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TCP/IP Model

TCP/IP Model

The TCP/IP Model is a conceptual framework that defines how data is transmitted over the internet and other networks. It consists of a set of rules and protocols that enable communication between different computer systems, ensuring data is sent, received, and understood correctly. The model was developed by the U.S. Department of Defense and is widely used in networking today.

Layers of the TCP/IP Model

The TCP/IP Model is divided into four layers, each responsible for specific network functions:

Application Layer

This layer provides network services directly to end users. It includes protocols like HTTP, FTP, SMTP, and DNS, which enable web browsing, file transfer, email communication, and domain name resolution.

Transport Layer

The Transport Layer ensures reliable data transmission between devices. It includes protocols such as Transmission Control Protocol (TCP) for reliable, connection-oriented communication and User Datagram Protocol (UDP) for faster, connectionless communication.

Internet Layer

This layer is responsible for logical addressing and routing of data packets. The Internet Protocol (IP) operates at this layer, ensuring that data is delivered to the correct destination using IP addresses.

Network Access Layer

The Network Access Layer handles physical data transmission over network hardware, such as cables and wireless connections. It includes protocols like Ethernet and Wi-Fi, which define how data is physically sent over the network.

TCP/IP Packet

A TCP/IP packet is a structured unit of data that travels through the network according to the TCP/IP protocol suite. It consists of two main parts:

Header

The header contains control information such as source and destination IP addresses, protocol type, sequence number, and error-checking data. Each layer of the TCP/IP model adds its own header information.

Payload

The payload is the actual data being transmitted. This could be a web page, an email message, a video stream, or any other type of data.

TCP/IP packets are essential for network communication, ensuring that data is efficiently transferred between devices over local and wide-area networks, including the internet.

---
title: "TCP Packet"
---
packet-beta
 0-15: "Source Port"
 16-31: "Destination Port"
 32-63: "Sequence Number"
 64-95: "Acknowledgment Number"
 96-99: "Data Offset"
 100-105: "Reserved"
 106: "URG"
 107: "ACK"
 108: "PSH"
 109: "RST"
 110: "SYN"
 111: "FIN"
 112-127: "Window"
 128-143: "Checksum"
 144-159: "Urgent Pointer"
 160-191: "(Options and Padding)"
 192-255: "Data (variable length)"

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