Wireless network interface controller: Difference between revisions

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{{shortShort description|hardwareHardware component that connects a computer to a wireless computer network}}

{{update|date=July 2013}}

[[File:USB-wireless-adapter.jpg|thumb|250px|A wireless network interface device with a USB interface and internal antenna]]

[[File:DELL TrueMobile 350 Bluetooth card.jpg|thumb|A Bluetooth interface card]]

A '''wireless network interface controller''' ('''WNIC''') is a [[network interface controller]] which is used to connectconnects to a [[wireless network]] through a wireless connection, such as [[Wi-Fi]] or, [[Bluetooth]], or [[LTE (telecommunication)|LTE]] (4G) or [[5G]] rather than a wired network, such as aan [[TokenEthernet]] Ringnetwork. It consists of a [[modem]], oran automated [[Ethernetradio transmitter]]. and A[[radio WNIC,receiver|receiver]] justwhich likeoperate otherin NICsthe background, worksexchanging ondigital data in the layersform 1of and[[data 2packet]]s ofwith theother wireless devices or [[OSIwireless modelrouter]]s andusing [[radio wave]]s radiated usesby an [[antenna (radio)|antenna]], tolinking communicatethe viadevices together transparently in a [[radiocomputer wavenetwork]]s. A WNIC, just like other [[network interface controller]]s (NICs), works on the layers 1 and 2 of the [[OSI model]].

A wireless network interface controller may be implemented as an [[expansion card]] and connected using [[Peripheral Component Interconnect|PCI]] bus or [[PCIe]] bus, or connected via [[USB]], [[PC Card]], [[ExpressCard]], [[Mini PCIe]] or [[M.2]].

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The low cost and ubiquity of the [[Wi-Fi]] standard means that many newer mobile computers have a wireless network interface built into the [[motherboard]].

The term is usually applied to adapters using the [[Wi-Fi]] ([[IEEE 802.11]]) adaptersnetwork protocol; it may also apply to a NIC using protocols other than 802.11, such as one implementing [[Bluetooth]] connections.

== Modes of operation ==

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; Infrastructure mode

: In an infrastructure mode network the WNIC needs a [[wireless access point]]: all data is transferred using the access point as the central hub. All wireless [[Node (networking)|nodes]] in an infrastructure mode network connect to an access point. All nodes connecting to the access point must have the same [[service set identifier]] (SSID) as the access point, and if a kind. ofIf wireless security is enabled on the access point (such as [[Wired Equivalent Privacy|WEP]] or [[Wi-Fi Protected Access|WPA]]), they must share the sameNIC keysmust orhave othervalid [[authentication]] parameters in order to connect to the access point.

; Ad hoc mode

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Specifications commonly used in marketing materials for WNICs include:

*Wireless [[data transfer]] rates (measured in Mbit/s); these range from 2 Mbit/s to 54 Mbit/s.<ref name="Meyers">Meyers, Mike: Network+ Certification All-in-One Exam Guide, McGraw-Hill, 2004, p. 230.</ref>

*Wireless transmit power (measured in [[dBm]])

*Wireless network standards (may include standardssupported, such as [[802.11b]], [[IEEE 802.11g11a-1999|802.11a]], [[802.11n11g]], etc.) [[802.11g11n]], offers data transfer speeds equivalent to[[IEEE 802.11a &ndash; up to 54 Mbit/s &ndash; and the wider {{convert11ac-2013|300|ft|m|adj=on}} range of 802.11b11ac]], and is backward compatible with[[Wi-Fi 6|802.11b.11ax]]

Most WNICs support one or more of 802.11, Bluetooth and 3GPP (2G, 3G, 4G, 5G) network standards.

Most Bluetooth cards do not implement any form of the 802.11 standard.

==Range==

Wireless range may be substantially affected by objects in the way of the signal and by the quality of the antenna. Large electrical appliances, such as refrigerators, fuse boxes, metal plumbing, and air conditioning units can impede a wireless network signal. The theoretical maximum range of IEEE 802.11 is only reached under ideal circumstances and true effective range is typically about half of the theoretical range.<ref name="Meyers">Meyers, Mike: Network+ Certification All-in-One Exam Guide, McGraw-Hill, 2004, p. 230.</ref> Specifically, the maximum throughput speed is only achieved at extremely close range (less than {{convert|25|ft|m}} or so); at the outer reaches of a device's effective range, speed may decrease to around 1 &nbsp;Mbit/s before it drops out altogether. The reason is that wireless devices dynamically negotiate the top speed at which they can communicate without dropping too many data packets.

== {{Anchor|MAC80211|MLME|FULLMAC|SOFTMAC|HARDMAC}}FullMAC and SoftMAC devices ==