Networking - Miscellaneous - OSI vs TCP/IP

The OSI (Open Systems Interconnection) model and the TCP/IP (Transmission Control Protocol/Internet Protocol) model are two different conceptual frameworks used to understand and describe network protocols and communication processes. 

OSI Model:

  • Developed by the International Organization for Standardization (ISO) in the 1980s.
  • Divides network communication into seven distinct layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.
  • Each layer has specific functions and protocols associated with it.
  • Provides a modular and hierarchical approach to network design and protocol development.
  • Encourages interoperability between different network technologies and vendors.
  • Allows for the easy addition or modification of protocols within each layer.
  • Each layer relies on the services provided by the layer below it.
  • Although widely adopted as a conceptual model, actual network implementations often combine or skip some layers.

TCP/IP Model:

  • Developed by the U.S. Department of Defense (DoD) in the 1970s.
  • Consists of four interconnected layers: Network Interface, Internet, Transport, and Application.
  • The layers in the TCP/IP model do not correspond directly to the layers in the OSI model.
  • The Network Interface layer handles the physical and data link aspects of network communication.
  • The Internet layer is responsible for IP addressing, routing, and packet forwarding.
  • The Transport layer provides reliable, connection-oriented (TCP) or connectionless (UDP) transport of data.
  • The Application layer includes protocols for specific applications, such as HTTP, FTP, SMTP, and DNS.
  • Reflects the architecture of the early Internet and is the foundation for modern internet communication.
  • Widely used and implemented in today's networks, including the Internet itself.


  • Layers: The OSI model has seven layers, while the TCP/IP model has four layers.
  • Level of Detail: The OSI model provides a more detailed and comprehensive breakdown of network functions, while the TCP/IP model offers a simpler and more practical approach.
  • Historical Context: The OSI model was developed after the TCP/IP model and influenced subsequent network protocols, while the TCP/IP model was created to suit the needs of early internet communication.
  • Implementation: The OSI model is more of a conceptual framework, whereas the TCP/IP model is widely implemented in modern networks, including the internet.