The document discusses the OSI and TCP/IP models for networking. It describes the seven layers of the OSI model and the functions of each layer, with a focus on the physical and data link layers. The physical layer is responsible for the actual connection and transmission of bits between devices, while the data link layer forms frames from packets and handles error control and synchronization of data being transmitted. The overall purpose is to break down the communication process into layers to reduce complexity and allow different systems to communicate.

1. OSI & TCP Model
Submitted By:
Md. Sohanur Rahman
ID: 1834902135
Batch: 49 (B)
Program: CSE(Day)

2. OBJECTIVES
 To discuss the OSI model and it’s layer architecture and to show the
interface between the layers
 To briefly discuss the function of each layers in the OSI model
 To introduce the TCP/IP protocol
 To show the functionality of each layer in the TCP/IP Model

3. Network Model
 A method of describing and analyzing data
communication networks by breaking the entire set
of communication process into a number of layers
 Each layer has a specific function

4. The OSI Model
 International standard organization (OSI)
established a committee in 1977 to devolop an
architecture for systems communication
 Open System Interconnection (OSI) reference
model is the result of this effort
 This model allows any two different systems to
communicate regardless of their underlying
architecture

5. Contradiction
 The OSI model describes how data flows one
computer, through a network to another computer
 The OSI model is not a protocol it’s a model for
understanding and designing a network
architecture.
 The OSI model consists of seven separate but
related layers, each of which defins a part of the
process of moving information across a network.

6. Seven Layers of the OSI model

7. Why so many layers?
 To reduce the complexity, network are organized as
a stack of layers, one below the other
 Each layer perform a specific task, It provides
services to an adjacent layer

8. OSI Layer

9. Physical Layer
 Physical layer is the bottom(layer 1) of OSI model
 It is responsible for the actual physical connection
between the devices
 The physical layer is responsible for movments of
individual bits from one node to next

10. Functions of physical layer
 Convert bits to signal
 Bit synchronization
 Manage physical connection
 Bit rate control
 Line configuration
 Physical topology
 Transmission mode
 Switching

11. Data Link Layer
 The data link layer is
responsible for moving frames
from one node to the next.
 It forms frames from the
packets that are recived from
network layer and gives it to
physical layer
 It also synchronizes the
information which is to be
transmitted over the data.
Error controlling is easily
done.