The TCP/IP model, developed by the Department of Defense in the 1970s, is the foundation of the internet and simplifies the OSI model into four layers. Here’s a detailed overview:
| Layer | Corresponding OSI Layers | Functions | Protocols/Technologies | Mnemonic |
|---|---|---|---|---|
| Application (Layer 4) | Application, Presentation, Session | Manages network applications and processes, combines functionalities of OSI Layers 5, 6, and 7 | HTTP, FTP, SNMP, SMTP, Telnet, DNS, LPD, X Windows | All |
| Host-to-Host (Layer 3) | Transport | Provides end-to-end data delivery, reliability, and flow control | TCP, UDP | Hosts |
| Internet (Layer 2) | Network | Defines IP datagram, routing, and logical addressing across networks | IP, ARP, RARP, ICMP | In |
| Network Access (Layer 1) | Data Link, Physical | Manages the physical transmission of data, hardware addressing, and electrical connections | Ethernet, PPP, Frame Relay, LPD | Networks |
Additional Information
- TCP/IP Model Mnemonic: “AHIN” stands for Application, Host-to-Host, Internet, and Network Access.
- Application Layer: Where high-level protocols such as HTTP, FTP, and SMTP operate.
- Host-to-Host Layer: Ensures reliable communication and data integrity.
- Internet Layer: Manages routing and forwarding of data packets across different networks.
- Network Access Layer: Handles the physical connection and data frame management.
This overview highlights how the TCP/IP model simplifies networking tasks, integrating key functions across fewer layers compared to the OSI model.