Wireless network interface controller

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A wireless network interface device with a USB interface and internal antenna USB-wireless-adapter.jpg
A wireless network interface device with a USB interface and internal antenna
A Bluetooth interface card DELL TrueMobile 350 Bluetooth card.jpg
A Bluetooth interface card

A wireless network interface controller (WNIC) is a network interface controller which connects to a wireless network, such as Wi-Fi, Bluetooth, or LTE (4G) or 5G rather than a wired network, such as an Ethernet network. A WNIC, just like other NICs, works on the layers 1 and 2 of the OSI model and uses an antenna to communicate via radio waves.

Contents

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

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 IEEE 802.11 adapters; it may also apply to a NIC using protocols other than 802.11, such as one implementing Bluetooth connections.

Modes of operation

An 802.11 WNIC can operate in two modes known as infrastructure mode and ad hoc mode :

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 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. If wireless security is enabled on the access point (such as WEP or WPA), the NIC must have valid authentication parameters in order to connect to the access point.
Ad hoc mode
In an ad hoc mode network the WNIC does not require an access point, but rather can interface with all other wireless nodes directly. All the nodes in an ad hoc network must have the same channel and SSID.

Specifications

The IEEE 802.11 standard sets out low-level specifications for how all 802.11 wireless networks operate. Earlier 802.11 interface controllers are usually only compatible with earlier variants of the standard, while newer cards support both current and old standards.

Specifications commonly used in marketing materials for WNICs include:

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

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. [1] Specifically, the maximum throughput speed is only achieved at extremely close range (less than 25 feet (7.6 m) or so); at the outer reaches of a device's effective range, speed may decrease to around 1 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.

FullMAC and SoftMAC devices

In an 802.11 WNIC, the MAC Sublayer Management Entity (MLME) can be implemented either in the NIC's hardware or firmware, or in host-based software that is executed on the main CPU. A WNIC that implements the MLME function in hardware or firmware is called a FullMAC WNIC or a HardMAC NIC [2] and a NIC that implements it in host software is called a SoftMAC NIC. [3]

A FullMAC device hides the complexity of the 802.11 protocol from the main CPU, instead providing an 802.3 (Ethernet) interface; a SoftMAC design implements only the timing-critical part of the protocol in hardware/firmware and the rest on the host. [4]

FullMAC chips are typically used in mobile devices because:

Popular example of FullMAC chips is the one implemented on the Raspberry Pi 3.

Linux kernel's mac80211 framework provides capabilities for SoftMAC devices and additional capabilities (such as mesh networking, which is known as the IEEE 802.11s standard) for devices with limited functionality. [5] [3]

FreeBSD also supports SoftMAC drivers. [6]

See also

Related Research Articles

IEEE 802.15 is a working group of the Institute of Electrical and Electronics Engineers (IEEE) IEEE 802 standards committee which specifies Wireless Specialty Networks (WSN) standards. The working group was formerly known as Working Group for Wireless Personal Area Networks.

A MAC address is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking technologies, including Ethernet, Wi-Fi, and Bluetooth. Within the Open Systems Interconnection (OSI) network model, MAC addresses are used in the medium access control protocol sublayer of the data link layer. As typically represented, MAC addresses are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or without a separator.

<span class="mw-page-title-main">Wireless LAN</span> Computer network that links devices using wireless communication within a limited area

A wireless LAN (WLAN) is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office building. This gives users the ability to move around within the area and remain connected to the network. Through a gateway, a WLAN can also provide a connection to the wider Internet.

<span class="mw-page-title-main">Wi-Fi</span> Wireless local area network

Wi-Fi is a family of wireless network protocols based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves. These are the most widely used computer networks, used globally in home and small office networks to link devices and to provide Internet access with wireless routers and wireless access points in public places such as coffee shops, hotels, libraries, and airports to provide visitors.

<span class="mw-page-title-main">Wireless access point</span> Device that allows wireless devices to connect to a wired network

In computer networking, a wireless access point, or more generally 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 connection to a switch or router, but, in a wireless router, it can also be an integral component of the router itself. An AP is differentiated from a hotspot, which is a physical location where Wi-Fi access is available.

<span class="mw-page-title-main">Network interface controller</span> Hardware component that connects a computer to a network

A network interface controller is a computer hardware component that connects a computer to a computer network.

In computer networking, promiscuous mode is a mode for a wired network interface controller (NIC) or wireless network interface controller (WNIC) that causes the controller to pass all traffic it receives to the central processing unit (CPU) rather than passing only the frames that the controller is specifically programmed to receive. This mode is normally used for packet sniffing that takes place on a router or on a computer connected to a wired network or one being part of a wireless LAN. Interfaces are placed into promiscuous mode by software bridges often used with hardware virtualization.

IEEE 802.15.4 is a technical standard which defines the operation of a low-rate wireless personal area network (LR-WPAN). It specifies the physical layer and media access control for LR-WPANs, and is maintained by the IEEE 802.15 working group, which defined the standard in 2003. It is the basis for the Zigbee, ISA100.11a, WirelessHART, MiWi, 6LoWPAN, Thread, Matter and SNAP specifications, each of which further extends the standard by developing the upper layers which are not defined in IEEE 802.15.4. In particular, 6LoWPAN defines a binding for the IPv6 version of the Internet Protocol (IP) over WPANs, and is itself used by upper layers like Thread.

<span class="mw-page-title-main">Wireless mesh network</span> Radio nodes organized in a mesh topology

A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. It can also be a form of wireless ad hoc network.

<span class="mw-page-title-main">Service set (802.11 network)</span> Group of all devices on the same wireless network

In IEEE 802.11 wireless local area networking standards, a service set is a group of wireless network devices which share a service set identifier (SSID)—typically the natural language label that users see as a network name. A service set forms a logical network of nodes operating with shared link-layer networking parameters; they form one logical network segment.

<span class="mw-page-title-main">Beacon frame</span> Type of management frame

A beacon frame is a type of management frame in IEEE 802.11 WLANs. It contains information about the network. Beacon frames are transmitted periodically; they serve to announce the presence of a wireless LAN and to provide a timing signal to synchronise communications with the devices using the network. In an infrastructurebasic service set (BSS), beacon frames are transmitted by the access point (AP). In ad hoc (IBSS) networks, beacon generation is distributed among the stations. For the 2.4 GHz spectrum, when having more than 15 SSIDs on non-overlapping channels, beacon frames start to consume significant amount of air time and degrade performance even when most of the networks are idle.

<span class="mw-page-title-main">Wireless router</span> Computer networking device

A wireless router or Wi-Fi router is a device that performs the functions of a router and also includes the functions of a wireless access point. It is used to provide access to the Internet or a private computer network. Depending on the manufacturer and model, it can function in a wired local area network, in a wireless-only LAN, or in a mixed wired and wireless network.

<span class="mw-page-title-main">Link aggregation</span> Using multiple network connections in parallel to increase capacity and reliability

In computer networking, link aggregation is the combining of multiple network connections in parallel by any of several methods. Link aggregation increases total throughput beyond what a single connection could sustain, and provides redundancy where all but one of the physical links may fail without losing connectivity. A link aggregation group (LAG) is the combined collection of physical ports.

<span class="mw-page-title-main">Wireless security</span> Aspect of wireless networks

Wireless security is the prevention of unauthorized access or damage to computers or data using wireless networks, which include Wi-Fi networks. The term may also refer to the protection of the wireless network itself from adversaries seeking to damage the confidentiality, integrity, or availability of the network. The most common type is Wi-Fi security, which includes Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA). WEP is an old IEEE 802.11 standard from 1997. It is a notoriously weak security standard: the password it uses can often be cracked in a few minutes with a basic laptop computer and widely available software tools. WEP was superseded in 2003 by WPA, a quick alternative at the time to improve security over WEP. The current standard is WPA2; some hardware cannot support WPA2 without firmware upgrade or replacement. WPA2 uses an encryption device that encrypts the network with a 256-bit key; the longer key length improves security over WEP. Enterprises often enforce security using a certificate-based system to authenticate the connecting device, following the standard 802.11X.

Monitor mode, or RFMON mode, allows a computer with a wireless network interface controller (WNIC) to monitor all traffic received on a wireless channel. Unlike promiscuous mode, which is also used for packet sniffing, monitor mode allows packets to be captured without having to associate with an access point or ad hoc network first. Monitor mode only applies to wireless networks, while promiscuous mode can be used on both wired and wireless networks. Monitor mode is one of the eight modes that 802.11 wireless adapter can operate in: Master, Managed, Ad hoc, Repeater, Mesh, Wi-Fi Direct, TDLS and Monitor mode.

Qualcomm Atheros is a developer of semiconductor chips for network communications, particularly wireless chipsets. The company was founded under the name T-Span Systems in 1998 by experts in signal processing and VLSI design from Stanford University, the University of California, Berkeley, and private industry. The company was renamed Atheros Communications in 2000 and it completed an initial public offering in February 2004, trading on the NASDAQ under the symbol ATHR.

Wireless tools for Linux is a collection of user-space utilities written for Linux kernel-based operating systems to support and facilitate the configuration of device drivers of wireless network interface controllers and some related aspects of networking using the Linux Wireless Extension. The Wireless tools for Linux and Linux Wireless Extension are maintained by Jean Tourrilhes and sponsored by Hewlett-Packard.

<span class="mw-page-title-main">Wireless repeater</span> Wireless computer networking device

A wireless repeater is a device that takes an existing signal from a wireless router or wireless access point and rebroadcasts it to create a second network. When two or more hosts have to be connected with one another over the IEEE 802.11 protocol and the distance is too long for a direct connection to be established, a wireless repeater is used to bridge the gap. It can be a specialized stand-alone computer networking device. Also, some wireless network interface controllers (WNIC)s optionally support operating in such a mode. Those outside of the primary network will be able to connect through the new "repeated" network. However, as far as the original router or access point is concerned, only the repeater MAC is connected, making it necessary to enable safety features on the wireless repeater. Wireless repeaters are commonly used to improve signal range and strength within homes and small offices.

IEEE 802.11s is a wireless local area network (WLAN) standard and an IEEE 802.11 amendment for mesh networking, defining how wireless devices can interconnect to create a wireless LAN mesh network, which may be used for relatively fixed topologies and wireless ad hoc networks. The IEEE 802.11s task group drew upon volunteers from university and industry to provide specifications and possible design solutions for wireless mesh networking. As a standard, the document was iterated and revised many times prior to finalization.

<span class="mw-page-title-main">ESP32</span> Low-cost, low-power SoC microcontrollers with Bluetooth and Wi-Fi

ESP32 is a series of low-cost, low-power system on a chip microcontrollers with integrated Wi-Fi and dual-mode Bluetooth. The ESP32 series employs either a Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations, Xtensa LX7 dual-core microprocessor or a single-core RISC-V microprocessor and includes built-in antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power-management modules. ESP32 is created and developed by Espressif Systems, a Chinese company based in Shanghai, and is manufactured by TSMC using their 40 nm process. It is a successor to the ESP8266 microcontroller.

References

  1. Meyers, Mike: Network+ Certification All-in-One Exam Guide, McGraw-Hill, 2004, p. 230.
  2. "Linux Wireless glossary". Definition of FullMAC. Retrieved 23 July 2020.
  3. 1 2 "Linux Wireless glossary". Definition of SoftMAC. Retrieved 23 July 2020.
  4. Al-Sakib Khan Pathan (2010). Security of Self-Organizing Networks: MANET, WSN, WMN, VANET. Taylor & Francis. p. 28. ISBN   978-1-4398-1919-7.
  5. "mac80211 documentation". kernel.org .
  6. "FreeBSD 11.0 - man page for upgt (freebsd section 4) - Unix & Linux Commands" . Retrieved 1 June 2016.