Isn't it a little sad that the Oasis model gets all the love, but this model really has the thanks
of the Department of Defense when it comes to its creation.
You see, the TCP IP architecture was worked out by the U.S. Department of Defense long before the Orci
model was created.
What the Department of Defense was working on was a way in which to really simplify the network communications
and build a system that would be able to survive very fast changes, massive changes, potentially.
What the Department of Defense really was working on was a system of computers that could stay communicating
during a nuclear holocaust.
That's right.
This was during the arms race time.
This is when the superpowers of the United States and Russia were, you know, attacking each other
from at least verbally and building up nuclear armaments.
And the Department of Defense was trying to build a system that could survive such an attack.
And that gave rise to the modern Internet, of course, and the TCP IP modern architecture that we have
today.
Notice their model was very simplified, so it was four total layers.
So they identified up at the top the application layer that became the application, the presentation
in the session, layers of the OSA model.
The host to host is like our transport layer.
The Internet layer is like our network layer.
And then they identified the physical and the data link together simply as network access.
So you have three layers in one and then kind of a 1 to 1 mapping and then two layers in the network
access layer.
It can be sometimes beneficial to be able to coordinate these layers to the OCI model as some certification
exams in our discipline will ask that silliness of you.
I think that is a bit silly, but suffice it to say, let's know these layers.
They actually predated the AOC model.