OSI Reference Model, 1st Ed. -- See also OSI Model, 2nd Edition The Open Systems Interconnection (OSI) model is a cornerstone of network communications. A thorough understanding of its layers and functioning is important for any internetworking professional. This tutorial presents a model overview and discusses: The seven elements (layers) of communications The functions that happen at each layer of the model Communications within, and between, layers How network adapters, hubs, switches, and routers function within the model Preparing data for transmission between devices at the same layer, and at different layers. Become a ZONE Subscriber and gain access to all Study Guides Author: Howard C. Berkowitz Technical Level: CCNA™ Date of Issue: 10-01-2023 Rating:   4 of 5    Table of Contents  Tutorial  3 Sample Study Questions  30 Study Questions Return to Study Guides