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40-540: An AP connects directly to a wired local area network , typically Ethernet , and the AP then provides wireless connections using wireless LAN technology, typically Wi-Fi, for other devices to use that wired connection. APs support the connection of multiple wireless devices through their one wired connection. There are many wireless data standards that have been introduced for wireless access point and wireless router technology. New standards have been created to accommodate

80-445: A hotspot service. Network topology describes the layout of interconnections between devices and network segments. At the data link layer and physical layer , a wide variety of LAN topologies have been used, including ring , bus , mesh and star . Simple LANs generally consist of cabling and one or more switches . A switch can be connected to a router , cable modem , or ADSL modem for Internet access. A LAN can include

120-404: A limited number of frequencies legally available for use by wireless networks. Usually, adjacent APs will use different frequencies (channels) to communicate with their clients in order to avoid interference between the two nearby systems. Wireless devices can "listen" for data traffic on other frequencies, and can rapidly switch from one frequency to another to achieve better reception. However,

160-673: A wide area network (WAN). 802.11ac IEEE 802.11ac-2013 or 802.11ac is a wireless networking standard in the IEEE 802.11 set of protocols (which is part of the Wi-Fi networking family), providing high-throughput wireless local area networks (WLANs) on the 5 GHz band . The standard has been retroactively labelled as Wi-Fi 5 by Wi-Fi Alliance . The specification has multi-station throughput of at least 1.1 gigabit per second (1.1 Gbit/s) and single-link throughput of at least 500 megabits per second (0.5 Gbit/s). This

200-540: A 2008 article for Wired magazine, Bruce Schneier asserted the net benefits of open Wi-Fi without passwords outweigh the risks, a position supported in 2014 by Peter Eckersley of the Electronic Frontier Foundation . The opposite position was taken by Nick Mediati in an article for PC World , in which he advocates that every wireless access point should be protected with a password. Local area network A local area network ( LAN )

240-561: A Defense Department teleconferencing application. This demonstrated the feasibility of employing TCP/IP LANs to interconnect Worldwide Military Command and Control System (WWMCCS) computers at command centers throughout the United States. However, WWMCCS was superseded by the Global Command and Control System (GCCS) before that could happen. During the same period, Unix workstations were using TCP/IP networking. Although

280-493: A polling/selecting central unit with a multidrop bus with Master/slave (technology) arbitration. The development and proliferation of personal computers using the CP/M operating system in the late 1970s, and later DOS -based systems starting in 1981, meant that many sites grew to dozens or even hundreds of computers. The initial driving force for networking was to share storage and printers , both of which were expensive at

320-519: A simple network operating system LAN Manager and its cousin, IBM's LAN Server . None of these enjoyed any lasting success; Netware dominated the personal computer LAN business from early after its introduction in 1983 until the mid-1990s when Microsoft introduced Windows NT . In 1983, TCP/IP was first shown capable of supporting actual defense department applications on a Defense Communication Agency LAN testbed located at Reston, Virginia. The TCP/IP-based LAN successfully supported Telnet , FTP , and

360-426: A small number of devices that are close to each other, but ad hoc networks do not scale well. Internet traffic will converge to the nodes with direct internet connection, potentially congesting these nodes. For internet-enabled nodes, access points have a clear advantage, with the possibility of having a wired LAN . It is generally recommended that one IEEE 802.11 AP should have, at a maximum, 10–25 clients. However,

400-495: A wide variety of other network devices such as firewalls , load balancers , and network intrusion detection . Advanced LANs are characterized by their use of redundant links with switches using the spanning tree protocol to prevent loops, their ability to manage differing traffic types via quality of service (QoS), and their ability to segregate traffic with VLANs . At the higher network layers, protocols such as NetBIOS , IPX/SPX , AppleTalk and others were once common, but

440-489: Is 1.3 Gbit/s, while Wave 2 can reach 2.34 Gbit/s. Wave 2 can therefore achieve 1 Gbit/s even if the real world throughput turns out to be only 50% of the theoretical rate. Wave 2 also supports a higher number of connected devices. Several companies are currently offering 802.11ac chipsets with higher modulation rates: MCS-10 and MCS-11 (1024-QAM), supported by Quantenna and Broadcom. Although technically not part of 802.11ac, these new MCS indices became official in

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480-564: Is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger geographic distance, but also generally involves leased telecommunication circuits . Ethernet and Wi-Fi are the two most common technologies in use for local area networks. Historical network technologies include ARCNET , Token Ring and AppleTalk . The increasing demand and usage of computers in universities and research labs in

520-413: Is accomplished by extending the air-interface concepts embraced by 802.11n : wider RF bandwidth (up to 160 MHz), more MIMO spatial streams (up to eight), downlink multi-user MIMO (up to four clients), and high-density modulation (up to 256-QAM ). The Wi-Fi Alliance separated the introduction of 802.11ac wireless products into two phases ("waves"), named "Wave 1" and "Wave 2". From mid-2013,

560-519: Is easy and does not require an access point, an ad hoc network is used in situations such as a quick data exchange or a multiplayer video game . Due to its peer-to-peer layout, ad hoc Wi-Fi connections are similar to connections available using Bluetooth . Ad hoc connections are generally not recommended for a permanent installation. Internet access via ad hoc networks , using features like Windows ' Internet Connection Sharing or dedicated software such as WiFi Direct Access Point , may work well with

600-540: Is still the basis of most commercial LANs today. While optical fiber cable is common for links between network switches , use of fiber to the desktop is rare. In a wireless LAN , users have unrestricted movement within the coverage area. Wireless networks have become popular in residences and small businesses, because of their ease of installation. Most wireless LANs use Wi-Fi as wireless adapters are typically integrated into smartphones , tablet computers and laptops . Guests are often offered Internet access via

640-463: The Acorn Atom and Acorn System 2 / 3 / 4 computers in 1981. In the 1980s, several token ring network implementations for LANs were developed. IBM released their own implementation of token ring in 1985, It ran at 4  Mbit/s . IBM claimed that their token ring systems were superior to Ethernet, especially under load, but these claims were debated. IBM's implementation of token ring

680-459: The Internet protocol suite (TCP/IP) has prevailed as the standard of choice. LANs can maintain connections with other LANs via leased lines, leased services, or across the Internet using virtual private network technologies. Depending on how the connections are established and secured, and the distance involved, such linked LANs may also be classified as a metropolitan area network (MAN) or

720-429: The finalization of the 802.11n standard in 2009 inherent problems integrating products from different vendors are less prevalent. Wireless access has special security considerations. Many wired networks base the security on physical access control, trusting all the users on the local network, but if wireless access points are connected to the network, anybody within range of the AP (which typically extends farther than

760-557: The 2.4 GHz and 5 GHz radios could achieve combined throughput approaching 1900 Mbit/s. Different possible stream configurations can add up to the same AC number. Quantenna released the first 802.11ac chipset for retail Wi-Fi routers and consumer electronics on November 15, 2011. Redpine Signals released the first low power 802.11ac technology for smartphone application processors on December 14, 2011. On January 5, 2012, Broadcom announced its first 802.11ac Wi-Fi chips and partners and on April 27, 2012, Netgear announced

800-711: The 802.11ax standard, ratified in 2021. 160 MHz channels are unavailable in some countries due to regulatory issues that allocated some frequencies for other purposes. 802.11ac-class device wireless speeds are often advertised as AC followed by a number, that number being the highest link rates in Mbit/s of all the simultaneously-usable radios in the device added up. For example, an AC1900 access point might have 600 Mbit/s capability on its 2.4 GHz radio and 1300 Mbit/s capability on its 5 GHz radio. No single client device could connect and achieve 1900 Mbit/s of throughput, but separate devices each connecting to

840-422: The actual maximum number of clients that can be supported can vary significantly depending on several factors, such as type of APs in use, density of client environment, desired client throughput, etc. The range of communication can also vary significantly, depending on such variables as indoor or outdoor placement, height above ground, nearby obstructions, other electronic devices that might actively interfere with

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880-415: The actual over-the-air rate for data throughput. Thus a typical 54 Mbit/s wireless connection actually carries TCP/IP data at 20 to 25 Mbit/s. Users of legacy wired networks expect faster speeds, and people using wireless connections keenly want to see the wireless networks catch up. By 2012, 802.11n based access points and client devices have already taken a fair share of the marketplace and with

920-460: The advent of Novell NetWare which provided even-handed support for dozens of competing card and cable types, and a much more sophisticated operating system than most of its competitors. Of the competitors to NetWare, only Banyan Vines had comparable technical strengths, but Banyan never gained a secure base. 3Com produced 3+Share and Microsoft produced MS-Net . These then formed the basis for collaboration between Microsoft and 3Com to create

960-829: The alliance started certifying Wave 1 802.11ac products shipped by manufacturers, based on the IEEE 802.11ac Draft 3.0 (the IEEE standard was not finalized until later that year). Subsequently in 2016, Wi-Fi Alliance introduced the Wave 2 certification, which includes additional features like MU-MIMO (down-link only), 160 MHz channel width support, support for more 5 GHz channels, and four spatial streams (with four antennas; compared to three in Wave 1 and 802.11n, and eight in IEEE's 802.11ax specification). It meant Wave 2 products would have higher bandwidth and capacity than Wave 1 products. New technologies introduced with 802.11ac include

1000-672: The benches of the European Parliament Hemicycles in Strasbourg and Luxembourg. Early Ethernet ( 10BASE-5 and 10BASE-2 ) used coaxial cable . Shielded twisted pair was used in IBM's Token Ring LAN implementation. In 1984, StarLAN showed the potential of simple unshielded twisted pair by using category 3 cable —the same cable used for telephone systems. This led to the development of 10BASE-T (and its twisted-pair successors ) and structured cabling which

1040-568: The consumer market can reach sustained real-world speeds of some 240 Mbit/s at 13 m behind two standing walls ( NLOS ) depending on their nature or 360 Mbit/s at 10 m line of sight or 380 Mbit/s at 2 m line of sight ( IEEE 802.11ac ) or 20 to 25 Mbit/s at 2 m line of sight ( IEEE 802.11g ), wired hardware of similar cost reaches closer to 1000 Mbit/s up to specified distance of 100 m with twisted-pair cabling in optimal conditions ( Category 5 (known as Cat-5) or better cabling with Gigabit Ethernet ). One impediment to increasing

1080-444: The first Broadcom-enabled router. On May 14, 2012, Buffalo Technology released the world’s first 802.11ac products to market, releasing a wireless router and client bridge adapter. On December 6, 2012, Huawei announced commercial availability of the industry's first enterprise-level 802.11ac Access Point. Motorola Solutions is selling 802.11ac access points including the AP 8232. In April 2014, Hewlett-Packard started selling

1120-473: The following: The single-link and multi-station enhancements supported by 802.11ac enable several new WLAN usage scenarios, such as simultaneous streaming of HD video to multiple clients throughout the home, rapid synchronization and backup of large data files, wireless display, large campus/auditorium deployments, and manufacturing floor automation. To fully utilize their WLAN capacities, 802.11ac access points and routers have sufficient throughput to require

1160-503: The inclusion of a USB 3.0 interface to provide various services such as video streaming, FTP servers, and personal cloud services. With storage locally attached through USB 2.0 , filling the bandwidth made available by 802.11ac was not easily accomplished. All rates assume 256-QAM, rate 5/6: Wave 2, referring to products introduced in 2016, offers a higher throughput than legacy Wave 1 products, those introduced starting in 2013. The maximum physical layer theoretical rate for Wave 1

1200-423: The increasing need for faster wireless connections. Access points can provide backward compatibility with older Wi-Fi protocols as many devices were manufactured for use with older standards. Some people confuse wireless access points with wireless ad hoc networks . An ad hoc network uses a connection between two or more devices without using a wireless access point; the devices communicate directly. Because setup

1240-532: The intended area) can attach to the network. The most common solution is wireless traffic encryption. Modern access points come with built-in encryption. The first generation encryption scheme, WEP , proved easy to crack; the second and third generation schemes, WPA and WPA2 , are considered secure if a strong enough password or passphrase is used. Some APs support hotspot style authentication using RADIUS and other authentication servers . Opinions about wireless network security vary widely. For example, in

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1280-503: The late 1960s generated the need to provide high-speed interconnections between computer systems. A 1970 report from the Lawrence Radiation Laboratory detailing the growth of their "Octopus" network gave a good indication of the situation. A number of experimental and early commercial LAN technologies were developed in the 1970s. Ethernet was developed at Xerox PARC between 1973 and 1974. Cambridge Ring

1320-434: The limited number of frequencies becomes problematic in crowded downtown areas with tall buildings using multiple APs. In such an environment , signal overlap becomes an issue causing interference, which results in signal degradation and data errors. Wireless networking lags wired networking in terms of increasing bandwidth and throughput . While (as of 2013) high-density 256-QAM modulation, 3-antenna wireless devices for

1360-439: The signal by broadcasting on the same frequency, type of antenna , the current weather, operating radio frequency , and the power output of devices. Network designers can extend the range of APs through the use of repeaters , which amplify a radio signal, and reflectors , which only bounce it. In experimental conditions, wireless networking has operated over distances of several hundred kilometers. Most jurisdictions have only

1400-414: The speed of wireless communications comes from Wi-Fi 's use of a shared communications medium: Thus, two stations in infrastructure mode that are communicating with each other even over the same AP must have each and every frame transmitted twice: from the sender to the AP, then from the AP to the receiver. This approximately halves the effective bandwidth, so an AP is only able to use somewhat less than half

1440-563: The time. There was much enthusiasm for the concept, and for several years, from about 1983 onward, computer industry pundits habitually declared the coming year to be, "The year of the LAN". In practice, the concept was marred by the proliferation of incompatible physical layer and network protocol implementations, and a plethora of methods of sharing resources. Typically, each vendor would have its own type of network card, cabling, protocol, and network operating system . A solution appeared with

1480-530: The workstation market segment is now much reduced, the technologies developed in the area continue to be influential on the Internet and in all forms of networking—and the TCP/IP protocol has replaced IPX , AppleTalk , NBF , and other protocols used by the early PC LANs. Econet was Acorn Computers's low-cost local area network system, intended for use by schools and small businesses. It was first developed for

1520-651: Was a relatively high-speed choice of that era, with speeds such as 100 Mbit/s. By 1994, vendors included Cisco Systems , National Semiconductor , Network Peripherals, SysKonnect (acquired by Marvell Technology Group ), and 3Com . FDDI installations have largely been replaced by Ethernet deployments. In 1979, the Electronic voting systems for the European Parliament was using 10 kilometers of simple unshielded twisted pair category 3 cable —the same cable used for telephone systems—installed inside

1560-530: Was developed at Cambridge University starting in 1974. ARCNET was developed by Datapoint Corporation in 1976 and announced in 1977. It had the first commercial installation in December 1977 at Chase Manhattan Bank in New York. In 1979, the Electronic voting systems for the European Parliament was the first installation of a LAN connecting hundreds (420) of microprocessor-controlled voting terminals to

1600-573: Was the basis of the IEEE 802.5 standard. A 16 Mbit/s version of Token Ring was standardized by the 802.5 working group in 1989. IBM had market dominance over Token Ring, for example, in 1990, IBM equipment was the most widely used for Token Ring networks. Fiber Distributed Data Interface (FDDI), a LAN standard, was considered an attractive campus backbone network technology in the early to mid 1990s since existing Ethernet networks only offered 10 Mbit/s data rates and Token Ring networks only offered 4 Mbit/s or 16 Mbit/s rates. Thus it

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