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Computer Network Protocol
Computer network protocols are the standard rules that define how data is transmitted and communicated over a network. They ensure that information is exchanged efficiently, accurately, and securely between computers and other devices. Every network follows these rules to enable effective communication.
Two types of network protocols
1) A physical protocol defines the actual physical rules for the transmission of data over a network. It specifies details such as the type of cables, voltage levels, signal timing, and data transmission rates. Examples of physical protocols include Ethernet, Wi-Fi, and USB.
2) A logical protocol defines the rules and procedures for logical communication between devices. It manages the software structure of data transmission rather than the physical structure. The key functions of a logical protocol are addressing and routing, error detection, flow control, and data formatting. Examples include IP, TCP, UDP, HTTP, HTTPS, and FTP.
OSI model
The OSI model is a framework that defines how data is transmitted through a network and how communication occurs between different devices. It divides the process of networking into seven layers, which helps organize and standardize communication across various systems and technologies. Each layer has a specific function that contributes to the successful transmission of data.
The 7 Layers of the OSI Model
Application Layer (Layer 7)
This is the topmost layer that provides network services directly to users and applications. It enables activities like web browsing, email, and file transfer.
Examples: HTTP, HTTPS, FTP, SMTP, DNS
Presentation Layer (Layer 6)
This layer translates data between the application and the network. It handles data encryption, compression, and format conversion to ensure compatibility between systems.
Examples: SSL, TLS, JPEG, MPEG
Session Layer (Layer 5)
The session layer manages sessions or connections between two devices. It establishes, maintains, and terminates communication sessions.
Examples: NetBIOS, PPTP, RPC
Transport Layer (Layer 4)
This layer ensures reliable data transfer between devices. It handles error detection, flow control, and data segmentation.
Examples: TCP, UDP
Network Layer (Layer 3)
The network layer is responsible for logical addressing and routing of data packets so they can travel across different networks to reach the destination.
Examples: IP, ICMP, IPsec, Routers
Data Link Layer (Layer 2)
This layer ensures reliable communication between devices on the same network. It handles framing, physical addressing (MAC), and error detection.
Examples: Ethernet, PPP, Switches
Physical Layer (Layer 1)
The physical layer deals with the actual transmission of raw data bits over a physical medium, such as cables, switches, and radio signals. It defines hardware specifications like voltage, data rate, and cable type.
Examples: Ethernet cables, Wi-Fi, Bluetooth, Hubs
TCP/IP model
The TCP/IP model is a framework that is also known as the simplified version of the OSI model. It focuses on practical data communication over the internet. The model consists of four layers, each performing different functions, and they all work together to make network communication efficient and reliable.
The 4 Layers of the TCP/IP Model
Application Layer: Provides services for applications such as email, file transfer, and web browsing.
Transport Layer: Ensures the reliable transmission of data between devices.
Internet Layer: Handles the routing of data packets and manages logical addressing.
Network Access Layer: Manages the physical transmission of data over hardware like cables and network interfaces.
IP Address
An IP address is a unique number assigned to every device connected to the internet that uses the Internet Protocol for communication. It acts as an identifier for a device and ensures that the data sent reaches the correct destination.
There are four main types of IP addresses:
Public IP: Used to identify a device on the internet.
Private IP: Used within a local or internal network.
Static IP: A fixed address that does not change.
Dynamic IP: Assigned automatically and may change over time.
Duplex communication
Duplex communication refers to the way data is transmitted between two devices. It defines whether communication happens in one direction or in both directions.
Half Duplex: Two-way communication, but only one device can send data at a time.
Full Duplex: Two-way communication that allows both devices to send and receive data simultaneously.
Ethernet
Ethernet is a technology used to connect computers and other devices in a Local Area Network (LAN). It defines how data is transmitted over a wired network between devices such as computers, routers, and switches.
Ethernet provides high-speed, stable, and secure data transmission, allowing multiple devices to communicate efficiently within a local area.
Examples: Ethernet, Fast Ethernet, Gigabit Ethernet, etc.