TCP/IP The DoD Model tutorials


  • TCP/IP protocol suite represent many protocols that run independently or with TCP (Transmission Control Protocol) and IP (Internet Protocol). The DoD model is basically a conceptual model for TCP/IP. It is condensed version of OSI model. It composed of Four instead of Seven layers of OSI model. Both the layers are similar in concept but each has a different number of layers.


TCP/IP Model or

DoD Model


OSI Model




Process /


























Data Link




  • Here vast array of protocols combine at the DoD Modelís Process/Application layer to integrate various activities and duties that were focus at OSI top 3 layers (i.e. Application, Presentation and Session). It defines protocols for node-to-node application communication and also controls user interface specification.

  • The Host to Host layer parallels the function of OSIís Transport Layer. It tackles issues such as creating reliable end-to-end communication and ensuring the error free delivery of data. It handles packet sequencing and maintains data integrity.

  • The Internet layer corresponds to the OSIís Network layer. It designates the protocols relating to the logical transmission of packets over the entire network. It takes care of the addressing of host by giving them an IP (Internet Protocol) address, and it handles the routing of packets among multiple networks.

  • At the bottom of the DoD model, the Network Access Layer is equivalent to Data Link and Physical Layer of ODI. It monitors the data exchange between the host and network. It oversees the hardware addressing and defines protocols for physical transmission of data.