Wi-Fi | Wikipedia audio article
Wi-Fi. Is a family, of radio technologies. Commonly, used for wireless local area networking. WLAN. Of devices, it. Is based on the I Triple E 800, and 2.11 family, of standards. Wi-Fi. Is a trademark, of the Wi-Fi Alliance. Which restricts, the use of the term Wi-Fi, certified to, products, that successfully. Complete interoperability. Certification. Testing, the. Wi-Fi, Alliance, includes, three calm now owned by HPE Hewlett, Packard Enterprise, era net now owned by Cisco, Harris, semiconductor. Now owned by Intersil Lucent, now owned by nokia, nokia and, symbol technologies, now owned by zebra, technologies, Wi-Fi. Uses, multiple parts, of the I Triple E 802. Protocol, family and is designed to seamlessly in to work with its wired sister protocol, Ethernet, devices. That, can use Wi-Fi technologies. Include, desktops, and laptops smartphones. And, tablets, Smart TVs, printers. Digital audio, players digital, cameras, cars and drones. Compatible. Devices can, connect to each other over Wi-Fi, through a wireless access point as, well as two connected, Ethernet devices and, may use it to access the Internet, such. An access, point or hot spots 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 overlapping, access, points, the, different. Versions of Wi-Fi, are specified, by various, I Tripoli, 802. Point 1 one protocol, standards, with the different radio technologies. Determining. The rangers radio, bands, and speeds that may be achieved. Wi-Fi. Most commonly, uses the 2.4. Gigahertz 12. Centimeters, UHF. And 5 gigahertz 6, centimeters, shf, ISM radio bands, these bands are subdivided, into multiple channels. Each. Channel, can be time shared by multiple networks. These. Wavelengths work, best for line-of-sight. Many. Common, materials, absorb or reflect them, which further restricts, range but, tend to help minimize interference between, different, networks in crowded environments. At. Close range some, versions, of Wi-Fi, running, on suitable, hardware can, achieve speeds of over one gigabit, per second gigabit, per second. Wi-Fi. Is potentially. More vulnerable, to attack than wired networks, because, anyone within range of a network with a wireless network interface. Controller, can attempt access. Wi-Fi. Protected, access WPA. Is a family, of technologies created. To protect information, moving across Wi-Fi, networks, and include solutions, for personal, and enterprise, networks. Security. Features, of WPA, have included, stronger, protections, and new security practices. As the security, landscape has, changed over time. Topic. History, in 1971. Alohanet connected, the great Hawaiian, Islands, with a UHF wireless, packet Network. Aloha. Net in the Aloha protocol, were early forerunners, to Ethernet, and later the I Triple, E 802. Point 1 1 protocols, respectively. A. 1985. Ruling, by the US Federal, Communications Commission. Released the ISM band for unlicensed, use these. Frequency. Bands are the same ones used by equipment, such as microwave, ovens, and a subject, to interference, in. 1991. NCR. Corporation, with AT&T, corporation invented. The precursor to 802. Point 1 1 intended. For use in cashier, systems, under, the name Waveland, the. Australian, radio astronomer. Dr. john o'sullivan with, his colleagues terrence Percival, graham Daniel's diet austrie and John Dean developed, a key patent used in Wi-Fi, as a by-product, of a Commonwealth Scientific and, Industrial Research, Organisation.
CSIRO. Research project. A failed experiment to, detect exploding. Mini black holes the size of an atomic particle. Dr.. O'Sullivan and his colleagues are credited with inventing Wi-Fi. In, 1992. And 1996. CSIRO. Obtained, patents, for a method later used in Wi-Fi, to inspire, the signal the first version, of the 802. Point 1 1 protocol, was released in. Seven, and provided, up to two megabits, per second, link speeds, this. Was updated in 1999. With 802, point 1 1 B to permit 11 megabits per second, link speeds and this proved popular in. 1999. The Wi-Fi, Alliance, formed as a trade association to, hold the Wi-Fi trademark, under which 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 dollars, for infringement, on CSIRO. Patents. This. Led to Australia. Labeling, Wi-Fi, as an australian, invention, though this has been the subject of some controversy. CSIRO. Won, a further two hundred and twenty million dollars, settlement, for Wi-Fi patent, infringement in, 2012, with global, firms in the United States, required, to pay CSIRO. Licensing. Rights estimated. At an additional 1 billion dollars, in royalties, in. 2016. The wireless local area network testbed. Was chosen as Australia's, contribution. To the exhibition, a history of the world in 100 objects. Held in the National Museum of Australia. Topic. Etymology. And terminology. The, name Wi-Fi, commercially. Used at least as early as August 1999. Was, coined by the brand consulting, firm Interbrand the. Wi-Fi, Alliance, had hired Interbrand to create a name that was a little, catchier than i tripoli. 802. Point 1 1 be direct, sequence. Phil. Bellinger. A founding, member of the Wi-Fi Alliance, who presided over the selection of the name Wi-Fi. Has. Stated that Interbrand, invented, Wi-Fi as a pun on the word HiFi high fidelity a term for high quality audio technology. The name Wi-Fi, has no further meaning and was never officially, a shortened, form of wireless. Fidelity. Nevertheless. The, Wi-Fi, Alliance, used the advertising. Slogan the, standard, for wireless fidelity. For. A short time after the brand name was created, and the Wi-Fi Alliance, was also called the wireless, fidelity, Alliance. Inc in, some, publications, Interbrand. Also, created, the Wi-Fi, logo, the, yin-yang Wi-Fi. Logo, indicates, the certification. Of a product for interoperability, non, Wi-Fi, technologies. Intended, for fixed points such as Motorola canopy. Are usually described, as fixed wireless. Alternative. Wireless, technologies. Include, mobile phone, standards such. As 2g, 3G. 4G and, LTE. The. Name is sometimes, written as Wi-Fi, Wi-Fi, or Wi-Fi, but these are not approved by the Wi-Fi, Alliance, I, Triple. E is a separate, but related, organization. And their website has stated, Wi-Fi. Is a short, name for wireless fidelity. To, connect to a Wi-Fi LAN, a computer, must be equipped with a wireless network interface, controller. The. Combination. Of computer and interface controllers. Is called a station, a, service. Set is the set of all the devices associated, with, a particular Wi-Fi. Network, the. Service, set can be local, independent. Extended. Or mesh, each. Service, set has an Associated. Identifier. The 32, byte service, set identifier. SSID. Which, identifies. The particular network. The. SSID, is configured, within the devices, that are considered, part of the network and it is transmitted, in the packets. Receivers. Ignore wireless packets, from networks, with a different, SSID. Wi-Fi. Nodes operating. In ad-hoc mode refers, to devices, talking, directly to each other without the need to first talk to an access point also known as base station. Ad-hoc. Mode was first invented, and realized by Chie canto in his 1996. Invention, of Wi-Fi, ad-hoc routing, implemented. On loosin Waveland 802. Point 1 1 a wireless, on IBM, ThinkPads, over a size node scenario, spanning, a region of over a mile the. Success, was recorded, in mobile computing magazine. 1999. And later published, formally, in I Triple E transactions. On wireless communications. 2002. And a CMS, igme, TR ICS. Performance, evaluation. Review, 2001. Topic. Certification. The, I Triple, E does not test equipment, for compliance with 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 technology, as, of. 2010, the Wi-Fi, Alliance consisted, of more than, 375. Companies. From around the world the. Wi-Fi, Alliance, enforces, the use of the Wi-Fi, brand to technologies, based on the I Triple, E 800. And 2.11. Standards. From the I Triple E this. Includes, wireless local area network. WLAN. Connections. Device, to device connectivity, such, as Wi-Fi peer-to-peer aka. Wi-Fi, direct personal. Area network pan local, area network, LAN and even some limited wide area, network want, connections.
Manufacturers. With membership, in the Wi-Fi Alliance, whose products, pass the certification process, gain, the right to mark those products, with the Wi-Fi logo. Specifically. The certification. Process requires. Conformance. To the I Triple, E 800, and 2.11, radio, standards, the WPA, and wpa2, security. Standards. And the EAP authentication, standard. Certification. May optionally, include tests, of I Triple E 802. Point 1 1 draft standards, interaction. With cellular, phone technology. In converged devices, and features relating, to security set, up multimedia. And power saving, not every Wi-Fi device is submitted, for certification. The. Lack of Wi-Fi, certification. Does not necessarily, imply that a device is incompatible, with other Wi-Fi, devices, the. Wi-Fi, Alliance, may or may not sanction. Derivative, terms such, as super Wi-Fi coined, by the US Federal, Communications Commission. FCC to. Describe proposed, networking, in the UHF TV, band, in the US. Topic. Versions. There, are many different, versions of Wi-Fi. 802.11. A. 802. Point 1 1 B, 802. Point 1 1 grams, 802. Point 1 1 n Wi-Fi, for. 802.11. H, 802. Point 1 1 I 802. Point 1 1 -. 2007. 802. Point 1 1 -, 2012. 802.11. AC Wi-Fi. 5, 802. Point one one AD, 802. Point one one a F, 802. Point 1 1 -. 2016. 802. Point one one our 802. Point 1 1 I 802. Point 1 1 aj. 802.11. A Q, 802. Point 1 1 ax Wi-Fi. 6, 802. Point 1 1 a. Equipment. Frequently, support multiple, versions, of Wi-Fi, to, communicate. Devices. Must use a common, Wi-Fi, version the. Versions, differ between the radio wave bands they operate on the radio bandwidth, they occupy, the maximum, data rates they can support and other details in. General. Lower frequencies. Have better range but have less capacity. Some. Versions, permit the use of multiple antennas, which permits greater speeds, as well as reduced interference. Historically. Equipment. Has simply, listed the versions of Wi-Fi, using, the name of the I Triple, E standard that, it supports, in. 2018. The Wi-Fi, Alliance, standardized, generational. Numbering, so that equipment can indicate that it supports, Wi-Fi 4 if the equipment supports. 802.11. N Wi-Fi, 5. 802. Point 1 1 AC and, Wi-Fi, 6, 802. Point one one-acts, these generations. Have a high degree of backward, compatibility with previous versions. The. Alliance, have stated that the generational, level 4 5 or 6 can, be indicated, in the user interface when, connected, along with the signal strength. Topic. Users. Topic. Internet. Access. Wi-Fi. Technology, may be used to provide internet access to devices that are within the range of a wireless network that, is connected, to the Internet, the. Coverage, of one or more interconnected, access. Points, hotspots, can extend from an area as small as a few rooms to as large as many square kilometers. Coverage. In the larger area may require a group of access, points with overlapping coverage. For. Example public, outdoor Wi-Fi technology. Has been used successfully, in wireless, mesh networks, in London an, international. Example, is fond. Wi-Fi. Provides, service, in private, homes businesses, as well as in public spaces, at Wi-Fi, hotspots, set up either free of charge or commercially, often, using a captive portal webpage for access. Organisations. And businesses such. As airports, hotels, and, restaurants often. Provide free use hotspots, to attract customers. Enthusiasts. Or authorities, who wish to provide services. Or even to promote business in selected, areas sometimes provide, free Wi-Fi access. Reuters, 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, Internet working to all devices connected to them wirelessly or via cable. Similarly. Battery-powered. Rooters, 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 technique, many. Smartphones, have a built-in capability. Of this sort including, those based on Android Blackberry, bada iOS. IPhone, Windows, Phone and Symbian, though carriers, often disable, the feature or charge a separate fee to enable it especially, for customers, with unlimited data plans, internet.
Packs, Provide. Standalone, facilities, of this type as well without, use of a smartphone examples. Include the MiFi and Wipro branded, devices. Some. Laptops that have a cellular modem card can also act as mobile internet, Wi-Fi access points. Wi-Fi. Also connects, places, that normally don't have network access such, as kitchens, and garden sheds. Google. Is intending, to use the technology, to allow rural, areas to enjoy connectivity. By utilizing, a broad mix of projection, and routing services. Google. Also intends, to bring connectivity. To Africa, and some Asian lands, by launching, blimps that will provide Internet, connection, with Wi-Fi technology. Topic. Citywide. In the, early 2000s. Many cities around the world announced. Plans to construct citywide. Wi-Fi networks. There. Are many successful examples in. 2004. My saw my saroo became, India's first Wi-Fi, enabled City a company. Called whiffy net has set up hotspots, in Mysore, covering, the complete city, and a few nearby villages, in 2005. Saint Cloud Florida. And Sunnyvale California became. The first cities, in the United, States to offer citywide, free Wi-Fi from, Metro fee. Minneapolis, has generated. 1.2. Million dollars, in profit annually, for its provider, in May 2010, London Mayor Boris Johnson pledged. To have London wide Wi-Fi, by 2012. Several. Boroughs, including, Westminster, in Islington already, had extensive, outdoor Wi-Fi coverage, at that point. Officials. In South Korea's, capital Seoul, are moving to provide free internet access at more than 10,000, locations around the city including, outdoor public spaces, major, streets, and densely populated residential. Areas. Seoul. Will grant leases, to KT LG. Telecom, and SK, Telecom, the. Companies, will invest 44. Million dollars in the project which was to be completed in 2015. Topic. Campus. Wide. Many, traditional, university, campuses, in the developed, world provide, at least partial, Wi-Fi, coverage. Carnegie. Mellon University built. The first campus-wide, wireless. Internet network called, Wireless Andrew, at its Pittsburgh campus in, 1993. Before Wi-Fi, branding, originated. By. February, 1997. The CMU Wi-Fi, zone was fully operational. Many. Universities. Collaborate. In providing Wi-Fi access, to students, and staff through, the eduroam international. Authentication. Infrastructure. Topic. Adhoc, versus, Wi-Fi, direct.
Wi-Fi. Also allows, communications. Directly, from one computer, to another without an access point intermediary. This. Is called ad-hoc, Wi-Fi, transmission. This, wireless, ad-hoc network. Mode has proven popular with multiplayer, handheld, game consoles, such, as the Nintendo, DS PlayStation, Portable. Digital, cameras, and other consumer, electronics devices. Some. Devices can also share, their internet connection using. Ad-hoc becoming, hotspots, or virtual. Rooters. Similarly. The Wi-Fi, Alliance, promotes, the specification. Wi-Fi, direct for, file transfers, and media sharing through a new discovery and security, methodology. Wi-Fi. Direct launched. In October, 2010, another mode of direct, communication over. Wi-Fi is tunneled, direct, link setup TD LS which, enables, two devices on the same Wi-Fi network to, communicate directly instead. Of via the access point. Topic. Radio. Spectrum. The, 802. Point 1 1 standard, provides several, distinct, radio frequency. Ranges, for use in Wi-Fi, communications. 900. Megahertz, 2.4. Gigahertz 5, gigahertz. 5.9. Gigahertz and 60, gigahertz bands. Each. Range, is divided, into a multitude of channels, countries. Apply their own regulations. To the allowable, channels, allowed users and maximum, power levels, within these frequency. Ranges, the. ISM band ranges, are also often used point 802, 11, B, per gram M can use the 2.4. Gigahertz ISM. Band operating. In the United, States and the part 15 rules and regulations, in. This, frequency, band equipment. May occasionally suffer, interference, from microwave, ovens cordless, telephones, USB. 3.0. Hubs and Bluetooth, devices. Spectrum. Assignments. And operational, limitations, are not consistent, worldwide, Australia. In Europe allow for an additional two channels, 1213, beyond, the 11 permitted, in the United, States for the 2.4. Gigahertz band. While Japan has three more 12 to 14 in. The, US and other countries, 802. Point 1 1 and 802. Point 1 1 grams devices, may be operated, without a license, as allowed in part 15, of the FCC, rules and regulations. A. Standard. Speed Wi-Fi signal, occupies, 5 channels, in the 2.4. Gigahertz band. Any, two, channel, numbers that differ by 5 or more such as 2 and 7 do not overlap, the. Oft-repeated adage. That channels, 1 6, and 11 are the only non-overlapping, channels, is, therefore, not accurate. Channels. 1 6, and 11 are the only group of three non-overlapping channels, in, North America, however. Channels, that are for apart interfere, a negligible, amount much, less than reusing, channels in. Europe, and Japan where, channel, 13, is available, using channels, 1 5, 9 and 13 for 802. Point 1 1 grams and 802. Point 1 1 n is recommended. 802. Point 1 1 a HJ. NAC axe, can use the 5 gigahertz uni, band which for much of the world offers at least twenty three non-overlapping 20. Megahertz channels rather, than the 2.4. Gigahertz ISM, frequency, band where the channels are only 5 megahertz wide, the. 5 gigahertz bands, are absorbed, to a greater degree by, common building materials, than the 2.4. Gigahertz bands, and usually, give shorter range as, the. 800, and 2.11. Specifications. Evolved, to support higher throughput, the bandwidth requirements. Also increased to support them.
802. Point 1 1m can use double the radio spectrum bandwidths. 40 megahertz 8, channels, compared, to 802. Point 1 1 or 800. And 2.11. Bram's, 20, megahertz. 802. Point 1 1m can also be set to limit itself to 20 megahertz bandwidth. To prevent interference in, dense communities. In the. 5 gigahertz band, 20, 40, 80 and 160. Megahertz. Bandwidth, signals, are permitted with some restrictions giving. Much faster, connections. Topic. Communication. Stack. Wi-Fi. Is part, of the I Triple E 802. Protocol, family the. Data is organized, into 800 and 2.11. Frames, that are very similar to Ethernet frames at the data link layer but with extra address, fields, MAC. Addresses are, used as Network addresses, for routing over the LAN wi-fi's, MAC and physical, layer fight. Specifications. Are defined by I Triple, E 802. Point 1 1 4 modulating, and receiving, one or more carrier waves to transmit the data in the infrared and to point four three point six five or 60, gigahertz frequency. Bands they. Are created, and maintained, by the I Triple E LAN man Standards, Committee I Triple E 802. The. Base version of the standard was released in, 1997. And has had many subsequent, amendments. The. Standard, and amendments, provide the basis, for wireless, network, products, using the Wi-Fi brand. While. Each amendment is officially, revoked when it is incorporated. In the latest version of the standard the, corporate, world tends to market to the revisions, because they concisely, denote, capabilities. Of their products, as a. Result, in the marketplace, each revision tends, to become its own standard. In. Addition to 802. Point 1 1 the I Triple, E 802. Protocol, family has specific, provisions, for Wi-Fi, these. Are required because Ethernet, cable, based media, are not usually, shared whereas with wireless all transmissions. Are received by all stations, within range that employ that radio channel. While. Ethernet, has essentially, negligible error rates wireless, communication. Media are subject, to significant, interference. Therefore. Accurate, transmission. Is not guaranteed, so delivery is therefore a best effort delivery mechanism. Because. Of this for Wi-Fi, the logical, link control LLC. Specified. By I Triple, E 802. Point to employees, wi-fi's media, access control Mac, protocols. To manage retries, without, relying on higher levels, of the protocol, stack. For. Internet working purposes, Wi-Fi, is usually, layered as a link layer equivalent. To the physical and data link layers, of the OSI. Below, the internet layer of the Internet Protocol. This. Means that nodes have an Associated, Internet address and with suitable connectivity. This allows full Internet access. Topic. Performance. Wi-Fi. Operational. Range depends, on factors such as the frequency band, radio, power output, receiver, sensitivity, antenna. Gain an antenna type as well as the modulation, technique, in. Addition, propagation. Characteristics. Of the signals can have a big impact. At. Longer, distances, and with greater signal, absorption, speed is usually reduced. Topic. Transmitter. Power. Compared. To cellphones, and similar technology, Wi-Fi, transmitters.
Are Low-power devices, in. General the, maximum, amount of power that a Wi-Fi, device can transmit is limited, by local regulations, such, as FCC. Part 15 in, the u.s., equivalent. Isotropically. Radiated. Power a, IRP, in the European, Union, is limited, to 20 DBM, 100. Milliwatts. To. Reach requirements. For wireless LAN applications. Wi-Fi, has higher power consumption, compared. To some other standards, designed to support wireless, personal area network, pan applications. For. Example Bluetooth. Provides, a much shorter propagation. Range between 1 and 100 meters. And so in general have a lower power consumption, other. Low-power. Technologies. Such as ZigBee have fairly long range but much lower data rate, the. High power consumption, of Wi-Fi, makes battery, life in some mobile devices our concern. Topic. Antennae. An access. Point compliant, with either 802. Point 1 1 B or 802. Point 1 1 grams using, the stock omnidirectional antenna. Might have a range of 100, meters. 0.06. 2 miles, the. Same radio with an external semi, parabolic, antenna 15, decibels gain with a similarly, equipped receiver, at the far end might have a range over 20, miles. Higher. Gain rating, DB I indicates. Further deviation. Generally, toward the horizontal, from a theoretical perfect. Isotropic, radiator and. Therefore, the antenna can project or accept a usable, signal further in particular directions, as, compared, to a similar output power on a more isotropic, antenna, for. Example, an 8 dbi, antenna used. With a 100, milliwatts driver, has a similar, horizontal, range to a 60, bi antenna, being driven at 500. Milliwatts. Note. That this assumes, that radiation, in the vertical, is lost, this may not be the case in some situations. Especially in large buildings or within a waveguide in. The, above example a directional. Waveguide, could cause the low power 6 dbi, antenna to. Project much further in a single direction, than the 8 dbi, antenna which. Is not in a waveguide even, if they are both driven at 100, milliwatts on, wireless. Reuters, with detachable antennas it is possible, to improve range, by fitting upgraded, antennas, that provide, higher gain in particular directions. Outdoor. Ranges, can be improved to many kilometres through. The use of high gain directional. Antennas, at the Reuter and remote devices. You. Topic. Mimmo, multiple-input. And multiple-output. Some, standards, such, as I Tripoli, 802. Point 1 1 n and I Tripoli, 802. Point 1 1 ac for, Wi-Fi allow a device to have multiple, antennas. Multiple. Antennas, enable, the equipment, to focus on the far end device reducing. Interference in, other directions and giving a stronger, useful signal, this. Greatly increases range, and network speed without exceeding the legal power limits, I, Tripoli. 802. Point 1 1 n can more than double the range, range. Also, varies, with frequency band. Wi-Fi. In the 2.4. Gigahertz frequency. Block has slightly better range, than Wi-Fi in the 5 gigahertz frequency. Block used by 802. Point 1 1 and optionally, by 802. Point 1 1 n under. Optimal. Conditions I, Triple E 802. Point 1 1 AC can, achieve communication, rates, of one gigabit, per second.
Topic. Radio. Propagation. With, Wi-Fi, signals, line-of-sight, usually, works best signals, can transmit, absorb, reflect, and diffract through and around structures. Due. To the complex nature of radio, propagation at, typical, Wi-Fi frequencies. Particularly. The effects, of signal reflection, off trees and buildings algorithms. Can only approximately, predict, Wi-Fi, signal, strength for, any given area in relation to a transmitter, this. Effect does not apply equally, to long-range, Wi-Fi, since longer, links typically operate from towers that transmit, above the surrounding foliage. Mobile. Use of Wi-Fi, over wider ranges, is limited, for instance, two uses such as in an automobile moving, from one hot spot to another other. Wireless, technologies. Are more suitable for communicating, with moving, vehicles. Distance. Records, distance, records, using non-standard, devices. Include. 382. Kilometers. 237. Miles in June 2007. Held by hermano, Petros moly and s Laird of Venezuela, transferring. About three megabytes, of data between, the mountain tops of a log euler and Patty on the. Swedish Space, Agency, transferred, data, 420. Kilometers. 260. Miles using. Six watt amplifiers, to reach an overhead stratospheric. Balloon. Topic. Radio. Bands. Many, newer consumer, devices support, the latest. 802.11. AC standard, which uses the five gigahertz band, exclusively. And is capable of multi station, WLAN. Throughput, of at least one gigabit, per second and a single station throughput, of at least 500. Megabits per second, in, the, first quarter, of 2016, the, Wi-Fi, Alliance, certifies, devices, compliant, with the, 802.11. AC, standard, as Wi-Fi. Certified AC. This. New standard, uses, several advanced signal, processing, techniques, such as multi-user. Mimo and 4x4, spatial. Multiplexing streams. And large channel, bandwidths. 160. Megahertz, to achieve the 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. Point 1 1 AC devices. Topic. Interference. Wi-Fi. Connections, can be disrupted, or the internet, speed lowered by having other devices in the same area. Wi-Fi. Protocols, are designed to share channels reasonably, fairly, and often, works with little to no disruption. However. Many, 2.4. Gigahertz 800. And 2.11, B and 802, point 1 1 grams access, points, default to the same channel on initial startup, contributing. To congestion on, certain, channels. Wi-Fi. Pollution, or an excessive, number of access, points in the area can, prevent access, and interfere, with other devices use of other access, points, as well as with decreased signal-to-noise, ratio. SNR, between, access points, in. Addition interference. Can be caused by overlapping channels, in the 802. Point 1 1 grams B spectrum, these. Issues, can become a problem in high-density areas, such, as large apartment, complexes or. Office buildings, with many Wi-Fi, access points. Wi-Fi. 6 has greatly improved, power control, and suffers, less from interference, in congested, areas, other. Devices, use, the 2.4. Gigahertz band, microwave. Ovens ISM, band devices, security. Cameras, ZigBee devices Bluetooth. Devices, video, senders. Cordless, phones baby, monitors, and in some countries amateur. Radio all of which can cause significant. Additional, interference, it. Is also an issue when municipalities. Or other large entities, such as universities. Seek to provide large area, coverage. To. Minimize collisions, with Wi-Fi, and non Wi-Fi, devices Wi-Fi. Employees carrier, sense multiple access, with collision avoidance. Csma/ca. Where transmitters. Listen before transmitting. And delay transmission. Of packets, if they detect that other users are active on the channel, nevertheless. Wi-Fi. Networks, are still susceptible to the hidden node and exposed, node problem, these bands are can be used by low power transmitters, without a license, and with few restrictions. However. While, unintended, interference. Is common users, that have been found to cause deliberate, interference, particularly. For attempting, to locally monopolize, these bands for purposes. Have been issued large fines. Topic, throughput. Various. Layer two variants, of I Tripoli, 802. Point one one has different characteristics.
Across. All flavors, of 802. Point one one maximum. Achievable throughput, SAR either given, based on measurements, under ideal conditions, or in the layer to data rates, this. However does, not apply to typical, deployments, in which data are transferred between two, endpoints of which at least one is typically connected to a wired infrastructure. And the other is connected to an infrastructure, via a wireless link. This. Means that typically data frames, pass an 802. Point 1 1 WLAN, medium. And are being converted to 802. Point 3 Ethernet, or vice-versa. Due. To the difference, in the frame header, lengths, of these two media the packet size of an application, determines. The speed of the data transfer, this. Means that an application, that uses small packets, eg, VoIP creates, a data flow with a high overhead traffic, eg, a low good put, other. Factors, that contribute, to the overall application. Data ray to the speed with which the application. Transmits, the packets, ie the, data rate and the energy with which the wireless signal, is received, the. Latter is determined, by distance, and by the configured, output power of the communicating. Devices, the same references. Apply to the attached throughput, graphs which show measurements, of UDP throughput. Measurements, each. Represents. An average throughput, of 25, measurements. The error bars are there but barely visible due, to the small variation. Is with a specific packet. Size small, or large and with a specific data, rate 10 kilobits, per second, to 100, megabits per second. Markers. For traffic profiles, of common applications. Are included, as well this, text, and measurements, do not cover packet, errors but information about, this can be found at the above references. The. Table below shows the, maximum achievable, application. Specific UDP. Throughput, in the same scenarios, same, references, again with various, different WLAN. 802. Point 1 1 flavors, the. Measurement, hosts, have been 25, meters apart from each other losses again ignore. Topic. Hardware. Wi-Fi. Allows wireless deployment. Of local area networks, plans, also. Spaces. Where cables, cannot be run such as outdoor areas, and historical, buildings, can host wireless, lands, however. Building, walls of certain, materials, such as stone with high metal content can, block Wi-Fi, signals. Since. The early 2000s. Manufacturers. Are building wireless network, adapters, into most laptops, the. Price of chipsets, for Wi-Fi, continues, to drop making, it an economical, networking, option included, in evermore devices, different competitive. Brands of access points and client network interfaces, can interoperate at, a basic level of service. Product. Designated. As Wi-Fi. Certified. By. The Wi-Fi, Alliance, are backward compatible. Unlike. Mobile, phones, any standard, Wi-Fi device works anywhere, in the world. Topic. Access. Point. A wireless. Access point WEP, connects, a group of wireless devices to, an adjacent, wired LAN an access. Point resembles, a network hub relaying, data between, connected. Wireless devices in addition, to it usually single connected, wired device, most, often an Ethernet, hub or switch allowing. Wireless, devices to communicate with other wired devices. Topic. Wireless. Adapter. Wireless. Adapters, allow devices, to connect to a wireless network these. Adapters, connect, to devices using, various, external, or internal interconnects.
Such As PCI, minnici. USB. Express, card card bus and PC card as of. 2010, most newer laptop, computers, come equipped with built-in internal, adapters. Topic. Rueter. Wireless, Reuters integrate, a wireless, access point Ethernet. Switch an internal, route a firmware application. That provides IP routing, Nats and DNS, forwarding, through an integrated, one interface, a wireless. Router allows, wired and wireless Ethernet, LAN devices, to connect to it usually single one device such as a cable modem DSL. Modem, or optical, modem a wireless. Router allows, all three devices mainly. The access point and Rooter to be configured, through one central, utility this. Utility, is usually, an integrated, web server that is accessible, to wired and wireless LAN, clients, and often optionally, to one clients, this. Utility, may also be an application, that is run on a computer as is the case with as Apple's Airport which is managed, with the airport utility, on Mac OS and iOS. Topic. Bridge. Wireless. Network bridges, can act to connect to networks, to form a single network at the data link layer over, Wi-Fi, the. Main standard, is the wireless distribution. System, WDS. Wireless. Bridging, can connect a wired network, to a wireless network a, bridge, differs, from an access point an access, point typically connects, wireless devices to one wired network, to. Wireless, bridge devices, may be used to connect to wired networks, over a wireless link useful, in situations where. A wired connection, may be unavailable, such, as between two separate, homes or four devices that have no wireless, networking, capability. But have wired networking, capability. Such as consumer, entertainment devices. Alternatively. A wireless, bridge can be used to enable a device that supports a wired connection, to operate at a wireless networking, standard. That is faster, than supported, by the wireless network, connectivity, feature, external. Dongle or inbuilt supported. By the device, eg. Enabling. Wireless end speeds up to the maximum supported, speed on the wired Ethernet, port on both the bridge and connected, devices including. The wireless, access point, for a device that only supports, Wireless G a, dual. Band wireless bridge can also be used to enable 5 gigahertz wireless. Network, operation. On a device that only supports, 2.4. Gigahertz Wireless, and has a wired Ethernet port. 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. Wireless. Device is connected, through repeaters, suffer from an increased latency for each hop and there may be a reduction, in the maximum, available data throughput in. Addition. The effect of additional, users, using a network employing. Wireless range extenders, is to consume the available, bandwidth, faster, than would be the case whereby a single user migrates, around the network employing, extenders. For. This reason, wireless, range extenders. Work best in networks supporting, low traffic throughput requirements, such as for cases, whereby a single user with a Wi-Fi, equipped tablet, migrates, around the combined extended, and non extended, portions, of the total connected, network also. A, wireless, device connected. To any of the repeaters in the chain has data throughput limited, by the weakest. Link in the, chain between the connection, origin, and connection, end networks. Using, wireless, extenders, are more prone to degradation from. Interference, from neighboring, access points, that border portions, of the extended, network and that happened to occupy, the same channel, as the extended, Network. Topic. Embedded. Systems. The, security, standard, Wi-Fi Protected. Setup allows. Embedded, devices with limited graphical, user interface. To connect, to the internet with ease. Wi-Fi. Protected, setup has, two configurations. The push-button configuration. And the pin configuration. These. Embedded devices, are also called, the Internet of Things and, a low-power battery, operated embedded, systems, a number, of, Wi-Fi, manufacturers. Design chips and modules, for embedded Wi-Fi, such as gain span increasingly. In the last few years particularly, as of 2007. Embedded. Wi-Fi modules, have become available that incorporate, a real-time, operating system. And provide a simple, means of wirelessly, enabling, any device that can communicate via, a serial, port this. Allows the design of simple, monitoring, devices an example. Is a portable, ECG device. Monitoring. A patient, at home this.
Wi-Fi, Enabled device, can communicate via the internet these Wi-Fi modules, are designed by, OEMs so, that implementers, need only minimal, Wi-Fi, knowledge to provide Wi-Fi connectivity, for their products, in. June, 2014, Texas. Instruments, introduced, the first arm cortex-m, for, microcontroller. With an onboard dedicated. Wi-Fi MCU. The simple links ec3 200. It. Makes embedded, systems, with Wi-Fi connectivity possible. To build a single chip devices, which reduces, their cost and minimum size, making, it more practical to build wireless, network, controllers, into inexpensive. Ordinary, objects. Topic. Multiple. Access, points. Increasing. The number of Wi-Fi, access points, for a network provides, redundancy better. Range support, for fast roaming, and increased overall network capacity, by using more channels, or by defining smaller cells. Except. For the smallest, implementations. Such as home or small office networks. Wi-Fi. Implementations. Have moved toward thin. Access. Points, with more of the network intelligence housed, in a centralized, network appliance, relegating. Individual, access, points, to the role of dumb. Transceivers. Outdoor. Applications. May use mesh topologies, an extended, service set may, be formed, by deploying multiple, access, points that are configured, with the same SSID and security. Settings, Wi-Fi. Client. Devices, typically, connect to the access point that can provide the strongest, signal within that service set. Topic. Network. Security. The, main issue with wireless network, security, is it's simplified access, to the network compared. To traditional wired, networks, such as Ethernet, with. Wired networking, one must either gain access to a building physically. Connecting, into the internal, network or, break through an external firewall, to. Access Wi-Fi one, must merely be within the range of the Wi-Fi network, most. Business, networks, protect, sensitive data, and systems, by attempting, to disallow external, access. Enabling. Wireless connectivity, reduces. Security, if the network uses, inadequate, or no encryption an attacker who has gained access to a Wi-Fi, network router, can initiate a DNS, spoofing, attack against, any other user of the network by forging a response, before the queried DNS, server has a chance to reply. Topic. Securing. Methods. A common. Measure to deter unauthorized users. Involves, hiding, the access, points named by disabling, the SSID broadcast. While. Effective, against the casual user it, is ineffective, as a security, method because the SSID, is broadcast, in the clear in response, to a client SSID, query. Another. Method is to only allow computers, with known MAC addresses to. Join the network but determined, eavesdroppers, may be able to join the network by spoofing, an authorized, address.
Wired. Equivalent privacy. WEP. Encryption was. Designed to protect against, casual snooping, but it is no longer considered, secure, tools. Such as air snort or aircrack-ng, can. Quickly recover WEP. Encryption keys. Because. Of WEP, s weakness, the Wi-Fi, Alliance, approved, Wi-Fi, protected access WPA. Which uses TK IP WPA. Was specifically, designed to work with older equipment usually, through a firmware upgrade, though. More secure, than WEP. WPA has. Known vulnerabilities. The. More secure, wpa2. Using. Advanced, encryption standard was. Introduced, in 2004. And is supported, by most new Wi-Fi, devices. Wpa2. Is, fully compatible, with WPA. In. 2017. A floor in the wpa2. Protocol. Was discovered, allowing, a key replay, attack known as KRA ck, a floor in a feature added to Wi-Fi, in 2007. Called Wi-Fi Protected, setup WPS. Let WPA, and wpa2, security, be. Bypassed, and effectively, broken in many situations. The. Only remedy, is of late 2011, was, to turn off Wi-Fi Protected. Setup which, is not always possible. Virtual. Private networks, can be used to improve the confidentiality. Of data carried. Through Wi-Fi networks, especially public, Wi-Fi networks. Topic. Data, security. Risks. The, older wireless encryption standard. Wired equivalent privacy. WEP. Has been shown easily breakable even, when correctly, configured. Wi-Fi. Protected, access WPA. And wpa2. Encryption, which. Became available in devices, in 2003. Aimed to solve this problem. Wi-Fi. Access points. Typically default, to an encryption free, open, mode, novice. Users, benefit, from a zero configuration device. That works out of the box but, this default does not enable any wireless, security providing. Open wireless access to a LAN to. Turn security. On requires, the user to configure the device usually. Via a 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 using other means of protection such, as a VPN, or secure, hypertext. Transfer, Protocol, over transport, layer security. HTTP. Wi-Fi. Protected, access encryption. Wpa2. Is considered, secure, provided. A strong passphrase is used in. 2018. WPA. 3 was announced as a replacement for wpa2. Increasing. Security, it rolled out On June 26. Topic. Piggybacking. Piggybacking. Refers, to access to a wireless internet connection by. Bringing one's own computer, within the range of another's wireless, connection, and using that service without the subscribers. Explicit, permission, or knowledge. During. The early popular, adoption, of 802. Point 1 1 providing. Open access, points for anyone within range to use was encouraged, to cultivate, wireless, community, networks, particularly. Since people on average use only a fraction of their downstream, bandwidth, at any given time. Recreational. Logging and mapping of other people's, access, points, has become known as war driving, indeed. Many, access, points are intentionally, installed without security, turned, on so that they can be used as a free service. Providing. Access to one's internet, connection, in this fashion may breach the Terms of Service or, contract, with the ISP, these. Activities. Do not result in sanctions, in most jurisdictions however. Legislation. And case law differ, considerably across. The world a proposal. To leave graffiti, describing. Available, services, was called war chalking, piggybacking, often, occurs unintentionally. A technically, unfamiliar, user might not change the default, unsecured.
Settings. To their access, point and operating, systems, can be configured to connect automatically. To any available, wireless network, a user. Who happens to start up a laptop in the vicinity of an access point may find the computer has joined the network without, any visible indication. Moreover. A user intending, to join one network may instead end up on another one if the latter has a stronger signal in. Combination. With automatic discovery, of other network, resources, see, DHCP. And zeroconf, this could possibly lead wireless, users to send sensitive data to the wrong middleman, when seeking a destination, see man-in-the-middle, attack, for. Example, a user could inadvertently use. An unsecured network to log into a web site thereby, making the login credentials, available, to anyone listening, if the web site uses, an unsecure, protocols, such as plain HTTP. Without TLS. An. Unauthorized. User can obtain security, information factory. Preset, passphrase, and/or Wi-Fi. Tected setup pin from a label on a wireless access point can use this information or, connect by the Wi-Fi, Protected, setup push, button method to commit unauthorized and/or. Unlawful, activities. Topic. Health, concerns. The, World Health Organization. Who says, no, health effects, are expected, from exposure, to RF fields, from base stations. And wireless, networks. But. Notes that they promote research into, effects, from other RF sources. Although. The whose International. Agency for, research on, cancer, IASE. Later classified, radiofrequency. Electromagnetic. Fields. EMF as possibly. Carcinogenic, to, humans' group, to be a category. Used, when a causal. Association. Is considered, credible but, when chance bias, or confounding. Cannot be ruled out with reasonable, confidence. This. Classification, was, based on risks associated with, wireless, phone use rather than Wi-Fi networks. The. United, Kingdom's, Health Protection, Agency, reported, in 2007. That exposure to Wi-Fi, for a year results, in the same, amount of radiation. From a 20-minute, mobile, phone call a review. Of studies involving. 725. People who claimed electromagnetic. Hypersensitivity. Suggests. That electromagnetic. Hypersensitivity is. Unrelated, to the presence of an EMF, although, more research into this phenomenon, is required. Topic. Alternatives. A number. Of other wireless. Technologies. Provide, alternatives. To Wi-Fi, in some cases. Bluetooth. Short, distance, network. Bluetooth. Low Energy, a low-power, variant. ZigBee. Low-power, low, data rate and close proximity. Cellular. Networks, as used by smartphones. WiMAX.
Provide, Wireless, internet, connection, from outside, individual, home some alternatives, are no, new wires. Reusing. Existing cable. G. H, n / existing, home wiring such. As phone and power Lena several, wired technologies. For computer, networking provide, in some cases viable, alternatives. In particular. Ethernet. Over twisted pair. Topic. See, also. Gee ëifí a term. Used by some trade press to refer to faster, versions, of the I Triple E 802. 11. Standards. Indoor. Positioning system. Leif. I, list. Of WLAN, channels. Operating. System. Wi-Fi support. San. Francisco, Digital, Inclusion strategy. WiGig. Wireless. Broadband, alliance.