One of the limiting factors of personal computers is the primary use of such devices as isolated workstations. This means that in most organizations it is difficult for personal computer users to share data and the use of peripheral devices, since such sharing normally requires physical activity to occur. Both the direct economic benefits of sharing data and the use of peripheral devices as well as productivity gains resulting from the integration of personal computers into a common network have contributed to an increasing demand for local area network. Local area networks, generally called LANs, are privately owned networks within a single building or campus of up to a few kilometers in size. They are widely used to connect personal computers and workstations in company offices and factories to share resources and exchange information.The book contains: IEEE Standards: data link layer, physical layer, Manchester encoding, Standard Ethernet: MAC Sub Layer, physical layer, Fast Ethernet: MAC Sub Layer, physical layer, IEE-802.11: Architecture, MAC sub layer, addressing mechanism, frame structure.