This document outlines the 7 layers of the OSI model from top to bottom. It shows that each layer has a specific function like presentation, session, transport, network, data link, and physical. The transport layer ensures reliable host-to-host communication with end-to-end delivery and checksums.

1. 1
4
7
2
5
6
3

2. 1. (Application
layer)
OSI
(Header)

3. 2. (Presention
layer)
(Text)

4. 3. (Session Layer)
(Header)

5. 4. (Transport Layer)
(Host-to-Host)
(End-to-End)
(Checksum)

6. 5. (Network Layer)
-

7. 6. (Data Link
Layer)
(Checksum)

8. 7. (Physical Layer)
-
RS-232-C (Pin)