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2. What’s In It For You?
 What Is an OSI Model?
 Structure of the OSI Model
 Layers of an OSI Model

3. What Is an OSI Model?

4. Click here to watch the video

5. What Is an OSI Model?
System 1 System 2
Communication
Channel
OSI Model – Layer Structure

6. What Is an OSI Model?
 The OSI model or Open System Interconnection model is a specifically designed set of protocols
that governs the communication channels through which network devices share information and data.
 This task of sharing information is divided among the 7 layers of the OSI model for microlevel network
communication.
Layer Format
Data Share

7. Layers of OSI Model?

8. Layers Of OSI Model
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer
Presentation Layer
Application Layer
7
5
4
3
2
1
6
Host Layers
Network Layers

9. Layer Information

10. Layer Information
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer
Presentation Layer
Application Layer
Data
Data
Segment
Packet
Frame
Bit
Data
Layer
Data Format Function
Applications access network services
Encryption and Compression of data
Connection management b/w nodes
Maintains data flow during transmission
Determine the path for data transfer
Connect physical nodes for transfer
Transfer raw bits using physical mode

11. Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer
Presentation Layer
Application Layer
Layers Of OSI Model
Top to Bottom
7
5
4
3
2
1
6

12. Application Layer
 This layer acts as an interface for the user
and the application being accessed.
 It manages the protocols required by the
application needed to present the data to the
user.
 They apply the HTTP & SMTP protocols for
the data for transmission.

13. Presentation Layer
 Performs the task of converting data into
an uncomplicated form for the application
layer.
 Is also responsible for encrypting and
decrypting data when sharing and
receiving data.
 Also execute the task of compressing the
data for transmission to the Session layer.
Shopping
1010110101 #2#A@E$
Encryption
Compress Data

14. Session Layer
 This layer controls and maintains
connections b/w devices.
 It can also establish and terminate
sessions.
 Also checks the authenticity and provides
recovery options in case of network failure
for the active session.
Authentication Data Recovery

15. Q1. What is the main action that takes place at the Presentation Layer?
1. Data Segmentation
2. Encryption of data
3. Framing of data
4. Bit conversion of data

16. Transport Layer
 This layer performs the task of segmenting the
data for proper transmission of data packets.
 Provides the data packets with the port number
for identification, like UDP & TCP.
Received Data
UDP | Data TCP | Data
Data Segments

17. Transport Layer
Server Client
50 Mbps 10 Mbps
Flow Control
Flow change
50 Mbps
This layer also overlooks the data transfer and maintains the flow of the data
being shared between devices.

18. Network Layer
 This is layer responsible for sending the received
segments and providing them with the destination
address.
 This layer also ensure that the data packets
transmits through the best possible route.
 This layer also uses the IP and IPv6 protocols.
Data Packets
Data Segments
IP Address
Client Devices
1 2
2

19. Data-Link Layer
 This layer maintains communication b/w two devices
on the same network.
 Divided into two sublayers:
 Medium Access control(MAC):
Controls how devices establish the connection.
 Logical Link control(LLC):
Identifies the address and provide flow control.
Data Packets
MAC Address
Data Packets
MAC
Address
Data Frame
Physical Layer
Shared over the
network

20. Q2. Which layer includes the MAC sub-layer in the OSI model?
1. Application Layer
2. Session Layer
3. Data-Link Layer
4. Transport Layer

21. Physical Layer
 This layer controls how the data is
transferred over the physical medium.
 It also converts the frames from the Data-
link layer into bits of 1’s and 0’s.
 Also maintains and performs network-
related protocols that can be applied over
different network modes.
Data Frame
Bits
1’s & 0’s
Wired Medium Wireless Medium

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