(The physical layer is necessary because it is required for physical connections as well as for bit-wise transmission over the medium. Since the routing problem does not exist in the local area network, the network layer can be omitted. Therefore, the reference model of the local area network is only equivalent to the lowest two layers of OSI---the data link layer and the physical layer
LAN Technology-1.ppt
Including multiple files, please download and view by yourself! This resource is collected by the resource sea IT data station.)