IEEE 802.11 Standards

IEEE 802.11 comprises the set of networking standards that provide connectivity over the wireless media. Currently, the most popular is the IEEE 802.11n standard, which operates over the 2.4 GHz band with the network speed up to 600 Mbps (Dean, 2009, p. 374). The wireless LAN (WLAN) can be the part of a larger network or operate independently. Usually, the network nodes connect to the wireless access points (AP), which forward the traffic further along the network. Alternative wireless topologies include the point-to-point and ad-hoc connectivity. In the point-to-point mode, two network devices exchange the data directly among themselves. Within the ad hoc topology, all nodes communicate with each other based on the dynamic rules that are determined by the current connectivity of every network device.

In order to ensure the network reliability in complex environments, the network must include the specialized wireless controllers. The WLAN controllers aggregate the traffic from the multiple wireless access points, providing the full coverage and smooth roaming within the network environment. The main concern with the Wi-Fi technology is the network security, as the initial WEP (Wired Equivalent Privacy) encryption algorithm has proven to be vulnerable to the hackers’ attacks. However, with the introduction of WPA2 (Wi-Fi Protected Access v. II) security mechanism the issue was successfully solved (Rackley, 2011, p. 219).

In contrast with the shared Ethernet media, the collision detection is impossible in the 802.11 standard. Thus, the media access control mechanism handles the collisions by means of the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) protocol instead of the CSMA/CD (Collision Detection) used in the Ethernet networking. Every 802.11 node listens to the media and, once there are no communications, waits for the random number of transmission slots to pass before starting the transmission. The use of the timing randomization algorithm guarantees the collision avoidance in the wireless network.