This document discusses the Open Systems Interconnection (OSI) model, which defines seven layers for network communication. It describes the functions of each layer, including the physical layer for transmitting bits, the data link layer for transmitting frames, the network layer for delivering packets from source to destination, the transport layer for process-to-process delivery, the session layer for establishing and synchronizing interactions, the presentation layer for syntax and semantics, and the application layer for user interfaces and services.

1. Prof.Neeraj Bhargava
Abhishek Kumar
Department of Computer Science
School of Engineering & System Sciences,
MDS, University Ajmer, Rajasthan, India

2.  Introduction of OSI
 OSI Model
 Types of OSI Model
 Physical layer
 Data link layer
 Network layer
 Transport layer
 Session layer
 Presentation layer
 Application layer

3.  It is stands for Open System Interconnection.
 The International Standard Organization has a
well-defined model for Communication Systems
known as Open System Interconnection, or the OSI
Model.
 This layered model is a conceptualized view of how
one system should communicate with the other,
using various protocols defined in each layer as
follow:

5.  The physical layer is responsible for
transmitting individual bits from one node
to the next .
 Functions of physical layer:
 Physical characteristics of interfaces and
media
 Representation of bits
 Data rate
 Synchronization of
bits

6.  The data link layer is responsible for transmitting
frames from one node to the next.
 FUNCTIONS OF DATA LINK LAYER:
 Framing
 Physical addressing
 Flow control
 Error control
 Access control

7.  The network layer is responsible for the
delivery of packets from the original source
to the final destination .
 FUNCTIONS OF NETWORK LAYER:
 Logical addressing
 Routing

8.  Transport layer is responsible for delivery of
a message from one process to
another(process-to-process delivery) .
 FUNCTIONS OF TRANSPORT LAYER:
 Segmentation and
reassembly
 Connection control
 Flow control
 Error control

9.  The session layer is the network dialog
controller. It establishes, maintains ,and
synchronizes the interaction between
communicating systems.
 FUNCTIONS OF SESSION LAYER:
 Dialog control
 synchronization

10.  The presentation layer is concerned with
the syntax and semantics of the information
exchanged between two systems .
 FUNCTONS OF PRESENTATION LAYER:
 Translation
 Encryption
 Compression

11.  It provides user interfaces and support for
services.
 FUNCTIONS OF APPLICATION LAYER:
 Network virtual terminal
 File transfer, access, and
management(FTAM)
 Mail services
 Directory services