We have talked in other posts about the OSI model, which is the de-facto standard model for describing and implementing IP communication networks. You might be thinking that the OSI model was the original standard created when the first computer networks started to appear, but this is wrong. The TCP/IP model is older than the OSI, despite that the OSI is the most well known model today.
The TCP/IP model originated by the U.S Department of Defense in the 1970s. It is very similar to the OSI Model, but with a simpler structure, as shown below:
As you can see from the diagram above, the TCP/IP model matches the OSI up to the Transport Layer. The top three layers of the OSI (Session, Presentation, Application) are represented just by one layer on the TCP/IP model (the Application Layer).
The strength of the TCP/IP model compared to the OSI is that its simpler and is completely aligned with the TCP/IP protocol stack. The weakness of the TCP/IP model compared to the OSI is that its mostly network-centric and does not describe the application interaction in much detail.