open systems interconnection model, breaks down how networks communicate into 7 layers
7. Application, [Data]
High-level protocols such as for resource sharing or remote file access, e.g. HTTP.
6. Presentation, [Data]
Translation of data between a networking service and an application; including character encoding, data compression and encryption/decryption
5. Session, [Data]
Managing communication sessions, i.e., continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes
4. Transport, [Segment, Datagram]
Reliable transmission of data segments between points on a network, including segmentation, acknowledgement and multiplexing
3. Network, [Packet]
Structuring and managing a multi-node network, including addressing, routing and traffic control
2. Data link, [Frame]
Transmission of data frames between two nodes connected by a physical layer
1. Physical, [Bit, Symbol]
Transmission and reception of raw bit streams over a physical medium