Layer Protocol data unit (PDU) Function
Host layers 7 (Application) Data High-level APIs, including resource sharing, remote file access
6 (Presentation) Translation of data between a networking service and an application; including character encoding, data compression and encryption/decryption
5 (Session) Managing communication sessions, i.e., continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes
4 (Transport) Segment, Diagram Reliable transmission of data segments between points on a network, including segmentation, acknowledgement and multiplexing
Media layers 3 (Network) Packet Structuring and managing a multi-node network, including addressing, routing and traffic control
2 (Data link) Frame Reliable transmission of data frames between two nodes connected by a physical layer
1 (Physical) Symbol Transmission and reception of raw bit streams over a physical medium


  • Last modified: 2020-05-21 20:38