Blog 04 – OSI Model

Intro to the OSI model and Top-Down network design.
The OSI model depicts the layers that make up a network with every layer depending on the ones below it. For example: the Application layer depends on the Presentation layer which depends on the Session layer and so forth.

Top-Down network design is an agile methodology used in the construction of a network. This process defines what the network must be capable by looking at the business requirements of an organisation. This ensures that every layer meets the needs of the one above it.

     Top-Down network design steps
1. Analyse requirements
2. Develop logical design
3. Develop physical design
4. Test, optimize and document design
5. Implement and test network
6. Monitor and optimize network performance
Repeat as needed

     OSI Model
7. Application layer
6.  Presentation layer
5.  Session layer
4.  Transport layer
3.  Network layer
2.  Data link layer
1.  Physical layer