Physical Layer: Concerned with the physical connection between devices. It deals with the transmission and reception of raw data bits over a physical medium.
Data Link Layer: Provides reliable node-to-node communication. It ensures that data frames are transmitted correctly between adjacent network nodes over a particular link.
Network Layer: Focuses on end-to-end communication, providing logical addressing, routing, and path determination. IP addresses and routers operate at this layer.
Transport Layer: Ensures data transfer between devices is reliable, orderly, and error-checked. Protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate at this layer.
Session Layer: Manages and controls communication sessions between applications, including establishing, maintaining, and terminating connections.
Presentation Layer: Responsible for data translation, encryption, and decryption. It ensures that data sent from one application-layer entity can be understood by another application-layer entity.
Application Layer: The closest layer to the end-user, responsible for providing network services directly to the end-user application.