There is nothing I enjoy more than teaching Cisco technology, especially CCNA candidates. Is it directly or online, everyone is happy to be there. There is anticipation in the air, and everyone is ready to work hard, get the router rack and the Cisco switch that I have … and then I issued an OSI model chart. Chin slumped. People sigh 300-115 dumps, or at least hope they don’t order decaf that morning.
Okay, it’s not too bad. But it’s a little angry. I always get a sense of “Why can’t we hurry and continue the router and switch? Why do we have to learn these dry things?”
One reason is that Cisco demands you know the OSI model inside and out for the intro and ICND exams. You must admit that is a pretty good reason, but still, students find information on OSI models very dry.
I understand that, because I’ve been there. My first exposure to the actual OSI model in the Novell “Networking Technologies” class, and humans, is the graph that has ever dried. They cram every known protocol (and some unknown 300-115 pdf, I think) into the OSI model. It looked like a giant jigsaw puzzle, and the real problem was that I didn’t know what most of it was.
So I obeyed trying to memorize this big graph. I managed to pass the exam, but I wondered what all the effort was. It’s not like you sit in the server room or cable cabinet and discuss the OSI model.
As a CCNA candidate, you don’t need to worry about all the protocols that I memorize back when, but you must know what happens in each layer. Which leads to this question:
“If I work with a router and switch, why should I know about all other layers? Don’t router and switch only work on layer 2 and 3?”
Yes, switch works on layer 2 and router in layer 3. But to truly understand the network, you must understand what is happening in another layer 300-115 practice tests. Why?
Most network administrators and engineers will spend more troubleshooting than installing. That’s how it is. And to solve problems effectively, you must know what happens in all layers of the OSI model, not just layer 2 and 3.