The OSI Model
The Open Systems Interconnection (OSI) model is a system by which every device connected to the network communication. It basically divides the process into easy to understand steps. There are 7 layers in the OSI model and an easy way to remember them is to remember this sentence:
All People Seems To Need Data Protection.
Application:- This provides an interface to the end user to initiate the communication process. Protocols such as HTTP, FTP, SMTP etc come under this layer.
Presentation:- This layer simply packages the data to present it to the device on the other end. File formats like Gif, Mpeg etc are good examples of this layer.
Session:- This layer is responsible to create manage and terminate sessions.
Transport:- This layer provide end to end transportation of data. Complex operations like multiplexing and buffering is handled at this layer. TCP and UDP are the protocols which transport data
Network:- Finding the best path, routing the data is carried out at this layer. Routers work at this layer.
Datalink:- Switches work at this layer and perform data switching. It deals with Physical addressing.
Physical:- This is the First layer of the OSI model and deals with electrical signalling.