Hello folks, this presentation will help you get started with the OSI Model, and build a better understanding of the protocols used in the real-world networking scenario.

1. THE OSI MODEL

2. WHAT IS THE OSI MODEL..?
The Open Systems Interconnection (OSI)
model is a conceptual model that provides a
common basis for the coordination of ISO
standards development for the purpose of
systems interconnection.
It is not used in real life, but it helps in
understanding how the protocols in the real
life works.

3. THE NEED…
In 1969, the first network known as ARPANET (Advanced Research
Projects Agency Network) was formed by the British Department of
Defence, followed by IBM, Microsoft and other tech companies.
The problem that they faced was the different architecture and
protocols of the networks of different companies, hence raising a need
to standardise the architecture to enable communication and transfer
of data between computers of two different companies.
And that’s when, at 1983, the OSI Model was devised by the ISO
(International Organization for Standardization)

4. APPLICATION LAYER
The application layer is used by end-user
software such as web browsers and email clients.
It provides protocols that allow software to send
and receive information and present meaningful
data to users
For example: HTTP, FTP, SMTP, DNS

5. PRESENTATION LAYER
The presentation layer is primarily responsible
for translating data between layers and
maintaining data integrity
Examples include: SSL, HTTP, FTP

6. SESSION LAYER
Session Layer controls the connections between
computers. It establishes, manages, and
terminates the connections between the local and
remote application.

7. TRANSPORT LAYER
Transport Layer provides transparent transfer of data
between end users, providing reliable data transfer
services to the upper layers. The transport layer
controls the reliability through flow control,
segmentation and desegmentation, and error control.
Examples: UDP, TCP, ARP

8. NETWORK LAYER
The main function of the Network Layer is to
transfer network packets from the source to the
destination. It is also known as the Packet Layer
Examples: ICMP or ping, IGMP

9. DATA LINK LAYER
The main functions of data link layer include
framing, error detection and correction,
acknowledgement, flow control, ensuring well-
defined reliable service interface to the
network layer, encapsulating packets from
network layer to frames
Examples: Ethernet, Point-to-Point Protocol
(PPP), ARP

10. PHYSICAL LAYER
The physical layer is the lowest layer of the OSI
model. This layer controls the way unstructured,
raw, bit -stream data is sent and received over a
physical medium. This layer is composed of the
electrical, optical, and physical components of the
network.
Examples: Copper or optical cables, hubs and
switches, etc.

11. COMPARISON
The model we use in real life is the TCP/IP
model, and it is very closely related to the OSI
model.

12. ACKNOWLEDGEMENTS:
Shoutout to NetworkChuck’s YouTube channel, that’s where I learned about this, you can get the
video about OSI and TCP/IP at https://www.youtube.com/watch?v=CRdL1PcherM&t=379s
Thanks
By Pratik C.