OSI Reference Model
The OSI reference model divides network operation and management into seven layers. Layers 1 through 4 are responsible for moving data form one place to another, whereas 5 through 7 handle the exchange of data between application programs. What are the seven layers?
1. The physical layer specifies the electrical connections between the transmission medium and the computer system. This includes specifying the type of transmission media, the types of connectors, the speed of transmission, the size and shape of the plug, the number of pins on the connector, and so on.
2. The data link layer checks the data flowing into and out of each device on the network. It makes sure that no data loss occurs between two adjacent points in a network ...
In 305 words, the solution describes the seven layers in a couple of sentences each.