Introduction
The TCP/IP (Transmission Control Protocol/Internet Protocol) model is the foundation of modern networking, enabling communication between devices across the internet. It defines how data is transmitted, routed, and received across networks.Layers of the TCP/IP Model
TCP/IP is a four-layered model that simplifies network communication compared to the OSI model.1. Application Layer
- Protocols: HTTP, HTTPS, FTP, SMTP, DNS, DHCP
- Responsible for end-user interactions and data formatting.
2. Transport Layer
- Protocols: TCP, UDP
- Ensures data delivery, flow control, and error handling.
3. Internet Layer
- Protocols: IP, ICMP, ARP
- Handles logical addressing (IP addressing) and routing.
4. Network Access Layer
- Protocols: Ethernet, Wi-Fi, PPP
- Deals with physical transmission of data over cables or wireless channels.
TCP vs. UDP
| Feature | TCP (Transmission Control Protocol) | UDP (User Datagram Protocol) |
|---|---|---|
| Connection-Oriented | Yes | No |
| Reliability | High (error checking, retransmission) | Low (no error checking) |
| Speed | Slower (due to reliability checks) | Faster (minimal overhead) |
| Use Cases | Web browsing, email, file transfer | Streaming, gaming, VoIP |
IP Addressing
Each device on a network needs a unique identifier, called an IP Address. There are two types:IPv4
- 32-bit address (e.g.,
192.168.1.1) - Divided into Network ID and Host ID
- Uses subnetting for efficient addressing
IPv6
- 128-bit address (e.g.,
2001:db8::ff00:42:8329) - Designed to replace IPv4 due to exhaustion of addresses
Data Encapsulation and Transmission
When data is sent over a network, it passes through different layers, each adding its own header.Network Security in TCP/IP
- Firewalls: Block unauthorized access
- Encryption (SSL/TLS): Secures data transmission
- VPNs: Encrypts network traffic
- Intrusion Detection Systems (IDS): Monitors suspicious activity