Physical layer: Concerned with transmitting raw bits over a communication channelPhysical layer is the only layer of OSI network model which actually deals with the physical connectivity of two different stations. This layer defines the hardware equipment, cabling, wiring, frequencies, pulses used to represent binary signals etc.Transport layer: True end-to-end layer from source to destinationIt is termed as an end-to-end layer because it provides a point-to-point connection rather than hop-to- hop, between the source host and destination host to deliver the services reliably.Session layer: Provide token management serviceThe session layer of OSI model is responsible for establishing, managing, synchronizing and terminating sessions between end-user application processes. Through token, this layer prevents the two users to simultaneously attempt the same critical operation.Presentation layer: Concerned with the syntax and semantics of the information transmittedIt is responsible for data encryption and decryption of sensitive data before they are transmitted over common channels.Data-link layer:This layer is responsible for moving frames from one hop to next.The Data-link layer divides the stream of bits received from the network layer into manageable units called frames.It adds a header to the frame to define the sender and receiver of the frame.It provides a flow and error control mechanism.