The Open Systems Interconnection (OSI) Model Explained
This e-book is aimed at:
· Anyone totally new to networking and needing to get up to speed with the OSI portion of the CCNA
· Anyone who finds networking books or manuals difficult to understand
· Anyone who gets the feeling that networking books and manuals seem to be aimed at people who already understand networking
· Anyone who’s been to a networking course already but wishes the trainer would have made just that little bit more effort to explain things better
· Anyone who’s been to a course, or read a book about the OSI model but would like it explained again, in a slightly different way.
If you’ve ever been reduced to an "I’ll never understand this in time for my exam!" panic by intimidating techno-speak, this e-book is for you.
My objective in writing this e-book is to explain the different layers of the OSI model once and for all. My strategy, which during my training career, I have found works every time, with hundreds of exam candidates is keeping it simple.
In the following chapters we shall discuss:
· Why have a networking model at all?
· The advantages of having the OSI model
· Understanding the layers
· What you need to pass the OSI portion of your exam
· Watch out! Layer Overlap!
Before we go on, I think the chaps behind the OSI deserve a mention.
The International Organization for Standardisation (ISO) developed the OSI Model in the early 80s, although the OSI is not all they are known for. These guys do standards for everything, and I mean, absolutely everything. Take a look at some of the technical committees they have:
TC 8 Ships and marine technology
TC 10 Technical product documentation
TC 20 Aircraft and space vehicles
TC 22 Road vehicles
TC 23 Tractors and machinery for agriculture and forestry
TC 68 Banking, securities and other financial services
The next page discusses why they bothered inventing the OSI model at all.