
- List of WLAN channels
- Wi-Fi support operating system
- San Francisco Digital Inclusion Strategy
- Super Wi-Fi - IEEE 802.22 proposal to use television bands
- Wi-Fi Alliance
- WiGig
- Wireless Broadband Alliance
- Wireless network interface controller (WNIC)
References
Further reading
-
Wireless Network in Developing World (Third Edition) (PDF) . ISBN: 978-1-4840-3935-9.
Source of the article : Wikipedia
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