network models OSI model and TCP/IP a OSI model is a conceptual framework for understanding relationships. the purpose of the OSI reference model is to guide vendors and developers so the difital communication products. the physical layer (layer 1) layer 1 of the OSI model is named the physical layer because it is responsible for the transmission and reception of wire level. for example, the physical layer is where it is dictated how bits are represented across a specific networking medium. the data link layer (layer 2) layer 2 of the OSI model is named the data link layer and is responsible for link establishment and termination, frame traffic control, sequencing, acknowledgement, error checking, and media accress management. the network layer (layer 3) layer 3 of the OSI model is named the network layer and is where routing of network traffic begins. the network layer not only makes the traffic routing decisions but also provides traffic control, fragmentation, and logica