It was a dual several decades ago that took play that saw OSI take on TCP/IP in a dual for supremacy. Well TCP/IP won, as that's what the majority of PCs you and I use today, however OSI was a better model as it makes troubleshooting network issues much easier. Using the OSI model you can break down the problem into chunks, thus allowing you to locate where an issue is and find a fix for it.
I've read the section about the OSI model in the official exam certification book, but must admit I much prefer the cbt nuggets video by Jeremy Ciora. He breaks down and talks you through each layer and then provides you with a real life example so you can see each layer in action (which are present in TCP/IP, but with different names and some are grouped together) and how the simple action of opening up a website in a browser actually does that - it's some cool stuff!
So the main points I covered were:
- The 7 Layers of the OSI model
- How to remember them - Please Do Not Throw Sausage Pizza's Away (Layer 1 - 7 bottom to top)
- Relating the OSI model to a real work example