ireless local area networks doesn't ensure security from eavesdropping at some experience in analog telephone modems, initiated work other point in the network. to develop a wireless data link. The initial experimental Error correction: The wireless medium is complex units used an existing Ethernet MAC chip. As discussed and time varying. There is no way to transmit all in more detail in section 5.1.3.2, there is no easy way to packets without errors. The link layer may insist on detect a collision in a wireless network; the experi- receiving a positive acknowledgment (ACK) before menters worked around this limitation by informing the a station may consider a transmission successful. MAC chip that a collision occurred any time a positive Incoming data packets may be fragmented into ACK was not received, thus initiating the Ethernet smaller chunks if packet errors are high; for example, backoff algorithm. In this fashion they were able to make in the presence of microwave oven interference, working wireless links with minimal modification of the which peaks in synchrony with power lines at 60 Hz, existing Ethernet MAC. The early workers understood fragmentation may be the only way to successfully that to make a true volume market for these products, transmit very long packets. Fragmented packets must standardization was necessary. When standardization be identified as such and reassembled at the receiving efforts were introduced at the IEEE shortly thereafter, station. the MAC was elaborated to deal with the many wireless- Coding and interleaving: Errors are inevitable in the specific issues that don't exist in Ethernet but remained wireless medium. Protection against bit errors can based on Ethernet, which had been introduced because be provided by encoding the data, SO that errors are of its availability and was successful because of its detected by the receiving station. Codes often allow simplicity and robustness. Thus, the standard today errors of up to a certain size to be corrected by the continues to refle