Which layers and main functions of the OSI/RM model are included?

Which layers does the OSI/RM model contain and the main functions of each layer the OSI/RM model contains seven layers: the Application Layer directly provides the service transport layer for your applications to provide services for communications between processes on two hosts. The network layer is responsible for providing communication services for different hosts on the group exchange network.
When data is transmitted between two adjacent nodes on the data link layer, the network layer is handed over and the IP datagram is assembled into frames, and the data in the frames is transmitted between nodes. The physical layer transparently transmits bits. The presentation layer of the Session Layer compares the main advantages and disadvantages of circuit switching, packet switching, and group switching in multiple aspects? Circuit Switching advantages: both users in a call always occupy end-to-end communication resources. Disadvantage: the transmission efficiency of lines is very low. Most of the communication lines occupied by users are idle and resources are not consumed.
Group exchange advantages: high exchange rate data transmission efficiency high reliability very efficient, flexible and fast. Disadvantages: delay and overhead
Packet Switching advantages: the user can send packets at any time, which is reliable, easy to find Code Conversion and rate matching, send multiple destination addresses at the same time, preferentially switch the priority message, and the communication line utilization is high. Disadvantage: Long latency.