Security in Computing 5th Edition by Shari Lawrence Pfleeger, Charles P Pfleeger, Jonathan Margulies

Exercise 10

Obviously, the physical layer has to be at the bottom of the OSI stack, with applications at the top. Justify the order of the other five layers as moving from low to high abstraction.

Step 1 of 3

Order of OSI Layers

The OSI stack model describes how network protocol and equipment should communicate and work with each other. The OSI model divides the complex networking tasks into series called layers. The model comprises of seven layers which are divided as following:

Upper Layers:

Application Layer

Presentation Layer

Session Layer

Lower Layers:

Transport Layer

Network Layer

Data Link Layer

Physical Layer

The upper layers of OSI stack model Performs application specific functions such as encryption, data formatting, and connection management. Lower layers of the model perform network specific functions such as routing, addressing and flow control. Example of upper layers technology includes HTTP, SSL and NFS. The example of lower layers technology includes TCP, IP and Ethernet.