Understanding Networking Models

The original networking model was developed by the Department of Defense in the 1970s. This is the original TCP/IP model. This broke down networking operations into 4 basic layers. When I started in the networking field in the 1980s, there was a need to expand on the layers of operations. Thus the OSI model was developed. We still use the OSI model today, however there is also a revised version of the TCP/IP model that is popular.

For this course and the CISCO CCNA 200-301 Exam, we will concentrate on the 5 Layer TCP/IP Model. In the introduction course I teach, we use the use the OSI Model. It is good to learn both as they both represent the same concepts.

I have made a chart that compares the different models for your reference. This video compares the Original TCP/IP and the OSI models. I highly recommend learning both even though we will reference the OSI model mostly in this course.

https://vle.phoenix.edu/courses/1/NTC_362_55659206/db/_51445575_1/embedded/OSI%20vs%20TCP-IP.jpg

The OSI Model is broken down into 7 layers. Layers 1-3 primarily are your hardware layers while layers 4-7 focus more on protocols and applications. Antaria's site may also help you understand the OSI Model.

We are going to mainly discuss Layers 1-4 (Transport, Network, Data Link, & Physical) in this course. Choose one of those 4 layers. Discuss what the layer covers. What are at least 2 examples of devices or technologies of that layer and what/how are they used in networking?