An AP is a device (or software running on a station with both wireless and wired connections) that transfers data between wireless stations and a wired network, and between wireless stations. APs are equipped with security functions to prevent snooping and intrusion on the network. A WLAN's range can be greatly extended by placing multiple APs on a wired network.
CardBus is the 32-bit version of the expansion interface originally standardized in 16-bit form by the Personal Computer Memory Card International Association (PCMCIA). Electrically similar to the PCI bus, CardBus has the advantage of allowing adapters to be inserted and removed while the computer is running. The body of a CardBus adapter is the size and shape of a stack of four or five credit cards. A CardBus WLAN adapter lets a computer connect to WLANs, and typically has an extension containing an antenna. Most notebook computers manufactured after 1998 have CardBus slots. Most CardBus slots will also accept 16-bit PCMCIA adapters (often called "PC Card" adapters).
An "AP router" is a device that combines the functions of a wireless access point (AP) and a router. As an AP, it transfers data between wireless stations and a wired network, as well as between the wireless stations. As a router, it acts as a link point between two or more separately addressable networks, or between an internal network and an external network.
Routers communicate with each other and maintain tables of paths so they can reliably forward data to its destination. In technical terms, a router operates at Layer 3 (the Network layer) of the Open Systems Interconnection (OSI) model. Routers are sometimes called "gateways," but it should be remembered that "gateway" is the technical term for a network protocol converter (which operates at Layer 7, the OSI model's highest layer, known as the Application layer).
Outdoor Bridge
A bridge connects two or more physically separate networks in such a way that they appear as one. The connected parts are referred to as "segments" of the full network. A bridge can be used to combine two networks, to expand a network, or to improve network performance: communications between stations on the same segment do not pass through the bridge to other segments. In technical terms, a bridge operates at Layer 2 (the Data Link layer) of the Open Systems Interconnection (OSI) model.
Outdoor bridges typically are weatherproofed wireless devices capable of point-to-point or point-to-multipoint operation. With suitable directional antennas, a pair of outdoor bridges in point-to-point configuration can link two sites over a great distance. To link multiple sites over somewhat lesser distances, a central outdoor bridge is configured for point-to-multipoint operation and equipped with an omnidirectional or semidirectional antenna, while the surrounding outdoor bridges (typically placed on nearby buildings) operate in point-to-point mode.
