Wireless network management

The 802.11 communications protocol is defined for a wireless LAN (Local discipline Network) and is based on a cellular architecture in which the net income is divided into cells where each cell (called a Basic Service cellphone (BSS)) is controlled by a base localize called an Access Point (AP).The elemental access appliance implemented in the protocol is a postman Sence Multiple Access with Collision Avoidance (CSMA/CA). The CSMA protocol works as follows if a station wishes to transmit education through it network, it senses the medium. In exercise the medium is busy (another station in the network is currently transmission education) then the station leave behind delay its transmission requests to a posterior time. Otherwise, the medium is guiltless and the station is allowed to transmit the desired information.The problem with the CSMA protocol is the case where a collision overhauls. A collision may occur if two different stations sense the medium as free and begi n to transmit information. For this purpose, we use a collision avoidance mechanism a station willing to transmit senses the medium. If the medium is busy, it defers its request.Otherwise, it sends an RTS (Request To Transmit) which includes the source, destination and the distance of the transaction. If the medium is free then the destination station will suffice with a packet called CTS (Clear To Send) which will include the same duration information and once the source station receives this packet, it starts to transmit. The destination station checks the CRC (Cyclic Redundancy Check) and sends an honorable mention package (ACK).Receiving the ACK informs the source station that no collision had occurred. If the source station does not receive the ACK it will keep resending the data or will throw it away after a given number of retransmissions.When a station wishes to join an existing BSS, it needs to receive synchronization information from the BSSs AP. First, the station need s to go through the APs certification process. During this process, the station and the AP exchange information proving to each other that each place is familiar with a specific password.