Peer-to-peer
A peer-to-peer (P2P) allows wireless devices to directly communicate with
each other. Wireless devices within range of each other can discover and
communicate directly without involving central access points. This method is
typically used by two computers so that they can connect to each other to form a
network.
If a signal strength meter is used in this situation, it may not read the
strength accurately and can be misleading, because it registers the strength of
the strongest signal, which may be the closest computer.
802.11 specs define the physical layer (PHY) and MAC (Media Access Control)
layers. However, unlike most other IEEE specs, 802.11 includes three alternative
PHY standards: diffuse infrared operating at 1 Mbit/s in; frequency-hopping
spread spectrum operating at 1 Mbit/s or 2 Mbit/s; and direct-sequence spread
spectrum operating at 1 Mbit/s or 2 Mbit/s. A single 802.11 MAC standard is
based on CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). The
802.11 specification includes provisions designed to minimize collisions.
Because two mobile units may both be in range of a common access point, but not
in range of each other. The 802.11 has two basic modes of operation: Ad hoc mode
enables peer-to-peer transmission between mobile units. Infrastructure mode in
which mobile units communicate through an access point that serves as a bridge
to a wired network infrastructure is the more common wireless LAN application
the one being covered. Since wireless communication uses a more open medium for
communication in comparison to wired LANs, the 802.11 designers also included a
shared-key encryption mechanism, called wired equivalent privacy (WEP), or Wi-Fi
Protected Access, (WPA, WPA2) to secure wireless computer networks.
Bridge
A bridge can be used to connect networks, typically of different types. A
wireless Ethernet bridge allows the connection of devices on a wired Ethernet
network to a wireless network. The bridge acts as the connection point to the
Wireless LAN.
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