> Wait, isn't TCP(/IP) the quick and dirty practical implementation that beat the much more theoretical OSI model? Yes, it is. It even has its own (four-layer)

> Wait, isn't TCP(/IP) the quick and dirty practical implementation that beat the much more theoretical OSI model? Yes, it is. It even has its own (four-layer) model but the IETF People aren't nearly as interested in layering as the OSI people were: Layering Considered Harmful https://tools.ietf.org/html/rfc3439#section-3 https://tools.ietf.org/html/rfc3439#section-3 Point being, this is why people who know history get a bit perturbed when people insist on shoving TCP/IP into the OSI Model, or, worse, insist that TCP/IP "implements" OSI somehow. OSI had its chance, it lost, and now we use POP and SMTP for email, not X.400.