CISCO CHAPTER 4
    OSI Layer Explanation          Physical Layer    This is the simplest layer; related to electrical (and optical) connections between equipment. Binary data is encoded in a form that can be transmitted through network media, for example cables, transceivers and connectors related to the Physical layer. Tools such as repeaters, hubs and network cards are on this layer.       Data-link Layer    This layer is slightly more "intelligent" compared to the physical layer, as it provides more tangible data transfer. As a link between the network medium and the higher-level protocol layer, the data link layer is responsible for the final packet of binary data coming from the higher level to the discrete packet prior to the physical layer. Will send frames (blocks of data) through a network. Ethernet (802.2 & 802.3), Tokenbus (802.4) and Tokenring (802.5) are protocols at the Data-link layer.      Network Layer    The main task of the network la...
