Editing Wireless access point

{{Short description|Device that allows wireless devices to connect to a wired network}}
{{Redirect|Access point}}
{{More citations needed|date=August 2019}}
{{Use mdy dates|date=December 2024}}
[[File:Cisco Aironet 1131AG - Close.jpg|thumb|[[Cisco]] Aironet wireless access point]]

In [[Computer networking device|computer networking]], a '''wireless access point''' ('''WAP''') (also just '''access point''' ('''AP''')) is a [[networking hardware]] device that allows other Wi-Fi devices to connect to a wired network or wireless network. As a standalone device, the AP may have a wired or wireless connection to a [[Network switch|switch]] or [[Router (computing)|router]], but in a [[wireless router]] it can also be an integral component of the networking device itself. A WAP and AP is differentiated from a [[Wi-Fi hotspot|hotspot]], which can be a physical location or digital location where Wi-Fi or WAP access is available.<ref name=":1" /><ref name=":2">{{Cite journal |last=Ma |first=Hong |date=June 5, 2012 |title=Google Refine – <nowiki>http://code.google.com/p/google-refine/</nowiki> |url=http://dx.doi.org/10.1080/07317131.2012.682016 |journal=Technical Services Quarterly |volume=29 |issue=3 |pages=242–243 |doi=10.1080/07317131.2012.682016 |issn=0731-7131|url-access=subscription }}</ref>

==Connections==
[[File:Linksys WAP54G.JPG|thumb|Linksys "WAP54G" 802.11g [[wireless router]]]]
[[File:RouterBoard 112 with U.FL-RSMA pigtail and R52 miniPCI Wi-Fi card.jpg|thumb|Embedded RouterBoard 112, widely used by [[wireless Internet service provider]]s (WISPs) across the world, with [[U.FL]]-[[SMA connector|RSMA]] pigtail and R52 [[mini PCI]] [[Wi-Fi]] card]]
An AP connects directly to a wired [[local area network|local]]<ref name=":0" /> [[local area network|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.

== Wireless data standards ==
There are many [[Comparison of wireless data standards|wireless data standards]] that have been introduced for wireless access point and [[wireless router]] technology. New standards have been created to accommodate 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.<ref name=":0">{{Cite web|url=https://breech.co/guides/wireless-routers/|title=Wireless Routers Guide: Everything You Need To Know|website=Breech.co|access-date=October 17, 2018}}</ref>

{{div col|colwidth=20em}}
* [[802.11a]]
* [[802.11b]]
* [[802.11g]]
* [[802.11n]] (Wi-Fi 4)
* [[802.11ac]] (Wi-Fi 5)
* [[802.11ax]] (Wi-Fi 6/6E)
* [[802.11be]] (Wi-Fi 7)
{{div col end}}

==Wireless access point vs. ad hoc network==
Some people confuse wireless access points with [[wireless ad hoc network]]s. An ad hoc network uses a connection between two or more devices ''without'' using a wireless access point; the devices communicate directly. Because setup 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.<ref name=":1">{{cite web |url=https://www.howtogeek.com/180649/htg-explains-whats-the-difference-between-ad-hoc-and-infrastructure-mode/ |title=What's the Difference Between Ad-Hoc and Infrastructure Mode Wi-Fi? |author=Chris Hoffman |date=September 22, 2016 |access-date=December 16, 2017}}</ref> [[Internet access]] via [[ad hoc network]]s, using features like [[Microsoft Windows|Windows]]' [[Internet Connection Sharing]] or dedicated software such as [https://apps.microsoft.com/detail/9n4lnn4hk7v6 WiFi Direct Access Point], may work well with 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]].

==Limitations==
It is generally recommended that one [[IEEE 802.11]] AP should have, at a maximum, 10–25 clients.<ref>{{cite web|url=https://www.mcnc.org/sites/default/files/Designing-and-Building-a-Campus-Wireless-Network-2012-v2.pdf|title=Designing and Building a Campus Wireless Network|year=2012|publisher=MCNC|quote=For areas that have high bandwidth and a concentrated area of users (i.e. classrooms in a 1:1 computing school), plan for approximately 15-25 data users per AP. When wireless devices are used for high bandwidth applications or concurrent use such as online testing, an even greater number of APs may be required to achieve a density closer to 10-15 users per AP.|access-date=June 15, 2017|archive-date=July 31, 2017|archive-url=https://web.archive.org/web/20170731232127/https://www.mcnc.org/sites/default/files/Designing-and-Building-a-Campus-Wireless-Network-2012-v2.pdf|url-status=dead}}</ref> However, 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 the signal by broadcasting on the same frequency, type of [[antenna (electronics)|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 [[repeater]]s, which [[Amplifier|amplify]] a radio signal, and [[Passive repeater|reflector]]s, which only bounce it. In experimental conditions, wireless networking has operated over distances of several hundred kilometers.<ref>{{cite web|title=Setting Long Distance WiFi Records: Proofing Solutions for Rural Connectivity|url=http://www.ci-journal.net/index.php/ciej/article/view/487/420|author=Ermanno Pietrosemoli|publisher=Fundación Escuela Latinoamericana de Redes [[University of the Andes (Venezuela)]]|access-date=March 17, 2012|archive-date=December 19, 2018|archive-url=https://web.archive.org/web/20181219000813/http://www.ci-journal.net/index.php/ciej/article/view/487/420|url-status=dead}}</ref>

Most jurisdictions have only 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 (communication)|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, the limited number of frequencies becomes problematic in crowded downtown areas with tall buildings using multiple APs. In such an [[Built environment|environment]], signal overlap becomes an issue causing interference, which results in signal degradation and data errors.<ref>{{Cite web|title=The overlapping channel problem|url=https://community.jisc.ac.uk/library/advisory-services/overlapping-channel-problem}}</ref>

Wireless networking lags wired networking in terms of increasing [[Bandwidth (computing)|bandwidth]] and [[throughput]]. While (as of 2013) high-density [[256-QAM#Quantized QAM|256-QAM]] modulation, 3-antenna wireless devices for the consumer market can reach sustained real-world speeds of some 240&nbsp;Mbit/s at 13 m behind two standing walls ([[Non-line-of-sight propagation|NLOS]]) depending on their nature or 360&nbsp;Mbit/s at 10 m line of sight or 380&nbsp;Mbit/s at 2 m line of sight ([[Institute of Electrical and Electronics Engineers|IEEE]] [[802.11ac]]) or 20 to 25&nbsp;Mbit/s at 2 m line of sight ([[IEEE]] [[802.11g]]), wired hardware of similar cost reaches closer to 1000&nbsp;Mbit/s up to specified distance of 100 m with twisted-pair cabling in optimal conditions ([[Cat‑5|Category 5 (known as Cat-5)]] or better cabling with [[Gigabit Ethernet]]). One impediment to increasing 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 the actual over-the-air rate for data throughput. Thus a typical 54&nbsp;Mbit/s wireless connection actually carries [[TCP/IP]] data at 20 to 25&nbsp;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 the [[IEEE 802.11n-2009|finalization of the 802.11n standard in 2009]] inherent problems integrating products from different vendors are less prevalent.

==Security==
{{Main|Wireless LAN security}}
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 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, [[Wired Equivalent Privacy|WEP]], proved easy to crack; the second and third generation schemes, [[Wi-Fi Protected Access|WPA]] and [[IEEE 802.11i|WPA2]], are considered secure<ref>{{Cite book|url=https://books.google.com/books?id=b3r81GCpOnYC&q=wpa+security+research&pg=PT108|title=Handbook of Research on Wireless Security|last1=Zhang|first1=Yan|last2=Zheng|first2=Jun|last3=Ma|first3=Miao|date=January 1, 2008|publisher=Idea Group Inc (IGI)|isbn=9781599048994}}</ref> if a strong enough [[Password cracking|password]] or [[passphrase]] is used.

Some APs support hotspot style authentication using [[RADIUS]] and other [[authentication server]]s.

Opinions about wireless network security vary widely. For example, in a 2008 article for ''[[Wired Magazine|Wired]]'' magazine, [[Bruce Schneier]] asserted the net benefits of open Wi-Fi without passwords outweigh the risks,<ref>{{cite web |url=https://www.wired.com/politics/security/commentary/securitymatters/2008/01/securitymatters_0110 |title=Steal This Wi-Fi |work=[[Wired Magazine]] |author=Bruce Schneier |author-link=Bruce Schneier |date=January 10, 2008}}</ref> a position supported in 2014 by Peter Eckersley of the [[Electronic Frontier Foundation]].<ref>{{cite web |url=https://www.eff.org/deeplinks/2011/04/open-wireless-movement |title=Why We Need An Open Wireless Movement |date=April 27, 2011 |publisher=[[Electronic Frontier Foundation]]}}</ref> 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.<ref>{{cite web |url=http://www.pcworld.com/article/226784/secure_your_wifi.html |title=How to Secure Your Home Wi-Fi Network |work=[[PC World]] |date=June 24, 2011 |author=Nick Mediati}}</ref>

==See also==
* [[Femtocell]] – a local-area base station using cellular network standards such as UMTS, rather than Wi-Fi
* [[HomePlug]] – wired LAN technology that has a few elements in common with Wi-Fi
* [[Lightweight Access Point Protocol]] – used to manage a large set of APs
* [[List of router firmware projects]]
* [[Wi-Fi Direct]] – a Wi-Fi standard that enables devices to connect with each other without requiring a (hardware) wireless access point and to communicate at typical Wi-Fi speeds
* [[WiMAX]] – wide-area wireless standard that has a few elements in common with Wi-Fi
* {{anl|Wireless Application Protocol}}, sometimes confused for access points, especially in mobile contexts

==References==
{{Reflist}}
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[[Category:IEEE 802.11|Access point]]
[[Category:Network access]]
[[Category:Telecommunications infrastructure]]
[[Category:Wireless networking hardware|Access point]]
[[Category:Wireless access points| ]]