The document describes the OSI (Open Systems Interconnection) model, which defines seven layers of abstraction to standardize the transfer of data between two entities in a network. It establishes a common framework that allows the development of detailed interfaces and standards for transmitting data packets. The seven layers are the physical, data, network, transport, session, presentation, and application layers. Each layer manages a different part of managing and transferring data, from electrical signals to packet delivery to application-level interactions. The OSI model was adopted as an international standard by ISO to facilitate interoperability across networks.

1. OSI MODEL (OPEN SYSTEMS
INTERCONNECTION)
PRESENTED BY:
Maria Afzal
BBA 8A

2. OSI MODEL
OSI was originally intended to be a detailed specification of
actual interfaces. Instead, the committee decided to establish
a common reference model with which others could then
develop detailed interfaces, which, in turn, could become
standards governing the transmission of data packets. The
OSI architecture was officially adopted as an international
standard by the International Organization for Standardization
(ISO).

3. OSI MODEL LAYERS

4. PHYSICAL LAYER
At the bottom of our OSI bean dip we have the Physical Layer, which
represents the electrical and physical representation of the system.
This can include everything from the cable type, radio frequency link,
as well as the layout of pins, voltages and other physical
requirements

5. DATA LAYER
This layer sets up links across the physical network, putting packets
into network frames. This layer has two sub-layers: the logical link
control layer and the media access control layer (MAC). MAC layer
types include Ethernet and 802.11 wireless specifications.

6. THE NETWORK LAYER
This layer handles addressing and routing the data -- sending it in
the right direction to the right destination on outgoing transmissions
and receiving incoming transmissions at the packet level. IP is the
network layer for the internet

7. THE TRANSPORT LAYER
This layer manages packetization of data, then the delivery of the
packets, including checking for errors in the data once it arrives. On
the internet, TCP and UDP provide these services for most
applications as well

8. THE SESSIONS LAYER
This layer sets up, coordinates and terminates conversations. Its
services include authentication and reconnection after an
interruption. On the internet, Transmission Control Protocol (TCP)
and User Datagram Protocol (UDP) provide these services for most
applications

9. THE PRESENTATION LAYER
This layer is usually part of an operating system (OS) and converts
incoming and outgoing data from one presentation format to another
-- for example, from clear text to encrypted text at one end and back
to clear text at the other.

10. THE APPLICATION LAYER
the Application Layer is the one at the top - it’s what most users see.
In the OSI model, this is the layer that is the “closest to the end user”.
Applications that work at Layer 7 are the ones that users interact with
directly. A web browser (Google Chrome, Firefox, Safari, etc.) or other
app - Skype, Outlook, Office - are examples of Layer 7 applications