Wireless network interface card


Wireless network interface card

A wireless network interface controller (WNIC) is a network card which connects to a radio-based computer network, unlike a regular network interface controller (NIC) which connects to a wire-based network such as token ring or ethernet. A WNIC, just like a NIC, works on the Layer 1 and Layer 2 of the OSI Model. A WNIC is an essential component for wireless desktop computer. This card uses an antenna to communicate through microwaves. A WNIC in a desktop computer usually is connected using the PCI bus. Other connectivity options are USB and PC card. Integrated WNIC's are also available, (typically in Mini PCI/PCI Express Mini Card form).

Modes of operation

A WNIC can operate in two modes known as infrastructure mode and ad hoc mode.

In an infrastructure mode network the WNIC needs an 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, and if the access point is enabled with WEP they must have the same WEP key or other authentication parameters.

In an ad-hoc mode network the WNIC does not require an access point, but rather can directly interface with all other wireless nodes directly. All the nodes in an ad-hoc network must have the same channel and SSID.

WNICs are designed around the IEEE 802.11 standard which sets out low-level specifications for how all wireless networks operate. Earlier 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:
*Wireless data transfer rates (measured in Mbit/s); these range from 2 Mbit/s to 54 Mbit/s.Meyers, Mike: Network+ Certification All-in-One Exam Guide, McGraw-Hill, 2004, p. 230.]
*Wireless transmit power (measured in dBm)
*Wireless network standards (may include standards such as 802.11b, 802.11g, etc.) 802.11g offers data transfer speeds equivalent to 802.11a – up to 54 Mbit/s – and the wider convert|300|ft|m|sing=on range of 802.11b, and is backward compatible with 802.11b.

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 a refrigerators, fuse boxes, metal plumbing, and air conditioning units can block a wireless network signal. The theoretical maximum range is only reached under ideal circumstances and true effective range is typically about half of the theoretical range. 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 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.

References

ee also

* List of device bandwidths


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Network Interface Card — 100 MBit/s PCI Ethernet Netzwerkkarte mit RJ45 Buchse Eine Netzwerkkarte (auch NIC für engl. Network Interface Card) ist eine elektronische Schaltung zur Verbindung eines Computers mit einem lokalen Netzwerk zum Austausch von Daten. Ihre primäre… …   Deutsch Wikipedia

  • Network interface controller — Network Interface Card (NIC) A 1990s Ethernet network interface controller card which connects to the motherboard via the now obsolete ISA bus. This combination card features both a (now obsolete) bayonet cap BNC connector (left) for use in… …   Wikipedia

  • Network card — Infobox Computer Hardware Generic name = Network Card caption = A 1990s Ethernet network interface controller card which connects to the motherboard via the now obsolete ISA bus. This combination card features both a (now obsolete) bayonet cap… …   Wikipedia

  • Wireless LAN — This notebook computer is connected to a wireless access point using a PC card wireless card …   Wikipedia

  • Network forensics — Forensic science Physiological sciences …   Wikipedia

  • interface — ▪ I. interface in‧ter‧face 1 [ˈɪntəfeɪs ǁ ər ] noun [countable] 1. the point at which two subjects, events etc are connected with each other or have an effect on one another: interface between • The next chapter discusses the interface between… …   Financial and business terms

  • Wireless tools for Linux — is a package of Linux commands to facilitate the manipulation of the Linux Wireless Extension. It is a fundamental set of simple text based utilities/tools for configuring wireless devices. It is intended to support the full wireless extension [… …   Wikipedia

  • Card server — is software which acts as a key host for card clients. Card server usually has one or moresmartcard readers and ethernet interface. Card server emulates CAM for accessing smartcard and offers virtual common interface to the clients.Operation… …   Wikipedia

  • Wireless security — An example wireless router, that can implement wireless security features Wireless security is the prevention of unauthorized access or damage to computers using wireless networks. Many laptop computers have wireless cards pre installed. The… …   Wikipedia

  • Network switching subsystem — (NSS) (or GSM core network) is the component of a GSM system that carries out call switching and mobility management functions for mobile phones roaming on the network of base stations. It is owned and deployed by mobile phone operators and… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.