OSI model

Open System Interconnection, or OSI, is a model of abstraction layers in a communication system.

There are five abstraction layers, from highest to lowest level: 1. Application Layer: High-level protocol for resource sharing (HTTP) 2. Transport Layer: Transmission of data segments between points on a network (segmentation, acknowledgements, multiplexing) 3. Network Layer: Management of a multi-node network (addressing, routing (router), traffic control) 4. Link Layer: Transmission of data frames ([[data frame]]) between two nodes (node) 5. Physical Layer: Transmission of raw bit streams over a physical medium