2. What is an OSI?
• OSI stands for Open System
Interconnection
• This was developed by the
ISO (International
Organization for
Standardization) in the year
1977.

3. What is the Main Objective
of the OSI Model?
–To standardize Networking to
make sure that everyone was
connected through a common
network standard.

4. 7 Layers
Layer Function
7 Application
6 Presentation
5 Session
4 Transport
3 Network
2 Data link
1 Physical

5. To Remember the 7
Layer
Layer Functio
n
Note
7 Application All
6 Presentation People
5 Session Seem
4 Transport To
3 Network Need
2 Data link Data
1 Physical Processing

6. PHYSICAL
• This is the Layer that
physically connect the
networks together.
• Hardware
• Medium of Signals
–Such as Cables, satellite, etc.

7. Some Physical Layer
Devices

8.  Split the data into packets
 This layer makes possible divide a
way to exchange data or a
common local media
DATA LINK

9.  Send packets to address
 Supplies the means to exchange
pieces of data over the network
between identified and devices.
NETWORK

10.  Ensures that packets arrive,
and error free and are in
correct order
TRANSPORT

11.  Established and coordinates connection
between computers
 This layer establishes, manages, and
terminates connection also known as
session between 2 network address
SESSION

12.  Allows transfer of files between different
formats. Encryption is one of the services
in this layer.
 Encryption is the translation of data into a
secret code. Encryption is the most
effective way for data security. To read an
encrypted file you must have a password
or a secret key.
PRESENTATION

13.  This is the layer where people do their work
, such as sending e-mail or requesting to
transfer a file across the network
 E-mail, files requests, file transfers, etc.
APPLICATION