I enjoyed how we got taught the two models in the 1990s, and why one has the four layers you need and the "standard" has seven layers instead. The professor as

I enjoyed how we got taught the two models in the 1990s, and why one has the four layers you need and the "standard" has seven layers instead. The professor asked "How many layers do you count?" - "Seven." - "How many members do you think the ISO/OSI committee had that designed it between them?" - [laughter] - "Seven.".