7 layers, network protocols

OSI Model

Understanding the 7-Layer Open Systems Interconnection Model

The Seven Layers of OSI Model

7
Application Layer
Provides network services directly to end-users and applications. Handles user interface and application-specific functions.
HTTP HTTPS FTP SMTP DNS DHCP
6
Presentation Layer
Handles data encryption, decryption, compression, and translation. Ensures data is readable by the receiving system.
SSL/TLS JPEG gIF ASCII EBCDIC
5
Session Layer
Manages sessions between applications. Establishes, maintains, and terminates connections between applications.
NetBIOS rPC SQL NFS
4
Transport Layer
Provides reliable data transfer services. Handles error detection, correction, and flow control.
TCP uDp SPX
3
network Layer
Handles routing and forwarding of data packets. Determines the best path for data transmission.
IP ICMP OSPF bgP RIP
2
Data Link Layer
Provides node-to-node data transfer. Handles error detection and correction from the physical layer.
Ethernet Wi-Fi PPP Frame Relay
1
Physical Layer
Transmits raw bit streams over physical medium. Defines electrical, mechanical, and procedural specifications.
Ethernet Cable Fiber Optic Radio Waves Bluetooth

Data Flow Through OSI Layers

Watch how data travels from sender to receiver through each layer

Sender Side - Data Encapsulation

Data moves down from Application Layer (7) to Physical Layer (1), with each layer adding its own header information.

Physical Transmission

Raw bits are transmitted over the physical medium (cables, wireless, fiber optic).

Receiver Side - Data Decapsulation

Data moves up from Physical Layer (1) to Application Layer (7), with each layer removing its header information.

Interactive OSI Demo

OSI Layer network simulator

Click "Initialize network" to start the simulation
Watch how data packets travel through different network nodes, representing the OSI layer processing at each hOp.

OSI Model Knowledge Test

Question 1: Which layer is responsible for routing?
A) Transport Layer (Layer 4)
B) network Layer (Layer 3)
C) Data Link Layer (Layer 2)
D) Session Layer (Layer 5)
Question 2: Which protocol operates at the Application Layer?
A) TCP
B) HTTP
C) IP
D) Ethernet
Question 3: What happens during data encapsulation?
A) Data is compressed
B) Headers are added at each layer
C) Data is encrypted
D) Data is fragmented