The document discusses the OSI and TCP/IP models for network communication. The OSI model has 7 layers - physical, data link, network, transport, session, presentation, and application layer. Each layer has a specific function in the flow of data from source to destination. The TCP/IP model is simpler and combines some OSI layers. It has 4 layers - network access, internet, transport, and application. The OSI model helps networking professionals understand information flow and determine hardware/software needs to build computer networks.

1. Assignment on
OSI in detail ( TCP/IP )
Course Title: Data Communication
Course Code: CSE 313
Submitted To Submitted by
Pronab nath bondhu Fairuz Fatemi
Lecturer ID:1834902087
City University Batch:49(B)Day
B.S.C in CSE
D:02/09/2021

2. What is the OSI Model
• (OSI) Open System Interconnection. There are 7 layers in the OSI
model and each layer has a different capability. OSI model helps
networking professionals in understanding information flow from one
source to destination.

3. TCP/IP Model
• The transfer control protocol /internet protocol is older than the OSI
model and was created by the US Department. A key difference
between the models is that TCP/IP is simpler, collapsing several OSI
layers into one:
• OSI layers 5, 6, 7 are combined into one Application Layer in TCP/IP
• OSI layers 1, 2 are combined into one Network Access Layer in TCP/IP

5. • OSI Model Explained: The OSI 7 Layers
• 7. Application Layer
• The application layer is used by end-user software such as web browsers and
email clients. File Transfer Protocol (FTP), Post Office Protocol (POP).
• 6. Presentation Layer
• The presentation layer prepares data for the application layer. It defines how two
devices should encode, encrypt so it is received correctly on the other end.
• 5. Session Layer
• The session layer creates communication channels, called sessions, between
devices. It is responsible for opening sessions, ensuring they remain open and
functional while data is being transferred
• 4. Transport Layer
• The transport layer takes data transferred in the session layer and breaks it into
“segments” on the transmitting end.

6. • 3. Network Layer
• The network layer has two main functions. One is breaking up segments
into network packets, and reassembling the packets on the receiving end.
• 2. Data Link Layer
• The data link layer is responsible for the node to node delivery of the
message. When a packet arrives in a network, it is the responsibility of DLL to
transmit it to the Host using its MAC address.
Data Link Layer is divided into two sub layers :
• Logical Link Control (LLC)
• Media Access Control (MAC)
• 1. Physical Layer
• The physical layer is responsible for the physical cable or wireless
connection between network nodes.

7. • Advantages of OSI Model
• The OSI model helps users and operators of computer networks:
• Determine the required hardware and software to build their
network.
• Understand and communicate the process followed by components
communicating across a network.

8. Reference :
• https://www.imperva.com/learn/application-security/osi-model/