access point (WLAN) (AP)
In general, an access point ( AP) is an access point to a network or a service. Depending on the network concept, network architecture and network service, one speaks of a cable access point( CAP) for broadband cable networks, a DECT access point ( DAP) for DECT, a link service access point (LSAP) for link services, a mesh access point( MAP) or wireless access point ( WAP) for wireless LANs, a network access point( NAP) for networks, and so on.
InWLANs, the access point (AP) functionally forms the bridge to the wired networks, i.e. it is directly connected to Ethernet or other network concepts. In the case of access points with high data rates of more than 1 Gbit/s, such as 802.11ac, the cabling is carried out via several data cables according to 2.5GbE or 802.3bz with 2.5 Gbit/s via UTP cables ofcategoryCat 5e or according to 5GbE with 5 Gbit/s via category Cat 6, in each case over distances of 100 meters. The connection of several access points to each other can be wired or wireless via the wireless access points.
Functions of the access point
The access point, which is connected to all connected network nodes, performs central functions such as filtering, roaming or security functions.
An access point forms a self-contained radio cell whose range depends on the transmission power, the frequency range, the radiation characteristics of the antenna, the transmission method and the data rate. In the in-house area, the range is between 15 and 50 meters. Outdoors, distances of several hundred meters can be achieved. Access points normally use omnidirectional antennas with 360° radiation characteristics. However, they can also be equipped with multiple antennas and beamforming to optimize the reception field strength. With antenna diversity, the access point can select the antenna with better reception.
Wireless access points serve as hotspots for wireless access to a network or the Internet. They are therefore also used in areas where many people are regularly present. For example, in airports, train stations, exhibition halls or convention centers. Via these access points, those present have the option of direct access to the Internet, but, also the option of wireless Internet telephony via VoWLAN. This technology is thus definitely in competition with UMTS in metropolitan areas, especially since the data rates exceed UMTS many times over.