Wireless network interface card

From Wikipedia, the free encyclopedia

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 is mostly located in the PCI slot. Other options are USB WNIC, PCMCIA WNIC and integrated WNIC (typically in Mini PCI/PCI Express Mini Card form).

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 doesn't require an access point, but rather can directly interface with all other wireless nodes directly. All the peer 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.