Fabio, I asked a real specialist on the subject to help me with your text. He also wrote ("off the top of his head" as he said) some lines on the subject to help you out.
The Layers of OSI Model
Standardize the communication data and allow interoperability independent of / regardless of the manufacturer's system
The processes are divided in logical groups called layers.
*The lower four layers are well designed and solid.
**Changes on the tasks of the layers don't interfere with other
* If you understand the subject, then this is how you explain your text. They are not easier to manage, they are just designed so well.
** The important thing is the interface between each layer.
The ISO (International Standards Organisation) OSI (Open Standards Interconnection) Model is a 7-layered model designed for this in order to force manufacturers in the beginning of the 80s to produce standard communication protocols.
Layer 7 – Application
Layer 6 – Presentation
Layer 5 – Session
Layer 4 – Transport
Layer 3 – Network
Layer 2 – Data or Link
Layer 1 – Physical
The lower layers 1 – 4 were very solid and drove the communication over WAN (Wide Area Network) and LAN (Local Area Network). Later on MAN (Metropolitan Area Network).
The upper layers were more “hazy” as they often came built in an application.
Check out Chapter 2 – OSI from this excellent list from Bath University.http://staff.bath.ac.uk/masrjb/AOCN/links.html
Note: He made a career out of this….