Network Maintenance and Troubleshooting Guide: Field-Tested Solutions for Everyday Problems, Second Editon

Chapter 1. Using the OSI Model

This book, and most other things related to networking, is best understood when aligned with or compared to the Open Systems Interconnection (OSI) Model for network communications.

In fact, it is exceptionally frustrating to troubleshoot today’s networks without understanding exactly which layer(s) each of the network infrastructure devices operate at and how that affects the flow of traffic and errors.

Quick Tour of the OSI Model

The OSI seven-layer basic reference model (see Figure 1-1) was created by the International Organization for Standardization (ISO) as standard ISO/IEC 7498. At the time of its creation the various networking protocols available were proprietary and offered little or no interoperability. ...